Difference between revisions of "Forensic pathology"

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'''Forensic pathology''' is figuring-out why people died... along with when and how (if possible).
'''Forensic pathology''' is figuring-out why, when, where and how people died, if the manner of death is ''not'' obviously natural.
 
=Death categorization=
Deaths are categorized foremost by the '''manner of death'''. The manner is the single most important legal categorization for a death.
The '''cause of death''' is important for understanding what happened.  The '''mechanism of death''' is the pathophysiologic reason for death and can be inferred from the cause.
 
Examples:
{| class="wikitable sortable"
!Cause of death
!Manner of death
!Mechanism of death
!Scenario
|-
| [[Electrocution]]
| accident
| [[cardiac arrhythmia]]
| man struck by lightning
|-
| Hyperthermia
| accident
| arrhythmias, seizures<ref name=fmuk>URL: [http://www.forensicmed.co.uk/pathology/mechanisms-of-death/ http://www.forensicmed.co.uk/pathology/mechanisms-of-death/]. Accessed on: 19 April 2012.</ref>
| man lost on hiking trip in desert
|-
| [[Epidural hemorrhage]] due to [[blunt force trauma]] to the head
| homicide
| brain stem compression or cerebral vascular spasm leading to autonomic dysregulation
| man hit with a hammer in the head
|-
| [[Carbon monoxide toxicity]]
| suicide
| cerebral hypoxia (CO binds to hemoglobin impairing oxygen transport)
| woman found in car with suicide note, long history of depression, previous suicide attempts
|-
| [[Atherosclerotic heart disease]]
| natural
| cardiac arrhythmia due to ischemia
| man found dead in bed, apartment locked, 95% stenosis of LMCA at autopsy, no other significant autopsy findings
|- <!--
| [[Peritonitis]] due to duodenal perforation as a consequence of [[peptic ulcer disease]]
| natural
| cerebral hypoxia secondary to hypotension
| man found in locked apartment, complained of abdominal pain before dead
|-
| Coronary artery stent thrombosis complicating the treatment of a [[myocardial infarction]] due to atherosclerotic heart disease
| natural
| cardiac arrhythmia due to ischemia
| woman found dead following hospital stay for a myocardial infarction, post-angioplasty and coronary stenting -->
|}


==Manner of death==
==Manner of death==
The manner of death is a legislatively defined classification. It varies slightly between jurisdictions.
<!--
<!--
MANNER OF DEATH
MANNER OF DEATH
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{{familytree | | | | | | | | | A | | | | | | | | |A=Manner}}
{{familytree | | | | | | | | | A | | | | | | | | |A=Manner}}
{{familytree | |,|-|-|-|v|-|-|-|+|-|-|-|v|-|-|-|.| |}}
{{familytree | |,|-|-|-|v|-|-|-|+|-|-|-|v|-|-|-|.| |}}
{{familytree | B | | C | | D | | E | | F |B=Homocide|C=Suicide|D=Natural|E=Accident|F=Undetermined}}
{{familytree | B | | C | | D | | E | | F |B=Homicide|C=Suicide|D=Natural|E=Accident|F=Undetermined}}
{{familytree/end}}
{{familytree/end}}


Notes:
Notes:
*''Undetermined'' - is a waste basket category.
*''Undetermined'' - is a waste basket category.
*''Homocide'' - not necessarily murder.
*''Homicide'' - not necessarily murder.
*Can be group into three:
*Can be group into three:
*#Intent to kill (homicide, suicide).
*#Intent to kill (homicide, suicide).
*#No intent to kill (natural, accidental).
*#No intent to kill (natural, accidental).
*#Undetermined.
*#Undetermined.
==Mechanism of death==
This is occasionally of interest. It is usually based on physiology.
The mechanism is often asked for [[asphyxial death]]s. The short answer it is: brain stem hypoxia due to ischemia caused by venous obstruction in the neck.<ref>URL: [http://www.forensicmed.co.uk/pathology/mechanisms-of-death/ http://www.forensicmed.co.uk/pathology/mechanisms-of-death/]. Accessed on: 1 May 2012.</ref><ref>URL: [http://www.forensicmed.co.uk/pathology/pressure-to-the-neck/ http://www.forensicmed.co.uk/pathology/pressure-to-the-neck/]. Accessed on: 1 May 2012.</ref>


==Cause of death==
==Cause of death==
If the death is natural:
*Abbreviated ''COD''.
*It should be a medical diagnosis - '''not''' the mechanism (e.g. ''cardiac arrest'', ''cachexia'', ''kidney failure'').
===General===
*The mechanism is irrelevant.
*The cause of death should be what started the sequence of events that lead to death.
 
====Word form for cause of death====
Examples:
*''[[C. difficile colitis]] complicating antibiotic treatment for a dental abscess''.<ref>MSP. 8 September 2010.</ref>
*''Complications of laparoscopic cholecystectomy for ascending cholangitis with [[mesothelioma]] and atherosclerotic heart disease''.<ref>TR. 3 September 2010.</ref>
 
General forms:
*''A'' complicating ''B'' for the treatment of ''C''.
*''A'' complicating ''B'' for the treatment of ''C'' with ''D'' and ''E''.
 
====World Health Organization form for cause of death====
General form:<ref name=pmid15914304>{{cite journal |author=Pollanen MS |title=Deciding the cause of death after autopsy--revisited |journal=J Clin Forensic Med |volume=12 |issue=3 |pages=113–21 |year=2005 |month=June |pmid=15914304 |doi=10.1016/j.jcfm.2005.02.004 |url=}}</ref>
*1a = ''immediate cause of death''.
*1b = what lead to the ''immediate cause of death''.
*1c... 1[x] -- where 'x' is the last letter used; 1x = What started the sequence of events. This is known as the ''underlying cause of death''.
*2 = contributing factors.
 
Example 1:
*1a. [[Ketoacidosis]].
*1b. [[Diabetes mellitus]].
*2. [[Alcoholism]] and acute [[bronchopneumonia]].
 
Example 2:
*1a. Hemoperitoneum.
*1b. [[Splenic laceration]].
*1c. Blunt force trauma.
*2. Liver [[cirrhosis]].
 
===Natural deaths===
{{Main|Natural death}}
*The cause should be a medical diagnosis, '''not''' the mechanism (e.g. ''cardiac arrest'', ''cachexia'', ''kidney failure'').
*The [[mechanism of death|mechanism]] is irrelevant.


Notes:
Notes:
*Cancer is rarely the immediate cause of death - it is usually something else.<ref>PS. 2009.</ref>
*Unnatural causes trump natural ones.  If a guy with (nothing more than) a 70% proximal LAD stenosis and an old [[myocardial infarct]] is found in the water, they are usually called [[drowning]].
*[[Cancer]] is rarely the immediate cause of death - it is usually something else.<ref>Shannon, P. 2009.</ref>
*Things (mechanisms) that shouldn't be used: [http://www.pallimed.org/2008/03/unacceptable-causes-of-death-other-web.html http://www.pallimed.org/2008/03/unacceptable-causes-of-death-other-web.html]
*Things (mechanisms) that shouldn't be used: [http://www.pallimed.org/2008/03/unacceptable-causes-of-death-other-web.html http://www.pallimed.org/2008/03/unacceptable-causes-of-death-other-web.html]
*A Nice summary: [http://www.eperc.mcw.edu/fastFact/ff_155.htm http://www.eperc.mcw.edu/fastFact/ff_155.htm]


===Legal frame work===
===Legal frame work===
====General====
*In Ontario, the ''manner'' is determined by the coroner.
*In Ontario, the ''manner'' is determined by the coroner.
*Coroners, in Ontario, are MDs -- usually family docs.
*Coroners, in Ontario, are MDs -- usually [[family docs]].
*The cause (e.g. "gunshot wound to the head") is determined by the pathologist.
*The cause (e.g. "gunshot wound to the head") is determined by the pathologist.


NB - the word ''coroner'' is not synoymous with MD.  British Columbia has coroners that aren't MDs.
NB - the word ''coroner'' is not synoymous with MD.  British Columbia has coroners that aren't MDs.


==Forensic triangle==
====Case classification (Ontario)====
Cases are classified as:
*''A case'' = homicide and suspicious for homicide, (all) gunshot wounds.
*''B case'' = adult, non-suspicious.
*''C case'' = child, non-suspicious.
 
Notes:
*All ''A cases'' are done at regional centers by certified forensic pathologists.
 
=Forensic golden triangle=
*History.
*Scene.
*[[Autopsy]].
 
=Forensic diagnostic triangle=
Most general differential diagnosis:
Most general differential diagnosis:
*Natural:
*Natural:
**Infection (e.g. pneumonia).
**Haemorrhage (e.g. cerebral bleed, gastrointestinal bleed, aortic aneurysm).
**Infarction (i.e. myocardial infarction); ''arrhythmias'' are more common in the forensic context, as individuals with MIs don't usu. drop dead-- they go to the ER.
**Infection (e.g. [[pneumonia]]).
**Haemorrhage (e.g. cerebral, GI).
**[[Coronary artery atherosclerosis]] ([[cardiac arrhythmia]]s - more common in the forensic context than [[myocardial infarction]] (MI); individuals with MIs don't usu. drop dead-- they go to the ER).
***Post [[myocardial infarction]] (free wall rupture).
***Ruptured (atherosclerotic) plaque.
*Toxic (memory device: ''PAIRO''):
*Toxic (memory device: ''PAIRO''):
**Poisons.
**Poisons.
**Alcohol (EtOH).  
**[[Alcohol]] (EtOH).  
**Illicit (e.g. cocaine, heroin, LSD).  
**Illicit (e.g. [[cocaine]], heroin, LSD).  
**Rx.  
**Rx.  
**Over-the-counter (OTC) (e.g. acetaminophen, warfarin).
**Over-the-counter (OTC) (e.g. acetaminophen, warfarin).
*Trauma (memory device ''AGE BS''):
*Trauma (memory device ''AGE BS''):
**Asphyxial.  
**[[asphyxial deaths|Asphyxial]].  
**Gunshot wound (GSW).  
**[[Gunshot wounds]] (GSWs).  
**Environmental (e.g. hypothermia, hyperthermia, drowning, lack of oxygen).
**Environmental (e.g. hypothermia, hyperthermia, [[drowning]], lack of oxygen, [[electrocution]]).
**Blunt force trauma.  
**[[Blunt force trauma]].  
**Sharp force trauma.  
**[[Sharp force trauma]].  


Difficulties arise when more than one point of the triangle is in play, i.e. the forensic pathologist has to earn their pay when an old man with a heart condition is known to be into erotic asphyxia, and dies after doing some drugs and whilst indulging in erotic asyphxiation with a friend...
Difficulties arise when more than one point of the triangle is in play, i.e. the forensic pathologist has to earn their pay when an old man with a heart condition is known to be into erotic asphyxia, and dies after doing some drugs and whilst indulging in erotic asyphxiation with a friend...
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*If he was a lone and depressed... he might have been trying to kill himself, ergo ''suicide''.
*If he was a lone and depressed... he might have been trying to kill himself, ergo ''suicide''.


==Death-related changes==
=Death-related changes=
===Rigor mortis===
===Rigor mortis===
Def'n: muscle rigidity following death (caused by depletion of ATP).
Definition:  
*Muscle rigidity following death (caused by depletion of ATP).


Dependent on:
Dependent on:
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*May never develop!
*May never develop!


Summary:
It is the explanation for post-mortem goose bumps.
Its onset & presence is '''highly variable'''.  Therefore, it is only marginally useful for determining the time of death.
 
====Summary====
*Its onset & presence is ''highly variable''.
*Forensic pathologists do '''not''' comment on time of death, as the above times are subject to such a large degree of variability, i.e. the estimates are essentially useless.


