Four children and 2 adults are currently being followed in a nephrology clinic for poststreptococcal glomerulonephritis. Three patients initially had gross hematuria and edema requiring diuretic administration. The remaining 3 patients had microscopic hematuria and hypertension. C3 levels were decreased in all patients, and antistreptolysin O titer was elevated in 4 of them. None of the patients have preexisting renal disease. Which of the following patient characteristics is most likely to indicate a poor long-term prognosis?
Poststreptococcal glomerulonephritis (PSGN) is the most common cause of acute pediatric glomerulonephritis (GN) and presents with acute onset of malaise, periorbital edema, hypertension, and either microscopic or gross hematuria. Symptoms generally occur 1-3 weeks following group A streptococcal pharyngitis or skin infection (eg, impetigo). The lag in symptoms corresponds to formation and deposition of the streptococcal antigen and antibody complex within the glomerular basement membrane and the subsequent activation of complement.
PSGN most commonly affects children age 5-12, and >95% recover completely. Increased age, conversely, is the most important poor prognostic factor; only 60% of adult cases resolve completely, and many of the remainder have residual hypertension, recurrent proteinuria, chronic renal insufficiency, or rapidly progressive GN resulting in end-stage renal disease.
(Choices B, D, and E) Elevated antistreptolysin O (ASO) titers and low C3 levels are present in the vast majority of patients with PSGN. ASO titers indicate recent streptococcal (usually pharyngeal) infection. C3 is decreased due to complement activation with deposition in the glomerulus. Initial urinalysis may show hematuria, proteinuria, and red blood cell casts, but none of these findings affect prognosis.
(Choice C) Corticosteroids are used in minimal change disease (the most common cause of nephrotic syndrome in children) but not in PSGN.
Educational objective:
Poststreptococcal glomerulonephritis presents with edema, hypertension, and hematuria after a streptococcal infection. Most children recover completely, but adult patients have a relatively poor prognosis and higher risk of chronic hypertension and renal insufficiency.