Low attenuation of the thyroid on computed tomography as a marker of thyroiditis in a woman with acquired immune deficiency syndrome

Computed tomography (CT) is a less commonly ordered test in the diagnosis and management of hyperthyroidism. The attenuation of the thyroid on CT varies among different thyroid disorders and may provide insight into a patient's disease. We discuss the case of a woman with acquired immune deficiency syndrome who presented with fever, neck pain, and severe hyperthyroidism. On CT, her thyroid was diffusely enlarged with very low attenuation in the range typically seen with cysts. She was treated with beta blockers, antithyroid medication, and high-dose glucocorticoids, which resulted in improved, but still elevated, levels of thyroid hormones after several weeks. Shortly before her death from multiorgan failure, a fine needle aspiration of the thyroid was performed. Pathology revealed cells infected with cytomegalovirus, which was confirmed by immunohistochemistry. The exact cause of the thyroiditis is unknown, but we propose that the attenuation of the thyroid on CT, as well as the structural imaging findings on CT, provide useful clues in the diagnosis of hyperthyroidism in patients with acquired immune deficiency syndrome and other immunocompromised states.