Acute Glomerulonephritis (PSGN)

Know the epidemiology of Post Streptococcal GlomeruloNephritis in the USA

• Generally follows upper respiratory infection, pharyngitis, or tonsillitis by Group A beta hemolytic Streptococcus when occurring in temperate areas
• More common in winter and spring
• Follows skin infection in tropic areas
• Peak incidence in summer and fall

Know the possible antigens that trigger the formation of immune complex in Post Streptococcal GlomeruloNephritis

• M protein – found in cell wall
• Endostreptosin – intracellular
• Cationic proteins – secreted

Know the Light Microscopy, ImmunoFluorescence, and Electron Microscopy findings in Post Streptococcal GlomeruloNephritis

• Light Microscopy

• Parietal cell proliferation  crescents

• Mesangial and endothelial cells, mononuclear phagocytes

• T lymphocytes

• Early – Helper > Cytotoxic

• Later – equal or reverse

• Immuno Fluorescence - Coarsely granular deposits of IgG and C3 along glomerular capillary wall and in mesangium

• Electron Microscopy - Subepithelial nodules of electron dense deposits that resolve in ~8 weeks

Why does Post Streptococcal GlomeruloNephritis usually occur in patients between 3-12 years of age

• This is when most people first come into contact with a serious Group A beta-hemolytic Strep infection.

• Children younger than 2 will likely not have a sufficiently developed immune system to develop significant amounts of immune complexes.

Know the clinical presentation and evolution of Post Streptococcal GlomeruloNephritis . Is Nephrotic Syndrome commonly seen in Post Streptococcal GlomeruloNephritis ?

• Hematuria

• Dysmorphic RBCs

• RBC casts

• Proteinuria

• Elevation of BUN

• Rapidly Progressive GlomeruloNephritis in about 1% of cases

• Nephrotic syndrome – 20% of cases in recovery phase

Know the urine abnormalities and serology of Post Streptococcal GlomeruloNephritis

• Streptozyme positive

• Depressed complements

• Usually returns to normal in 6-8 weeks

• Alternative pathway indicated by depressed c3 and properdin

• Classical pathway occasionally indicated by depressed c2 and c4

Know how to make the diagnosis of Post Streptococcal GlomeruloNephritis . When is the renal biopsy needed?

• Based on clinical background

• Nephritic syndrome following Strep infection by appropriate latent period

• Serologic evidence of recent Strep infection

• Hypocomplementemia

• Biopsy required only with prolonged oliguria, hypocomplementemia, and nephrotic syndrome to rule out GlomeruloNephritis and Membrano Proliferative GlomeruloNephritis

Know the prognosis of Post Streptococcal GlomeruloNephritis in infants and adults

• 90% of children have complete spontaneous recovery w/in 4-7 days

• 67% of adults

• Some hematuria and proteinuria may persist for up to 2 years

Category: Pathology Notes