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. Which condition should the nurse suspect?
Explanation & Rationale
Choice A reason: Acute post-streptococcal glomerulonephritis (APSGN) commonly develops 1 to 3 weeks after an infection with group A beta-hemolytic streptococcus, typically following pharyngitis or impetigo. The immune response triggers the formation of antigen-antibody complexes that deposit in the glomeruli, causing inflammation and damage. This leads to hematuria (producing tea- or cola-colored urine), proteinuria, hypertension, periorbital edema, and reduced urine output. The presence of reddish-brown urine and a history of recent strep throat strongly indicate APSGN. Early recognition and management are crucial to prevent complications such as acute kidney injury and hypertension. Choice B reason: Kidney agenesis refers to the congenital absence of one or both kidneys. This condition is present at birth, not acquired after an infection. It would not present with sudden-onset hematuria, proteinuria, or a history of recent streptococcal infection. Therefore, it is not consistent with the symptoms described in this scenario. Choice C reason: A urinary tract infection (UTI) may cause hematuria and abdominal discomfort, but it would not result in significant proteinuria (4+) or occur following a strep throat infection. UTIs are typically associated with dysuria, urgency, and frequency rather than reddish-brown urine and systemic symptoms. Therefore, it is not the correct diagnosis. Choice D reason: Polycystic kidney disease (PKD) is a genetic disorder characterized by multiple cysts in the kidneys that progressively impair renal function. It presents chronically with hypertension, flank pain, and palpable abdominal masses—not acute post-infectious hematuria. The abrupt onset of symptoms following strep infection rules out PKD.