The influence of ethanol on the level of ketone bodies in hypothermia.

Presently available possibilities of macro- and microscopic diagnosis of death from hypothermia are very limited as the changes observed are either weakly specific (ecchymoses in the mucous membrane of the stomach, histological features of haemorrhagic pancreatic necrosis, cardiomyocyte necrosis or decreased content of glycogen in hepatocytes) or represent only local action of low temperatures (frostbites, violet patches in the region of knees and elbows, red livores) and they may not be present in cases of death from cooling at environmental temperature close to zero or higher. The study evaluated the usefulness of acetoacetic acid (Ac-Ac), beta-hydroxybutyric acid (beta-HBA) and acetone determinations in blood, urine and vitreous humour for diagnosis of death from hypothermia. These three substances called ketone bodies, are easily assimilated energetic substrates that get oxidized preferentially before glucose and fatty acids. In hypoglycaemia (also hypothermia-induced one), the tissues dependent on glucose (e.g. the brain) cover most of their energetic needs from oxidation of these compounds. The analysis of 16 cases of death in circumstances suggesting hypothermia (mainly of the alcohol abusers) showed that the degree of ketosis was inversely proportional to the blood ethanol concentration. This relation may result from stimulation of insulin release and a decrease in the release of its antagonists by ethanol, as well as from inhibition of free fatty acid (FFA) beta-oxidation due to increase in the NADH/NAD ratio. So, the antiketonaemic effects of ethanol (together with its influence on the dilatation of the peripheral vessels and inhibition of shivering thermogenesis by muscle relaxation), explain increased sensitivity of intoxicated persons to low temperatures.