What is the treatment for an Acetylsalicylic Acid (ASA) overdose?

Treatment of Acetylsalicylic Acid (ASA) Overdose

Immediate management of ASA overdose requires aggressive supportive care with fluid and electrolyte management as the cornerstone of therapy, supplemented by gastrointestinal decontamination, urinary alkalinization, and hemodialysis in severe cases. 1, 2

Immediate Actions

Supportive Care and Stabilization

• Ensure airway, breathing, and cardiovascular support as the first priority, with particular attention to respiratory status given the respiratory alkalosis followed by metabolic acidosis that characterizes salicylate toxicity 3, 2
• Obtain immediate serum salicylate level, electrolytes, blood gases (pH, PO2, PCO2), glucose, and renal function 3, 2
• Contact poison control center immediately 1

Gastrointestinal Decontamination

• Administer activated charcoal if the patient presents within 1-2 hours of ingestion and can protect their airway 4, 2
• Consider gastric lavage only for massive, life-threatening ingestions presenting very early 4

Metabolic Management

Fluid and Electrolyte Therapy

• Aggressive IV fluid resuscitation is essential, as salicylate toxicity causes significant fluid losses through hyperpnea, vomiting, and hyperpyrexia 2
• Monitor and correct electrolyte abnormalities frequently, particularly potassium, as hypokalemia will prevent effective urinary alkalinization 3, 2
• Maintain high urinary output to enhance salicylate elimination 4, 2

Urinary Alkalinization

• Administer IV sodium bicarbonate to achieve urine pH of 7.5-8.0, which dramatically increases renal salicylate clearance by ion trapping 2
• Monitor serum pH closely to avoid excessive systemic alkalemia 3
• Ensure adequate potassium repletion before and during alkalinization, as hypokalemia prevents urinary alkalinization 2

Glucose Management

• Monitor blood glucose frequently and treat hypoglycemia aggressively, even if serum glucose appears normal, as CNS glucose may be depleted despite normal serum levels 3, 2
• Consider empiric dextrose administration in altered mental status 2

Enhanced Elimination

Hemodialysis Indications

• Hemodialysis is indicated for severe poisoning including: serum salicylate levels >100 mg/dL in acute ingestions, severe acidemia (pH <7.2), refractory metabolic abnormalities, pulmonary edema, cerebral edema, renal failure, or progressive clinical deterioration despite aggressive supportive care 2
• Hemodialysis is highly effective for salicylate removal but rarely necessary with appropriate supportive care 2
• Hemoperfusion is also effective but offers no advantage over hemodialysis 2

Monitoring and Clinical Assessment

Serial Laboratory Monitoring

• Obtain serial salicylate levels every 2-4 hours until levels are clearly declining, as delayed absorption from enteric-coated preparations or bezoar formation can occur 3, 2
• Monitor arterial blood gases, electrolytes, and glucose frequently (every 1-2 hours initially) 3
• Blood salicylate levels are good prognostic indicators for acute ingestions but less reliable in chronic therapeutic overdose 2

Clinical Manifestations to Monitor

• Watch for progression of toxicity: nausea, vomiting, tinnitus, hyperpnea, hyperpyrexia, disorientation, coma, and convulsions 2
• In chronic, therapeutically-induced salicylism, symptoms may be mistaken for the underlying illness being treated, making diagnosis more challenging 2
• Respiratory pattern changes indicate worsening toxicity: initial respiratory alkalosis from direct medullary stimulation, followed by metabolic acidosis from uncoupling of oxidative phosphorylation 3, 2

Critical Pitfalls to Avoid

• Do not rely solely on initial salicylate level in acute ingestions, as levels may continue rising for hours due to delayed absorption 2
• Never assume normal serum glucose excludes CNS hypoglycemia in salicylate toxicity 2
• Chronic therapeutic overdose is often missed because symptoms mimic the underlying condition being treated (e.g., confusion in elderly patients) 2
• Attempting urinary alkalinization without first correcting hypokalemia will fail 2
• In chronic overdose, even "therapeutic" salicylate levels may be associated with significant toxicity 2