Rapidly progressive crescentic glomerulonephritis: Early treatment is a must.

The term crescentic glomerulonephritis (GN) refers to a pathologic condition characterized by extracapillary proliferation in >50% of glomeruli. Clinically crescentic GN is characterized by a nephritic syndrome rapidly progressing to end stage renal disease (ESRD). Three types of crescentic GN have been identified. Type 1 includes cases of Goodpasture syndrome characterized by linear deposits of antibodies along the glomerular basement membrane (GBM) at immunofluorescence. Type 2 is a heterogeneous group of primary or secondary glomerular diseases complicated by crescentic GN. In this category there are granular deposits of immunoglobulins and complement fractions on the glomerular tuft. Type 3 includes cases of ANCA-associated small-vessel vasculitis. Immunofluorescence is negative or may show only faint deposits of immunoglobulins. The etiology and the initial pathogenetic factors are different in the three types, but the final mechanisms leading to crescent formation and the renal symptoms and signs are similar. The prognosis depends on the timeline of diagnosis and treatment. Although some patients requiring dialysis may recover a good renal function, usually the higher the serum creatinine at presentation the worse the outcome. When treatment is initiated early, most patients obtain a complete or partial remission. High-dose corticosteroids and cyclophosphamide represent the standard therapy for crescentic GN. The addition of plasma exchange may also be helpful, particularly in patients with massive alveolar hemorrhage. Anti-B monoclonal antibodies have also been used in some patients with crescentic GN, but their role in this particular area is still poorly established.