Pathophysiology
Clinical meaning
Acute postinfectious glomerulonephritis (APIGN) is an inflammatory condition of the glomeruli that occurs 1-3 weeks after a group A beta-hemolytic streptococcal infection, most commonly pharyngitis or impetigo. The immune system produces antibodies against the streptococcal antigens, and these antibody-antigen complexes deposit in the glomerular basement membrane, triggering inflammation and damage. This impairs the kidney's ability to filter blood properly, leading to fluid retention, hypertension, and characteristic cola-colored or tea-colored urine from blood leaking through the damaged glomeruli. The condition is most common in children ages 5-12 and is usually self-limiting with supportive care.