Poison hemlock determination in postmortem samples.

Poison hemlock (Conium maculatum L.) is a weed that grows rampant in many areas of North America. Forensic toxicology laboratories rarely receive requests to analyze biological specimens for the presence of poison hemlock. This report discusses two postmortem cases that were encountered over a decade apart and describes different analytical approaches that may be used to quantify coniine, a primary poison hemlock alkaloid, in biological specimens. The first case is from 2004 and involves a 27-year-old female that was found deceased in a relatively isolated area of California. Based on the presence of plant material at the scene and signs of its ingestion at autopsy, the possibility of hemlock poisoning was considered. Toxicological testing of the blood and gastric content by quantitative selected-ion monitoring Gas Chromatography/Mass Spectrometry (SIM-GC/MS) revealed the presence of coniine at concentrations of 410 ng/mL and 9300 ng/mL, respectively. The second case is from Pennsylvania and was sent for analysis in the spring of 2019. In this case, a male in his forties was found deceased in the kitchen area of a camper. Green substances, in liquid and residue forms, were observed in the sink. Mixtures of leaf-like material were also found in several bowls and pans. Subclavian blood screened positive for coniine by full-scan Gas Chromatography/Mass Spectrometry (GC/MS). Semi-quantitative confirmation testing was performed by Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS) and showed the presence of coniine at a concentration of 35 ng/mL. These analytical approaches can be used to substantiate or exclude poison hemlock exposure as a cause of death.

Melatonin Supplementation in Undetermined Pediatric Deaths.

Since 2015, the North Carolina Office of the Chief Medical Examiner has investigated seven deaths of infants and toddlers, aged 2 months to 3 years, with exogenous melatonin detected upon toxicological analysis. Melatonin concentrations ranged from 3 to 1,400 ng/mL in postmortem whole blood. While the cause and the manner of all seven deaths were classified as undetermined, the analytical findings are noteworthy. Melatonin is generally considered a safe, natural product appearing in many over-the-counter supplements geared toward young children to facilitate calmness and improve sleep. Melatonin is a neurohormone, which regulates not only circadian rhythms and natural sleep but also other physiological functions. Endogenous melatonin production, derived from essential amino acid metabolism, does not begin until pineal gland maturation at ∼3 months of age with concentrations in plasma peaking during periods of darkness at ∼0.2 ng/mL. Administering commercially available melatonin supplements to infants results in levels substantially greater than endogenous sources, which should not be assumed to be safe just because of their endogenous nature. The finding of exogenous concentrations in some postmortem pediatric cases warrants attention. Several topics of interest surrounding these postmortem melatonin findings will be considered, such as minimal regulatory control over commercial products as well as the potential impact on hazardous sleeping conditions. This manuscript will outline the physiological effects of melatonin and detail the case studies from the North Carolina medical examiner system. Forensic toxicology laboratories should consider including melatonin at exogenous concentrations in their testing schemes for appropriate postmortem infant and toddler cases.