Altered Mental Status after a Handful of Pills

Credit John Nakamura Remy   A 30-year-old woman presented with altered mental status. Her boyfriend reported that she took a handful of unknown pills about two hours before. Initial vital signs include a temperature of 38°C, heart rate of 130 beats/min, respiratory rate of 18 breaths/min, blood pressure of 112/83 mm Hg, and pulse oximetry of 97% on room air.   Her physical exam is significant for pupils 6 mm bilaterally and reactive to light, dry mucous membranes and skin, and decreased bowel sounds. She was alert but confused. Her initial ECG showed a sinus tachycardia with a rate of 133 and a QRS of 89 and QTc of 443.           The differential diagnosis in this patient includes: n Anticholinergic (antihistamines, TCA, phenothiazines) n Sympathomimetic agents (amphetamines, caffeine, cocaine, PCP) n Salicylate toxicity n Sedative/hypnotic withdrawal   A single therapeutic adult dose of diphenhydramine ranges from 25 to 100 mg every six hours. Manifestations of toxicity may occur after ingestion of three to five times the daily dose. The fatal oral dose is estimated to be between 20 to 40 mg/kg.   Radovanovic et al. analyzed the dose-dependent toxicities associated with diphenhydramine in a retrospective analysis of 232 diphenhydramine intoxications followed by a prospective analysis of 50 patients. It demonstrated that a critical ingestion limit of 1,000 mg was necessary to produce severe symptoms (delirium/psychosis, seizures and coma), but card...
Source: The Tox Cave - Category: Emergency Medicine Tags: Blog Posts Source Type: blogs