====Time estimates====
A crude guess for time of death based on rigor:<ref name=Ref_KFP61>{{Ref KFP|61}}</ref>
A crude guess for time of death based on rigor:<ref name=Ref_KFP61>{{Ref KFP|61}}</ref>
*Warm & flaccid <3 h.
*Warm & flaccid <3 h.
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Notes:
Notes:
*Memory device: '''3s''': cut points are at ''3 hours'', ''1/3 of a day'', ''3/2 of a day.''
*Memory device: '''3s''': cut points are at ''3 hours'', ''1/3 of a day'', ''3/2 of a day.''
===Livor mortis===
===Livor mortis===
Def'n: pooling of blood in the dependent position, due to blood stasis.   
Definition: pooling of blood in the dependent position, due to blood stasis.   
*Onset may preceed death in the context of congestive heart failure.
*Onset may preceed death in the context of congestive heart failure.
*If pressure is applied to a dependent area-- no blood can enter there; thus, a pressure area is blanched (i.e. white).
*If pressure is applied to a dependent area-- no blood can enter there; thus, a pressure area is blanched (i.e. white).
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**Liver mortis does NOT tell one the position the decedent was in at the time of death-- only the position the decedent was at the time liver mortis became fixed.  '''If''' the decedent wasn't moved liver mortis can help determine the position the person was in when they died.
**Liver mortis does NOT tell one the position the decedent was in at the time of death-- only the position the decedent was at the time liver mortis became fixed.  '''If''' the decedent wasn't moved liver mortis can help determine the position the person was in when they died.


===Decomposition===
Averages:
According to textbooks one of two things happens post-mortem:
*Start: 30 minutes to 2 hours
*Mummification, or
*Fixed: 8-12 hours.
*Putrefaction.
 
DDx:
*[[Blunt force trauma]] - especially to the inexperienced eye.
*Post-mortem hypostatic bruising.
 
===Tache noire===
Literally ''black spot''.
 
Features:<ref name=emed1680032>URL: [http://emedicine.medscape.com/article/1680032-overview http://emedicine.medscape.com/article/1680032-overview]. Accessed on: 6 March 2012.</ref>
*Brown/black horizontal line of the eye due to drying.
**Arises if the eye remains open after death.
**May mimic a traumatic injury.
 
Images:
*[http://img.medscape.com/pi/emed/ckb/pathology/1603817-1607640-1680032-1714463.jpg Tache noire (medscape.com)].<ref name=emed1680032/>
*[http://www.demussen.net/carbon-monoxide/images/1856_23_12-vitreous-potassium.jpg Tache noire (demussen.net)].<ref>URL: [http://www.demussen.net/carbon-monoxide/chemical-changes-in-body-fluids.html http://www.demussen.net/carbon-monoxide/chemical-changes-in-body-fluids.html]. Accessed on: 6 March 2012.</ref>
 
===Post-mortem decomposition/preservation===
One of three things happens post-mortem:<reF name=Ref_HospAuto102>{{Ref HospAuto|102}}</ref>
#Mummification.
#Putrefaction (skeletonisation).
#*Green colour due to break down of hemoglobin (biliverdin).<ref>{{cite journal |author=NOIR BA, GARAY ER, ROYER M |title=SEPARATION AND PROPERTIES OF CONJUGATED BILIVERDIN |journal=Biochim. Biophys. Acta |volume=100 |issue= |pages=403–10 |year=1965 |month=May |pmid=14347937 |doi= |url=linkinghub.elsevier.com/retrieve/pii/0304416565900097}}</ref>
#Adipocere - transformation into wax (due to anaerobic bacterial hydrolysis of fat).
#*Useless for toxicology and DNA.


Real life:
*A mix of the above often occur, i.e. part of the corpse is mummified... part of it decomposed through putrefaction.
*A mix of mummification and putrefaction occur, i.e. part of the corpse is mummified... part of it decomposed through putrefaction.


Mummification:
Mummification:
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===Artefacts===
===Artefacts===
*Prinsloo and Gordon artefact = artefactual post-morten haemorrhage on the posterior surface of the esophagus.<ref name=pmid16378701/>
*Prinsloo and Gordon artefact = artefactual post-morten haemorrhage on the posterior surface of the esophagus.<ref name=pmid16378701>{{cite journal |author=Piette MH, De Letter EA |title=Drowning: still a difficult autopsy diagnosis |journal=Forensic Sci. Int. |volume=163 |issue=1-2 |pages=1–9 |year=2006 |month=November |pmid=16378701 |doi=10.1016/j.forsciint.2004.10.027 |url=}}</ref>
**Minimized by removing cranial contents & thoracic contents ''before'' undertaking neck dissection.<ref name=Ref=HospAuto118>{{Ref HospAuto|118}}</ref>
*Artefactual fractures (see fractures).
*Dilated anus (in isolation).<ref>URL: [http://www.kingstonwhigstandard.com/ArticleDisplay.aspx?archive=true&e=736464 http://www.kingstonwhigstandard.com/ArticleDisplay.aspx?archive=true&e=736464]. Accessed on: 6 October 2010.</ref><ref name=pmid17961873 >{{Cite journal  | last1 = Elder | first1 = DE. | title = Interpretation of anogenital findings in the living child: Implications for the paediatric forensic autopsy. | journal = J Forensic Leg Med | volume = 14 | issue = 8 | pages = 482-8 | month = Nov | year = 2007 | doi = 10.1016/j.jflm.2007.03.005 | PMID = 17961873 }}</ref>
*Towel clip injury, usu. paired (in organ donors) - may be mistaken for an electroshock weapon (e.g. Taser) wound.<ref>MSP. 12 October 2010.</ref>
*Subclavian stab for vascular access - may be confused with a gunshot exit wound.
 
====Infants====
*Lumpy neck - small superficial nodules on anterior neck ~2-5 mm (???).<ref>MSP. 6 October 2010.</ref>
*Intussusception of small bowel - often multiple.
 
=Wounds=
==General==
*''Wound'' - definition: defect in skin or mucous membrane<ref>URL: [http://dictionary.reference.com/browse/wound http://dictionary.reference.com/browse/wound]. Accessed on: 20 April 2012.</ref> - usually due to trauma.


==Classification of wounds==
Special types of wounds:
*[[Gunshot wounds]].
*Incised wounds - see [[sharp force trauma]].
 
===Gross pathologic classification of injuries===
Mnemonic ''CALI'':
Mnemonic ''CALI'':
*Contusion - "bruise", haemotoma
*'''C'''ontusion - "bruise", [[hematoma]].
*Abrasion - "scrape", e.g. motorcyclist slide across the roadway... skin ripped-off
**Age (usual colour change sequence): red, blue, green, yellow, brown.<ref name=Ref_HospAuto108>{{Ref HospAuto|108}}</ref>
*Laceration - "tear", trauma distant from where skin split
**Etiology: bleeding from arterioles or venules (not capillaries).<ref name=Ref_HospAuto105>{{Ref HospAuto|105}}</ref>
*Incised - "cut", e.g. caused by a knife.<ref name=Ref_HoFP154>{{Ref_HoFP|154}}</ref>
*'''A'''brasion - "scrape", e.g. motorcyclist slide across the roadway... skin scraped-off.
**Can be subclassified as ''brush abrasions'' (has skin tags) and ''crush abrasions'' (do not have skin tags).
***Skin tags suggest directionality; they are found at the distal point / point of last contact.<ref name=Ref_HospAuto105>{{Ref HospAuto|105}}</ref>
*'''L'''aceration - "tear", indicates blunt force trauma; contact point may be distant from where skin splits.
*'''I'''ncised - "cut", e.g. caused by a knife,<ref name=Ref_HoFP154>{{Ref_HoFP|154}}</ref> subdivided as follows:
*#"Cut" or "slash" = length > depth.
*#"Cut" or "slash" = length > depth.
*#"Stab" = depth > length.
*#"Stab" = depth > length.
*#"Chop" = typically have a contusion at the margin of the wound, classically caused by an axe. May be caused by a propeller.<ref name=pmid19733336>{{Cite journal  | last1 = Ihama | first1 = Y. | last2 = Ninomiya | first2 = K. | last3 = Noguchi | first3 = M. | last4 = Fuke | first4 = C. | last5 = Miyazaki | first5 = T. | title = Fatal propeller injuries: three autopsy case reports. | journal = J Forensic Leg Med | volume = 16 | issue = 7 | pages = 420-3 | month = Oct | year = 2009 | doi = 10.1016/j.jflm.2009.04.006 | PMID = 19733336 }}</ref>


