Rapidly progressive nephritis

Rapidly progressive nephritis is short for acute rapidly progressive glomerulonephritis (APG). It has abrupt onset, with renal function deteriorating sharply over days, weeks or months, most often as oliguric (anuric) acute renal failure.

Common Symptoms

Decreased urine osmolality; hematuria; anuria; oliguria; proteinuria; increased urine calcium

Causes

Diseases causing rapidly progressive nephritis: (1) Primary glomerular diseases. 1. Primary diffuse crescentic nephritis: (1) Type I: linear IgG deposition (anti-GBM antibody-mediated). (2) Type II: granular IgG deposition (immune-complex-mediated). (3) Type III: little or no Ig deposition (pauci-immune). (4) ANCA-induced (vasculitis). 2. Secondary to other primary GN: membranoproliferative GN (especially type II), membranous GN with added anti-GBM nephritis, IgA nephropathy (rare). (2) With infectious diseases: acute post-streptococcal GN, acute or subacute infective endocarditis, chronic sepsis from visceral pyogenic foci and GN; other infections: shunt nephritis, hepatitis B virus nephritis, HIV. (3) With multisystem disease: SLE, pulmonary hemorrhage-nephritis syndrome, allergic purpura, diffuse vasculitis such as necrotizing granuloma, hypersensitivity vasculitis, mixed cryoglobulinemia, rheumatoid arthritis with vasculitis, malignancy and relapsing polychondritis. (4) Drugs: penicillamine, hydralazine, allopurinol and rifampin. Mechanism: (1) Light microscopy: early, many parietal and visceral epithelial cells proliferate in Bowman's capsule, overlapping into crescents or ring bodies; crescents may form within days; between proliferating cells are fibrin, multinucleate macrophages, neutrophils and red cells, involving up to about 80% of glomeruli; long-standing cases show collagen forming fibrous crescents. Crescent number and severity correlate with prognosis. Macrophages promote fibrinogen deposition and transform into epithelioid cells. Focal necrosis in crescentic tufts leads to capillary collapse, adhesion to the crescent, and finally hyalinization or fibrosis; interstitium may show infiltration, edema and fibrosis. (2) Immunofluorescence: granular immune complexes or linear anti-GBM antibodies; linear cases are mostly IgG-positive, about 1/2-2/3 with C3; immune-complex cases show C3, IgG and fibrin at damaged loops; over 70% have fibrin in crescents, absent in old ones. (3) EM: fresh crescent epithelial cells swell to 32 μm, with fibrin strands; endothelial and mesangial cells proliferate, basement membrane thickens, thins, ruptures or spikes; hump-like deposits may appear.

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 and growth. 3. After controlling active lesions, repeat renal biopsy to assess chronicity. Protecting residual renal function, correcting low renal blood flow (hypoproteinemia, dehydration, hypotension) 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.