A 70-year-old man with heart failure (EF 35%) and Stage 3b chronic kidney disease presents with weakness and palpitations. Vitals: BP 128/76 mmHg, HR 92/min, RR 16/min, Temp 37°C, SpO2 98% on room air. One month after starting spironolactone, labs show serum potassium 6.2 mEq/L (normal 3.5-5.0), creatinine 2.1 mg/dL (baseline 1.8), and normal magnesium. No concurrent ACE inhibitor use is documented. Which mechanism best explains the hyperkalemia?
- A)Displacement of potassium from intracellular stores to plasma
- B)Increased proximal tubule reabsorption of filtered potassium
- C)Direct inhibition of Na-K-ATPase pump activity
- D)Aldosterone antagonism reducing urinary potassium excretion in collecting ductGABARITO
- E)Enhanced glomerular filtration of potassium-albumin complexes
Explicação
Spironolactone is a potassium-sparing diuretic that blocks aldosterone receptors in the collecting duct. Aldosterone normally promotes sodium reabsorption and potassium secretion. Without aldosterone activity, potassium is retained. This risk is magnified in r... Ver explicação completa e trilha adaptativa →