====Images====
<gallery>
Image:Hand_Abrasion_-_32_minutes_after_injury.JPG | Abrasion. (WC)
Image:Black_eye_2.jpg | Contusion ("black eye"). (WC)
</gallery>
====DDx====
How to decide what you're looking at:
How to decide what you're looking at:
*Contusion:  
*Contusion:  
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***Bridges are fine strands of tissue that cross the long axis of the skin defect.
***Bridges are fine strands of tissue that cross the long axis of the skin defect.
****You can think of the wound as partially "sutured" by the bridges of tissue.
****You can think of the wound as partially "sutured" by the bridges of tissue.
**Lacerations are usually associated with a contusion and/or crush and have an irregular margin.<ref name=Ref_HospAuto109>{{Ref HospAuto|109}}</ref>
**Lacerations are classically on the skull and face.  They are rarely on the abdomen.
===Wound dating===
*Colour is somewhat useful for contusions (bruises).
*Post-mortem injuries tend to be orange-yellow.<ref name=pmid19237864>{{Cite journal  | last1 = Campobasso | first1 = CP. | last2 = Marchetti | first2 = D. | last3 = Introna | first3 = F. | last4 = Colonna | first4 = MF. | title = Postmortem artifacts made by ants and the effect of ant activity on decompositional rates. | journal = Am J Forensic Med Pathol | volume = 30 | issue = 1 | pages = 84-7 | month = Mar | year = 2009 | doi = 10.1097/PAF.0b013e318187371f | PMID = 19237864 }}</ref>
*Wounds age is difficult to determine as [[wound healing]] is affected by a large number of variables.
*Old wounds (scars), generally, cannot be dated - one can only say they are ''old''.
===Microscopic===
Wounds can be grouped into:
*Pre-mortem.
*Post-mortem.
Signs a wound was inflicted during life:
*Blood.
**Hypostasis/decomposition can mess with this, i.e. blood oozing out of vessels post-mortem shouldn't be called an injury.
**Hemosiderin demonstrated by an iron stain - hard sign.
*Inflammation:<ref name=Ref_PCPBoD8_26>{{Ref PCPBoD8|26}}</ref>
**[[PMN]]s 6-24 hours after injury.
**PMNs replaced monocytes in 24-48 hours.
===Stains===
*[[Iron stain]] for siderophages (hemosiderin-laden macrophages) -- presence suggests 2-3 days or older.<ref name=pmid7529545>{{Cite journal  | last1 = Betz | first1 = P. | title = Histological and enzyme histochemical parameters for the age estimation of human skin wounds. | journal = Int J Legal Med | volume = 107 | issue = 2 | pages = 60-8 | month =  | year = 1994 | doi =  | PMID = 7529545 }}</ref>
=Bone fractures=
*[[AKA]] ''fractures''.
*[[AKA]] ''fracture of bone''.
==Artefactual fractures==
*"Undertaker's fracture" - cervical fracture due to rough handling.<ref>URL: [http://www.the-crankshaft.info/2010/07/postmortem-changes_29.html http://www.the-crankshaft.info/2010/07/postmortem-changes_29.html]. Accessed on: 29 September 2010.</ref>
*Basal skull fracture due to opening of skull.<ref>MSP. 29 September 2010.</ref>
**Classically does not cross sella turcica.
**Notably absent features of a real (ante-mortem) fracture: hematoma, brain injury.
**Mechanism to explain trauma not present in history; a fall/tripping not sufficient.
==Healing of fractures==
===Simplified classification===
*Primary callus (cartilaginous) - early.
*Secondary callus (bone) - late.
===Microscopic===
Features:
*Fragmentation of bone.
*+/-Dead bone = lacunae have no osteocytes.<ref name=pmid22460748>{{Cite journal  | last1 = Fondi | first1 = C. | last2 = Franchi | first2 = A. | title = Definition of bone necrosis by the pathologist. | journal = Clin Cases Miner Bone Metab | volume = 4 | issue = 1 | pages = 21-6 | month = Jan | year = 2007 | doi =  | PMID = 22460748 }}</ref>
**Takes days for osteocyte loss.
*+/-Inflammatory cells.
*+/-Hemosiderin-laden macrophages.
*+/-Osteoblastic rimming.
DDx:
*Fracture secondary to a tumour:
**Metastatic carcinoma.
**[[Osteosarcoma]] - typically does '''not''' have osteoblastic rimming.
Notes:
*Radiology is not good at dating fratures;<ref name=pmid15788611>{{Cite journal  | last1 = Prosser | first1 = I. | last2 = Maguire | first2 = S. | last3 = Harrison | first3 = SK. | last4 = Mann | first4 = M. | last5 = Sibert | first5 = JR. | last6 = Kemp | first6 = AM. | title = How old is this fracture? Radiologic dating of fractures in children: a systematic review. | journal = AJR Am J Roentgenol | volume = 184 | issue = 4 | pages = 1282-6 | month = Apr | year = 2005 | doi =  | PMID = 15788611 | url=http://www.ajronline.org/cgi/content/full/184/4/1282 }}
</ref> however, it is good at finding 'em.
==Pattern and cause==
===Child abuse-related===
*Paravertebral (bony) nodules = classic location for rib fractures in child abuse.
*Metaphyseal fractures  - "classical metaphyseal lesions".<ref name=pmid8615271>{{Cite journal  | last1 = Kleinman | first1 = PK. | last2 = Marks | first2 = SC. | title = A regional approach to classic metaphyseal lesions in abused infants: the distal tibia. | journal = AJR Am J Roentgenol | volume = 166 | issue = 5 | pages = 1207-12 | month = May | year = 1996 | doi =  | PMID = 8615271 }}</ref>
===Motor vehicle versus pedestrian===
If the pedestrian is standing during the initial impact one classically finds, at bumper level, a lower limb fracture with a ''Messerer wedge'' (German: ''Messerer-Kiel'');<ref name=pmid11376986>{{Cite journal  | last1 = Karger | first1 = B. | last2 = Teige | first2 = K. | last3 = Fuchs | first3 = M. | last4 = Brinkmann | first4 = B. | title = Was the pedestrian hit in an erect position before being run over? | journal = Forensic Sci Int | volume = 119 | issue = 2 | pages = 217-20 | month = Jun | year = 2001 | doi =  | PMID = 11376986 }}
</ref> the wedge points in the direction of the (impact) force.
==Location or type==
===Orbital floor fractures===
*[[AKA]] ''blow-out fractures''.<ref name=pmid17333039>{{Cite journal  | last1 = Punke | first1 = C. | last2 = Fritsche | first2 = A. | last3 = Martin | first3 = H. | last4 = Schmitz | first4 = KP. | last5 = Pau | first5 = HW. | last6 = Kramp | first6 = B. | title = [Investigation of the mechanisms involved in isolated orbital floor fracture. Simulation using a finite element model of the human skull]. | journal = HNO | volume = 55 | issue = 12 | pages = 938-44 | month = Dec | year = 2007 | doi = 10.1007/s00106-007-1545-5 | PMID = 17333039 }}</ref>
====General====
*Classically due to fights, followed by traffic accidents.<ref name=pmid20165966>{{Cite journal  | last1 = Gosau | first1 = M. | last2 = Schöneich | first2 = M. | last3 = Draenert | first3 = FG. | last4 = Ettl | first4 = T. | last5 = Driemel | first5 = O. | last6 = Reichert | first6 = TE. | title = Retrospective analysis of orbital floor fractures--complications, outcome, and review of literature. | journal = Clin Oral Investig | volume = 15 | issue = 3 | pages = 305-13 | month = Jun | year = 2011 | doi = 10.1007/s00784-010-0385-y | PMID = 20165966 }}</ref>
*Thought to result from loading on the orbital rim directly or the orbit - both are transmitted to the orbital floor.<ref name=pmid17333039/>
Note:
*The orbital floor tends to the be weaker than other components of the orbital cavity wall; thus, it is the most common site of fracture in the orbital cavity wall.
===Basal skull fracture===
====General====
Etiology:
*Blunt force trauma - high energy & velocity.
**Seen in ''motor vehicle collisions'', ''descent from height''.
Clinical/external findings:
*Raccoon eyes = periorbital ecchymosis.
*Battle sign = mastoid ecchymosis.
**Associated with orbital roof fractures.<ref>URL: [http://emedicine.medscape.com/article/1680107-overview#showall http://emedicine.medscape.com/article/1680107-overview#showall]. Accessed on: 28 March 2012.</ref>
*Cerebrospinal fluid rhinorrhea.
*Hemorrhage from nose and ears.
*Hemotympanum.
Note:
*There is a dictum that states ''bilateral petrous bone fractures are due to impact to the side of the head'' - it isn't true.<ref name=pmid7391790>{{Cite journal  | last1 = Harvey | first1 = FH. | last2 = Jones | first2 = AM. | title = Typical basal skull fracture of both petrous bones: an unreliable indicator of head impact site. | journal = J Forensic Sci | volume = 25 | issue = 2 | pages = 280-6 | month = Apr | year = 1980 | doi =  | PMID = 7391790 }}</ref>
===Hinge fracture of the skull===
*A special type of [[basal skull fracture]].
*Complete hinge fractures are considered severe; they are a 4 on the ''abbreviated injury scale'' (AIS).<ref>{{Cite journal  | last1 = Adams | first1 = VI. | last2 = Carrubba | first2 = C. | title = The Abbreviated Injury Scale: application to autopsy data. | journal = Am J Forensic Med Pathol | volume = 19 | issue = 3 | pages = 246-51 | month = Sep | year = 1998 | doi =  | PMID = 9760090 }}</ref>
*Classically due to a blow to the chin - resulting in a fracture across the medial fossa and sella turcica.<ref>URL: [http://wiki.answers.com/Q/Hinge_fracture_of_skull_is_seen_in_accidents_involving http://wiki.answers.com/Q/Hinge_fracture_of_skull_is_seen_in_accidents_involving]. Accessed on: 28 March 2012.</ref>
===Pathologic fracture===
{{Main|Pathologic fracture}}
*A fracture due to an underlying pathology.


===Terminology - not categorized===
===Hip fractures===
''Gutter butter'' = adipose tissue in a decomp case; looks like butter topping put on popcorn.
*[[Traumatic fracture of the femoral neck]].
''Gutter blood'' = blood in the empty thorax - after extraction of the organ block.
''Tardieu spots'' = postmortem hypostatic hemorrhages;<ref name=pmid19901802>{{cite journal |author=Pollanen MS, Perera SD, Clutterbuck DJ |title=Hemorrhagic lividity of the neck: controlled induction of postmortem hypostatic hemorrhages |journal=Am J Forensic Med Pathol |volume=30 |issue=4 |pages=322–6 |year=2009 |month=December |pmid=19901802 |doi=10.1097/PAF.0b013e3181c17ec2 |url=}}</ref> look like large petechiae - in dependent areas.


==Autopsy==
=Autopsy=
{{Main|Autopsy}}
{{Main|Autopsy}}
The ''autopsy'' article covers procedural things.  Heart dissection is covered in the ''[[heart]]'' article.
The ''autopsy'' article covers procedural things.  Heart dissection is covered in the ''[[heart]]'' article.
Line 149: Line 406:
*Forensic autopsies are focused on the external exam.
*Forensic autopsies are focused on the external exam.


===Marking conventions===
===Marking conventions for common findings===
There are no universal marking conventions for injuries.
There are no universal marking conventions for injuries.


Line 158: Line 415:


The above makes sense in that:
The above makes sense in that:
*Abrasions and incised wounds bleed - are red.
*Abrasions and incised wounds typically bleed - are red.
*Contusions (bruises) don't bleed and are classically blue.
*Contusions (bruises) don't classically bleed and are classically blue.


==Causes of death==
===External exam findings===
==Hanging==
Colour of the corpse:<ref name=Ref_Shkrum33>{{Ref Shkrum|33}}</ref>
Classic:
*Red (Pink) = [[carbon monoxide toxicity|carbon monoxide]], cyanide, fluoroacetate,<ref name=pmid17288493>{{cite journal |author=Proudfoot AT, Bradberry SM, Vale JA |title=Sodium fluoroacetate poisoning |journal=Toxicol Rev |volume=25 |issue=4 |pages=213–9 |year=2006 |pmid=17288493 |doi= |url=}}</ref> [[hypothermia]].
*V-shaped furrow on the neck.
*Purple (intense) = propane.
*V "open" at the point of suspension.
*Green = [[hydrogen sulfide]].
*Brown = nitrites (methemoglobinemia).


==Drowning==
===Autopsy terminology===
Classic:
*''Gutter butter'' = adipose tissue in a decomp case; looks like butter topping put on popcorn.  A Toronto-ism.
*Autopsy is often negative, i.e. there is no anatomical cause of death.
*''Gutter blood'' = blood in the empty thorax - after extraction of the organ block.
*''Tardieu spots'' = postmortem hypostatic hemorrhages;<ref name=pmid19901802>{{cite journal |author=Pollanen MS, Perera SD, Clutterbuck DJ |title=Hemorrhagic lividity of the neck: controlled induction of postmortem hypostatic hemorrhages |journal=Am J Forensic Med Pathol |volume=30 |issue=4 |pages=322–6 |year=2009 |month=December |pmid=19901802 |doi=10.1097/PAF.0b013e3181c17ec2 |url=}}</ref> look like petechiae - in dependent areas, i.e. in the zone of livity.


Drowning is difficult to prove on autopsy.<ref name=pmid16378701>{{cite journal |author=Piette MH, De Letter EA |title=Drowning: still a difficult autopsy diagnosis |journal=Forensic Sci. Int. |volume=163 |issue=1-2 |pages=1–9 |year=2006 |month=November |pmid=16378701 |doi=10.1016/j.forsciint.2004.10.027 |url=}}</ref>  The diagnosis is often based on circumstance, i.e. the scene.
===Autopsy on decomposed remains===
*[[AKA]] "decomp autopsy" or simply "decomp".
====General====
*Histology usually very limited ''or'' useless.
*Often done to exclude trauma.
*Typical scenario: decedent lives alone -- body not discovered for prolonged period of time.
*More likely to be a ''[[negative autopsy]]'' than non-decomp cases.


===Macroscopic===
====Suspicious decomp====
External:
Common sense rules for if skin is '''not''' intact:
*Plume of froth at the mouth/nostrils (fresh drowning only).<ref name=pmid16378701/>
#Blunt dissection (to avoid artefactual injuries to the bones).
#Clean the bones (''not'' with bleach)
#*Bones cooked for 1+ hours... with frequent checks to avoid that they become mushy.


Internal:
=Causes of death=
*Lung emphysema.
*Froth in the trachea.
*Patlauf spots<ref name=pmid12134758>{{cite journal |author=Bohnert M, Ropohl D, Pollak S |title=[Forensic medicine significance of the fluid content of the sphenoid sinuses] |language=German |journal=Arch Kriminol |volume=209 |issue=5-6 |pages=158–64 |year=2002 |pmid=12134758 |doi= |url=}}</ref> -- ???


===Micro/Lab===
==Environmental==
There are a few tests of debated value:<ref name=pmid16378701/>
{{Main|Environmental causes of death}}
*Diffusion of particulates into the blood (left ventricle) from the water.
They include:  
**Diatom test.
*[[Hypothermia]].  
*Haemodilution.  
*[[Hyperthermia]].  
**Mostly useless - CPR interferes with it, not reliable if there putrefaction or autolysis.
*Drowning - see [[asphyxial deaths]].
*Transport of aveolar element into blood circulation.
*Lack of oxygen - see [[asphyxial deaths]].  
*[[Electrocution]].


