Vignette: A 45-year-old woman presents to the clinic complaining of weakness, fatigue, and an unexplained weight loss over the past two months. She also reports frequent urination and excessive thirst. Physical examination reveals multiple hyperpigmented patches around her neck and in the axillae. Laboratory results show hyperglycemia and low cortisol level. An ACTH stimulation test is performed, and the results confirm a diagnosis of adrenal insufficiency.
Which of the following additional findings is most likely in this patient?
A. Decreased skin turgor
D. Low plasma renin activity
E. Metabolic alkalosis
This patient's symptoms of weakness, fatigue, weight loss, hyperpigmentation, and laboratory findings of hyperglycemia and low cortisol level are suggestive of primary adrenal insufficiency or Addison's disease. This condition occurs due to the destruction or dysfunction of the adrenal cortex, leading to decreased production of glucocorticoids (cortisol), mineralocorticoids (aldosterone), and androgens. Aldosterone helps regulate electrolyte and fluid balance by increasing renal sodium reabsorption and potassium excretion. Therefore, deficiency in aldosterone, as seen in Addison's disease, often results in hyperkalemia (choice B) and hyponatremia (not listed), leading to symptoms such as weakness and fatigue. The hyperpigmentation seen in this patient is due to increased ACTH production as a result of decreased cortisol levels. ACTH shares a common precursor with melanocyte-stimulating hormone, which can lead to increased pigmentation.