A 58-year-old woman abruptly discontinues high-dose prednisone used for autoimmune disease. She presents with fatigue, nausea, and abdominal pain. Vital signs show BP 88/54 mmHg, HR 102/min, RR 18/min, temp 37°C. Laboratory studies reveal cortisol 2 μg/dL (normal 10-20), ACTH 8 pg/mL (normal 7-46), potassium 4.2 mEq/L, and glucose 95 mg/dL. Which mechanism best explains her clinical presentation and preserved electrolyte homeostasis?
- A)Posterior pituitary failure increases mineralocorticoid release
- B)Zona glomerulosa is destroyed by autoimmune disease
- C)Aldosterone is primarily regulated by the renin angiotensin systemGABARITO
- D)Cortisol directly inhibits renal potassium secretion
- E)TSH excess compensates for loss of ACTH
Explicação
Chronic glucocorticoid use suppresses the hypothalamic pituitary adrenal axis, causing secondary adrenal insufficiency when steroids are stopped abruptly. ACTH falls, so cortisol falls, but aldosterone remains largely intact because it is regulated mainly by t... Ver explicação completa e trilha adaptativa →