Nephritic Syndrome PDF

# Nephritic Syndrome ## Basic Principles - Glomerular disorders characterized by glomerular inflammation and bleeding - Limited proteinuria (< 3.5 g/day) - Oliguria and azotemia - Salt retention with periorbital edema and hypertension - RBC casts and dysmorphic RBCs in urine -...

# Nephritic Syndrome ## Basic Principles - Glomerular disorders characterized by glomerular inflammation and bleeding - Limited proteinuria (< 3.5 g/day) - Oliguria and azotemia - Salt retention with periorbital edema and hypertension - RBC casts and dysmorphic RBCs in urine - Biopsy reveals hypercellular, inflamed glomeruli ## Poststreptococcal Glomerulonephritis (PSGN) - Nephritic syndrome that arises after group A β-hemolytic streptococcal infection of the skin (impetigo) or pharynx - Occurs with nephritogenic strains, which have M protein virulence factor - May occur after infection with nonstreptococcal organisms as well - Presents 2-3 weeks after infection as hematuria, oliguria, hypertension, and periorbital edema - Usually seen in children, but may occur in adults - Hypercellular, inflamed glomeruli on H&E - Mediated by immune complex deposition (granular IF); subepithelial ‘humps’ on EM - Treatment is supportive - Children rarely (1%) progress to renal failure - Some adults (25%) develop rapidly progressive glomerulonephritis (RPGN) ## Rapidly Progressive Glomerulonephritis (RPGN) - Nephritic syndrome that progresses to renal failure in weeks to months - Characterized by crescents in Bowman space (of glomeruli) on H&E stain; crescents are comprised of fibrin and macrophages - Clinical picture and IF help resolve etiology ### Immunofluorescence Findings in Rapidly Progressive Glomerulonephritis | Immunofluorescence Pattern | Disease | Comments | |---|---|---| | Linear (anti-basement membrane antibody) | Goodpasture syndrome | Antibody against collagen in glomerular and alveolar basement membranes, presents as hematuria and hemoptysis, classically in young, adult males | | Granular (immune complex deposition) | PSGN (most common) or diffuse proliferative glomerulonephritis | Diffuse proliferative glomerulonephritis is due to diffuse antigen-antibody complex deposition, usually sub-endothelial, most common type of renal disease in SLE | | Negative IF (pauci-immune) | Wegener granulomatosis, microscopic polyangiitis, and Churg-Strauss syndrome | Wegener granulomatosis is associated with c-ANCA, microscopic polyangiitis and Churg-Strauss are associated with p-ANCA. Granulomatous inflammation, eosinophilia and asthma distinguish Churg-Strauss from microscopic polyangiitis. | ## IgA Nephropathy (Berger Disease) - IgA immune complex deposition in mesangium of glomeruli; most common nephropathy worldwide - Presents during childhood as episodic gross or microscopic hematuria with RBC casts, usually following mucosal infections (e.g., gastroenteritis) - IgA production is increased during infection - IgA immune complex deposition in the mesangium is seen on IF (Fig. 12.16) - May slowly progress to renal failure ## Alport Syndrome - Inherited defect in type IV collagen, most commonly X-linked - Results in thinning and splitting of the glomerular basement membrane - Presents as isolated hematuria, sensory hearing loss, and ocular disturbances