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A6905 - Organophosphate Toxicity Secondary to Malathion Use in a Patient with Delusional Parasitosis
Author Block: C. J. Van Hook, B. Warner, A. Taylor, M. Beer, J. Gould; Longmont United Hospital, Longmont, CO, United States.
Introduction-Organophosphate toxicity is manifest through muscarinic, nicotinic, and central nervous systems effects. SLUDGEM (salivation, lacrimation, urination, defecation, gastrointestinal motility, emesis, and miosis) is the mnemonic used to recall the classic clinical presentation. Malathion is a topical organophosphate acetylcholinesterase inhibitor that is used to treat lice and scabies infestation. Delusional parasitosis is a rare psychiatric disorder in which the patient maintains a fixed, false belief of parasitic infection. We report the unique case of a patient with delusional parasitosis whose excessive use of topical malathion resulted in organophosphate toxicity.
Case Report-A 35-year-old male was brought to the emergency department after he was observed by a police officer to be vomiting from the window of his parked car. The attending officer reported that the patient was distressed, agitated, drooling, and sweating profusely. On arrival to the emergency department the patient complained of nausea, vomiting, abdominal pain and cramping, diarrhea, and severe sweating. The patient admitted to treating himself with topical malathion for what he believed to be persistent scabies. Several empty malathione containers were found in his car by the involved police officer. Review of the patient's medical record revealed multiple encounters for complaints of scabies infestation, with no objective evidence of infection. Physical exam was remarkable for a very anxious appearing man who was drooling and severely diaphoretic. Blood pressure was elevated at 168/104 mm Hg. Physical exam was remarkable for miosis and lacrimation. Laboratory exam was unremarkable. The patient was treated with intravenous hydration, ondansetron, and diazepam. His symptoms resolved and his blood pressure returned to normal after approximately twelve hours. He was referred for psychiatric consultation, but declined, and was discharged to follow up with his primary care physician.
Discussion-Delusional parasitosis is a rare psychiatric disorder. Patients are typically resistant to psychiatric evaluation and are prone to self-treatment. Organophosphate toxicity secondary to topical malathion use is also distinctly unusual. This case raises awareness of the potential causal relationship between delusional parasitosis and inadvertent, self-inflicted organophosphate toxicity.