A 75-year-old woman with heart failure on furosemide and ibuprofen presents with acute confusion. Vital signs show BP 92/58, HR 108, RR 20. Labs reveal Na+ 124 mEq/L, serum osmolality 265 mOsm/kg, urine osmolality 580 mOsm/kg, urine Na+ 45 mEq/L, and BUN 32 mg/dL with normal creatinine. Physical exam confirms hypovolemia with dry mucous membranes. Urine output is reduced. Which mechanism best explains her hyponatremia?
- A)Adrenal insufficiency from chronic loop diuretic use
- B)Primary SIADH from CNS disease or malignancy unmasked by diuretics
- C)NSAID-induced acute kidney injury with uremic hyponatremia
- D)Dilutional hyponatremia from excessive free water intake
- E)Diuretic-induced volume depletion stimulating ADH release despite low serum osmolalityGABARITO
Explicação
This is hypovolemic hyponatremia. Diuretics cause volume depletion, triggering ADH release as a compensatory mechanism to restore blood pressure, despite low serum osmolality. NSAIDs worsen by reducing renal perfusion. The concentrated urine and elevated urine... Ver explicação completa e trilha adaptativa →