In a bipolar disorder patient showing weight gain and puffy facial features, what is the best next step?

In the scenario with a bipolar disorder patient experiencing weight gain and puffy facial features, assessing thyroid function is crucial. The presence of these symptoms raises the possibility of hypothyroidism, which is known to be a potential side effect of lithium therapy. Lithium can cause thyroid dysfunction, leading to weight gain, changes in energy levels, and other metabolic effects.

By ordering thyroid stimulating hormone (TSH) levels, a healthcare provider can determine if an underactive thyroid is contributing to the patient’s symptoms. If hypothyroidism is detected, appropriate management can be initiated, such as thyroid hormone replacement therapy.

Monitoring TSH levels is an important consideration in patients with bipolar disorder on lithium due to the known interactions and side effects. This makes ordering TSH levels the best next step in this clinical scenario.