Postmortem toxicology in the elderly

Autor: Steven B. Karch
Rok vydání: 2013
Předmět:
Zdroj: Forensic Science, Medicine, and Pathology. 9:256-257
ISSN: 1556-2891
1547-769X
Popis: Dr. Roger Byard has written a comprehensive and uncontroversial review [1]. There is little new, useful or controversial I can add. However, based upon my own experiences I can discuss some of the consequences of what he has said which, as all of you must realize, is of great consequence to anyone who must determine the manner of death in an elderly polydrug user. Dr. Byard uses the Shipman case as an example of the problem. As Dr. Byard observes, there will soon be an ever-expanding population of the elderly, some of whom will be poisoned accidentally and some on purpose. As one of the Crown Pathologists in the Shipman case, I am almost embarrassed to admit that, at least so far as forensic issues are concerned, it was a relatively easy case. Once the bodies were exhumed we first sought to establish that they had, in fact, been poisoned. Luckily, we were right; morphine is stable postmortem although its metabolites are not. As a consequence of bacterial contamination, the ratio of free to bound morphine is not fixed and, therefore, is an unreliable indicator of the time of poisoning. On the other hand, the mere presence of morphine in an otherwise healthy decedent is grounds for concern. It has been some years now, and I cannot remember precisely, but I believe that we did quantitate morphine concentrations in liver and muscle, but did not rely upon the quantitation at all. The body rapidly loses weight after death, concentrating any remaining drug and, to my way of thinking, rendering interpretation of drug concentrations in exhumed bodies essentially impossible. Our only interest in the test was qualitative. We wanted to establish whether or not morphine was present—as it was in every case. In itself the mere presence of morphine does not prove morphine poisoning, but if there is nothing to indicate that the drug has ever been taken before, the probability increases that acute exposure (and by extension, poisoning or overdose) occurred. Deciding whether exposure was acute or chronic is surprisingly easy: we tested hair. Someone who has never taken narcotics would not be expected to have morphine in their hair (except, perhaps, in some circumstances, from some sort of environmental exposure) unless ingestion had occurred. The absolute blood concentration, no matter how many decimal points, is irrelevant. When tested we found that hair from only one of the decedents contained morphine, and that person had remained comatose for several hours before death. Shipman had created false entries in his database suggesting that some of the patients were addicts. The absence of morphine in their hair proved they were not. Which brings me to the more controversial of my comments. It is agreed by virtually all experienced toxicologists (and pathologists), that there is no predictable relationship between blood drug concentrations in the immediate antemortem period and concentrations after death. No one should find this assertion very startling. Just look at all the factors listed by Dr. Byard in the very first paragraph of his article. For all the reasons listed, it makes very little sense to make cause of death determinations based on the quantitation of postmortem blood (at least for most drugs). If a decedent has track marks, pulmonary and cerebral edema, a colon crammed with feces, and a syringe by his side, is it really necessary to know the free or total morphine blood concentration, and whether it is high or low? If it is low, will you revise your diagnosis? Similarly, does the blood cocaine concentration, in a chronic cocaine user, old or young (in one of our case series, many of the S. B. Karch (&) PO Box 5139, Berkeley, CA 94705, USA e-mail: skarch@sonic.net
Databáze: OpenAIRE
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