Using ultrasonography to determine thyroid size and prevalence of goiter in lithium-treated patients with affective disorders.

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.