Rapidly progressive(RPGN) is a syndrome characterized by nephronal hematuria(red blood cell casts and/or dysmorphic red blood cells) with renal failure developing over weeks to months and diffuse glomerular crescent formation evident on renal biopsy.
Classification is complicated by the fact that RPGN can occur with immune deposits(either anti-GBM or immune complex type) or without immune deposits. In addition, it can be an idiopathic primary glomerular disease or can be superimposed on other glomerular diseases either primary or secondary .
The classification scheme used here is based on the immunofluorescence information obtained from renal biopsy. Anti-GBM GN, characterized by linear capillary loop staining with IgG and C3 and extensive crescent formation, accounts for 10% to 20% of all cases of RPGN, although overall it accounts for less than 5% of all forms of GN. About two thirds of these patients syndrome with associated pulmonary have Goodpasture’s hemorrhage. The remainder have an idiopathic anti-GBM GN. The pathogenesis of anti-GBM antibody disease appears to be linked to the development of autoinmmunity to the noncollagenous domain of the a3 chain of type IV collagen(NCIa3 IV), and there is a strong association with human leukocyte antigen HLA-DR2. Good pasture’s syndrome affects young men six times more frequently than women and usually presents as hemoptysis and dyspnea. Idiopathic anti-GBM GN is seen in older patients(older than 50 years) and affects both sexes equally. Anti-GBM antibodies are present in(detectable using indirect immunofluorescence on normal kidney); serum is normal. consists of high-dose oral prednisone, cytotoxic agents such as cyclophosphamide, and plasma exchange. A high index of suspicion resulting in earlier diagnosis and vigorous treatment has increased survival to more than 50%, as opposed to 10% to 15% a decade ago, Immune complex RPGN is almost always associated with another underlying disease, and the correct diagnosis can usually be made by seeking the other clinical and is laboratory features of these conditions. About 30% of all cases of RPGN are of this type(gran deposits of immunoglobulins and complement) Non-immune-mediated RPGN(also called pauci immune GN) is found in about 50% of patients with crescentic GN and is seen in association with one of the systemic vasculitides such as polyarteritis nodosa or Wegener’s granulomatosis or as an idiopathic form that is thought to represent a vasculitis limited to the glomerular capillaries.
The idiopathic form is usually found in patients in their 50s or 60s. A helpful diagnostic is the presence of ANCA, which is found in approximately 80% of patients with pauci-immune GN. is detected by indirect immunofluorescence, two major patterns are observed: cytoplasmic staining(C-ANCA) and perinuclear staining(P-ANCA) NCA is most common in pauci-immune necrotizing and crescentic GN and in patients with microscopic polyarteritisnodosa. Patients with sinus involvement(Wegener’s granulomatosis) commonly have CANCA, although there is a great deal of overlap.
Because of the success in treatment of Wegener’s granulomatosis with cytotoxic agents such as cyclophosphamide and corticosteroids, patients with GN receive a similar type of treatment, although the duration of treatment with not been resolved.