Urine pH: allows monitoring of adequacy of urinary alkalinization
Acetaminophen level: Acetaminophen may be a coingestant.
Ferric chloride test: A few drops of 10% ferric chloride will turn brown or purple in 1 mL of urine that contains salicylate.
Alert
Respiratory acidosis suggests central nervous system depression and is an ominous sign.
Salicylate levels after chronic or acute-on-chronic overdose correlate poorly to clinical condition.
Serial salicylate levels may be necessary to rule out ongoing drug absorption.
Differential Diagnosis
Gastroenteritis
Pneumonia
Metabolic disease
Ketoacidosis
Sepsis
Meningitis/encephalitis
Treatment
General Measures
Fluids/alkalinization
Intravascular volume should be repleted with intermittent boluses of 10 " 20 mL/kg of isotonic crystalloid.
Altered mentation may imply CNS hypoglycemia and should be treated with dextrose.
Acidemia should be treated with sodium bicarbonate to limit salicylate distribution to the brain. Serum pH of 7.5 is reasonable goal.
With significant poisoning, an IV infusion of 5% dextrose with 100 " 150 mEq/L of sodium bicarbonate and 20 " 40 mEq/L of potassium chloride should be initiated at 1.5 " 2 times maintenance requirements. Titrate fluid volume to produce urine output of 2 " 3 mL/kg/h. Titrate alkalinization to produce urine pH between 7.5 and 8, which greatly increases the urinary elimination of salicylate via "ion-trapping " effect.
Hemodialysis indications
Acute serum salicylate level >100 mg/dL
Chronic serum salicylate level >60 mg/dL
Severe acidosis or severe electrolyte disturbance
Renal failure
Pulmonary edema
Persistent neurologic dysfunction
Progressive clinical deterioration
Alert
Hypokalemia may interfere with the ability to achieve urinary alkalinization.
Sedating a salicylate-poisoned patient may lead to respiratory depression and clinical deterioration.
Endotracheal intubation is dangerous and, if performed, must be accompanied by sodium bicarbonate IV bolus and hyperventilation to prevent worsening acidemia and salicylate distribution to the brain.
Hemodialysis equipment must be carefully primed to prevent worsening hypovolemia and cardiovascular collapse.
If hemodialysis is performed, adjust dialysate to maintain alkalemia.
Pulmonary edema and/or cerebral edema may complicate fluid management.
Inpatient Considerations
Initial Stabilization
GI decontamination
Activated charcoal 1 g/kg (maximum 75 g) may be administered if aspirin is judged to be present in the stomach or proximal intestine.
Many authorities suggest a 2nd charcoal dose 2 " 4 hours after the 1st or if salicylate levels continue to rise.
Whole-bowel irrigation may reduce drug absorption after large overdoses.
Ongoing Care
Follow-up Recommendations
Drug administration education should be offered to victims of chronic overdose.
Mental health services should be provided to victims of intentional overdose.
Prognosis
Chronic therapeutic misuse often leads to delayed diagnosis and has the most serious prognosis.
Single acute ingestion of >300 mg/kg acetylsalicylic acid should be considered life threatening.
Complications
Nausea and vomiting
Dehydration
Metabolic acidosis
Electrolyte abnormalities
Disorientation, coma, seizures
Noncardiogenic pulmonary edema
Renal failure
Cerebral edema and death
Additional Reading
Chyka PA, Erdman AR, Christianson G, et al. Salicylate poisoning: an evidence-based consensus guideline for out-of-hospital management. Clin Toxicol (Phila). 2007;45(2):95 " 131. [View Abstract]
Glatstein M, Garcia-Bournissen F, Scolnik D, et al. Sudden-onset tachypnea and confusion in a previously healthy teenager. Ther Drug Monit. 2010;32(6):700 " 703. [View Abstract]
Pearlman BL, Gambhir R. Salicylate intoxication: a clinical review. Postgrad Med. 2009;121(4):162 " 168. [View Abstract]
Stolbach AI, Hoffman RS, Nelson LS. Mechanical ventilation was associated with acidemia in a case series of salicylate-poisoned patients. Acad Emerg Med. 2008;15(9):866 " 869. [View Abstract]
Codes
ICD09
965.1 Poisoning by salicylates
276.2 Acidosis
ICD10
T39.014A Poisoning by aspirin, undetermined, initial encounter
E87.2 Acidosis
T39.011A Poisoning by aspirin, accidental (unintentional), init
T39.012A Poisoning by aspirin, intentional self-harm, init encntr
SNOMED
7248001 Poisoning by salicylate (disorder)
35528000 Metabolic acidosis due to salicylate (disorder)
216471009 Accidental poisoning by salicylates (disorder)
290148002 Intentional salicylic acid salt poisoning (disorder)
FAQ
Q: What amount of the candy-scented oil of wintergreen is toxic to a toddler?
A: Oil of wintergreen may contain as much as 98% methyl salicylate. 1 mL of methyl salicylate is the equivalent of 1,400 mg of aspirin. Therefore, 1 teaspoon of oil of wintergreen represents a very serious "aspirin " overdose.
Q: Is there a prognostic nomogram for aspirin poisoning similar to that used for acetaminophen overdose?
A: The Done nomogram is applicable only to ingestion of non " enteric-coated aspirin by children with normal mentation and normal blood pH, and the validity of its prognostication is suspect. Its use is not widely recommended.