View source for Asphyxial deaths

This article deals with '''asphyxial deaths''', where "asphyxia" is used in the conventional context, i.e. it is not used appropriately when considered from the perspective of its etymology (as pointed-out by Knight).<ref>{{Ref KFP|352}}</ref>

Asphyxia is, etymologically, ''lacking pulsation''; in common usage it is essentially ''hypoxia'' (blood lacking oxygen)<ref>URL: [http://dictionary.reference.com/browse/hypoxia http://dictionary.reference.com/browse/hypoxia]. Accessed on: 12 September 2010.</ref><ref>{{Ref PCPBoD8|10}}</ref> and ''anoxia'' (tissues lacking oxygen).<ref>URL: [http://dictionary.reference.com/browse/anoxia http://dictionary.reference.com/browse/anoxia]. Access ed on: 12 September 2010.</ref>

An introduction to forensic pathology is in the ''[[forensic pathology]]'' article.

==Overview==
===DiMaio classification<ref>{{Ref HoFP|155-64}}</ref>===
{{familytree/start}}
{{familytree | | | | | | | | | | | | A01 | | | | | | | | | | | |A01=Asphyxia}}
{{familytree | | | | | |,|-|-|-|-|-|-|+|-|-|-|-|-|-|-|-|.| |}}
{{familytree | | | | | B01 | | | | | B02 | | | | | | | B03 |B01=Strangulation| B02=Chemical| B03=Suffocation}}
{{familytree | |,|-|-|-|+|-|-|-|.| | | | | |,|-|-|-|v|-|^|-|v|-|-|-|.| | |}}
{{familytree | C01 | | C02 | | C03 | | | | C04 | | C05 | | C07 | | C08 | |C01=Hanging|C02=Ligature|C03=Manual|C04=Mechanical|C05=Environmental|C07=Choking|C08=Smothering}}
{{familytree | | | | | | | | | | | | |,|-|-|^|-|-|.| | | | | | | | | | | |}}
{{familytree | | | | | | | | | | | | D4  | | | | D5  | | | | | | | | | | |D4=Positional|D5=Overlay}}
{{familytree/end}}

===Practical classification===
{{familytree/start}}
{{familytree | | | | | | | | | | | A01 | | | | | | | | | |A01=Suspected<br>asphyxia}}
{{familytree | | | | | |,|-|-|-|-|-|^|-|-|-|-|-|.| |}}
{{familytree | | | | | B01 | | | | | | | | | | B03 |B01=Signs of neck<br>compression<br>(Strangulation)| B03=No signs of <br>neck compression}}
{{familytree | |,|-|-|-|+|-|-|-|.| | | | | |,|-|^|-|.| | | | | | |}}
{{familytree | C01 | | C02 | | C03 | | | | C05 | | C07 | | | | | |C01=Hanging|C02=Ligature|C03=Manual|C05=Abnormal<br>skin colour|C07=No abnormality|}}
{{familytree/end}}

==The obsolete asphyxia quintet==
Components of quintet (memory device: ''[[FRCPC]]''):<ref name=pmid18665887>{{cite journal |author=Gilbert JD, Jensen L, Byard RW |title=Further observations on the speed of death in hanging |journal=J. Forensic Sci. |volume=53 |issue=5 |pages=1204–5 |year=2008 |month=September |pmid=18665887 |doi=10.1111/j.1556-4029.2008.00840.x |url=}}</ref>
*Fluid blood.
*Right heart engorgement.
*Cyanosis.
*Petechiae.
*Congestion, facial.

Notes:
*The most useful are ''petechiae'' and ''facial congestion''.  Both are thought to result from an occlusion of the venous circulation without significant compromise of the arterial circulation, as may occur in ''partial suspension hangings''.
**The corollary to the above is that complete occlusion of the venous ''and'' arterial circulation (as may be seen in a complete suspension hanging) does ''not'' result in petechiae ''or'' facial congestion.
*''Fluid blood'' is considered totally useless as a sign of anything.

==Hanging==
===General===
*Common way to suicide.
*May be accidental in the context of adolescents playing - see ''[[choking]]''.

===Gross=== 
Classic findings:
*V-shaped furrow on the neck.
*V "open" at the point of suspension.

