salicylate toxicity

Etiology

• aspirin ingestion is the most cause of salicylate toxicity
  • ingestion of > 10 grams of aspirin (adults)
• cutaneous exposure to salicylate-containing topical agents such as oil of wintergreen

Pathology

• cerebral edema
• acute lung injury
  • non-cardiogenic pulmonary edema
• hepatic toxicity
• respiratory alkalosis
• more with severe intoxication, anion gap metabolic acidosis
  • lactic acidosis, ketoacidosis

Clinical manifestations

• initially respiratory alkalosis with
  • tinnitus
  • confusion
  • tachypnea
  • low-grade fever occasionally
  • nausea/vomiting from gastric mucosal toxicity
• later metabolic acidosis
• CNS disturbance with EEG abnormalities

Laboratory

• arterial blood gas
  • respiratory alkalosis progresses to metabolic acidosis
• chem8 (calculate anion gap)
  • serum Na+
  • serum K+
  • serum bicarbonate
  • serum chloride
• plasma osmolality & osmolal gap (none)
• salicylate in serum/plasma
• international normalized ratio (INR)

Complications

• fatal brainstem herniation

Management

• activated charcoal 50-100 g if presenting within 1 hour of ingestion; multiple doses may be useful
• alkaline diuresis for patients with plasma salicylate levels > 40 mg/dL
  • 150 meq (3 ampules) of NaHCO3 in 1 liter of D5W at 10-15 mL/kg/hour until urine flow is achieved
  • maintenance 2-3 mL/kg/hour
  • monitor urine output, urine pH (target pH=7-8; > 7.5), serum K+
  • 40 meq KCl over 4-5 hours
    • successful alkaline diuresis requires simultaneous administration of KCl
  • mitigates CNS toxicity
  • do not use acetazolamide (increases CNS salicylate toxicity)
• hemodialysis for cerebral edema, pulmonary edema, anion gap metabolic acidosis or plasma salicylate > 80-100 mg/dL
• hyperventilate patients requiring endotracheal intubation
• treat altered mental status with IV glucose (despite normal serum glucose)
  • 100 mL of 50% glucose
• vitamin K for increased INR

More general terms

• toxicity; poisoning; overdose

Additional terms

• salicylate