Background/Objective.
Thyrotoxicosis, a condition resulting from excessive peripheral
thyroid hormone, is typically accompanied by thyroid function tests demonstrating a high free
thyroxine (free T4) with appropriate suppression of
thyroid-stimulating hormone (TSH). Case report. We describe a 17-year-old female presenting with symptoms of
thyrotoxicosis along with suppressed TSH and low free T4, a laboratory pattern concerning for
central hypothyroidism. Further history revealed that she was prescribed
liothyronine as an adjunct
therapy for depression. Discussion. Due to the short half-life of
liothyronine, clinical signs and symptoms of
thyrotoxicosis may develop before detection by interval lab monitoring. Conclusion. This case highlights the need for close monitoring and caution when treating adolescents with
liothyronine and the importance of interpreting atypical laboratory findings within clinical context.