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

Which condition is characterized by chronic adrenal insufficiency and diffuse hyperpigmentation?

1. Primary hyperparathyroidism

2. Primary B-cell lymphoma

3. Addison disease

4. Neuroblastoma

The correct answer is: Addison disease

The condition characterized by chronic adrenal insufficiency and diffuse hyperpigmentation is Addison disease. This disease typically results from damage to the adrenal glands, leading to insufficient production of cortisol and, in many cases, aldosterone. The lack of cortisol leads to a compensatory increase in adrenocorticotropic hormone (ACTH), which stimulates melanocyte activity and results in increased pigmentation. In Addison disease, patients may exhibit symptoms such as fatigue, weight loss, low blood pressure, and hyperkalemia, in addition to hyperpigmentation that is often most apparent in areas such as the gums, scars, and sun-exposed skin. This presentation aligns with the combined effects of adrenal hormone deficiency and elevated ACTH levels. Other conditions listed do not commonly result in the specific combination of symptoms found in Addison disease. For instance, primary hyperparathyroidism primarily causes hypercalcemia and does not involve adrenal insufficiency or hyperpigmentation. Primary B-cell lymphoma is a hematologic malignancy that presents with lymphadenopathy and systemic symptoms but does not typically relate to adrenal function or pigmentation changes. Neuroblastoma, which is most commonly seen in children, may cause various symptoms including abdominal masses and bone pain, but diffuse hyperpigmentation is not a defining characteristic.