Dietary Supplement Use Leads to a Diagnosis of Thyrotoxicosis

This case details the potential dietary supplement adverse effect, thyrotoxicosis.

Given the number of available dietary supplements on the market and their easy accessibility, reports of adverse events in connection with these products have been increasing, particularly the incidence of hepatotoxicity.1  However, a case study detailed in the latest issue of the Centers for Disease Control and Prevention’s (CDC) Morbidity and Mortality Weekly Report (MMWR) highlights another potential adverse effect of dietary supplement use, thyrotoxicosis.2

This case reports on a 30-year-old woman who presented to the emergency department with her mother who reported that the patient had become acutely confused at home, was unable to recognize her family, and had repetitive speech. The patient had a history of bipolar disorder and polysubstance abuse. Her current medications included lithium, risperidone, benztropine, and bupropion. In addition to her regular medications, she had recently started taking diet pills, which she purchased off the Internet two weeks prior; the supplement was found to contain thyroid hormone with the active ingredient on the label listed as “triiodothyronine hormone 25mcg”. In an attempt to lose more weight, the patient had doubled the dose of the supplement one week prior. After counting the remaining pills in the bottle, it was noted that 25 were missing.

  • Laboratory and physical examination revealed the following:
  • Patient awake but unaware of location or date
  • Heart rate: 130 beats/min
  • Tremor at rest, not ataxic
  • Temp: 101.5° F
  • Lithium concentration: in therapeutic range
  • Serum salicylates, acetaminophen: undetectable
  • Urine toxicology: Negative for cocaine, tetrahydrocannabinol, opioids, phencyclidine, benzodiazepines
  • Thyroid stimulating hormone: <0.01mIU/mL (normal range: 0.27–4.20mIU/mL)
  • Triiodothyronine (T3): >32.5pg/mL (normal range: 1.80–4.60pg/mL)
  • Thyroxine (T4) >7.8ng/dL (normal range: 0.9–1.8ng/dL)