A 68-year-old man with hypertension presents with acute dyspnea and orthopnea. Vital signs: BP 168/95 mmHg, HR 110/min, RR 22/min, SpO2 88% on room air. He takes lisinopril but reports medication non-adherence for 2 weeks. Serum creatinine is 2.8 mg/dL (baseline 1.0), and urinalysis shows no proteinuria. Elevated angiotensin II causes marked efferent arteriolar constriction with modest renal plasma flow decrease. Which physiologic change occurs initially?
- A)Complete loss of autoregulation
- B)Decrease in filtration fraction
- C)No change in glomerular filtration rate
- D)Increase in urine pH only
- E)Increase in filtration fractionGABARITO
Explicação
Increase in filtration fraction is correct. Preferential efferent constriction tends to preserve or initially increase glomerular hydrostatic pressure and GFR while reducing renal plasma flow, so the ratio of GFR to renal plasma flow rises. This is an importan... Ver explicação completa e trilha adaptativa →