A 70-year-old man with systolic heart failure presents with dyspnea and orthopnea. He receives aggressive loop diuretic therapy and becomes euvolemic within 48 hours. Vitals: BP 128/76, HR 92, RR 16, SpO2 98% on room air. He now reports generalized weakness without dyspnea. Labs show pH 7.49, HCO3− 34 mEq/L, chloride 90 mEq/L, and potassium 3.2 mEq/L. Urine chloride is 8 mEq/L. Which mechanism best explains his alkalosis?
- A)Retention of ketoacids
- B)Bicarbonate loss in the stool
- C)Loss of chloride-rich fluid with volume contractionGABARITO
- D)Retention of hydrogen ions due to hypoventilation
- E)Failure of distal H+ secretion
Explicação
Loop diuretics can produce contraction alkalosis by causing loss of chloride-rich fluid, activating RAAS, and increasing distal sodium delivery that drives hydrogen and potassium secretion. The low chloride and recent diuresis are classic clues. Ver explicação completa e trilha adaptativa →