A case of rhabdomyolysis and axonal neuropathy from ingestion of "Spanish Fly" cantharidin

Objective: To report the first case of axonal neuropathy following ingestion of a blister beetle. Cantharidin, a type of terpenoid, is a toxin and vesicant secreted by many species of blister beetle, most notably the Spanish fly, Lytta vesicatoria. To date there are no published reports of rhabdomyolysis and/or axonal neuropathy following ingestion of cantharidin. Case report: A 29-year-old male residing in Malta presented to the emergency department 24 hours after voluntary ingestion of a single blister beetle. He presented in renal failure with a creatine kinase increased of 17,000 IU/L. Despite three days of haemofiltration and noradrenaline infusion, he subsequently developed disseminated intravascular coagulation (DIC), ascending neuropathy and fixed pupils. Electromyography and nerve conduction studies confirmed axonal neuropathy. We are not aware if the patient recovered from this clinical situation. Discussion: The toxicity of cantharidin is well documented and as little as 10 mg of the pure chemical has resulted in death.¹ The cantharidin content of one beetle ranges from 0.6% to greater than 5% dry weight.² The most common features reported from ingestion of cantharidin are burning of the tongue and pharynx, dysphagia, drowsiness, lethargy³, crampy abdominal pain, vomiting, diarrhoea, haematemesis, gross haematuria and dysuria^2,3. Renal dysfunction is common and related to acute tubular necrosis and glomerular destruction. Priapism, DIC², seizures and cardiac abnormalities are less common². This is the first reported case in humans where rhabdomyolysis and axonal neuropathy have been attributed to ingestion of cantharidin although signs of neurological dysfunction have been reported in horses following ingestion of blister beetles. Conclusion: Treatment of patients poisoned with cantharidin should take into account its properties as a cellular toxin with ability to cause multisystem organ damage and neuropathy and also its corrosive effects on the mucosa. References: 1. Till JS, Majmudar BN. Cantharidin poisoning. South Med J 1981; 74:444–7. 2. Karras DJ, Farrell SE, Harrigan RA, et al. Poisoning from “Spanish Fly”. Am J Emerg Med 1996; 14:478–83. 3. Mallari RQ, Saif M, Elbualy MS, et al. Ingestion of a blister beetle (Mecoidae family). Pediatrics 1996; 98:458–9.