Documentation (The Rose method):<ref>Rose, T. 28 September 2010.</ref>
*Anterior mid-line:
**Measure distance from angle of neck to superior aspect of ligature mark.
**Measure width of ligature mark.
*Left ear lobe-head junction:
**Measure distance from ear lobe-head junction to superior aspect of ligature mark.
**Measure width of ligature mark.
*Right ear lobe-head junction:
**Measure distance from ear lobe-head junction to superior aspect of ligature mark.
**Measure width of ligature mark.
*Posterior mid-line:
**Measure distance from C7 (???) to inferior aspect of ligature mark.
**Measure width of ligature mark.

DDx:
*[[Ligature strangulation]].

==Choking==
===General===
*Typical accidental.
*May be part of game adolescents play known as the ''choking game''.<ref name=pmid19190276>{{Cite journal  | last1 = Macnab | first1 = AJ. | last2 = Deevska | first2 = M. | last3 = Gagnon | first3 = F. | last4 = Cannon | first4 = WG. | last5 = Andrew | first5 = T. | title = Asphyxial games or the choking game: a potentially fatal risk behaviour. | journal = Inj Prev | volume = 15 | issue = 1 | pages = 45-9 | month = Feb | year = 2009 | doi = 10.1136/ip.2008.018523 | PMID = 19190276 }}</ref>
**Known by many synonyms, e.g. ''asphyxial game'', ''fainting game'', ''black-out game''.

Associations:
*Ethanol intoxication.<ref name=pmid20666919>{{Cite journal  | last1 = Nikolić | first1 = S. | last2 = Zivković | first2 = V. | last3 = Dragan | first3 = B. | last4 = Juković | first4 = F. | title = Laryngeal choking on food and acute ethanol intoxication in adults--An autopsy study. | journal = J Forensic Sci | volume = 56 | issue = 1 | pages = 128-31 | month = Jan | year = 2011 | doi = 10.1111/j.1556-4029.2010.01510.x | PMID = 20666919 }}</ref>
*Neurologic disease.<ref name=pmid17209932>{{Cite journal  | last1 = Dolkas | first1 = L. | last2 = Stanley | first2 = C. | last3 = Smith | first3 = AM. | last4 = Vilke | first4 = GM. | title = Deaths associated with choking in San Diego county. | journal = J Forensic Sci | volume = 52 | issue = 1 | pages = 176-9 | month = Jan | year = 2007 | doi = 10.1111/j.1556-4029.2006.00297.x | PMID = 17209932 }}</ref>

Epidemiology:
*Extremes of age.<ref name=pmid17209932/>

===Gross===
*Large laryngeal bolus of food - obstructs the airway. 
**Usually meat.<ref name=pmid17209932/>

==Drowning==
===General===
Classic:
*Autopsy is often negative, i.e. there is no anatomical cause of death.

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.

===Macroscopic===
External:
*''[[Plume of froth]]'' ([[AKA]] ''cone of foam'') at the mouth/nostrils (fresh drowning only).<ref name=pmid16378701/><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>
**Classic DDx for this finding is: narcotics, [[congestive heart failure]].
**Underlying etiology of this finding: pulmonary edema (as may be seen in a cerebral vascular malformation<ref name=pmid8454093>{{cite journal |author=Bilotti A |title=Noncardiogenic pulmonary edema: a certain etiology? |journal=Del Med J |volume=65 |issue=1 |pages=25–7 |year=1993 |month=January |pmid=8454093 |doi= |url=}}</ref>).
*Wrinkled skin ([[AKA]] ''washerwoman skin'' and ''hydration changes'') - changes due to water immersion; changes may be present in the context of immersion post-mortem.<ref name=pmid6741294>{{cite journal |author=Reh H |title=[Early postmortem course of washerwoman's skin of the fingers] |language=German |journal=Z. Rechtsmed. |volume=92 |issue=3 |pages=183–8 |year=1984 |pmid=6741294 |doi= |url=}}</ref>

Internal:<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><ref>URL: [http://netk.net.au/Forensic/Drowning.pdf http://netk.net.au/Forensic/Drowning.pdf]. Accessed on: 20 September 2010.</ref>
*Lung emphysema; "kissing lungs" = lungs touch one another -- on opening the chest. 
*Froth in the trachea.
*Paltauf spots -- light-red washed-out appearing fingertip-sized spots.<ref>URL: [http://www.mijnwoordenboek.nl/EN/theme/ME/EN/DE/P/3 http://www.mijnwoordenboek.nl/EN/theme/ME/EN/DE/P/3]. Accessed on: 20 September 2010.</ref>
**Thought to arise from hemolysis + fluid decedent drown in.
*Fluid in the paranasal sinuses.<ref name=pmid8643988>{{cite journal |author=Hottmar P |title=[The presence of fluid in the paranasal sinuses in comparison with other diagnostic signs of drowning] |language=Czech |journal=Soud Lek |volume=40 |issue=4 |pages=34–6 |year=1995 |month=December |pmid=8643988 |doi= |url=}}</ref>

===Microscopic/Laboratory===
There are a few tests of debated value:<ref name=pmid16378701/>
*Diffusion of particulates into the blood (left ventricle) from the water.
**Diatom test.
*Haemodilution. 
**Mostly useless - CPR interferes with it, not reliable if there putrefaction or autolysis.
*Transport of aveolar element into blood circulation.

