LIFE-THREATENING DIPHENHYDRAMINE TOXICITY PRESENTING WITH STATUS EPILEPTICUS AND WIDE COMPLEX TACHYCARDIA: A CASE REPORT

Abstract

SESSION TITLE: Wednesday Medical Student/Resident Case Report Posters SESSION TYPE: Med Student/Res Case Rep Postr PRESENTED ON: 10/23/2019 09:45 AM - 10:45 AM INTRODUCTION: Anticholinergic toxicity can be caused by exposure to any of a large number of substances containing anticholinergics, including plants and drugs, many of which are readily accessible. Therefore, anticholinergic toxicity is commonly encountered in the emergency department, however, very rarely associated with major effects or fatalities. Diphenhydramine is an antihistamine with anticholinergic and sodium channel blockade effects. We report a rare case with severe Diphenhydramine toxicity due to suicidal attempt that was successfully managed with Physostigmine and Sodium Bicarbonate. CASE PRESENTATION: A 26 years old previously healthy female was admitted to the Intensive Care Unit after intentional ingestion of 5,000 mg of Diphenhydramine. She was delirious, tachycardic, febrile with a temperature of 103.3, hypotensive, and required intubation for airway protection. She developed recurrent seizures and was started on Levetiracetam, Fosphenytoin and Propofol infusion. All these signs were attributed to anticholinergic toxicity. Her initial EKG showed QTc interval prolongation, attributed to sodium channel blockade effect that resolved with sodium bicarbonate administration. Her lab work was negative for Acetaminophen and Salicylate. Urine drug screen was negative and her osmolar gap was normal. The patient was given 1mg of Physostigmine with an immediate improvement in her heart rate, blood pressure, and temperature. Her seizures became less frequent and completely resolved by the third day of admission. Fosphenytoin was given for 5 days and Levetiracetam for 7 days then discontinued without any seizure recurrence. She was extubated after 6 days and discharged home after 15 days. DISCUSSION: Though most diphenhydramine ingestions do not result in severe nervous and cardiac toxicity, there are previous reports of patients presenting with status epilepticus and wide complex tachycardia after diphenhydramine overdose. Our patient had a severe life-threatening reaction due to the large dose of Diphenhydramine. Most cases of anticholinergic toxicity respond well to supportive care. In severe toxicity, physostigmine may be indicated. Physostigmine binds reversibly to inhibit acetylcholinesterase in both the peripheral and central nervous system. Physostigmine is only given in the event of both peripheral and central signs and symptoms of anticholinergic poisoning. Our patient was a good candidate for Physostigmine therapy, due to the very large dose of antihistamine ingested and the severity of her anticholinergic toxicity. CONCLUSIONS: Anticholinergic toxicity is a common occurrence. This case highlights that timely recognition of the antimuscarinic toxidrome and that appropriate use of physostigmine is crucial in patients with severe anticholinergic toxicity. Reference #1: Mowry JB, Spyker DA, Brooks DE, Zimmerman A, Schauben JL. 2015 Annual Report of the American Association of Poison Control Centers' National Poison Data System (NPDS): 33rd Annual Report. Clinical toxicology. 2016;54(10):924-1109. Reference #2: Jang DH, Manini AF, Trueger NS, Duque D, Nestor NB, Nelson LS, et al. Status epilepticus and wide-complex tachycardia secondary to diphenhydramine overdose. Clinical toxicology. 2010;48(9):945-8. Reference #3: Sharma AN, Hexdall AH, Chang EK, Nelson LS, Hoffman RS. Diphenhydramine-induced wide complex dysrhythmia responds to treatment with sodium bicarbonate. The American journal of emergency medicine. 2003;21(3):212-5. DISCLOSURES: No relevant relationships by Saif El Naser El Nawaa, source=Web Response No relevant relationships by John Makram, source=Web Response No relevant relationships by Haneen Mallah, source=Web Response No relevant relationships by Swagat Parajulee, source=Web Response No relevant relationships by Victor Test, source=Web Response No relevant relationships by Wasawat Vutthikraivit, source=Web Response No relevant relationships by Andres Yepes-Hurtado, source=Web Response