==Carbon monoxide==
=Gunshot wounds=
Carbon monoxide (CO) is a common way to commit suicide.
{{main|Gunshot wounds}}
Gunshot wounds (GSWs) are a relatively uncommon finding in Canada.  They are dealt within a separate article.


Pathophysiology:
=Asphyxia=
*CO binds to haemoglobin -- prevents oxygen from binding there.
{{main|Asphyxial deaths}}


Findings:
*This is a big topic and covered by a separate article.
*Salmon pink skin.
*CO level (blood test) elevated (???).


==Gunshot wounds==
===Classification===
{{main|Gunshot wounds}}
*''Strangulation'' - where there are signs of neck compression.
Are a relatively uncommon finding in Canada. They are dealt within a separate article.
**Includes: ganging, ligature strangulation and manual strangulation.
*''Chemical asphyxia'' - usually no signs of neck compression.
**Includes: carbon monoxide poisoning.
*''Suffocation'' - usually no signs of neck compression.
**Includes: smothering, [[choking]], positional asphyxia, [[drowning]].


==Asphyxia==
=Blunt force injury=
*This is a big topic.
*[[AKA]] ''blunt force trauma''.
 
==General==
===Manual strangulation===
Classification:
Features:<ref name=Ref_HoFP>{{Ref HoFP|155}}</ref>
*Contusions.
*Petechiac of sclerae (white part of eye) & conjunctivae (cover sclerae); present ~ 90% of the time.
*Laceration.
*Hyoid bone fracture.
*Acceleration/deceleration injury, e.g. [[diffuse axonal injury]].
*Thyroid cartilage fracture.
*Haemorrhage in strap muscles of the neck.


==Blunt force trauma==
Weapons:
*Pretty much anything.
*Fist.
*Foot.
*Baseball bat... pretty much anything.
*Beer bottles are common... and strong enought to fracture a skull.
*Beer bottles are common... and strong enought to fracture a skull.
**Empty bottles have a higher fracture energy than full ones.<ref name=pmid19239964>{{cite journal |author=Bolliger SA, Ross S, Oesterhelweg L, Thali MJ, Kneubuehl BP |title=Are full or empty beer bottles sturdier and does their fracture-threshold suffice to break the human skull? |journal=J Forensic Leg Med |volume=16 |issue=3 |pages=138–42 |year=2009 |month=April |pmid=19239964 |doi=10.1016/j.jflm.2008.07.013 |url=}}</ref>
**Empty bottles have a higher fracture energy than full ones.<ref name=pmid19239964>{{cite journal |author=Bolliger SA, Ross S, Oesterhelweg L, Thali MJ, Kneubuehl BP |title=Are full or empty beer bottles sturdier and does their fracture-threshold suffice to break the human skull? |journal=J Forensic Leg Med |volume=16 |issue=3 |pages=138–42 |year=2009 |month=April |pmid=19239964 |doi=10.1016/j.jflm.2008.07.013 |url=}}</ref>


==Sharp force trauma==
==Cause of death==
*Knife or other sharp object.
===Commotio cordis===
Features:<ref name=pmid11334832>{{cite journal |author=Kohl P, Nesbitt AD, Cooper PJ, Lei M |title=Sudden cardiac death by Commotio cordis: role of mechano-electric feedback |journal=Cardiovasc. Res. |volume=50 |issue=2 |pages=280–9 |year=2001 |month=May |pmid=11334832 |doi= |url=}}</ref><ref>{{cite journal |author=Maron BJ, Estes NA |title=Commotio cordis |journal=N. Engl. J. Med. |volume=362 |issue=10 |pages=917–27 |year=2010 |month=March |pmid=20220186 |doi=10.1056/NEJMra0910111 |url=http://www.nejm.org/doi/full/10.1056/NEJMra0910111}}</ref>
*Often negative autopsy; no cardiac pathology.
*Etiology: [[cardiac arrhythmia|arrhythmia]].
*History: trauma to chest.
 
Note:
*May be spelled ''Commodio cordis''.<ref name=pmid11555799>{{cite journal |author=Perron AD, Brady WJ, Erling BF |title=Commodio cordis: an underappreciated cause of sudden cardiac death in young patients: assessment and management in the ED |journal=Am J Emerg Med |volume=19 |issue=5 |pages=406–9 |year=2001 |month=September |pmid=11555799 |doi=10.1053/ajem.2001.24455 |url=}}</ref>
*Analogous to ''[[commotio medullaris]]''.
 
==Scenarios==
===Motor vehicle collisions===
*Pedestrian vs. motor vehicle: heel to injury measurement, remember to include the thickness of the heel/sole of shoe.<ref>{{Ref OPMfP|18}}</ref>
*Dicing injuries: tempered glass used in side window construction fragments into cubes when fractured causing L-shaped wounds.
 
===Descent from height===
*Relatively common way to suicide.
**May be an ''accident'', e.g. decedent thought they can fly (due to a psychosis).
**May be a ''homicide'', e.g. decedent was pushed.
 
====Gross====
Features:
*Multiple injuries - often including multiple fractures, e.g. basal skull fracture, flail chest.
*+/-Haemothorax - can be proved with a large bore needle.
**Sufficient for cause of death - can be used to do an abbreviated post-mortem.
*+/-Haemoaspiration (due to facial trauma) - presence suggest that decendent was alive shortly after landing/impact and thus likely very alive during the descent.
**Patchy red centrilobular spots on gross examination.
 
==Injury patterns==
===Seromuscular tear===
* [[AKA]] ''seatbeat syndrome''.
* Intestinal injury associated with motor vehicle collisions and more specifically seatbelts.
 
Features:
* Def'n: separation of (inner) muscularis propria from submucosa.<ref name=pmid12198344>{{Cite journal  | last1 = Slavin | first1 = RE. | last2 = Borzotta | first2 = AP. | title = The seromuscular tear and other intestinal lesions in the seatbelt syndrome: a clinical and pathologic study of 29 cases. | journal = Am J Forensic Med Pathol | volume = 23 | issue = 3 | pages = 214-22 | month = Sep | year = 2002 | doi = 10.1097/01.PAF.0000023001.32202.2D | PMID = 12198344 }}</ref>
 
===Bite injury===
*A special type of [[blunt force trauma]].
*May be seen in the context of a sexual assault.
*A ''forensic dentist'' may be able to assist.
 
In the context of a suspicious case:
*Human vs. animal.
*Bite marks, as evidence, have a limited value for identification purposes.
**In the context of identifying a potential perpetrator, it is essential to swab the bite mark for saliva, which is rich in DNA.<ref>{{Cite journal  | last1 = Pretty | first1 = IA. | title = Forensic dentistry: 2. Bitemarks and bite injuries. | journal = Dent Update | volume = 35 | issue = 1 | pages = 48-50, 53-4, 57-8 passim | month =  | year =  | doi =  | PMID = 18277695 }}</ref>
 
====Images====
<gallery>
Image: Dog_bite.JPG | Bite injury. (WC)
</gallery>
 
===Aortic trauma===
*Classic location of transection of the aorta is distal the the left subclavian branch point near the insertion of the ligamentum arteriosum (e.g. peri-isthmus).<ref name=pmid1934437>{{cite journal |author=Kodali S, Jamieson WR, Leia-Stephens M, Miyagishima RT, Janusz MT, Tyers GF |title=Traumatic rupture of the thoracic aorta. A 20-year review: 1969-1989 |journal=Circulation |volume=84 |issue=5 Suppl |pages=III40–6 |year=1991 |month=November |pmid=1934437 |doi= |url=}}</ref>
*[[Aortic dissection]] due to trauma is often catastrophic. Several mechanisms have been proposed and there is a body of trauma biomechanics research that explores this.
 
==Trauma with delayed death==
*[[Epidural hemorrhage]] with a lucid interval.
*Subcapsular splenic hematoma with subsequent rupture.
*Subcapsular hepatic hematoma with subsequent rupture.
*[[Aortic dissection]] with subsequent rupture.
 
=Sharp force injury=
*[[AKA]] ''sharp force trauma''.
===General===
Injuries caused by:<ref name=Ref_HospAuto111-2>{{Ref HospAuto|111-2}}</ref>
*Knife.
*Scissors - classic "Z" shape.
*Screwdriver.
*Glass.
 
===Gross===
Features:<ref name=Ref_HospAuto111-2>{{Ref HospAuto|111-2}}</ref>
*Incised wound (see: ''[[Wounds|Classification of wounds]]'').
**"Clean" edge (no contusion, no abrasion).
**Well-demarcated edges.
*+/-Hilt mark.
**Due to contact of hilt.
 
Subclassified into - see ''[[Wounds|classification of wounds]]'':
*''Cut/slash''.
*''Stab''.
*''Chop'' - a mixed injury, sharp force and blunt force.
 
====Images====
<gallery>
Image: Thorax-Messerstichwunden.jpg | Sharp force trauma - thorax. (WC)
</gallery>
 
=Head injuries=
===Accidental vs. intentional===
Features of non-accidental injuries:<ref name=pmid20141554>{{cite journal |author=Guyomarc'h P, Campagna-Vaillancourt M, Kremer C, Sauvageau A |title=Discrimination of falls and blows in blunt head trauma: a multi-criteria approach |journal=J. Forensic Sci. |volume=55 |issue=2 |pages=423–7 |year=2010 |month=March |pmid=20141554 |doi=10.1111/j.1556-4029.2009.01310.x |url=}}</ref>
*Lacerations:
**More than three.
**Length >= 7 cm or more.
**Location:
***Above hat brim line (HBL).
***[[Ear]].
***Left-sided.
*Fractures:
**Comminuted or depressed calvarial fractures.
**Location:
***Fractures located above the HBL.
***Left-sided fractures.
***Facial fractures.
*Contusions:
**Greater than four facial contusions.
*Other:
**"Postcranial osseous" [sic] (non-rib, non-skull) and/or visceral trauma.


==Aortic trauma==
Note: The paper doesn't give odds ratios for the the different features -- like in the rational clinical exam series... it is a shame.
*Aortic dissection due to trauma is often catastrophic.
*Classic location of injury is subclavian branch point.<ref>NEED ONE</ref>


Dissections often classified as:<ref name=pmid9362838>{{cite journal |author=Finkelmeier BA |title=Dissection of the aorta: a clinical update |journal=J Vasc Nurs |volume=15 |issue=3 |pages=88-93 |year=1997 |month=September |pmid=9362838 |doi= |url=}}</ref>
==Diffuse axonal injury==
*Type A - aortic root to just distal of left subclavian artery.
*Abbreviated ''DAI''.
*Type B - distal to (left) subclavian artery.
===General===
Clinical:
*Vegetative state.  
*Imaging findings: no anatomical cause apparent (in some cases).


==Head injuries==
Etiology:
===Diffuse axonal injury===
General:
*Hypothesized to arise from high shear loading of white mater tracts.<ref name=pmid2769276>{{cite journal |author=Blumbergs PC, Jones NR, North JB |title=Diffuse axonal injury in head trauma |journal=J. Neurol. Neurosurg. Psychiatr. |volume=52 |issue=7 |pages=838–41 |year=1989 |month=July |pmid=2769276 |pmc=1031929 |doi= |url=}}</ref>
*Hypothesized to arise from high shear loading of white mater tracts.<ref name=pmid2769276>{{cite journal |author=Blumbergs PC, Jones NR, North JB |title=Diffuse axonal injury in head trauma |journal=J. Neurol. Neurosurg. Psychiatr. |volume=52 |issue=7 |pages=838–41 |year=1989 |month=July |pmid=2769276 |pmc=1031929 |doi= |url=}}</ref>


===Gross===
Macroscopic findings:<ref name=pmid2769276/>
Macroscopic findings:<ref name=pmid2769276/>
*Tears - corpus callosum.
*Tears - corpus callosum.
*Haemorrhage.
*Haemorrhage.


