Poststreptococcal acute glomerulonephritis superimposed on bilateral renal hypoplasia

An 8-year-old girl with preexisting chronic renal failure (CRF) due to bilateral renal hypoplasia presented with edema, gross hematuria and acute deterioration of renal function. The diagnosis of poststreptococcal acute glomerulonephritis (PSAGN) was made based on clinical presentation, red blood cell casts, low level of C3 and elevated antistreptolysin 0 titer. Her course was prolonged with serum creatinine increased from the baseline level of 1.1 mg/dl to 2.2 mg/dl, returning toward the baseline level (1.2 mg/dl) after one month. Serum creatinine then started to increase again. The slope of creatinine clearance over time became steeper after the episode of PSAGN. A severe course of PSAGN and subsequent deterioration of renal function have previously been reported in patients with diabetic nephropathy or focal glomerulosclerosis. The present case along with a literature review suggests that individuals with fewer nephrons are at higher risk of severe course and outcome of PSAGN. Conversely, patients with severe PSAGN may be born with fewer nephrons due to low birth weight, unrecognized renal hypoplasia or other unknown causes.