USMLE (United States Medical Licensing Examination) Step 1 Practice Exam

Which autoimmune condition involves the destruction of the pituitary gland during or after pregnancy?

1. Empty sella syndrome

2. Estrogen Effects on TBG and Thyroid Hormones

3. Lymphocytic hypophysitis

4. Subacute granulomatous thyroiditis

The correct answer is: Lymphocytic hypophysitis

The correct answer is the condition known as lymphocytic hypophysitis. This autoimmune condition is characterized by the infiltration of lymphocytes into the pituitary gland, leading to inflammation and ultimately destruction of pituitary tissue. It is particularly associated with pregnancy and the postpartum period, during which it can manifest due to hormonal changes and an altered immune response. In lymphocytic hypophysitis, the inflammatory process primarily targets the pituitary gland, which can result in various hormonal deficiencies, impacting the patient's overall endocrine function. The symptoms may include fatigue, loss of libido, and other signs of pituitary hormone deficiency, which align with the timing of onset that often occurs during or after pregnancy. The other conditions mentioned are not associated with the autoimmune destruction of the pituitary gland. For example, empty sella syndrome describes a condition where the sella turcica (the bony structure housing the pituitary gland) appears empty, often due to an enlargement of the subarachnoid space; it isn’t specifically immune-mediated. Estrogen effects on thyroid-binding globulin (TBG) and thyroid hormones involve thyroid hormone regulation rather than pituitary destruction. Subacute granulomatous thyroiditis, often referred to as de Quervain's thyroiditis