A 41-year-old man with recently diagnosed Cushing syndrome secondary to a pituitary corticotroph adenoma presents with hypertension (160/98 mmHg), tachycardia (102 bpm), and hypokalemia (K+ 2.9 mEq/L). Laboratory studies reveal hyperglycemia (285 mg/dL) and elevated 24-hour urinary free cortisol (450 mcg/24h). MRI confirms a 1.2-cm sellar mass. He denies polyuria. Which pathophysiologic mechanism best explains these metabolic derangements?
- A)Excess cortisol causes hypokalemia via renal potassium wasting and hyperglycemia via increased hepatic gluconeogenesisGABARITO
- B)Aldosterone deficiency leads to sodium retention and potassium depletion
- C)Impaired potassium absorption in the GI tract is the primary mechanism of hypokalemia
- D)ACTH excess directly stimulates pancreatic beta cells to produce insulin-resistant diabetes
- E)Concurrent catecholamine excess from adrenal medulla causes hypokalemia and hyperglycemia
Explicação
Excess cortisol causes multiple metabolic derangements: (1) Hypokalemia via enhanced renal potassium excretion through mineralocorticoid activity at the collecting duct and urinary potassium wasting; (2) Hyperglycemia via stimulation of hepatic gluconeogenesis... Ver explicação completa e trilha adaptativa →