Glomerular Pathology Associated with Nephritic Syndrome

Info

🌱 來自: Huppert’s Notes

Glomerular Pathology Associated with Nephritic Syndrome🚧 施工中

Glomerular Pathology Associated with Nephritic Syndrome

Post-streptococcal glomerulonephritis

•   Epidemiology: More common in children

•   Pathophysiology: Glomerular damage is due to deposition of anti-streptococcal Ab in the glomeruli, so hematuria, hypertension, edema begin 1–3 weeks after infection with Streptococcus bacteria

•   Diagnosis: Anti-streptolysin O may be elevated; low complement

•   Treatment: Supportive: Antihypertensives, loop diuretics, steroids if severe; majority of cases self-resolve in weeks to months

IgA nephropathy (Berger disease)

•   Pathophysiology: Caused by deposition of dysregulated IgA immune complexes

•   Clinical features:

-   Usually immediately preceded by or co-presenting with respiratory or GI infection (“syn-pharyngitic” hematuria as opposed to post-streptococcal GN, which occurs weeks after pharyngitis); can also be “silent” and go undetected for years

-   Manifests as episodic gross hematuria (more common in patients <25 yr) or persistent microscopic hematuria (more common in patients >25 yr)

-   Can be primary or secondary to systemic IgA vasculitis

•   Diagnosis: Mesangial deposits of predominantly IgA immune complexes on biopsy. Complement levels are often normal.

•   Treatment: No effective treatment, some advocate for steroids or fish oil; most patients have good prognosis

Membranoproliferative GN

•   Pathophysiology: Hypercellularity and thickening of GBM on light microscopy

-   Type I (subendothelial GN): Immune complex mediated, typically caused by infections (e.g., HBV, HCV, endocarditis, schistosomiasis)

-   Type II (dense deposit disease): Complement mediated, rare, typically in children, but also occurs in adults with monoclonal gammopathy

•   Treatment: Treat underlying cause, immunosuppression with steroids if idiopathic

Rapidly progressive (crescentic) glomerulonephritis (RPGN)

•   Clinical features: Acute decline in renal function over days to weeks due to severe glomerular injury

•   Diagnosis: Light microscopy with crescents in >50% of glomeruli due to fibrin formation and macrophages. Pathology and immunopathology distinguish between the three major etiologies:

-   Anti-GBM disease: Autoantibody to type IV collagen; called Goodpasture’s syndrome when kidney and lung are involved. Linear immunofluorescence. Treatment: Cyclophosphamide, steroids, plasmapheresis.

-   Immune complex disease: Can be caused by systemic infections (e.g., post-streptococcal glomerulonephritis, infective endocarditis), systemic immune complex disease (e.g., IgA vasculitis, SLE) or primary GN (e.g., IgA nephropathy). Granular immunofluorescence.

-   Pauci-immune disease: Due to small-vessel vasculitis (GPA, EGPA, MPA) or can be drug-induced (penicillamine, hydralazine). Absence or paucity of glomerular staining for immunoglobulins. Most are ANCA-positive (80%)