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Abstract

Background: Lithium is a cornerstone therapy for Bipolar I Disorder, yet its use necessitates vigilant monitoring for adverse drug reactions (ADRs). While lithium-induced hypothyroidism is a well-documented complication, the emergence of thyrotoxicosis secondary to destructive thyroiditis is a rare and diagnostically challenging event. This report presents a systematic analysis of a case of suspected lithium-induced thyroiditis notable for its paradoxical clinical presentation as a severe depressive episode.


Case presentation: A 33-year-old female with a 10-year history of Bipolar I Disorder, stable on lithium for two years, was admitted with a severe depressive episode and active suicidal ideation. The onset of her psychiatric decompensation was temporally correlated with a diagnosis of thyrotoxicosis (suppressed TSH <0.005 uIU/mL; elevated FT4 >7.77 ng/dL). A formal causality assessment using the Naranjo Adverse Drug Reaction Probability Scale yielded a score of 6, indicating a "probable" relationship between lithium and the thyroiditis. Critically, the thyrotoxic state, which conventionally mimics mania, presented atypically as severe depression.


Conclusion: This case of probable lithium-induced destructive thyroiditis, presenting paradoxically with severe depression, underscores the critical need for a high index of suspicion for iatrogenic endocrinopathies in patients on lithium who exhibit any mood destabilization. A systematic approach to ADR assessment is essential to guide appropriate clinical management in such complex presentations.

Keywords

Adverse drug reaction Bipolar disorder Lithium Thyroiditis Thyrotoxicosis

Article Details

How to Cite
Ni Wayan Saka Rahayu. (2025). Destructive Thyroiditis: A Rare and Perplexing Complication of Lithium Therapy in Bipolar Disorder. Bioscientia Medicina : Journal of Biomedicine and Translational Research, 9(12), 9805-9822. https://doi.org/10.37275/bsm.v9i12.1459