Salicylate Poisoning

Basics

Description

  • Mixed acid–base disorder with initial alkalemia secondary to respiratory alkalosis progressing to acidemia due to metabolic acidosis and respiratory failure:
    • Alkalosis due to direct action on respiratory drive. Acidosis secondary to inhibition of Krebs cycle and uncoupling of oxidative phosphorylation
  • Diaphoresis, emesis, and hyperventilation may lead to metabolic derangements:
    • Hyponatremia or hypernatremia
    • Hypocalcemia
  • Noncardiogenic pulmonary edema:
    • Toxic effect of salicylate on pulmonary endothelium resulting in extravasation of fluids
  • Seizures are common in salicylate toxicity and may occur due to:
    • Hypoglycemia or hypoglycorrhachia
    • Direct toxic effect resulting in cerebral edema

Geriatric Considerations

  • Greater morbidity and mortality
  • Diagnosis of salicylate intoxication often delayed due to broad differential diagnosis (eg, sepsis) and inability to obtain history

Pediatric Considerations

  • Children exhibit faster onset and more severe signs and symptoms than adults:
    • Results from salicylate being distributed more quickly into target organs such as brain, kidney, and liver
  • Do not solely rely on respiratory rate to identify respiratory alkalosis. Hyperpnea (increased tidal volumes) may be more common in children
  • Children may decompensate more quickly than adults
  • Hypoglycemia more common than hyperglycemia
  • Any ingestion of concentrated salicylates, eg, of oil of wintergreen (98% methyl salicylate w/v) by children <6 yr old or > 4 mL of oil of wintergreen by patients >6 yr old warrants ED assessment

Etiology

Sources of salicylate:

  • Aspirin (acetylsalicylic acid):
    • Ingestion of >150 mg/kg can cause serious toxicity
  • Oil of wintergreen (methyl salicylate):
    • Any exposure should be considered dangerous
  • Bismuth subsalicylate:
    • Salsalate (salicylsalicylic acid)
    • Naturopathic medications containing willow bark

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