Post-infectious glomerulonephritis.

Post-infectious glomerulonephritis (PIGN) is one of the most common causes of acute glomerulonephritis in children. Although post-streptococcal glomerulonephritis (PSGN) is still common, there is a wide spectrum of causative agents of PIGN. Non-streptococcal organisms are emerging as the main aetiological agents in high-income countries. Nephritis-associated plasmin receptor (NAPlr) and streptococcal pyrogenic exotoxin B (SPeB) are the two common antigens implicated in the pathogenesis of PSGN. Both NAPlr and SPeB activate the alternative complement pathway, resulting in low serum complement levels, and have an affinity to plasmin and glomerular proteins. The clinical presentation of PIGN varies from a benign asymptomatic condition to rapidly progressive glomerulonephritis requiring dialysis. In most cases, PIGN is self-limiting and the evidence base for the treatments used is quite weak. Renal biopsy is indicated when there are atypical features, rapid progression or inadequate recovery, or where an alternative diagnosis has to be considered. IgA-dominant nephritis, endocarditis-associated nephritis and shunt nephritis are special sub-subtypes of PIGN. The prognosis is generally excellent, although long-term follow-up may be needed.