The challenges presented by decomposition.

A feature of forensic practice that is often remarked upon by non-pathologists is the requirement to sometimes undertake examinations of bodies that have undergone considerable changes due to decomposition. The value of such an exercise is sometimes questioned. The following editorial reviews issues that may arise in the postmortem evaluation of such cases based on studies and observations that the authors have undertaken and made over time. Decomposition refers to the variety of processes of degradation that commence as soon as an organism has died. The combined effects of putrefaction from bacterial overgrowth, and autolysis from tissue self-digestion, result in a predictable sequence of events commencing with venous marbling and blistering of the skin, followed by purging of fluids through the mouth and nose, gaseous distention of subcutaneous tissues and body cavities, and insect colonization. Under specific circumstances less common changes such as mummification or adipocere (‘‘grave wax’’) formation occur [1, 2]. Death scene evaluations may be more complicated when decomposition is present as it may be a marker for social isolation and domestic disorder. This is best demonstrated by the Diogenes syndrome, where elderly reclusive individuals living in squalor may not be found for some time after their deaths [3]. Lesions caused by the postmortem activity of both domestic and nondomestic animals living in the house may be found [4], and inexperienced scene examiners may conclude that purging of reddish fluid from the mouth and nose represents bleeding from an assault. Determining the time of death cannot be done with any precision, although entomological examination of insects and the temperature of maggot masses may provide some guide to this [1, 2]. Stiffening of the limbs from subcutaneous gas accumulation, so-called ‘‘putrefactive rigor mortis’’, should not be misinterpreted as true rigor due to ATP depletion [5]. Decomposition also complicates autopsy evaluations by distorting and changing tissue morphology. Tissues and organs may be absent in advanced cases, and dissections are often more difficult to perform as the normal anatomy has either been considerably modified or disguised. Putrefied and liquefied fat may make tissues and floors slippery creating a potentially dangerous work environment. This may be particularly so in temporary mortuaries used for disaster victim identification, as proper cleaning facilities may not be available. Despite marked tissue changes, determination of the cause and manner of death has been shown to be achievable [6], although cases were not stratified according to the degree of decomposition in this retrospective study. The exact effect of decompositional changes on particular tissues is also not always known and it may be possible that lesions such as non-calcific, grumous coronary artery atherosclerotic plaques may liquefy and so disappear by the time that the arteries are being examined at autopsy. If this is the case, then determining the degree of antemortem coronary artery stenosis may simply not be possible. Sometimes even the finding of coronary arteries in a decomposed heart may be a challenge. On occasion, R. W. Byard School of Health Sciences, The University of Adelaide, Adelaide, SA, Australia