Influence of Preservatives on Insulin in Postmortem Blood: Application to a Case of Insulin Aspart Suicide.

Insulin aspart (NovoRapid®, NovoMix®, Novolog® and Fiasp®) is a fast-acting analog of human insulin, indicated in the treatment of type I and II diabetes. It is administered before meals to mimic the physiological insulin secretion that follows a rise in blood glucose. Its misuse for the purposes of suicide and murder and in the context of factitious order has often been described. In forensic medicine, the identification of insulin in biological samples has always been complex. In this paper, we present a case of suicide of a 64-year-old man who died after the injection of insulin aspart. He was suffering from terminal lung cancer and left a letter explaining the reasons for his suicide. Four empty NovoRapid® pens were found near the body. Body examination was unremarkable, and the femoral blood was collected in two dry Vacutainer™ tubes (red cap) and two sodium fluoride (NaF) tubes (gray cap). A liquid chromatography coupled to high-resolution mass spectrometry method was used to identify and discriminate insulin aspart from human insulin after immunopurification in the blood samples and in the pens. Blood specimens tested positive for insulin aspart with the concentrations of 36 and 37 ng/mL in dry tubes and 58 and 71 ng/mL in tubes containing NaF when tested ∼3 weeks after the collection of the specimens. The contents of the pens also matched with insulin aspart. The stability of insulin in blood is a critical point in the interpretation of the concentrations due to their rapid decrease caused by the activity of proteases in blood. During a degradation study implemented to compare three preservatives and dry tubes, suitable insulin aspart stability was observed with disodium salt of ethylenediaminetetracetic acid and NaF. Given that NaF is standard in forensic toxicology for measuring blood alcohol concentrations, the authors suggest its use for blood collection when insulin intoxication is suspected.

The Importance of Autopsy in a Case of Digestive Perforation Undetected by Postmortem Computed Tomography.

ABSTRACT: Cases of foreign body ingestion in the forensic literature are mainly described in children or psychiatric patients. Postmortem imaging can detect most foreign bodies, but its sensitivity depends, among other things, on the type of item and its location. In some cases, the ingestion of foreign bodies can remain unnoticed and have serious consequences for the patient. We describe the case of a patient who died in a psychiatric seclusion room with no obvious cause and for whom a forensic autopsy was requested. Further investigations showed the existence of a subdural hematoma associated with a midline shift, secondary to a skull fracture that was considered to be the cause of death. Toxicological analyses identified in blood several drugs, including diazepam (24 ng/mL) and its major metabolite nordazepam (24 ng/mL), propranolol (57 ng/mL), paliperidone (9 ng/mL), and loxapine (620 ng/mL). The forensic autopsy revealed the existence of a gastrointestinal perforation after the ingestion of a plastic teaspoon, which the postmortem CT scan had failed to detect. Although technological advances continue to assist the forensic pathologist in his diagnosis, autopsy still has a leading role in forensic investigations and does not yet seem to be replaceable by imaging techniques alone.