==Carbon monoxide toxicity==
*Abbreviated ''CO toxicity''.
===General===
*Carbon monoxide (CO) is a common way to commit suicide.

Pathophysiology:
*CO binds to haemoglobin -- prevents oxygen from binding there.
*CO binds to myoglobin.

===Gross findings===
External: 
*Salmon pink skin.

Internal:
*General: organs pink hue.
*Brain: globus pallidus [[necrosis]] - bilateral.<ref name=pmid21150349>{{Cite journal  | last1 = Fielding | first1 = J. | last2 = Lang | first2 = W. | last3 = White | first3 = OB. | title = Carbon monoxide poisoning: impact on ocular motility. | journal = Cogn Behav Neurol | volume = 23 | issue = 4 | pages = 256-61 | month = Dec | year = 2010 | doi = 10.1097/WNN.0b013e3181c5e2c1 | PMID = 21150349 }}</ref>

Notes:
*The DDx of pink skin includes: 
**[[Hypothermia]].
**Cyanide poisoning.
**Fluoroacetate poisoning
*Bilateral necrosis of the putamen is seen in [[methanol toxicity]].

Image:
*[http://i.dailymail.co.uk/i/pix/2011/02/14/article-1357042-0D0AEDBC000005DC-598_468x286.jpg CO toxicity of the brain (dailymail.co.uk)].

===Microscopic===
Features:<ref>{{Ref PBoD8|1329}}</ref>
*Neuronal loss in the:
**Cerebral cortex layers III and V.
**Hippocampus CA1.
**Purkinje cells.

===Laboratory findings===
*CO level (blood test) elevated.

COHb concentrations (by CO-oximetry):<ref name=pmid20348410>{{cite journal |author=Olson KN, Hillyer MA, Kloss JS, Geiselhart RJ, Apple FS |title=Accident or arson: is CO-oximetry reliable for carboxyhemoglobin measurement postmortem? |journal=Clin. Chem. |volume=56 |issue=4 |pages=515–9 |year=2010 |month=April |pmid=20348410 |doi=10.1373/clinchem.2009.131334 |url=http://www.clinchem.org/cgi/content/full/56/4/515}}</ref>
*Smokers 10-15%.
*Non-smokers <3%.
*Fatal >50%.
**Some say >35% % is fatal.<ref>TR. 28 September 2010.</ref>

Notes:
*Two different methods:<ref name=pmid16126621>{{cite journal |author=Boumba VA, Vougiouklakis T |title=Evaluation of the methods used for carboxyhemoglobin analysis in postmortem blood |journal=Int. J. Toxicol. |volume=24 |issue=4 |pages=275–81 |year=2005 |pmid=16126621 |doi=10.1080/10915810591007256 |url=}}</ref>
*#Spectrophotometric methods - includes CO-oximeters. 
*#Gas chromatographic methods.
*Spectrophotometric methods are considered good enough.
*Gas chromatographic methods are considered the gold standard.

==Fire deaths==
===General===
Many artefactual findings:
*Postmortem [[epidural hematoma]].<ref name=pmid2309533>{{Cite journal  | last1 = Ritter | first1 = C. | title = [A heat gelatinized subdural hematoma in a burned cadaver as an indication of a vital accident]. | journal = Z Rechtsmed | volume = 103 | issue = 3 | pages = 227-30 | month =  | year = 1990 | doi =  | PMID = 2309533 }}</ref>
**[[Subdural hematoma]]s are ''not'' considered artefactual.
*Pugilistic attitude (boxer's position/stance).<ref>{{Cite journal  | last1 = Levy | first1 = AD. | last2 = Harcke | first2 = HT. | last3 = Getz | first3 = JM. | last4 = Mallak | first4 = CT. | title = Multidetector computed tomography findings in deaths with severe burns. | journal = Am J Forensic Med Pathol | volume = 30 | issue = 2 | pages = 137-41 | month = Jun | year = 2009 | doi = 10.1097/PAF.0b013e3181879cc9 | PMID = 19465802 }}</ref>
*Heat fractures.
**Base of skull seems to be an exception.<ref name=pmid9219359>{{Cite journal  | last1 = Bohnert | first1 = M. | last2 = Rost | first2 = T. | last3 = Faller-Marquardt | first3 = M. | last4 = Ropohl | first4 = D. | last5 = Pollak | first5 = S. | title = Fractures of the base of the skull in charred bodies--post-mortem heat injuries or signs of mechanical traumatisation? | journal = Forensic Sci Int | volume = 87 | issue = 1 | pages = 55-62 | month = May | year = 1997 | doi =  | PMID = 9219359 }}</ref>

