A 38-year-old woman presents to the clinic with a 3-month history of progressive headaches, polyuria, and muscle weakness. Her blood pressure is 162/98 mmHg. Laboratory studies show: Serum electrolytes: - Na+ 148 mEq/L - K+ 2.8 mEq/L - Cl- 102 mEq/L - HCO3- 38 mEq/L Arterial blood gas: - pH 7.48 - PaCO2 48 mmHg - PaO2 95 mmHg Plasma aldosterone 24 ng/dL (normal <12 ng/dL) Plasma renin activity 0.3 ng/mL/hr (normal 0.6-3.0 ng/mL/hr) Urine chloride 28 mEq/L Urine output 2.5 L/day Which of the following best explains why the urine chloride level is elevated in this patient?
- A)Impaired proximal tubule reabsorption of sodium and chloride due to metabolic acidosis
- B)Resistance of the collecting duct to aldosterone, preventing sodium reabsorption and chloride retention
- C)Continued delivery of sodium and chloride to the distal tubule due to aldosterone-mediated volume expansion, exceeding the tubule's reabsorptive capacityGABARITO
- D)Loss of gastric hydrochloric acid from recurrent vomiting or nasogastric suction
- E)Acute kidney injury with inability to concentrate urine appropriately
Explicação
In primary hyperaldosteronism, elevated aldosterone promotes sodium reabsorption and potassium excretion in the collecting duct. This increases intravascular volume and delivers excess sodium and chloride to the distal nephron. Despite enhanced aldosterone act... Ver explicação completa e trilha adaptativa →