Other (chronic) changes:<ref name=Ref_AoGP639>{{Ref AoGP|639}}</ref>{{fact}}
*Thalamus - shrinkage.
*Enlargement of third ventricle.
DDx (medical imaging):<ref name=pmid22406792>{{Cite journal  | last1 = Kumar | first1 = S. | last2 = Gupta | first2 = V. | last3 = Aggarwal | first3 = S. | last4 = Singh | first4 = P. | last5 = Khandelwal | first5 = N. | title = Fat embolism syndrome mimicker of diffuse axonal injury on magnetic resonance imaging. | journal = Neurol India | volume = 60 | issue = 1 | pages = 100-2 | month =  | year =  | doi = 10.4103/0028-3886.93597 | PMID = 22406792 }}</ref>
*[[Cerebral fat embolism]].
===Microscopic===
Microscopic findings:<ref name=pmid2769276/>
Microscopic findings:<ref name=pmid2769276/>
*Axonal retraction balls.
*Axonal retraction balls.
Line 244: Line 627:
*Degeneration of fibre tracts.
*Degeneration of fibre tracts.


==Excited delirium==
Grading:<ref>URL: [http://wiki.cns.org/wiki/index.php/Diffuse_axonal_injury_%28DAI%29 http://wiki.cns.org/wiki/index.php/Diffuse_axonal_injury_%28DAI%29]. Accessed on: 13 February 2012.</ref>
General:
*Grade 1: only microscopic findings.
*Also known as "agitated delirium".<ref name=pmid8768172>{{cite journal |author=Wetli CV, Mash D, Karch SB |title=Cocaine-associated agitated delirium and the neuroleptic malignant syndrome |journal=Am J Emerg Med |volume=14 |issue=4 |pages=425–8 |year=1996 |month=July |pmid=8768172 |doi= |url=}}</ref>
*Grade 2: macroscopic corpus callosum injury + microscopic findings of DAI.
*Dx is considered controversial, especially outside of the forensic pathology community.<ref>[http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=2374865 http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=2374865]</ref>
*Grade 3: macroscopic corpus callosum and midbrain injuries + microscopic findings of DAI.
*The diagnosis has garnered considerable attention in the context of electroshock weapon use, as ''Taser International'' (a manufacturer of electroshock weapons) has blamed all deaths involving its weapons on it.
 
===Stains===
*[[Bielschowsky stain]] to highlight axonal swellings - appear 12-18 hours after injury.<ref name=Ref_Shkrum_562>{{Ref Shkrum|562}}</ref>
 
===IHC===
*Beta-amyloid precursor protein (beta-APP ''or'' APP).<ref name=pmid10050789>{{cite journal |author=Gleckman AM, Bell MD, Evans RJ, Smith TW |title=Diffuse axonal injury in infants with nonaccidental craniocerebral trauma: enhanced detection by beta-amyloid precursor protein immunohistochemical staining |journal=Arch. Pathol. Lab. Med. |volume=123 |issue=2 |pages=146–51 |year=1999 |month=February |pmid=10050789 |doi= |url=}}</ref><ref name=pmid17368446>{{Cite journal  | last1 = Mac Donald | first1 = CL. | last2 = Dikranian | first2 = K. | last3 = Song | first3 = SK. | last4 = Bayly | first4 = PV. | last5 = Holtzman | first5 = DM. | last6 = Brody | first6 = DL. | title = Detection of traumatic axonal injury with diffusion tensor imaging in a mouse model of traumatic brain injury. | journal = Exp Neurol | volume = 205 | issue = 1 | pages = 116-31 | month = May | year = 2007 | doi = 10.1016/j.expneurol.2007.01.035 | PMID = 17368446 | PMC = 1995439 }}</ref>
*NF.<ref name=pmid17368446/>
 
==Intracranial hemorrhage==
{{main|Intracranial hematoma}}
Intracranial hemorrhage may be a consequence of blunt force trauma.
 
Classification:
*[[Epidural hematoma]].
*[[Subdural hematoma]].
*[[Subarachnoid hematoma]].
*[[Intracerebral hematoma]].
 
==Cerebral contusion==
===General===
*Due to blunt force trauma.
 
===Gross===
Features:
*Focal superficial hemorrhage.
*Location, usually, ''frontal lobe'' and ''temporal lobe''.<ref name=Ref_HoFP_102>{{Ref HoFP|102}}</ref>
 
Notes:
*Classically, come in pairs:<ref name=Ref_HoFP_102>{{Ref HoFP|102}}</ref>
*#''Coup contusion'' - at the site of the (primary) impact
*#''Contrecoup contusion'' - secondary internal impact.
**Example - fall on back of head:
***Occipital lobe contusion = coup contusion.
***Frontal lobe contusion = contrecoup contusion.
*May be associated with contusions of the:<ref name=Ref_HoFP_103>{{Ref HoFP|103}}</ref>
**Deep brain structures, known as an "intermediary coup".
**Dorsal surface of the cerebral hemispheres, known as "gliding contusions".
*Resolve as a yellow lesion (like at other sites), known as a ''[[plaque]] jaune'' in the brain.
**Classically, inferior aspect of the frontal lobe.
 
DDx:
*Hemorrhagic [[stroke]] - usually temporal lobe and/or parietal lobe.
 
==Traumatic brain injury in infants==
{{main|Traumatic brain injury in infants}}
 
*Shaken-impact syndrome, [[AKA]] shaken baby syndrome.
 
==Commotio medullaris==
Features:<ref name=Ref_Shkrum613>{{Ref Shkrum|613}}</ref>
*Sudden death after head trauma that is insufficient to explain death.
*Etiology: unknown - thought to be related to apnea.
 
Note:
*Analogous to ''[[commotio cordis]]''.
 
=Excited delirium=
*[[AKA]] ''agitated delirium''.<ref name=pmid8768172>{{cite journal |author=Wetli CV, Mash D, Karch SB |title=Cocaine-associated agitated delirium and the neuroleptic malignant syndrome |journal=Am J Emerg Med |volume=14 |issue=4 |pages=425–8 |year=1996 |month=July |pmid=8768172 |doi= |url=}}</ref>
===General===
*[[Diagnosis]] is considered somewhat controversial outside of the forensic pathology community.<ref name=pmid18450833>{{Cite journal  | last1 = Stanbrook | first1 = MB. | last2 = Hébert | first2 = PC. | last3 = Kale | first3 = R. | last4 = Sibbald | first4 = B. | last5 = Flegel | first5 = K. | last6 = MacDonald | first6 = N. | title = Tasers in medicine: an irreverent call for proposals. | journal = CMAJ | volume = 178 | issue = 11 | pages = 1401-2, 1403-4 | month = May | year = 2008 | doi = 10.1503/cmaj.080592 | PMID = 18450833 |PMC = 2374865 }}</ref>
*The [[diagnosis]] has garnered attention in the context of electroshock weapon use, as ''Taser International'' (a manufacturer of electroshock weapons) has often ascribed the deaths involving its weapons to it - when it is alleged that their electroshock weapon caused the death.


*There is no "official" definition for ''excited delirium''.
*There is no "official" definition for ''excited delirium''.
Line 259: Line 702:


Excited delirium - hypothesis:
Excited delirium - hypothesis:
*Thought to arise in the context of severe chronic mental disorders (e.g. schizophrenia) and protracted cocaine binges.<ref name=pmid9645173>{{Cite journal  | last1 = Pollanen | first1 = MS. | last2 = Chiasson | first2 = DA. | last3 = Cairns | first3 = JT. | last4 = Young | first4 = JG. | title = Unexpected death related to restraint for excited delirium: a retrospective study of deaths in police custody and in the community. | journal = CMAJ | volume = 158 | issue = 12 | pages = 1603-7 | month = Jun | year = 1998 | doi =  | PMID = 9645173 | PMC = 1229410 | url=http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1229410}}</ref>
*Thought to arise in the context of severe chronic mental disorders (e.g. schizophrenia) and protracted [[cocaine]] binges.<ref name=pmid9645173>{{Cite journal  | last1 = Pollanen | first1 = MS. | last2 = Chiasson | first2 = DA. | last3 = Cairns | first3 = JT. | last4 = Young | first4 = JG. | title = Unexpected death related to restraint for excited delirium: a retrospective study of deaths in police custody and in the community. | journal = CMAJ | volume = 158 | issue = 12 | pages = 1603-7 | month = Jun | year = 1998 | doi =  | PMID = 9645173 | PMC = 1229410 | url=http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1229410}}</ref>
*Thought to result from alteration of dopamine receptor density.  The D2 receptor in particular, which is thought to be important in temperature regulation, is decreased in psychotic cocaine abusers.<ref name=pmid8768172/>
*Thought to result from alteration of dopamine receptor density.  The D2 receptor in particular, which is thought to be important in temperature regulation, is decreased in psychotic cocaine abusers.<ref name=pmid8768172/>


==Toxicology==
=Toxicology & biochemistry=
===Cocaine===
===General===
*No agreed upon toxic dose.<ref name=pmid15075681>{{cite journal |author=Stephens BG, Jentzen JM, Karch S, Wetli CV, Mash DC |title=National Association of Medical Examiners position paper on the certification of cocaine-related deaths |journal=Am J Forensic Med Pathol |volume=25 |issue=1 |pages=11–3 |year=2004 |month=March |pmid=15075681 |doi= |url=}}</ref> (due to tolerance)
Things usually collected at autopsy:
*Chronic use may lead to cardiac enlargement.
#Blood in EDTA tube (genetic testing).
#Urine toxicology:
#*Useful to evaluate ''myoglobin''.
#Vitreous:
#*Biochemistry.
#*Ketones.
#*Urea (???).
#Bile:<ref>{{Ref HospAuto|220}}</ref>
#*Acetaminophen overdoses.
#*Opiate overdoses.
 
Myoglobin DDx:
*Neuroleptic malignant syndrome.
*Malignant hyperthermia.
*Serotonin syndrome.
 
===Biochemistry===
*[[Diabetes mellitus]]:<ref name=Ref_HospAuto221>{{Ref HospAuto|221}}</ref>
**Plasma:
***Hemoglobin A1c - increased.
***Acetone - increased.
***Beta-hydroxybutyrate - increased.
****Also increased in alcoholic ketoacidosis (though ketones low).
**Urine:
***Aceto-acetate - increased.
 
Death by insulin overdose:<ref name=Ref_HospAuto224>{{Ref HospAuto|224}}</ref>
*C-peptide - low.
*Insulin - high.
 
====Serum====
*Potassium - rises quickly and rapidly after death; completely useless.
*Sodium - tends to decrease after death; usually useless.
*Glucose - drops quickly; useless unless sky high.
*Urea, creatinine and urate - stable for ~48 hours post-mortem.<ref name=Ref_HospAuto222>{{Ref HospAuto|222}}</ref>
 
===Vitreous===
*Creatinine and urea - approximate those at time of death.<ref name=Ref_HospAuto222>{{Ref HospAuto|222}}</ref>
*Glucose - used to assess for hyperglycemia (due to [[diabetes mellitus|diabetic coma]]) in life.<ref name=pmid19167848>{{Cite journal  | last1 = Zilg | first1 = B. | last2 = Alkass | first2 = K. | last3 = Berg | first3 = S. | last4 = Druid | first4 = H. | title = Postmortem identification of hyperglycemia. | journal = Forensic Sci Int | volume = 185 | issue = 1-3 | pages = 89-95 | month = Mar | year = 2009 | doi = 10.1016/j.forsciint.2008.12.017 | PMID = 19167848 }}</ref>
 
===Toxicology===
*Should be submitted with anatomical findings and history.
 
Common submissions:
#Alcohol only.
#Suspected toxicologic death - need details on drugs.
 
