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).[1]
Asphyxia is, etymologically, lacking pulsation; in common usage it is essentially hypoxia (blood lacking oxygen)[2] and anoxia (tissues lacking oxygen).[3]
An introduction to forensic pathology is in the forensic pathology article.
Overview
DiMaio classification[4]
| Asphyxia | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Strangulation | Chemical | Suffocation | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Hanging | Ligature | Manual | Mechanical | Choking | Smothering | Environmental | |||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Positional | Overlay | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Practical classification
| Suspected asphyxia | |||||||||||||||||||||||||||||||||||||||||||||||||||||
| Signs of neck compression (Strangulation) | No signs of neck compression | ||||||||||||||||||||||||||||||||||||||||||||||||||||
| Hanging | Ligature | Manual | Abnormal skin colour | No abnormality | |||||||||||||||||||||||||||||||||||||||||||||||||
The obsolete asphyxia quintet
Components of quintet (memory device: FRCPC):[5]
- Fluid blood.
- Right heart engorgement.
- Cyanosis.
- Petechiae.
- Congestion, facial.
Hanging
Gross (classic)
- V-shaped furrow on the neck.
- V "open" at the point of suspension.
Documentation (The Rose method):[6]
- 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.
Drowning
Classic:
- Autopsy is often negative, i.e. there is no anatomical cause of death.
Drowning is difficult to prove on autopsy.[7] The diagnosis is often based on circumstance, i.e. the scene.
Macroscopic
External:
- Plume of froth at the mouth/nostrils (fresh drowning only).[7][8]
- Classic DDx for this finding is: narcotics, congestive heart failure.
- Underlying etiology of this finding: pulmonary edema (e.g. cerebral vascular malformation[9]).
- Lung emphysema.
- Froth in the trachea.
- Paltauf spots -- light-red washed-out appearing fingertip-sized spots.[11]
- Thought to arise from hemolysis + fluid decedent drown in.
- Fluid in the paranasal sinuses.[12]
Micro/Lab
There are a few tests of debated value:[7]
- 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
Carbon monoxide (CO) is a common way to commit suicide.
Pathophysiology:
- CO binds to haemoglobin -- prevents oxygen from binding there.
Gross findings
- Salmon pink skin.
Laboratory findings
- CO level (blood test) elevated.
COHb concentrations (by CO-oximetry):[13]
- Smokers 10-15%.
- Non-smokers <3%.
- Fatal >50%.
- Some say >35% % is fatal.[14]
Notes:
- Two different methods:[15]
- Spectrophotometric methods - includes CO-oximeters.
- Gas chromatographic methods.
- Spectrophotometric methods are considered good enough.
- Gas chromatographic methods are considered the gold standard.
Manual strangulation
Features:[16]
- Petechiac of sclerae (white part of eye) & conjunctivae (cover sclerae); present ~ 90% of the time.
- Hyoid bone fracture.
- Thyroid cartilage fracture.
- Haemorrhage in strap muscles of the neck.
See also
References
- ↑ Saukko, Pekka; Knight, Bernard (2004). Knight's Forensic Pathology (3rd ed.). A Hodder Arnold Publication. pp. 352. ISBN 978-0340760444.
- ↑ URL: http://dictionary.reference.com/browse/hypoxia. Accessed on: 12 September 2010.
- ↑ URL: http://dictionary.reference.com/browse/anoxia. Access ed on: 12 September 2010.
- ↑ DiMaio, Vincent J.M.; Dana, Suzanna E. (2006). Handbook of Forensic Pathology (2nd ed.). CRC Press. pp. 155-64. ISBN 978-0849392870.
- ↑ Gilbert JD, Jensen L, Byard RW (September 2008). "Further observations on the speed of death in hanging". J. Forensic Sci. 53 (5): 1204–5. doi:10.1111/j.1556-4029.2008.00840.x. PMID 18665887.
- ↑ TR. 28 September 2010.
- ↑ 7.0 7.1 7.2 Piette MH, De Letter EA (November 2006). "Drowning: still a difficult autopsy diagnosis". Forensic Sci. Int. 163 (1-2): 1–9. doi:10.1016/j.forsciint.2004.10.027. PMID 16378701.
- ↑ 8.0 8.1 Bohnert M, Ropohl D, Pollak S (2002). "[Forensic medicine significance of the fluid content of the sphenoid sinuses]" (in German). Arch Kriminol 209 (5-6): 158–64. PMID 12134758.
- ↑ Bilotti A (January 1993). "Noncardiogenic pulmonary edema: a certain etiology?". Del Med J 65 (1): 25–7. PMID 8454093.
- ↑ URL: http://netk.net.au/Forensic/Drowning.pdf. Accessed on: 20 September 2010.
- ↑ URL: http://www.mijnwoordenboek.nl/EN/theme/ME/EN/DE/P/3. Accessed on: 20 September 2010.
- ↑ Hottmar P (December 1995). "[The presence of fluid in the paranasal sinuses in comparison with other diagnostic signs of drowning]" (in Czech). Soud Lek 40 (4): 34–6. PMID 8643988.
- ↑ Olson KN, Hillyer MA, Kloss JS, Geiselhart RJ, Apple FS (April 2010). "Accident or arson: is CO-oximetry reliable for carboxyhemoglobin measurement postmortem?". Clin. Chem. 56 (4): 515–9. doi:10.1373/clinchem.2009.131334. PMID 20348410. http://www.clinchem.org/cgi/content/full/56/4/515.
- ↑ TR. 28 September 2010.
- ↑ Boumba VA, Vougiouklakis T (2005). "Evaluation of the methods used for carboxyhemoglobin analysis in postmortem blood". Int. J. Toxicol. 24 (4): 275–81. doi:10.1080/10915810591007256. PMID 16126621.
- ↑ DiMaio, Vincent J.M.; Dana, Suzanna E. (2006). Handbook of Forensic Pathology (2nd ed.). CRC Press. pp. 155. ISBN 978-0849392870.