Background: To determine thyroid gland volume and the prevalence of goiter in patients receiving long-term lithium treatment for affective disorders.
Methods: In this cross-sectional study, we performed ultrasonographic examinations in 96 patients on long-term lithium treatment, including those with bipolar, major depressive, and schizoaffective disease. Patients with documented continuous and adequate serum lithium levels for more than or equal to 6 months were recruited consecutively from the Berlin Lithium Clinic. Ultrasonographic examinations were also performed in 96 gender- and age-matched control subjects. Patients and controls were 18 years of age or older and were residents of Berlin, Germany and surrounding areas.
Results: Total thyroid volume was significantly greater in the lithium-treated group than among controls (23.7 ml vs. 13.6 ml). Ultrasonography detected that significantly more lithium-treated subjects had goiter than did control subjects (N=53 vs. N=19). Clinical inspection and palpation only detected goiter in 24 of the lithium-treated patients and in 12 control subjects. In a patient subgroup taking levothyroxine, the prevalence of goiter was still 37%. Patients who were not taking levothyroxine had significantly higher TSH basal levels than normal controls (2.1 mU/L vs. 1.3 mU/L).
Limitations: Cross-sectional study; no control for other factors related to thyroid enlargement and goiter such as dietary issues, smoking, or iodine intake; affectively ill subjects were treated with additional psychotropic medications.
Conclusions: Thyroid enlargement was found in a significant number of lithium-treated patients. Ultrasonography proved superior to palpatory inspection in detecting goiter. Regular use of ultrasonography for early detection of thyroid enlargement in patients on long-term lithium treatment is therefore recommended.