Diagnostic values of combined glucose and lactate values in cerebrospinal fluid and vitreous humour--our experiences.

Abstract

The final diagnosis of death in hypoglycaemic or diabetic coma should always be done as a synopsis of anamnestic response, morphology, biochemical (glucose, lactate, HBA1c, ketonic bodies, insulin, and C-peptide) and toxicological findings. High glucose levels in vitreous humour (more than 13 mmol/L, 234 mg/dL) or combined values of glucose and lactate in vitreous humour or in cerebrospinal fluid over threshold values of 23.7 mmol/L (427 mg/dL) and 23.4 mmol/L (422 mg/dL) respectively, can be an indicator of the pre-mortem hyperglycaemic state with fatal outcome. The determination of glycated haemoglobin, acetone and other ketone bodies improve the diagnostic values of the whole procedure. Diabetic ketoacidosis (blood acetone >0.3 g/L) is more often the cause of death of diabetic patients than the non-ketotic hyperosmolal state. Hypoglycaemia is deemed fatal if the combined values are lower than 5.5 mmol/L (100 mg/dL) and can not be excluded if they are lower than 8.9 mmol/L (160 mg/dL). Two cases of detected hypoglycaemia are described further. A psychiatric patient with diabetes (Hba1c 8.4%) committed suicide with an insulin overdose. The combined values of glucose and lactate in vitreous humour and in cerebrospinal fluid were 3.3 and 4.1 mmol/l, respectively. In another case a low combined glucose and lactate value (8.7 mmol/L) in vitreous humour indicated, besides the high concentration of glibenclamide (0.9 mg/L) in the blood of a driver with a poorly controlled diabetic condition (Hba1c = 10.6%), a state of decreasing blood glucose in the time before the accident causing the driver to feel un-well and behave inappropriately.