====Mandated by case====
In Ontario, the following are mandated by the case:<ref>{{Ref OPMfP|14}}</ref>
*Sudden death of child under five years old.
*Workplace death.
*Fatal motor vehicle collision - esp. driver.
*Aviation death - esp. pilot & co-pilot.
*Fire-related death (carboxyhemoglobin).
 
===Toxins===
====Ethanol toxicity====
{{Main|Ethanol abuse}}
*Usually measured (in Canada) as: ''mass of EtOH (mg)/volume of blood (mL)''.
**Limit (Ontario): 80 milligrams of alcohol in 100 millilitres of blood (0.08 gm/100 mL).<ref>URL: [http://www.mto.gov.on.ca/english/safety/impaired/fact-sheet.shtml http://www.mto.gov.on.ca/english/safety/impaired/fact-sheet.shtml]. Accessed on: 28 September 2010.</ref>
**Enough to be fatal ~ 350 mg/dL ~= 76 mmol/L.
 
=====Ethanol intoxication as a table<ref name=southendnhs>URL: [http://www.southend.nhs.uk/pathologyhandbook/clinical_chemistry/Guidelines/ethanol_poisoning.htm http://www.southend.nhs.uk/pathologyhandbook/clinical_chemistry/Guidelines/ethanol_poisoning.htm]. Accessed on: 19 October 2010.</ref>=====
{| class="wikitable"
|
|Concentration
|Concentration
|Concentration
|Concentration
|-
|Legal limit - Ontario<ref>URL: [http://www.mto.gov.on.ca/english/safety/impaired/fact-sheet.shtml http://www.mto.gov.on.ca/english/safety/impaired/fact-sheet.shtml]. Accessed on: 28 September 2010.</ref>
| 80 mg/dL
| ~17 mmol/L
| 0.8 g/L
| 0.08 g/dL
|-
|Mild
| < 180 mg/dL
| < 39 mmol/L
| < 1.8 g/L
| < 0.18 g/dL
|-
|Moderate
| 180-350 mg/dL
| 39-76 mmol/L
| 1.8-3.5 g/L
| 0.18-0.35 g/dL
|-
|Severe
| 350-450 mg/dL
| 76-98 mmol/L
| 3.5-4.5 g/L
| 0.35-0.45 g/dL
|}
 
Notes:
*1 mg/dL = 1/4.607 mmol/L.
**Ethanol's molar mass = 46.07 g/mol.
 
====Methanol toxicity====
*Minimum lethal dose: 40 mg/dl.<ref>URL: [http://path.upmc.edu/cases/case242/dx.html http://path.upmc.edu/cases/case242/dx.html. Accessed on: 13 January 2012.</ref>
 
*Typically an accidental death; person consumes methanol as an ethanol substitute.
*Blindness.
*[[Putamen]] [[necrosis]] (bilateral).<ref name=pmid16484428>{{Cite journal  | last1 = Blanco | first1 = M. | last2 = Casado | first2 = R. | last3 = Vázquez | first3 = F. | last4 = Pumar | first4 = JM. | title = CT and MR imaging findings in methanol intoxication. | journal = AJNR Am J Neuroradiol | volume = 27 | issue = 2 | pages = 452-4 | month = Feb | year = 2006 | doi =  | PMID = 16484428 }}</ref>
*+/-Pancreatic injury.<ref name=pmid10866330>{{Cite journal  | last1 = Hantson | first1 = P. | last2 = Mahieu | first2 = P. | title = Pancreatic injury following acute methanol poisoning. | journal = J Toxicol Clin Toxicol | volume = 38 | issue = 3 | pages = 297-303 | month =  | year = 2000 | doi =  | PMID = 10866330 }}</ref>
 
====Cocaine toxicity====
*No agreed upon toxic dose<ref name=pmid15075681>{{cite journal |author=Stephens BG, Jentzen JM, Karch S, Wetli CV, Mash DC |title=National Association of Medical Examiners position paper on the certification of cocaine-related deaths |journal=Am J Forensic Med Pathol |volume=25 |issue=1 |pages=11–3 |year=2004 |month=March |pmid=15075681 |doi= |url=}}</ref> - due to tolerance.
*Usual mechanism ''cardiac failure''.
 
Features - heart:
*Usually anatomically normal heart.
**+/-Advanced [[coronary artery atherosclerosis]] for age.
**+/-[[Myocardial infarction]].
***+/-Contraction band necrosis.
**+/-Cardiac hypertrophy.


===Ethylene glycol===
Other:
*+/-Nasal septum perforation.
*+/-Track marks (other drug use).
*+/-Finger burns (during preparation of crack).
*+/-Drug paraphernalia, e.g. crack pipe.
 
====Ethylene glycol toxicity====
:For a more general discussion see ''[[Crystals_in_body_fluids#Urine_crystals|urine crystals]]''
*Not done in routine toxicology screening.
*Not done in routine toxicology screening.
*Birefringent calcium oxalate crystals found in kidney (with polarized light).<ref name=Ref_KFP589>{{Ref KFP|589}}</ref>
*Birefringent calcium oxalate crystals found in kidney (with [[polarized light]]).<ref name=Ref_KFP589>{{Ref KFP|589}}</ref>


==Natural death==
====Anaphylaxis====
*Allergic reaction, e.g. peanut allergy.
 
Diagnosis - serology:<ref name=pmid20176258>{{cite journal |author=Simons FE |title=Anaphylaxis |journal=J. Allergy Clin. Immunol. |volume=125 |issue=2 Suppl 2 |pages=S161–81 |year=2010 |month=February |pmid=20176258 |doi=10.1016/j.jaci.2009.12.981 |url=}}</ref>
*IgE.
*Tryptase.
 
=Natural death=
{{main|Natural death}}
There is a lot that can kill ya... but only a few of those are quickly, i.e. within a hour or so.
There is a lot that can kill ya... but only a few of those are quickly, i.e. within a hour or so.


Generally, these things are:
Generally, these things are:
*Cardiovascular:
*Cardiovascular:
**Arrhythmia.
**[[Cardiac arrhythmia|Arrhythmia]].
**Myocardial infarction.
**[[Myocardial infarction]].
**Haemorrhage.
**Haemorrhage.
***Ruptured aneurysm.
***Ruptured aneurysm.
**[[Hypertensive heart disease]].
*Respiratory:
*Respiratory:
**Pulmonary embolism (PE).
**[[Pulmonary embolism]] (PE).
**Asthma.
**[[Asthma]].
*GI:
*GI:
**Haemorrhage.
**Haemorrhage.
***Esophageal varices.
***[[Esophageal varices]].
***Gastric varices.
***Gastric varices.
*Neurologic:
*Neurologic:
**Intracranial haemorrhage.
**Intracranial haemorrhage.
***Ruptured aneurysm.
***Ruptured aneurysm.
***Spontaneous subdural haemorrhage.
***Spontaneous [[subdural hemorrhage]].
**Stroke:
**[[Stroke]]:
***Haemorrhagic.
***Haemorrhagic.
***Thrombotic (more common than haemorrhagic).
***Thrombotic (more common than hemorrhagic).
 
==Intracranial hemorrhage==
{{main|Intracranial hematoma}}
 
Classification:
*Epidural hematoma.
*Subdural hematoma.
*Subarachnoid hematoma.


==Forensic entomology==
=Forensic entomology=
{{main|Forensic entomology}}
{{main|Forensic entomology}}
*Study of the bugs that eat corpses.
*Study of the bugs that eat corpses.
*Bugs may hide a wound... it is important to know where they like to be.
*Bugs may hide a wound... it is important to know where they like to be.


==See also==
=Forensic anthropology=
{{main|Forensic anthropology}}
Forensic anthropology is looking at skeletal remains.  It may be useful of [[decendent identification|identification]] and, rarely, the cause of death.  Important in skeletonized remains and decomp cases.
 
=Forensic taphonomy=
*The study of post-mortem decay to assist in a medicolegal investigation.
**''Taphonomy'' = postmortem fate of biological remains; derived from the Greek word ''taphos'' (grave).<ref>{{cite journal |author=Milroy CM |title=Forensic taphonomy: the postmortem fate of human remains |journal=BMJ |volume=319 |issue=7207 |pages=458 |year=1999 |month=August |pmid=10445946 |pmc=1127062 |doi= |url=}}</ref>
 
=See also=
*[[Forensic entomology]].
*[[Forensic entomology]].
*[[Autopsy]].
*[[Autopsy]].
*[[Heart]].
*[[Heart]].


==References==
=References=
{{reflist|2}}
{{reflist|2}}


==External links==
=External links=
*[http://cap-acp.org/forensic.cfm Forensic pathology (cap-acp.org)].
*[http://cap-acp.org/forensic.cfm Forensic pathology (cap-acp.org)].
*[http://emedicine.medscape.com/article/1680032-overview Post-mortem changes (emedicine.medscape.com)].
*[http://neurobio.drexelmed.edu/goldmanweb/forensicanthro/trauma.pdf Fractures (drexelmed.edu)].
*[http://www.forensicmed.co.uk/pathology/mechanisms-of-death/ Mechanisms of death (forensicmed.co.uk)].
 
==Post-mortem changes==
*[http://emedicine.medscape.com/article/1680032-overview#showall Post-mortem changes (emedicine.medscape.com)].
*[http://emedicine.medscape.com/article/1680107-overview#showall Autopsy of blunt force trauma (emedicine.medscape.com)].
*[http://www.the-crankshaft.info/2010/07/postmortem-changes_29.html Post-mortem changes (the-crankshaft.info)].


[[Category:Autopsy]]
[[Category:Autopsy]]
[[Category:Forensic pathology]]
[[Category:Forensic pathology]]

Latest revision as of 13:47, 27 March 2017

Forensic pathology is figuring-out why, when, where and how people died, if the manner of death is not obviously natural.

Death categorization

Deaths are categorized foremost by the manner of death. The manner is the single most important legal categorization for a death. The cause of death is important for understanding what happened. The mechanism of death is the pathophysiologic reason for death and can be inferred from the cause.

Examples:

Cause of death Manner of death Mechanism of death Scenario
Electrocution accident cardiac arrhythmia man struck by lightning
Hyperthermia accident arrhythmias, seizures[1] man lost on hiking trip in desert
Epidural hemorrhage due to blunt force trauma to the head homicide brain stem compression or cerebral vascular spasm leading to autonomic dysregulation man hit with a hammer in the head
Carbon monoxide toxicity suicide cerebral hypoxia (CO binds to hemoglobin impairing oxygen transport) woman found in car with suicide note, long history of depression, previous suicide attempts
Atherosclerotic heart disease natural cardiac arrhythmia due to ischemia man found dead in bed, apartment locked, 95% stenosis of LMCA at autopsy, no other significant autopsy findings

Manner of death

The manner of death is a legislatively defined classification. It varies slightly between jurisdictions.

 
 
 
 
 
 
 
 
Manner
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Homicide
 
Suicide
 
Natural
 
Accident
 
Undetermined

Notes:

  • Undetermined - is a waste basket category.
  • Homicide - not necessarily murder.
  • Can be group into three:
    1. Intent to kill (homicide, suicide).
    2. No intent to kill (natural, accidental).
    3. Undetermined.

Mechanism of death

This is occasionally of interest. It is usually based on physiology.

The mechanism is often asked for asphyxial deaths. The short answer it is: brain stem hypoxia due to ischemia caused by venous obstruction in the neck.[2][3]

Cause of death

  • Abbreviated COD.

General

  • The cause of death should be what started the sequence of events that lead to death.

Word form for cause of death

Examples:

  • C. difficile colitis complicating antibiotic treatment for a dental abscess.[4]
  • Complications of laparoscopic cholecystectomy for ascending cholangitis with mesothelioma and atherosclerotic heart disease.[5]

General forms:

  • A complicating B for the treatment of C.
  • A complicating B for the treatment of C with D and E.

