Acute Hemolysis Caused by Incidental Trichlorfon Exposure

Trichlorfon (o-o-dimethyl-2,2,2-trichloro-hydroxyethylphosphate), an organophosphate, has a moderately potent anticholinesterase activity. Organophosphate poisoning is well known for its characteristic symptoms and signs, but acute hemolysis caused by trichlorfon is rarely reported. We present a patient who developed acute hemolysis and renal function impairment after percutaneous trichlorfon exposure. A 54-year-old man applied trichlorfon powder to his dog to kill its parasites. Half an hour later, the dog was suspected to die of cholinergic crisis and the patient felt abdominal cramping pain. Later, he developed severe nausea, vomiting, chills, high fever, and cold sweat. Laboratory work-up disclosed a picture of acute hemolysis, jaundice, renal function impairment and leukocytosis. However, there were no clinical features of acute cholinergic syndrome except gastrointestinal symptoms, and blood cholinesterase activities were also normal. He eventually had a full recovery. Trichlorfon should be added to the toxins known to cause acute hemolysis. [J Chin Med Assoc 2009;72(4):214-218]