Sections View Full Chapter Figures Tables Videos Annotate Full Chapter Figures Tables Videos Supplementary Content + Download Section PDF Listen ++ For further information, see CMDT Part 38-53: Salicylates Overdose + Key Features Download Section PDF Listen +++ +++ Essentials of Diagnosis ++ Tachypnea, altered mental status Metabolic acidosis Typical arterial blood gases reveal respiratory alkalosis and metabolic acidosis Elevated salicylate level diagnostic +++ General Considerations ++ Salicylates (eg, aspirin, methyl salicylate, bismuth subsalicylate) are found in a variety of over-the-counter and prescription medications Salicylates uncouple cellular oxidative phosphorylation, resulting in anaerobic metabolism and excessive production of lactic acid and heat, and interfere with several Krebs cycle enzymes A single ingestion of more than 200 mg/kg of salicylate can cause intoxication Poisoning may also occur as a result of excessive dosing over several days Although the half-life of salicylate is 2–3 h after small doses, it may increase to 20 h or more in patients with intoxication + Clinical Findings Download Section PDF Listen +++ +++ Symptoms and Signs ++ Acute ingestion Nausea and vomiting, occasionally with gastritis Moderate intoxication Hyperpnea (deep and rapid breathing), tachycardia, and tinnitus Serious intoxication Agitation, confusion, seizures Cardiovascular collapse, pulmonary edema, hyperthermia Death +++ Differential Diagnosis ++ Other causes of anion gap acidosis Alcoholic ketoacidosis Metformin toxicity Isoniazid poisoning Iron poisoning Methanol or ethylene glycol toxicity Carbon monoxide poisoning Acetaminophen poisoning (common coingestion) + Diagnosis Download Section PDF Listen +++ +++ Laboratory Tests ++ Diagnosis is suspected in any patient with an anion gap metabolic acidosis and is confirmed by measuring the stat serum salicylate level Patients with serum salicylate levels > 100 mg/dL (1000 mg/L or 7.2 mcmol/L) after an acute overdose are more likely to have severe poisoning Patients with subacute or chronic intoxication may suffer severe symptoms with serum salicylate levels of only 60–70 mg/dL (4.3–5 mcmol/L) Arterial blood gases typically reveal a respiratory alkalosis with an underlying metabolic acidosis Prothrombin time is often elevated owing to salicylate-induced hypoprothrombinemia Central nervous system intracellular glucose depletion can occur despite normal measured serum glucose levels + Treatment Download Section PDF Listen +++ +++ Medications +++ Emergency and supportive measures ++ Activated charcoal Administer 60–100 g orally or via gastric tube, mixed in aqueous slurry Do not use for comatose or convulsing patients unless it can be given by gastric tube and the airway is protected by a cuffed endotracheal tube Extra doses of activated charcoal may be needed in patients who ingest more than 10 g of aspirin (desired ratio of charcoal to aspirin: ~10:1 by weight) Although extra doses cannot always be given as a single dose, they may be administered over the first 24 h in divided doses every 2–4 h along with whole bowel irrigation Give glucose-containing fluids to reduce the risk of cerebral hypoglycemia Treat metabolic acidosis with intravenous sodium bicarbonate This is critical because acidosis (acidemia, pH < 7.40) promotes greater entry of salicylate into cells, worsening toxicity +++ Specific treatment ++ Alkalinization of the urine enhances renal salicylate excretion by trapping the salicylate anion in the urine Add 100 mEq (2 ampules) of sodium bicarbonate to 1 L of 5% dextrose in 0.2% saline Infuse intravenously at a rate of ~150–200 mL/h Unless the patient is oliguric or hyperkalemic, add 20–30 mEq of potassium chloride to each liter of intravenous fluid Patients who are volume depleted often do not produce an alkaline urine (paradoxical aciduria) unless potassium is given +++ Therapeutic Procedures ++ Hemodialysis may be lifesaving and is indicated for patients with Severe metabolic acidosis Markedly altered mental status Significantly elevated salicylate levels (> 100–120 mg/dL [1000–1200 mg/L or 7.2-8.6 mcmol/L] after acute overdose or > 60–70 mg/dL [600–700 mg/L or 4.3–5 mcmol/L] with subacute or chronic intoxication) + Outcome Download Section PDF Listen +++ +++ Follow-Up ++ Monitor serum salicylate level every 2 h initially to determine if it is continuing to rise Patients with massive ingestion (eg, > 100 tablets) May have delayed absorption May require prolonged observation until levels fall into normal range +++ Complications ++ Sudden and severe deterioration can occur after rapid sequence intubation and controlled ventilation if the pH is allowed to fall during the apneic period +++ When to Admit ++ Suicidal ingestion History of massive ingestion with rising levels Evidence of significant intoxication Altered mental status Metabolic acidosis Elevated salicylate level +++ Prognosis ++ Good if blood pH is maintained above 7.4 and hemodialysis is promptly performed in patients with serious toxicity + References Download Section PDF Listen +++ + +Bowers D et al. Managing acute salicylate toxicity in the emergency department. Adv Emerg Nurs J. 2019 Jan/Mar;41(1):76–85. [PubMed: 30702537] + +Kashani KB et al. Spurious hyperchloremia in the presence of elevated plasma salicylate: a cohort study. Nephron. 2018;138:186–91. [PubMed: 29131112] + +McCabe DJ et al. The association of hemodialysis and survival in intubated salicylate-poisoned patients. Am J Emerg Med. 2017 Jun;35(6):899–903. [PubMed: 28438446] + +Shively RM et al. Acute salicylate poisoning: risk factors for severe outcome. Clin Toxicol (Phila). 2017 Mar;55(3):175–80. [PubMed: 28064509]