Acute Post-Streptococcal Glomerulonephritis in a 22-Month-Old Toddler: A Rare and Uncustomary Age of Onset.

Acute post-streptococcal glomerulonephritis (APSGN) is an important immunological complication that follows Group A Streptococcus (GAS) infections. It usually affects children between 5 and 15 years of age and is rarely seen in children younger than 3 years, likely because their immature immune systems limit the exaggerated immune response. The condition typically presents with hematuria, edema, hypertension, and renal insufficiency. Diagnosis is supported by elevated antistreptolysin O (ASO) titers, low complement levels, and a recent history of GAS infection. Although the prognosis in children is generally good, APSGN continues to be a significant concern in regions where GAS is endemic. A 22-month-old girl, previously healthy, developed periorbital swelling, generalized edema, and tea-colored urine after a recent upper respiratory tract infection. Laboratory tests showed proteinuria, hematuria, reactive ASO titers, and mild anemia, while imaging studies were unremarkable. Based on clinical and laboratory findings, APSGN was diagnosed. She was managed with furosemide, nifedipine, and ceftriaxone. Her condition improved markedly, with complete resolution of hematuria and proteinuria within 2 months. ASO titers returned to normal, and renal function was fully restored. This case demonstrates the uncommon occurrence of APSGN in children under 3 years of age and stresses the importance of including it in the differential diagnosis of nephritic syndrome in toddlers. The excellent outcome in this patient reflects the generally favorable prognosis of APSGN in pediatric populations. Early recognition and treatment remain essential, as GAS infections in infants, though less common, can still lead to post-infectious complications such as APSGN.