LabMed
Toxicity Associated with Salicylate/Reye Syndrome
-
At a Glance
-
What Tests Should I Request to Confirm My Clinical Dx? In addition, what follow-up tests might be useful?
-
Are There Any Factors That Might Affect the Lab Results? In particular, does your patient take any medications - OTC drugs or Herbals - that might affect the lab results?
-
What Lab Results Are Absolutely Confirmatory?
-
Are There Any Factors That Might Affect the Lab Results? In particular, does your patient take any medications - OTC drugs or Herbals - that might affect the lab results?
At a Glance
Aspirin (acetylsalicylic acid) is a pro-drug metabolized to salicylic acid, which exerts its pharmacologic action through a blockade of prostaglandin synthesis. The active form of the drug is highly protein-bound, so, following overdose, the free fraction is typically elevated. Clinical symptoms of salicylate overdose include tinnitus, nausea and vomiting, increased rate of respiration, hyperthermia, lethargy, and, in some cases, seizures. In addition, acid-base abnormalities are observed in salicylate overdose.
In pediatric patients with a fever, administration of aspirin can result in Reye syndrome. The exact cause of this syndrome remains unknown, but there is significant evidence linking Reye syndrome to salicylate-containing medications and previous viral infections. Reye syndrome develops in two stages: Stage I includes persistent vomiting, changes in mental status, listlessness, and drowsiness; Stage II includes personality changes, irritability, aggressive behavior, confusion and disorientation, seizures, and coma.
What Tests Should I Request to Confirm My Clinical Dx? In addition, what follow-up tests might be useful?
To confirm exposure to salicylate, a blood salicylate test should be ordered with concentrations greater than 300 mg/L indicative of toxicity. Historically, the Done Nomogram has been used to evaluate blood salicylate results. However, this nomogram was developed based on an immediate release, single-drug formulation; it does not apply to chronic ingestion, extended release formulations, or combinations with opiates or other drugs (e.g., Percodan). In addition, the nomogram was developed in a pediatric population, so its utility is limited in adult populations. An alternative approach is to take serial measurements of blood salicylate and calculate the half-life of the drug in the patient; since the pharmacokinetic elimination pathways for salicylate are saturable, an extended half-life is suggestive of salicylate overdose.
In addition, blood gas testing is useful to assess acid-base changes that may accompany salicylate toxicity. An unexplained increase in Anion Gap ([Na+] - [Cl-] - [HCO3-]) may be a clue that a metabolic acidosis is present in the patient, caused by excessive salicylate ingestion.(
Table 1
Test Results Indicative of the Disorder
Blood Salicylate | Blood pH | Anion Gap |
---|---|---|
> 300 mg/L | < 7.4 | > 12 |
Are There Any Factors That Might Affect the Lab Results? In particular, does your patient take any medications - OTC drugs or Herbals - that might affect the lab results?
Salicylate testing is colorimetric in nature, so anything that will interfere with absorbance measurements may also impact the measurement of salicylate, including excessive hemolysis or lipemia. Icteric specimens may also present a challenge.
Other substances that may impact the colorimetric salicylate measurement include ketones, catecholamines, and oxalate, which is sometimes used as a preservative in some blood collections tubes. Enzymatic methods do not share these interferences.
What Lab Results Are Absolutely Confirmatory?
Blood salicylate testing is the only laboratory method that will absolutely confirm salicylate exposure or intoxication.
Are There Any Factors That Might Affect the Lab Results? In particular, does your patient take any medications - OTC drugs or Herbals - that might affect the lab results?
Occasionally, a clinical laboratory may perform a screening method called a "spot test." These tests are colorimetric, qualitative methods based on a reaction with ferric chloride, or something called Trinder's reagent. When these tests are used, phenothiazines, acetoacetate (present in ketosis), and sodium azide may interfere with the screening tests.
Copyright © 2017, 2013 Decision Support in Medicine, LLC. All rights reserved.
No sponsor or advertiser has participated in, approved or paid for the content provided by Decision Support in Medicine LLC. The Licensed Content is the property of and copyrighted by DSM.
Sign Up for Free e-newsletters
ONA Articles
- FDA: Number of U.S. Women With Breast Implant-Caused Cancer Has Increased
- Takeda to Collaborate With MSKCC on CAR-T Therapies for Multiple Myeloma
- Sequential Immunotherapy, Targeted Therapy Linked to Cutaneous Adverse Events in Advanced Melanoma
- NIH Establishes Educational Program on Genomics, Genetics for Oncology Nurses
- Immunotherapy for HER2-positive Breast Cancer: Recent Advances and Combination Therapeutic Approaches
- Oncology Nurse Navigation Facilitates Timely Treatment of Pancreatic Cancer
- Helping Patients Face the Challenge of Eating Healthy During Cancer Treatment
- Oncology Nurses Weigh In on Their Patient-Centered Communication Practices, Needs
- Substitute for Lidocaine
- CART cell therapy for prostate cancer: status and promise
- Immunotherapy for HER2-positive Breast Cancer: Recent Advances and Combination Therapeutic Approaches
- Survey Demonstrates Relationship Between Symptom Burden, Medical Disability Leave Among Myeloproliferative Neoplasms
- A Review of Clinical Outcomes in Patients With Early-Stage Burkitt Lymphoma
- FDA: Number of U.S. Women With Breast Implant-Caused Cancer Has Increased
- USPSTF Still Recommends Against Pancreatic Cancer Screening
Regimen and Drug Listings
GET FULL LISTINGS OF TREATMENT Regimens and Drug INFORMATION
Bone Cancer | Regimens | Drugs |
Brain Cancer | Regimens | Drugs |
Breast Cancer | Regimens | Drugs |
Endocrine Cancer | Regimens | Drugs |
Gastrointestinal Cancer | Regimens | Drugs |
Genitourinary Cancer | Regimens | Drugs |
Gynecologic Cancer | Regimens | Drugs |
Head and Neck Cancer | Regimens | Drugs |
Hematologic Cancer | Regimens | Drugs |
Lung Cancer | Regimens | Drugs |
Other Cancers | Regimens | |
Rare Cancers | Regimens | |
Skin Cancer | Regimens | Drugs |