11 Interesting Facts of poststreptococcal glomerulonephritis (PSGN)
1. Postinfectious glomerulonephritis (PIGN) describes a unique sequence of events consisting of an infection followed by complete resolution with a subsequent latent period of 1 or more weeks before the development of an immune complex–mediated glomerulonephritis. Only streptococcal infections can conclusively cause this pattern; therefore the term poststreptococcal glomerulonephritis (PSGN) is preferred over PIGN. However, the two terms can be used interchangeably.
2. The course of PSGN begins 7 to 14 days after the onset of streptococcal pharyngitis, whereas it takes about 21 days for the development of glomerulonephritis after a skin infection.
3. The use of steroids or more aggressive forms of immunosuppression for PSGN has not been shown to alter the natural history of the disease and exposes the patient to the potential short- and long-term risks of immunosuppression.
4. In older adults, staphylococcal-associated acute glomerulonephritis (SAAG) is more common than PSGN, especially after skin and lung infections, with Staphylococcus aureus being the primary species cultured.
5. SAAG occurs coincident with the active infection, and there is no latent period.
6. Complement activation of the alternate pathway is found in both PSGN and SAAG.
7. Diffuse proliferative and exudative glomerulonephritis with subepithelial and scattered subendothelial and mesangial deposits is seen with both PSGN and SAAG.
8. IgA-dominant immunofluorescence is seen exclusively with SAAG and not with PSGN.
9. The immunofluorescent pattern in both SAAG and PSGN is described as a “garland” or “starry sky” appearance because of the subepithelial deposits.
10. SAAG has a significantly worse prognosis than PSGN, with more than half the patients developing chronic kidney disease or requiring dialysis.
11. The treatment of SAAG is strictly antibiotic therapy—immunosuppression is contraindicated due to active staphylococcal infection.
