Medico-legal aspects of fatal ricin poisoning: a systematic review of clinical manifestations, toxicological findings and autopsy results.

Ricin, a potent protein toxin derived from Ricinus communis, is considered one of the most significant threats in cases of bioterrorism, homicide, suicide, and accidental acute poisoning. However, its clinical and pathological features in fatal cases have not been systematically summarized. This systematic review aimed to summarize the current evidence regarding the clinical manifestations, toxicological biomarkers, autopsy findings, and medico-legal aspects of fatal ricin poisoning. A comprehensive literature search was conducted in accordance with PRISMA guidelines. Original studies, case reports, and case series reporting detailed clinical, toxicological, or autopsy data following fatal or near-fatal human exposure to ricin were included in the review. The available evidence suggests a relatively consistent clinical course, characterized by rapid progression from mild, nonspecific gastrointestinal symptoms to hypovolemic shock, multi-organ failure, and refractory cardiovascular collapse. Ricinine was consistently detected in blood, urine, and postmortem tissues, supporting its role as a reliable biomarker of ricin exposure, although current evidence is insufficient to establish definitive correlations with poisoning severity or toxicokinetics. Reported autopsy findings commonly included hemolysis, hemorrhagic necrosis of the gastrointestinal tract, hepatic injury, renal tubular necrosis, and evidence supporting the presence of a capillary leak syndrome. Several specific medico-legal challenges emerged from the reviewed literature, including the need for the development of novel analytical methods with improved detection limits and quantification capabilities for ricinine, the interpretation of postmortem redistribution phenomena, the distinction between lethal and non-lethal exposures, and the differential diagnosis with other septic shock-like syndromes. Overall, the available evidence suggests a relatively consistent clinicopathological pattern associated with fatal ricin poisoning that can be corroborated through ricinine detection, while emphasizing the importance of early toxicological investigations, particularly when no history of exposure is available. These findings provide a concise and integrated body of evidence to support clinical management, inform forensic investigations, and enhance public health preparedness, while highlighting the need for standardized postmortem sampling protocols and further research into the toxicodynamics of ricin in humans.