A 27-year-old woman presents with weight loss, fatigue, and weakness. She also experiences nausea and vomiting but no dysphagia. Her physical examination is normal except for increased generalized skin pigmentation. Her serum sodium is low and potassium is high. Which of the following features is also most likely to be present? (See Figure below.)
High-Yield Explanation
Water diuresis is impaired in adrenocortical insufficiency. Lack of aldosterone also favors the development of hyperkalemia and mild acidosis. The decreased circulating volume, secondary to aldosterone deficiency, is one of the factors resulting in elevated basal antidiuretic hormone (ADH) levels and thus hyponatremia.