Long-term lithium therapy commonly affects which organ system?

Long-term lithium therapy commonly affects which organ system?

• A. Thyroid (hypothyroidism)
• B. Liver
• C. Pancreas
• D. Adrenal

Answer: (A)

Long-term lithium therapy commonly affects the thyroid, leading to hypothyroidism. Lithium can accumulate in thyroid cells and disrupt hormone synthesis and release, notably by interfering with iodine organification and the coupling steps that make thyroid hormones, and by blunting the gland’s response to TSH. Clinically, this may present as fatigue, weight gain, cold intolerance, or mood symptoms, and some patients may have subclinical changes detected on labs (elevated TSH with normal free T4). Because of this risk, baseline thyroid function tests (TSH and free T4) are recommended before starting lithium and should be repeated periodically during treatment. If hypothyroidism develops, treatment with levothyroxine is effective, and many patients can continue lithium with thyroid replacement. Liver, pancreas, and adrenal glands are not typical sites of chronic lithium toxicity, whereas renal effects are more classically associated with long-term use (such as nephrogenic diabetes insipidus), which isn’t among the listed options.

Long-term lithium therapy commonly affects the thyroid, leading to hypothyroidism. Lithium can accumulate in thyroid cells and disrupt hormone synthesis and release, notably by interfering with iodine organification and the coupling steps that make thyroid hormones, and by blunting the gland’s response to TSH. Clinically, this may present as fatigue, weight gain, cold intolerance, or mood symptoms, and some patients may have subclinical changes detected on labs (elevated TSH with normal free T4). Because of this risk, baseline thyroid function tests (TSH and free T4) are recommended before starting lithium and should be repeated periodically during treatment. If hypothyroidism develops, treatment with levothyroxine is effective, and many patients can continue lithium with thyroid replacement.

Liver, pancreas, and adrenal glands are not typical sites of chronic lithium toxicity, whereas renal effects are more classically associated with long-term use (such as nephrogenic diabetes insipidus), which isn’t among the listed options.