An 8-year-old boy and his father visit the pediatrician's office with reports of a sudden onset of abdominal pain and reddish-brown urine. A urinalysis shows 4+ protein. On taking the boy's health history, the nurse learns that he had strep throat a little over a week ago. Assessment findings: Temp 100.6F, RR-22. HR-105, BP= 130/89 Which condition should the nurse suspect?

The correct answer is A: Acute glomerulonephritis. This condition presents with sudden onset abdominal pain, reddish-brown urine (hematuria), and proteinuria, as seen in the urinalysis with 4+ protein. The history of recent strep throat suggests post-streptococcal glomerulonephritis, a common cause in children. The elevated temperature, heart rate, and blood pressure are indicative of inflammation and volume overload, common in acute glomerulonephritis. Renal agenesis (B) is a congenital condition where one or both kidneys fail to develop, not consistent with the presentation. Nephrotic syndrome (C) typically presents with heavy proteinuria but without hematuria or abdominal pain. Polycystic kidney disease (D) is a genetic disorder presenting with kidney cysts, not acute symptoms like in this case.