Effect of lithium maintenance therapy on thyroid and parathyroid function.

Area of Science:

• Endocrinology
• Psychiatry
• Pharmacology

Background:

• Lithium maintenance therapy is a cornerstone treatment for bipolar disorder.
• Potential side effects include endocrine and electrolyte disturbances.
• Understanding risk factors for these alterations is crucial for patient management.

Purpose of the Study:

• To evaluate the impact of lithium maintenance therapy on thyroid, parathyroid, and ion levels.
• To investigate the influence of therapy duration, age, sex, and family history on these changes.
• To assess the incidence of hypothyroidism and alterations in calcium and magnesium.

Main Methods:

• Prospective study conducted at an Affective Disorders Clinic.
• 101 patients with bipolar disorder on lithium therapy and 82 controls were analyzed.
• Laboratory tests for calcium, magnesium, and thyroid-stimulating hormone were performed at baseline and biannually.

Main Results:

• Hypothyroidism developed in 40 patients (excluding baseline cases).
• Patients with a family history of thyroid disease experienced earlier hypothyroidism onset (3.7 vs. 8.6 years).
• Lithium treatment led to increased calcium levels, potentially mitigating age-related decline, while magnesium levels remained stable.

Conclusions:

• A family history of thyroid illness is a significant risk factor for developing hypothyroidism during lithium therapy.
• Lithium therapy is associated with hypercalcemia, which may offer a protective effect against age-related decreases in calcium.
• Regular monitoring of thyroid function and electrolyte balance is recommended for patients on long-term lithium treatment.