Ethanol Concentration in Decomposing Bodies : Another Look , Less Concern

To the Editor: TThe forensic pathologist is sometimes faced with cases in which bodily putrefaction and other decomposition changes have begun and in which blood ethanol is detected toxicologically. Whether part, or even all, of the ethanol has been produced postmortem sometimes becomes an issue when cause, manner, and circumstances of death are being evaluated. Forensic pathology textbooks usually mention this issue, and it is not uncommon to find statements that postmortem alcohol production usually does not exceed 100 mg%, is often much lower, but rarely can reach 200 mg% or higher. Such statements are based on numerous studies, many of which are quite old, and which may have used alcohol detection methodologies that were not specific for ethanol. Standard texts and other articles include such references and they will not be listed here. In an attempt to shed further light on the issue of postmortem ethanol production (or lack thereof), I reviewed all cases in which blood alcohol (or decomposition fluid in the thorax, when necessary) was tested for ethanol in the years 2003 through 2006, inclusive, on cases managed at the Fulton County Medical Examiner’s Center (FCMEC) in Atlanta, Georgia. The FCMEC electronic case database provides a specific item in which the condition of bodies (extent of decomposition) is indicated as “none,” “early color changes,” “blisters/ bloating,” “advanced,” or “skeletonizing. ” I examined blood ethanol concentrations for cases with early color changes, bloating/blisters, advanced, and no decomposition. The results are shown in Table 1. The data show that as decomposition advances, the per cent of cases positive for ethanol increases and the median ethanol concentration does not vary significantly. Although the group with blisters/bloating has a higher proportion of cases with blood ethanol concentration at 200 mg% or above, the absolute number of such cases is relatively small, and the per cent of cases with blood ethanol concentration above 200 mg% (20%) is lower than is observed in cases with no decomposition (27%). These data suggest that multiple factors are operative. Of all 24 cases with some degree of decomposition and an ethanol concentration of 200 mg% or higher, 23 (96%) had a history of chronic alcohol use and/or alcoholic beverages present at the scene of death. The presence of alcohol at the scene was documented in written investigative reports and/or scene photographs in 17 (71%) of the 24 cases. Further, in 18 (75%) of the 24 cases, the cause of death was either directly related to alcohol use or death involved circumstances in which acute ethanol intoxication would have been likely or not unexpected, such as a fall from height, a fall down stairs, or suicide. An important point to remember is that those persons who are found dead in a decomposing state are often found that way because they live alone and lack regular social contact with someone who would miss them or find them dead within the first day of death. Social isolation (being alone) may be a factor that predisposes to alcohol abuse or social isolation may be a result of alcohol abuse. Thus, it is not surprising that those found decomposed often have positive blood ethanol concentrations, and that some ethanol concentrations are 200 mg% or higher. Another factor to consider is that there may be a bias in selecting cases involving decomposition and the possibility of performing blood alcohol testing. For example, the cases tested in the “bloating” and “advanced” categories may have had blood alcohol tests performed because the scene investigation strongly suggested alcohol involvement, whereas many other cases with decomposition may not have been tested. Thus, the large portion of cases with positive results may not be surprising. For example, there were 68 of 341 (20%) decomposed cases in which blood ethanol tests were not performed. Of 107 “blister/bloating” cases, 19 were not tested for ethanol. Although the data presented are by no means definitive, I believe the data support a hypothesis that blood ethanol concentrations of 200 mg% of higher in a decomposed body are usually and mostly reflective of antemortem alcohol ingestion, and that probably, so are lower concentrations in most cases, especially those above 70 mg%. This opinion is consistent with statements in the literature, such as blood ethanol concentrations in the 0.01–0.03 g/dL would ordinarily be expected from postmortem ethanol formation, keeping in mind that multiple factors must be considered in interpretation and there will be exceptions to the rules in selected cases. The hypothesis is also consistent with the results of a 1982 study by Zumwalt et al (a study somewhat similar to the review I conducted), which showed that most cases with probable postmortem alcohol production had concentrations of 0.070 g/dL (70 mg%) or lower. The only way to prove this hypothesis in humans would be to measure blood alcohol concentrations immediately at the time of death and then allow decomposition to occur–with multiple samples taken at various postmortem intervals–a study that would be difficult to organize and conduct. Animal studies could be performed, but the differences between animals and humans (and their bacterial flora) would remain an issue and point of controversy. In summary, the data are consistent with previous studies and suggest that decomposition is rarely an important factor in causing blood ethanol concentrations above 70 mg%, but further study needs to be undertaken.