Thyroid Function Abnormalities in HIV-Infected Patients

Abstract

Abnormal thyroid function test results are common among human immunodeficiency virus (HIV)–infected patients. Although the prevalence of overt thyroid disease does not appear to be significantly increased in HIV-infected patients, compared with the general population, specific patterns of abnormal thyroid function test findings are more frequently identified among HIV-infected patients. Among patients with advanced acquired immunodeficiency syndrome, nonthyroidal illness (i.e., euthyroid sick syndrome) is common. During antiretroviral therapy, the prevalence of 2 generally asymptomatic conditions (subclinical hypothyroidism, which is characterized by isolated elevated thyroid-stimulating hormone levels, and isolated low free thyroxine levels) is increased. In addition, Graves disease, which is marked by low thyroid-stimulating hormone and elevated thyroxine levels, may occur during immune reconstitution. Testing for thyroid disease among symptomatic patients should begin with measurement of the thyroid-stimulating hormone level. However, there is insufficient evidence to recommend routine thyroid screening of asymptomatic HIV-infected individuals. This review summarizes the current evidence regarding the optimal laboratory evaluation of thyroid function; highlights the causes, presentation, and treatment of thyroid dysfunction in HIV-infected patients; and discusses the controversies regarding screening.