CURRENT Essentials of Critical Care.pdf

Chapter 16 Toxicology 241■■■Sympathomimetic OverdoseEssentials of Diagnosis• Confusion, tremor, paranoia, anxiety, agitation and irritability• Mydriasis, tachyarrhythmias, hypertension, hyperreflexia,seizures, hyperthermia, rhabdomyolysis, and renal failure• Overdose of prescribed drugs (methylphenidate, dextroamphetamine,ephedrine, pseudoephedrine, diethylpropion, phentermine)or use of recreational agents such as methamphetamine(“crank”) or 3,4-methylenedioxymethamphetamine (“ecstasy”)• In severe cases, life-threatening hyperthermia, arrhythmias, statusepilepticus, intracranial hemorrhage, aspiration pneumonia,acute hepatic failureDifferential Diagnosis• Thyrotoxicosis• CNS infection• Ethanol or benzodiazepine withdrawal• Toxicity from theophylline, tricyclic antidepressants, anticholinergics,isoniazid, phencyclidine, salicylatesTreatment• Supportive care, maintenance of airway and mechanical ventilationif needed• Gastric lavage within 2 hours of ingestion; activated charcoaland cathartic• Active cooling for rectal temperatures 40°C• Evaluation of electrolytes and CK• Phentolamine or nitroprusside can be used for severe hypertension• Beta-adrenergic blockers (esmolol or propranolol) for tachyarrhythmias• For severe agitation, benzodiazepines, phenothiazines, orhaloperidol• Phenobarbital or phenytoin for seizures■ PearlWhile duration of toxicity is usually limited for most sympathomimetics,duration may be prolonged if patients have ingested bags containingthe drug for illicit transport (“body-packing”) or have used“ice,” a long-acting smokable form of methamphetamine.ReferenceMokhlesi B et al:Adult toxicology in critical care: Part II: specific poisonings.Chest 2003;123:897. [PMID: 12628894]