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Toxicity, Salicylate: Differential Diagnoses & Workup
Updated: Jul 11, 2008
- Overview
- Differential Diagnoses & Workup
- Treatment & Medication
- Follow-up
Differential Diagnoses
Other Problems to Be Considered
Caffeine toxicity
Workup
Laboratory Studies
- Obtain measurements of serum electrolytes, blood urea nitrogen (BUN), creatinine, calcium, magnesium, and glucose.
- Repeat these tests at least every 12 hours until the salicylate level falls and the acid-base disturbance improves. If hemodialysis is required, testing is needed more frequently.
- Monitor serum potassium concentrations; normal levels may be difficult to obtain during alkalinization therapy.
- Serum salicylate level
- If managing an acute or acute-on-chronic ingestion, repeat this test every 2 hours until the salicylate level falls.
- If the levels increase, consider the possibility that a sustained-release preparation was ingested or that a concretion in the GI tract has formed.
- In general, the Done nomogram (noted in numerous emergency medicine and toxicology textbooks) is not as useful in salicylate ingestions as other nomograms are in other ingestions. The Done nomogram has not been proven valid in the following instances:
- Acute ingestions when other salicylates have been taken within the past 24 hours
- Acute overdoses when salicylates have been ingested over several hours
- Chronic salicylate ingestions
- Ingestions of enteric-coated or sustained-release preparations
- Renal failure patients
- Many toxicologists suggest avoiding the use of the Done nomogram. The Done nomogram assumes complete absorption by 6 hours postingestion; 6-hour postingestion levels may be correlated with the following degrees of toxicity:
- Less than 50 mg/dL - Asymptomatic
- 51-110 mg/dL - Mild-to-moderate toxicity
- 110-120 mg/dL - Severe toxicity
- Serum levels determined less than 6 hours postingestion (acute overdose) do not rule out impending toxicity because salicylates are in the absorption-distribution phase. Likewise, in cases of chronic salicylism, measured toxic levels may be only 30-40 mg/d.
- Urinalysis
- Monitor and maintain an alkaline urine pH every 2 hours during alkalinization therapy.
- Maintain a urine pH of 7.5-8 (monitor the serum pH rather than the urine pH). Excessive sodium bicarbonate induces severe alkalemia and/or hypernatremia. Consider obtaining a urine specimen for a qualitative toxicology screen.
- Obtain hepatic, hematologic, and coagulation profiles for patients with clinical evidence of moderate-to-severe toxicity (eg, those that need to be admitted for inpatient care).
- Arterial blood gas
- Repeat approximately every 2 hours until metabolic acidosis improves.
- During urinary alkalinization therapy, the arterial pH should remain between 7.3 and 7.5.
Imaging Studies
- A chest x-ray is indicated if evidence of severe intoxication, pulmonary edema, or hypoxemia is present.
- Consider an abdominal x-ray if an aspirin concretion is suspected. For better sensitivity, this should be performed before administration of activated charcoal.
- Other methods of identifying gastric salicylate pharmacobezoars include the following:
- Ultrasonography
- CT scan of the head
- Endoscopy
Other Tests
- ECG
- The ferric chloride test and the Ames Phenistix test are sensitive but nonspecific screening tests that may be available in the ED. However, these tests are currently almost never performed because of the availability of rapid and accurate quantitative serum assays.
- If acetylsalicylic acid is present, combining 1 mL of urine and a few drops of 10% ferric chloride causes a purple color change.
- The Phenistix turns brown if salicylates are present in the urine, but this test lacks specificity.
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 Differential Diagnoses & Workup: Toxicity, Salicylate |
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References
Acetylsalicylic Acid. National Library of Medicine, TOXNET, Hazardous Substances Data Bank. Available at http://toxnet.nlm.nih.gov/cgi-bin/sis/search/f?./temp/~yiK5GU:1.
Brenner BE, Simon RR. Management of salicylate intoxication. Drugs. Oct 1982;24(4):335-40. [Medline].
Chan TY, Chan AY, Ho CS, Critchley JA. The clinical value of screening for salicylates in acute poisoning. Vet Hum Toxicol. Feb 1995;37(1):37-8. [Medline].
Chapman BJ, Proudfoot AT. Adult salicylate poisoning: deaths and outcome in patients with high plasma salicylate concentrations. Q J Med. Aug 1989;72(268):699-707. [Medline].
Chiaretti A, Schembri Wismayer D, Tortorolo L, et al. Salicylate intoxication using a skin ointment. Acta Paediatr. Mar 1997;86(3):330-1. [Medline].
Danel V, Henry JA, Glucksman E. Activated charcoal, emesis, and gastric lavage in aspirin overdose. Br Med J (Clin Res Ed). May 28 1988;296(6635):1507. [Medline].
Dargan PI, Wallace CI, Jones AL. An evidence based flowchart to guide the management of acute salicylate (aspirin) overdose. Emerg Med J. May 2002;19(3):206-9. [Medline].
Done AK, Temple AR. Treatment of salicylate poisoning. Mod Treat. Aug 1971;8(3):528-51. [Medline].
Dugandzic RM, Tierney MG, Dickinson GE, et al. Evaluation of the validity of the Done nomogram in the management of acute salicylate intoxication. Ann Emerg Med. Nov 1989;18(11):1186-90. [Medline].
Gabow PA, Anderson RJ, Potts DE, Schrier RW. Acid-base disturbances in the salicylate-intoxicated adult. Arch Intern Med. Oct 1978;138(10):1481-4. [Medline].
Gilman AG, Goodman LS, Gilman A, eds. The Pharmacological Basis of Therapeutics. 6th ed. New York: McGraw-Hill; 1980.
Gittelman DK. Chronic salicylate intoxication. South Med J. Jun 1993;86(6):683-5. [Medline].
Johnson D, Eppler J, Giesbrecht E, Verjee Z, Rais A, Wiggins T. Effect of multiple-dose activated charcoal on the clearance of high-dose intravenous aspirin in a porcine model. Ann Emerg Med. Nov 1995;26(5):569-74. [Medline].
Krause DS, Wolf BA, Shaw LM. Acute aspirin overdose: mechanisms of toxicity. Ther Drug Monit. Dec 1992;14(6):441-51. [Medline].
O'Malley GF. Emergency department management of the salicylate-poisoned patient. Emerg Med Clin North Am. May 2007;25(2):333-46; abstract viii. [Medline].
Proudfoot AT. Toxicity of salicylates. Am J Med. Nov 14 1983;75(5A):99-103. [Medline].
Teece S, Crawford I. Best evidence topic report. Gastric lavage in aspirin and non-steroidal anti-inflammatory drug overdose. Emerg Med J. Sep 2004;21(5):591-2. [Medline].
Temple AR. Acute and chronic effects of aspirin toxicity and their treatment. Arch Intern Med. Feb 23 1981;141(3 Spec No):364-9. [Medline].
Further Reading
Keywords
aspirin overdose, aspirin, aspirin poisoning, aspirin ingestion, salicylate toxicity, salicylate ingestion, salicylate overdose, salicylate poisoning
