Autoimmune adrenalitis is the most common cause of primary adrenal insufficiency in developed countries. It destroys which tissue of the adrenal gland?

• A. Adrenal cortex
• B. Adrenal medulla
• C. Hypothalamus
• D. Pituitary

Answer: (A)

autoimmune adrenalitis destroys the adrenal cortex, the outer layer of the gland that makes cortisol, aldosterone, and androgens. In primary adrenal insufficiency, loss of cortical tissue impairs both glucocorticoid and mineralocorticoid production, leading to fatigue, hypotension, hyponatremia, hyperkalemia, and hyperpigmentation from elevated ACTH. The adrenal medulla, which makes catecholamines, is not the primary target of this autoimmune process, so its function is typically preserved. Problems in the hypothalamus or pituitary cause secondary or tertiary adrenal insufficiency, not primary, because the issue is outside the adrenal gland itself. In developed countries, autoimmune destruction of the cortex is the most common cause of primary adrenal insufficiency, unlike infections or hemorrhage which affect other scenarios.