Snapshot A 20-year-old man presents to the emergency room after an intentional overdose of aspirin. He reports ingesting an unknown amount of aspirin about 30 minutes prior to presentation with the intention of committing suicide. However, he changed his mind and asked to be saved. He reports some nausea, vomiting, and ringing in his ears. He is started on intravenous hydration and given activated charcoal. Introduction Clinical definition a constellation of symptoms resulting from toxicity or overdose from salicylates, most commonly aspirin Epidemiology demographics patients taking chronic pain medications Etiology intentional overdose accidental overdose Pathogenesis salicylates have multiple effects on the body hyperventilation and early respiratory alkalosis aspirin directly stimulates the respiratory centers in the brainstem later metabolic acidosis, resulting in mixed metabolic acidosis-respiratory alkalosis aspirin uncouples oxidative phosphorylation, which impairs the Krebs cycle this results in a lactic acidosis tinnitus aspirin is toxic to cranial nerve VIII acute respiratory distress syndrome aspirin is also toxic to the lungs renal insufficiency aspirin is toxic to the renal tubules increased bleeding time aspirin inhibits platelet aggregation Prognosis depends on the severity of toxicity severe cases may be fatal Presentation Symptoms tinnitus nausea vomiting fever lethargy seizure or coma (in cases of severe poisoning) Physical exam tachypnea tachycardia hyperthermia Studies Labs arterial blood gas to evaluate for acidosis or alkalosis serum salicylate level to confirm the diagnosis measure every 3 hours as toxicity can be delayed chemistry panel with liver function tests to assess renal and hepatic function Making the diagnosis based on clinical presentation and laboratory studies especially if patients present with tinnitus, anion gap metabolic acidosis, and elevated serum salicylate levels Differential Acetaminophen overdose distinguishing factors hepatic failure no tinnitus or acid-base derangement the antidote is N-acetylcysteine Treatment Conservative supportive care indication for all patients modalities intravenous hydration Medical activated charcoal indications for patients with known salicylate ingestion within the past hour to block absorption sodium bicarbonate indications for patients in whom supportive care is not sufficient, or if patients are not good candidates for activated charcoal alkalinize urine to increase excretion of salicylates alkalinize serum to decrease central nervous system toxicity Non-operative dialysis indication for severe cases (salicylate concentration > 100 mg/dL) or if clinical features are severe Complications Renal failure