World Health Organization form for cause of death

General form:[6]

  • 1a = immediate cause of death.
  • 1b = what lead to the immediate cause of death.
  • 1c... 1[x] -- where 'x' is the last letter used; 1x = What started the sequence of events. This is known as the underlying cause of death.
  • 2 = contributing factors.

Example 1:

Example 2:

Natural deaths

  • The cause should be a medical diagnosis, not the mechanism (e.g. cardiac arrest, cachexia, kidney failure).
  • The mechanism is irrelevant.

Notes:

Legal frame work

General

  • In Ontario, the manner is determined by the coroner.
  • Coroners, in Ontario, are MDs -- usually family docs.
  • The cause (e.g. "gunshot wound to the head") is determined by the pathologist.

NB - the word coroner is not synoymous with MD. British Columbia has coroners that aren't MDs.

Case classification (Ontario)

Cases are classified as:

  • A case = homicide and suspicious for homicide, (all) gunshot wounds.
  • B case = adult, non-suspicious.
  • C case = child, non-suspicious.

Notes:

  • All A cases are done at regional centers by certified forensic pathologists.

Forensic golden triangle

Forensic diagnostic triangle

Most general differential diagnosis:

Difficulties arise when more than one point of the triangle is in play, i.e. the forensic pathologist has to earn their pay when an old man with a heart condition is known to be into erotic asphyxia, and dies after doing some drugs and whilst indulging in erotic asyphxiation with a friend...

  • If he had an arrhythmia and there was no stressor... natural death.
  • If he over did it with the drugs, it is an overdose, ergo accidental.
  • If he did the erotic asphyxia a bit too long it is accidental.
  • If the friend held the plastic bag over his head just a bit long to asphyxiate him... it is a homicide.
  • If he was a lone and depressed... he might have been trying to kill himself, ergo suicide.

Death-related changes

Rigor mortis

Definition:

  • Muscle rigidity following death (caused by depletion of ATP).

Dependent on:

  • Temperature of patient at death.
  • Temperature variations in the environment since death.
  • Presence of some medical conditions.
  • May never develop!

It is the explanation for post-mortem goose bumps.

Summary

  • Its onset & presence is highly variable.
  • Forensic pathologists do not comment on time of death, as the above times are subject to such a large degree of variability, i.e. the estimates are essentially useless.

Time estimates

A crude guess for time of death based on rigor:[8]

  • Warm & flaccid <3 h.
  • Warm & stiff 3-8 h.
  • Cold & stiff 8-36 h.
  • Cold & flaccid > 36 h.

Notes:

  • Memory device: 3s: cut points are at 3 hours, 1/3 of a day, 3/2 of a day.

Livor mortis

Definition: pooling of blood in the dependent position, due to blood stasis.

  • Onset may preceed death in the context of congestive heart failure.
  • If pressure is applied to a dependent area-- no blood can enter there; thus, a pressure area is blanched (i.e. white).
  • Can be seen externally, i.e. on the skin, and internally.
  • Liver mortis becomes fixed some time after death.
    • Liver mortis does NOT tell one the position the decedent was in at the time of death-- only the position the decedent was at the time liver mortis became fixed. If the decedent wasn't moved liver mortis can help determine the position the person was in when they died.

Averages:

  • Start: 30 minutes to 2 hours
  • Fixed: 8-12 hours.

DDx:

  • Blunt force trauma - especially to the inexperienced eye.
  • Post-mortem hypostatic bruising.

Tache noire

Literally black spot.

Features:[9]

  • Brown/black horizontal line of the eye due to drying.
    • Arises if the eye remains open after death.
    • May mimic a traumatic injury.

Images:

Post-mortem decomposition/preservation

One of three things happens post-mortem:[11]

  1. Mummification.
  2. Putrefaction (skeletonisation).
    • Green colour due to break down of hemoglobin (biliverdin).[12]
  3. Adipocere - transformation into wax (due to anaerobic bacterial hydrolysis of fat).
    • Useless for toxicology and DNA.
  • A mix of the above often occur, i.e. part of the corpse is mummified... part of it decomposed through putrefaction.

Mummification:

  • Predominant in dry environments.
  • Body becomes dry and leathery.

Putrefaction:

  • Body wet/moist after death -- ideal environment for putrefactive bacteria and organisms.

Artefacts

  • Prinsloo and Gordon artefact = artefactual post-morten haemorrhage on the posterior surface of the esophagus.[13]
    • Minimized by removing cranial contents & thoracic contents before undertaking neck dissection.[14]
  • Artefactual fractures (see fractures).
  • Dilated anus (in isolation).[15][16]
  • Towel clip injury, usu. paired (in organ donors) - may be mistaken for an electroshock weapon (e.g. Taser) wound.[17]
  • Subclavian stab for vascular access - may be confused with a gunshot exit wound.

Infants

  • Lumpy neck - small superficial nodules on anterior neck ~2-5 mm (???).[18]
  • Intussusception of small bowel - often multiple.

Wounds

General

  • Wound - definition: defect in skin or mucous membrane[19] - usually due to trauma.

Special types of wounds:

Gross pathologic classification of injuries

Mnemonic CALI:

  • Contusion - "bruise", hematoma.
    • Age (usual colour change sequence): red, blue, green, yellow, brown.[20]
    • Etiology: bleeding from arterioles or venules (not capillaries).[21]
  • Abrasion - "scrape", e.g. motorcyclist slide across the roadway... skin scraped-off.
    • Can be subclassified as brush abrasions (has skin tags) and crush abrasions (do not have skin tags).
      • Skin tags suggest directionality; they are found at the distal point / point of last contact.[21]
  • Laceration - "tear", indicates blunt force trauma; contact point may be distant from where skin splits.
  • Incised - "cut", e.g. caused by a knife,[22] subdivided as follows:
    1. "Cut" or "slash" = length > depth.
    2. "Stab" = depth > length.
    3. "Chop" = typically have a contusion at the margin of the wound, classically caused by an axe. May be caused by a propeller.[23]

Images

DDx

How to decide what you're looking at:

  • Contusion:
    • Can be demonstrated histologically... there are extravascular RBCs.
      • If pre-morten there is vital reaction, i.e. WBCs come to clean-up the trauma.
    • If the post mortem interval is not known and long-- differentiation from decomposition may be non-trivial/impossible.
  • Abrasion vs. contusion:
    • Contusions skin is intact... in abrasion it is not.
    • Abrasions and contusions may be co-localized, i.e. in the same place.
  • Laceration vs. incision:
    • Lacerations have "bridges", incisions do NOT have bridges.
      • Bridges are fine strands of tissue that cross the long axis of the skin defect.
        • You can think of the wound as partially "sutured" by the bridges of tissue.
    • Lacerations are usually associated with a contusion and/or crush and have an irregular margin.[24]
    • Lacerations are classically on the skull and face. They are rarely on the abdomen.

Wound dating

  • Colour is somewhat useful for contusions (bruises).
  • Post-mortem injuries tend to be orange-yellow.[25]
  • Wounds age is difficult to determine as wound healing is affected by a large number of variables.
  • Old wounds (scars), generally, cannot be dated - one can only say they are old.

Microscopic

Wounds can be grouped into:

  • Pre-mortem.
  • Post-mortem.

Signs a wound was inflicted during life:

  • Blood.
    • Hypostasis/decomposition can mess with this, i.e. blood oozing out of vessels post-mortem shouldn't be called an injury.
    • Hemosiderin demonstrated by an iron stain - hard sign.
  • Inflammation:[26]
    • PMNs 6-24 hours after injury.
    • PMNs replaced monocytes in 24-48 hours.

Stains

  • Iron stain for siderophages (hemosiderin-laden macrophages) -- presence suggests 2-3 days or older.[27]

Bone fractures

  • AKA fractures.
  • AKA fracture of bone.

Artefactual fractures

  • "Undertaker's fracture" - cervical fracture due to rough handling.[28]
  • Basal skull fracture due to opening of skull.[29]
    • Classically does not cross sella turcica.
    • Notably absent features of a real (ante-mortem) fracture: hematoma, brain injury.
    • Mechanism to explain trauma not present in history; a fall/tripping not sufficient.

Healing of fractures

Simplified classification

  • Primary callus (cartilaginous) - early.
  • Secondary callus (bone) - late.

Microscopic

Features:

  • Fragmentation of bone.
  • +/-Dead bone = lacunae have no osteocytes.[30]
    • Takes days for osteocyte loss.
  • +/-Inflammatory cells.
  • +/-Hemosiderin-laden macrophages.
  • +/-Osteoblastic rimming.

DDx:

  • Fracture secondary to a tumour:
    • Metastatic carcinoma.
    • Osteosarcoma - typically does not have osteoblastic rimming.

Notes:

  • Radiology is not good at dating fratures;[31] however, it is good at finding 'em.

Pattern and cause

Child abuse-related

  • Paravertebral (bony) nodules = classic location for rib fractures in child abuse.
  • Metaphyseal fractures - "classical metaphyseal lesions".[32]

Motor vehicle versus pedestrian

If the pedestrian is standing during the initial impact one classically finds, at bumper level, a lower limb fracture with a Messerer wedge (German: Messerer-Kiel);[33] the wedge points in the direction of the (impact) force.

Location or type

Orbital floor fractures

General

  • Classically due to fights, followed by traffic accidents.[35]
  • Thought to result from loading on the orbital rim directly or the orbit - both are transmitted to the orbital floor.[34]

Note:

  • The orbital floor tends to the be weaker than other components of the orbital cavity wall; thus, it is the most common site of fracture in the orbital cavity wall.

Basal skull fracture

General

Etiology:

  • Blunt force trauma - high energy & velocity.
    • Seen in motor vehicle collisions, descent from height.

Clinical/external findings:

  • Raccoon eyes = periorbital ecchymosis.
  • Battle sign = mastoid ecchymosis.
    • Associated with orbital roof fractures.[36]
  • Cerebrospinal fluid rhinorrhea.
  • Hemorrhage from nose and ears.
  • Hemotympanum.

Note:

  • There is a dictum that states bilateral petrous bone fractures are due to impact to the side of the head - it isn't true.[37]

Hinge fracture of the skull

  • A special type of basal skull fracture.
  • Complete hinge fractures are considered severe; they are a 4 on the abbreviated injury scale (AIS).[38]
  • Classically due to a blow to the chin - resulting in a fracture across the medial fossa and sella turcica.[39]

Pathologic fracture

  • A fracture due to an underlying pathology.

Hip fractures

Autopsy

The autopsy article covers procedural things. Heart dissection is covered in the heart article.

Types

Forensic vs. hospital:

  • Forensic autopsies are focused on the external exam.

Marking conventions for common findings

There are no universal marking conventions for injuries.

One system in use (the Rose system) is:[40]

  • One red line for an incised wound.
  • Multiple closely spaced red lines, i.e. red hatching, for abrasions.
  • Multiple closely-spaced blue lines, i.e. blue hatching, for contusions.

The above makes sense in that:

  • Abrasions and incised wounds typically bleed - are red.
  • Contusions (bruises) don't classically bleed and are classically blue.

External exam findings

Colour of the corpse:[41]

Autopsy terminology

  • Gutter butter = adipose tissue in a decomp case; looks like butter topping put on popcorn. A Toronto-ism.
  • Gutter blood = blood in the empty thorax - after extraction of the organ block.
  • Tardieu spots = postmortem hypostatic hemorrhages;[43] look like petechiae - in dependent areas, i.e. in the zone of livity.

Autopsy on decomposed remains

  • AKA "decomp autopsy" or simply "decomp".

General

  • Histology usually very limited or useless.
  • Often done to exclude trauma.
  • Typical scenario: decedent lives alone -- body not discovered for prolonged period of time.
  • More likely to be a negative autopsy than non-decomp cases.

Suspicious decomp

Common sense rules for if skin is not intact:

  1. Blunt dissection (to avoid artefactual injuries to the bones).
  2. Clean the bones (not with bleach)
    • Bones cooked for 1+ hours... with frequent checks to avoid that they become mushy.

