Abstract

Introduction: The role of lithium (Li) in the treatment of Graves’ disease (GD) remains a contentious issue. A literature review revealed no reports of lithium poisoning in patients with hyperthyroidism treated with lithium. Here we present a case of hyperthyroidism in a patient who developed lithium poisoning after lithium treatment and was initially misdiagnosed as hyperthyroid crisis.
Case report: A 31-year-old female patient with hyperthyroidism presented with dyspnea, chest tightness, abdominal swelling, and diarrhea for 3 consecutive days. Physical examination revealed typical features associated with hyperthyroidism. Further laboratory investigations confirmed a hyperthyroid state with decreased thyroid stimulating hormone levels, significantly increased free thyroxine levels, and high levels of thyroid receptor antibodies. Additional diagnostic tests revealed pulmonary edema and compromised left ventricular function. Initially, the patient was treated with methimazole; however, she experienced agranulocytosis, which necessitated switching to lithium carbonate. After 18 days of lithium carbonate treatment, the patient again developed chest tightness, dyspnea, edema, accompanied by lethargy, confusion, visual hallucination, and other symptoms, and was diagnosed with hyperthyroidism crisis. However, subsequent lithium concentration monitoring revealed elevated serum lithium levels (2.82 mmol/L), indicating lithium poisoning. When lithium was stopped, the symptoms disappeared quickly. After this episode, the patient received final treatment with iodine-131 to effectively control hyperthyroidism.
Conclusions: Our case highlights the potential lithium toxicity of low doses of lithium carbonate in the treatment of hyperthyroidism, especially in patients with an imminent hyperthyroidism crisis. Close monitoring of serum lithium levels is essential for patients receiving lithium therapy for hyperthyroidism.


Author Details

Authors

• Zichen Rao
• Chunyan Zhu
• Yiming Zhang

Departments

• Department of Endocrinology, The Quzhou Affiliated Hospital of Wenzhou Medical University, Quzhou People’s Hospital, Quzhou, Zhejiang, China

Address

Yiming Zhang, MD
Department of Endocrinology
The Quzhou Affiliated Hospital of Wenzhou Medical University
Quzhou People’s Hospital
Quzhou, 324000, Zhejiang, China
Email: [email protected]

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