Rapidly progressive glomerulonephritis

Rapidly progressive glomerulonephritis (RPGN) is a clinical syndrome of hematuria, proteinuria and progressive renal decline, the most severe type of glomerulonephritis, usually pathologically crescentic nephritis. RPGN accounts for 2% of renal biopsies and 7 per million population, and is a common critical nephrology emergency. It starts abruptly and progresses rapidly; without timely treatment over 90% die within 6 months or survive on dialysis. Early pathologic diagnosis and targeted treatment improve prognosis.

Common Symptoms

Zhan Siqiao; hematuria; anuria; oliguria; proteinuria

Causes

(1) Etiology. Cases with extrarenal manifestations or a clear primary disease are secondary RPGN (allergic purpura, SLE), occasionally secondary to primary GN such as mesangiocapillary GN and membranous nephropathy; those with unknown cause are primary RPGN, the focus here. Over half of primary RPGN have an upper respiratory precursor infection; a few are typical streptococcal, others viral; coxsackie B5 serologic evidence exists, but influenza titers do not rise. A few have tuberculin sensitization and develop it on rifampin. Classification: 1. Primary glomerular diseases. 2. Idiopathic crescentic GN: (1) Type I anti-GBM antibody (without pulmonary hemorrhage). (2) Type II immune-complex. (3) Type III pauci-immune (70%-80% being small-vessel vasculitis or ANCA-positive). 3. Membranoproliferative nephritis: membranous nephropathy, IgA nephropathy, secondary GN. 4. Goodpasture syndrome. 5. Post-infectious nephritis: post-streptococcal, post-endocarditis, post-sepsis. 6. Secondary to other systemic disease: purpura nephritis, lupus nephritis, Takayasu arteritis, Wegener granulomatosis, scleroderma, cryoglobulinemia. Chemical poisons, hydrocarbon exposure, penicillamine-D, hydralazine may cause type I; HLA-DR2 in over 85% of type I. (2) Mechanism, 3 immunopathologic types. 1. Anti-GBM antibody deposition (type I): over 30% have linear IgG, occasional IgA, often with C3; anti-GBM antibodies cross-react with tubular and pulmonary basement membranes, causing pulmonary hemorrhage. 2. Immune-complex deposition (type II): about 30% have positive serum immune complexes with granular IgG, IgM deposition. 3. Pauci-immune (type III): no immune deposits but focal segmental necrosis and neutrophil exudation; ANCA-positive, activating neutrophils to release lysosomal enzymes and oxygen radicals that degrade GBM. 4. Cell-mediated: about 1/3 lack immune deposits but have many monocytes and T cells (CD4, CD8, IL-2R+); depletion reduces proteinuria. In sum, crescents relate to GBM rupture; fibrinogen escapes into Bowman's space, and collagen fibroblasts form fibrosis within 1-2 days.

Treatment

Medication, rehabilitation therapy

Prevention

1. Rest, avoid fatigue, prevent infection, eat low-protein food, supplement vitamins, avoid nephrotoxic drugs. 2. During drug therapy, revisit every 1-2 weeks to monitor urinalysis, liver and kidney function. 3. After controlling active lesions, repeat renal biopsy. Protecting residual renal function, correcting low renal blood flow and preventing infection are important.

Recommended Department

It is recommended to visit the nephrology department; before the visit you may first book an appointment and connect with experts through this platform.

Warm reminder: The above information is provided for health education reference only and cannot replace professional medical diagnosis. If you have related symptoms, please seek care at a regular hospital in time.