Prolonged coagulopathy related to coumarin rodenticide in a young patient: superwarfarin poisoning

Abstract

Superwarfarins (brodifacoum, difenacoum, bromodialone and chlorphacinone) are anticoagulant rodenticides that were developed in 1970s to overcome resistance to warfarin in rats. A 26-year-old previously healthy man was admitted to the emergency department with epigastric pain, severe upper and lower gastrointestinal haemorrhage, gingival bleeding and melena. The patient stated that he had been healthy with no prior hospital admissions and no personal or family history of bleeding diathesis. The patient, who later admitted attempted suicide, stated that he had taken 400 g rodenticide including brodifacoum orally for five days prior to admission to hospital. He had oral mucosal bleeding, numerous bruises over the arms, legs and abdomen, and an abdominal tenderness, together with melena. Laboratory tests revealed a haemoglobin level of 12.3 g/dl, leucocyte count of 9.1 × 10(9) /l, haematocrit of 28% and platelet count of 280 × 10(9) /l. The prothrombin time (PT) was > 200 s (normal range 10.5-15.2 s) and the activated partial thromboplastin time (aPTT) was 91 s (normal range 20-45 s). The INR (International normalised ratio) was reported to be > 17 (normal range 0.8-1.2). The thrombin time and plasma fibrinogen levels were in the normal range. The results showed the presence of brodifacoum at a concentration of 61 ng/ml, detected by reversed-phase liquid chromatography.