===Gross===
Features:
*Soot in mucosa of respiratory tract - '''diagnostic'''.

===Microscopic===
Features:
*Black crap on the airway epithelium.

===Toxicology===
*Carboxyhemoglobin.<ref>{{Ref OPMfP|18}}</ref>

==Hydrogen sulfide toxicity==
===General===
*Fashionable for suicides; has high mortality and may be toxic to responders/death investors.<ref name=pmid20920221>{{cite journal |author=Morii D, Miyagatani Y, Nakamae N, Murao M, Taniyama K |title=Japanese experience of hydrogen sulfide: the suicide craze in 2008 |journal=J Occup Med Toxicol |volume=5 |issue= |pages=28 |year=2010 |pmid=20920221 |pmc=2954931 |doi=10.1186/1745-6673-5-28 |url=}}</ref>
**Can be generated by mixing a source of sulfide with an acid ''or'' ingesting the sulfide which will then react with stomach acid.
*Mechanism: bonds to mitochondrial cytochrome enzymes.<ref name=pmid18695173>{{cite journal |author=Truscott A |title=Suicide fad threatens neighbours, rescuers |journal=CMAJ |volume=179 |issue=4 |pages=312–3 |year=2008 |month=August |pmid=18695173 |pmc=2492967 |doi=10.1503/cmaj.080878 |url=http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2492967/?tool=pubmed}}</ref>

===Toxicology===
*Classically has the smell of "rotten eggs".<ref name=pmid20920221>{{cite journal |author=Morii D, Miyagatani Y, Nakamae N, Murao M, Taniyama K |title=Japanese experience of hydrogen sulfide: the suicide craze in 2008 |journal=J Occup Med Toxicol |volume=5 |issue= |pages=28 |year=2010 |pmid=20920221 |pmc=2954931 |doi=10.1186/1745-6673-5-28 |url=}}</ref>
*Lab: ''thiosulfate'' - not available in Canada as of 2010.

===Gross===
*Green discolourization of the skin.<ref name=Ref_Shkrum33>{{Ref Shkrum|33}}</ref>

==Manual strangulation==
===General===
*Hands - from in front.
*Sleeper hold - from behind.

===Gross===
Features:<ref name=Ref_HoFP155>{{Ref HoFP|155}}</ref>
*Petechiac of sclerae (white part of eye) & conjunctivae (cover sclerae); present ~ 90% of the time.
*Hyoid bone fracture.
*Thyroid cartilage fracture.
*Hemorrhage in strap muscles of the neck.
*Patterned ovoid contusions (from the fingers).
*+/-Defensive-type injuries.

===Microscopic===
*Usually not contributory.

Features:
*+/-Siderophages.
*+/-Inflammation - esp. [[neutrophil]]s.

==Ligature strangulation==
===General===
*May be suicide ''or'' homicide.
*In females may be associated with a sexual assault.<ref name=pmid10739219/>
*More likely to be homicide than hanging.

===Gross===
Features:
*Horizontal furrow/depression on the neck - due to ligature.
*Petechiae - very common.<ref name=pmid10739219>{{Cite journal  | last1 = DiMaio | first1 = VJ. | title = Homicidal asphyxia. | journal = Am J Forensic Med Pathol | volume = 21 | issue = 1 | pages = 1-4 | month = Mar | year = 2000 | doi =  | PMID = 10739219 }}</ref>
*+/-Fractures of the hyoid, thyroid or cricoid cartilage - more common in males.<ref name=pmid10739219/>

DDx:
*[[Hanging]] - furrow/depression typically rises to a point of suspension.

==See also==
*[[Forensic pathology]].

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

==External links==
*[http://failuremag.com/index.php/feature/article/the_game_that_makes_parents_gasp/ The choking game (failuremag.com)].

[[Category:Forensic pathology]]