O34: Castor bean self-poisoning: Report of a case with blood and urine ricinine measurements

Ricin is a highly toxic protein from the castor bean plant (Ricinus communis) and is among the deadliest natural poisons available. We report the case of a 23 year-old man who committed suicide through both oral and intravenous self-administration of a castor bean extract. Since it has been shown that ricin determination in clinical or post-mortem samples was difficult in real cases, ricinine, another alkaloid present in small amount in the castor bean plant, was used as a surrogate biomarker of ricin intoxication. Ricinine determination was isolated from the samples by liquid-liquid extraction and quantitatively determined by a specific LC-MS/MS method dedicated to the screening of plant toxins. MRM transitions applied for ricinine MS/MS measurement were: m/z 165 > 138 (quantification ion), 165 > 93, 165 > 84 and 165 > 82. A 23 year-old man was referred to the emergency department three hours after a suicidal attempt with castor bean extract. He vainly tried an intravenous self-administration of a Ricinus communis seed decoction with trimipramine, then ate twenty seeds together with 1 200 mg trimipramine (Surmontil® 4%). On admission, he was conscious and fully orientated (GCS 15). Clinical examination only revealed tachycardia (128/min); EKG disclosed no conduction or repolarization abnormalities. Blood tests were unremarkable except for a mild hypokalemia (3.4 mmol/L). Febrile diarrhea occurred 35 hours after ingestion. Lymphangitis of the left arm was also observed and blood cultures revealed Gram + cocci, when urine culture was sterile. The clinical course was transitorily complicated by: hypoglycemia (2.91 mmol/L), hyponatremia (133 mmol/L), and hyperkalemia (5.4 mmol/L) which were symptomatically compensated. Hepatic enzymes and serum creatinine were always normal. Besides symptomatic support, the patient received antibiotics and his symptoms amended, when 25 hours after admission, he escaped, threw himself out of a window, and died. Blood and urine samples had been taken 22 hours after castor bean seed self-administration and were submitted to the laboratory for analytical assessment. Blood and urine ricinine concentrations were respectively 46 and 720 ng/mL. In this case, clinical signs and symptoms were consistent with a minor ricin poisoning. However, ricinine blood and urine concentrations were high, when compared with those measured in previous case reports. In our case, as in previous reports of castor bean poisoning, ricinine levels were poorly correlated with poisoning severity. As a matter of fact, the toxic effects of the plant are mainly due to ricin which is poorly absorbed in the digestive tract. Ricinine digestive absorption is much better, but its toxicity is much lower. As a consequence, high ricinine blood and urine levels can be observed after ingestion, together with mild systemic poisoning. On the contrary, a severe poisoning may result from parenteral administration of a small amount of the plant extract with associated low serum and urine levels of ricinine.