Causes of death

Environmental

They include:

Gunshot wounds

Gunshot wounds (GSWs) are a relatively uncommon finding in Canada. They are dealt within a separate article.

Asphyxia

  • This is a big topic and covered by a separate article.

Classification

  • Strangulation - where there are signs of neck compression.
    • Includes: ganging, ligature strangulation and manual strangulation.
  • Chemical asphyxia - usually no signs of neck compression.
    • Includes: carbon monoxide poisoning.
  • Suffocation - usually no signs of neck compression.

Blunt force injury

  • AKA blunt force trauma.

General

Classification:

Weapons:

  • Fist.
  • Foot.
  • Baseball bat... pretty much anything.
  • Beer bottles are common... and strong enought to fracture a skull.
    • Empty bottles have a higher fracture energy than full ones.[44]

Cause of death

Commotio cordis

Features:[45][46]

  • Often negative autopsy; no cardiac pathology.
  • Etiology: arrhythmia.
  • History: trauma to chest.

Note:

Scenarios

Motor vehicle collisions

  • Pedestrian vs. motor vehicle: heel to injury measurement, remember to include the thickness of the heel/sole of shoe.[48]
  • Dicing injuries: tempered glass used in side window construction fragments into cubes when fractured causing L-shaped wounds.

Descent from height

  • Relatively common way to suicide.
    • May be an accident, e.g. decedent thought they can fly (due to a psychosis).
    • May be a homicide, e.g. decedent was pushed.

Gross

Features:

  • Multiple injuries - often including multiple fractures, e.g. basal skull fracture, flail chest.
  • +/-Haemothorax - can be proved with a large bore needle.
    • Sufficient for cause of death - can be used to do an abbreviated post-mortem.
  • +/-Haemoaspiration (due to facial trauma) - presence suggest that decendent was alive shortly after landing/impact and thus likely very alive during the descent.
    • Patchy red centrilobular spots on gross examination.

Injury patterns

Seromuscular tear

  • AKA seatbeat syndrome.
  • Intestinal injury associated with motor vehicle collisions and more specifically seatbelts.

Features:

  • Def'n: separation of (inner) muscularis propria from submucosa.[49]

Bite injury

  • A special type of blunt force trauma.
  • May be seen in the context of a sexual assault.
  • A forensic dentist may be able to assist.

In the context of a suspicious case:

  • Human vs. animal.
  • Bite marks, as evidence, have a limited value for identification purposes.
    • In the context of identifying a potential perpetrator, it is essential to swab the bite mark for saliva, which is rich in DNA.[50]

Images

Aortic trauma

  • Classic location of transection of the aorta is distal the the left subclavian branch point near the insertion of the ligamentum arteriosum (e.g. peri-isthmus).[51]
  • Aortic dissection due to trauma is often catastrophic. Several mechanisms have been proposed and there is a body of trauma biomechanics research that explores this.

Trauma with delayed death

  • Epidural hemorrhage with a lucid interval.
  • Subcapsular splenic hematoma with subsequent rupture.
  • Subcapsular hepatic hematoma with subsequent rupture.
  • Aortic dissection with subsequent rupture.

Sharp force injury

  • AKA sharp force trauma.

General

Injuries caused by:[52]

  • Knife.
  • Scissors - classic "Z" shape.
  • Screwdriver.
  • Glass.

Gross

Features:[52]

  • Incised wound (see: Classification of wounds).
    • "Clean" edge (no contusion, no abrasion).
    • Well-demarcated edges.
  • +/-Hilt mark.
    • Due to contact of hilt.

Subclassified into - see classification of wounds:

  • Cut/slash.
  • Stab.
  • Chop - a mixed injury, sharp force and blunt force.

Images

Head injuries

Accidental vs. intentional

Features of non-accidental injuries:[53]

  • Lacerations:
    • More than three.
    • Length >= 7 cm or more.
    • Location:
      • Above hat brim line (HBL).
      • Ear.
      • Left-sided.
  • Fractures:
    • Comminuted or depressed calvarial fractures.
    • Location:
      • Fractures located above the HBL.
      • Left-sided fractures.
      • Facial fractures.
  • Contusions:
    • Greater than four facial contusions.
  • Other:
    • "Postcranial osseous" [sic] (non-rib, non-skull) and/or visceral trauma.

Note: The paper doesn't give odds ratios for the the different features -- like in the rational clinical exam series... it is a shame.

Diffuse axonal injury

  • Abbreviated DAI.

General

Clinical:

  • Vegetative state.
  • Imaging findings: no anatomical cause apparent (in some cases).

Etiology:

  • Hypothesized to arise from high shear loading of white mater tracts.[54]

Gross

Macroscopic findings:[54]

  • Tears - corpus callosum.
  • Haemorrhage.

Other (chronic) changes:[55][citation needed]

  • Thalamus - shrinkage.
  • Enlargement of third ventricle.

DDx (medical imaging):[56]

Microscopic

Microscopic findings:[54]

  • Axonal retraction balls.
  • "Microglial stars".
  • Degeneration of fibre tracts.

Grading:[57]

  • Grade 1: only microscopic findings.
  • Grade 2: macroscopic corpus callosum injury + microscopic findings of DAI.
  • Grade 3: macroscopic corpus callosum and midbrain injuries + microscopic findings of DAI.

Stains

IHC

  • Beta-amyloid precursor protein (beta-APP or APP).[59][60]
  • NF.[60]

Intracranial hemorrhage

Intracranial hemorrhage may be a consequence of blunt force trauma.

Classification:

Cerebral contusion

General

  • Due to blunt force trauma.

Gross

Features:

  • Focal superficial hemorrhage.
  • Location, usually, frontal lobe and temporal lobe.[61]

Notes:

  • Classically, come in pairs:[61]
    1. Coup contusion - at the site of the (primary) impact
    2. Contrecoup contusion - secondary internal impact.
    • Example - fall on back of head:
      • Occipital lobe contusion = coup contusion.
      • Frontal lobe contusion = contrecoup contusion.
  • May be associated with contusions of the:[62]
    • Deep brain structures, known as an "intermediary coup".
    • Dorsal surface of the cerebral hemispheres, known as "gliding contusions".
  • Resolve as a yellow lesion (like at other sites), known as a plaque jaune in the brain.
    • Classically, inferior aspect of the frontal lobe.

DDx:

  • Hemorrhagic stroke - usually temporal lobe and/or parietal lobe.

Traumatic brain injury in infants

  • Shaken-impact syndrome, AKA shaken baby syndrome.

Commotio medullaris

Features:[63]

  • Sudden death after head trauma that is insufficient to explain death.
  • Etiology: unknown - thought to be related to apnea.

Note:

Excited delirium

General

  • Diagnosis is considered somewhat controversial outside of the forensic pathology community.[65]
  • The diagnosis has garnered attention in the context of electroshock weapon use, as Taser International (a manufacturer of electroshock weapons) has often ascribed the deaths involving its weapons to it - when it is alleged that their electroshock weapon caused the death.
  • There is no "official" definition for excited delirium.
    • Most agree it includes fever.

One paper defines it in relation neuroleptic malignant syndrome:[64]

  • Fever.
  • Disorientation and confusion.
  • Increased energy/superhuman strength.

Excited delirium - hypothesis:

  • Thought to arise in the context of severe chronic mental disorders (e.g. schizophrenia) and protracted cocaine binges.[66]
  • Thought to result from alteration of dopamine receptor density. The D2 receptor in particular, which is thought to be important in temperature regulation, is decreased in psychotic cocaine abusers.[64]

Toxicology & biochemistry

General

Things usually collected at autopsy:

  1. Blood in EDTA tube (genetic testing).
  2. Urine toxicology:
    • Useful to evaluate myoglobin.
  3. Vitreous:
    • Biochemistry.
    • Ketones.
    • Urea (???).
  4. Bile:[67]
    • Acetaminophen overdoses.
    • Opiate overdoses.

Myoglobin DDx:

  • Neuroleptic malignant syndrome.
  • Malignant hyperthermia.
  • Serotonin syndrome.

Biochemistry

  • Diabetes mellitus:[68]
    • Plasma:
      • Hemoglobin A1c - increased.
      • Acetone - increased.
      • Beta-hydroxybutyrate - increased.
        • Also increased in alcoholic ketoacidosis (though ketones low).
    • Urine:
      • Aceto-acetate - increased.

Death by insulin overdose:[69]

  • C-peptide - low.
  • Insulin - high.

Serum

  • Potassium - rises quickly and rapidly after death; completely useless.
  • Sodium - tends to decrease after death; usually useless.
  • Glucose - drops quickly; useless unless sky high.
  • Urea, creatinine and urate - stable for ~48 hours post-mortem.[70]

Vitreous

  • Creatinine and urea - approximate those at time of death.[70]
  • Glucose - used to assess for hyperglycemia (due to diabetic coma) in life.[71]

Toxicology

  • Should be submitted with anatomical findings and history.

Common submissions:

  1. Alcohol only.
  2. Suspected toxicologic death - need details on drugs.

Mandated by case

In Ontario, the following are mandated by the case:[72]

  • Sudden death of child under five years old.
  • Workplace death.
  • Fatal motor vehicle collision - esp. driver.
  • Aviation death - esp. pilot & co-pilot.
  • Fire-related death (carboxyhemoglobin).

Toxins

Ethanol toxicity

  • Usually measured (in Canada) as: mass of EtOH (mg)/volume of blood (mL).
    • Limit (Ontario): 80 milligrams of alcohol in 100 millilitres of blood (0.08 gm/100 mL).[73]
    • Enough to be fatal ~ 350 mg/dL ~= 76 mmol/L.
Ethanol intoxication as a table[74]
Concentration Concentration Concentration Concentration
Legal limit - Ontario[75] 80 mg/dL ~17 mmol/L 0.8 g/L 0.08 g/dL
Mild < 180 mg/dL < 39 mmol/L < 1.8 g/L < 0.18 g/dL
Moderate 180-350 mg/dL 39-76 mmol/L 1.8-3.5 g/L 0.18-0.35 g/dL
Severe 350-450 mg/dL 76-98 mmol/L 3.5-4.5 g/L 0.35-0.45 g/dL

Notes:

  • 1 mg/dL = 1/4.607 mmol/L.
    • Ethanol's molar mass = 46.07 g/mol.

Methanol toxicity

  • Minimum lethal dose: 40 mg/dl.[76]
  • Typically an accidental death; person consumes methanol as an ethanol substitute.
  • Blindness.
  • Putamen necrosis (bilateral).[77]
  • +/-Pancreatic injury.[78]

Cocaine toxicity

  • No agreed upon toxic dose[79] - due to tolerance.
  • Usual mechanism cardiac failure.

Features - heart:

Other:

  • +/-Nasal septum perforation.
  • +/-Track marks (other drug use).
  • +/-Finger burns (during preparation of crack).
  • +/-Drug paraphernalia, e.g. crack pipe.

Ethylene glycol toxicity

For a more general discussion see urine crystals
  • Not done in routine toxicology screening.
  • Birefringent calcium oxalate crystals found in kidney (with polarized light).[80]

Anaphylaxis

  • Allergic reaction, e.g. peanut allergy.

Diagnosis - serology:[81]

  • IgE.
  • Tryptase.

Natural death

There is a lot that can kill ya... but only a few of those are quickly, i.e. within a hour or so.

Generally, these things are:

Forensic entomology

  • Study of the bugs that eat corpses.
  • Bugs may hide a wound... it is important to know where they like to be.

Forensic anthropology

Forensic anthropology is looking at skeletal remains. It may be useful of identification and, rarely, the cause of death. Important in skeletonized remains and decomp cases.

Forensic taphonomy

  • The study of post-mortem decay to assist in a medicolegal investigation.
    • Taphonomy = postmortem fate of biological remains; derived from the Greek word taphos (grave).[82]

See also

References

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External links

Post-mortem changes