A CONFUSED STATE

Learning objectives: Importance of a good medication history Importance of obtaining medication blood levels Identifying toxidromes for anti-epileptic medications

Case information: 54 yo AAF, hx of HTN, asthma, CHF, heroin abuse, seizure disorder, on Dilantin, presents with 4 days of headache, vomiting, and a seizure that morning, off all medications for 3 months according to patient. BP was 216/118 and on exam was somnolent with diminished reflexes. Patient then had a seizure, given Dilantin 1 gram, Valium and Ativan. After medications became increasingly disoriented, confused, restless with slurred speech, BP dropped to 110/56. CT, LP both normal, transferred to MICU for persistent AMS. Dilantin level came back next morning at 62. Daughter stated patient had been taking her Phenytoin regulary and was likely suprathereaputic at home, having ataxia and vision changes. Her AMS and seizures was a result of Dilantin toxicity from the initial loading dose (given without checking a Dilantin level ). Discharged 8 days later with normal mentation

Discussion: In a 2007 report, 2395 Dilantin toxicity cases were reported: 1216 unintentional, 600 intentional, and 485 as an adverse reaction, resulting in 4 deaths making lethal overdose rare. (1) Dilantin toxicity can present differently based on route, IV causing hypotension, fatal arrhythmias (3) and PO causing first nystagmus, then ataxia, slurred speech then confusion and coma/seizures at levels above 50. Activated charcoal is first line therapy for overdose. Dialysis has not been thought traditionally to be helpful but recent studies suggest a limited role. (2) 1 Bronstein AC, et al. 2007 Annual Report of the American Association of Poison Control Centers' National Poison Data System. Clin Toxicol. 2008 2 Ghannoum M, et al. Successful hemodialysis in a phenytoin overdose. Clin Nephrol. 2010 3 Adams BD et al. Fosphenytoin may cause hemodynamically unstable bradydysrhythmias. J Emerg Med.  2006