[Early diagnosis of rapidly progressive glomerulonephritis]

The term rapidly progressive glomerulonephritis (RPGN) designates a group of glomerular diseases with different pathogenetic and clinical features, rapidly leading to renal or patient death in about 90% of the untreated cases. Histopathologically, it is characterized by glomerular crescents in at least 50-75% of the glomeruli (necrotizing crescentic glomerulonephritis), and very often, glomerular necrosis. The situation is, however, potentially reversible if adequately treated, and a favourable outcome depends largely on early diagnosis and treatment. Early diagnosis can be achieved if due importance is given to even seemingly unspecific manifestations such as "flu like syndrome" associated with "glomerular" hematuria. These manifestations are detectable before the down-hill course of renal functional derangement becomes evident and should lead the physician to consider RPGN among the diagnostic possibilities. Final diagnosis rests on serological tests and kidney biopsy. The battery of diagnostic serological tests (anti-GBM, anti-DNA antibodies, cryoglobulins, etc.) has recently been enriched by the assay of anti-neutrophil cytoplasmic antibodies (ANCA). These antibodies are detectable in over 90% of cases of Wegener's granulomatosis and primary necrotizing crescentic glomerulonephritis with or without lung involvement. ANCA-associated glomerulonephritis is the commonest form of RPGN, and the new serological assay provides an important tool for its early recognition. Renal biopsy is necessary to evaluate the severity of the nephritic process and modulate treatment accordingly. Timely diagnosis is one of the most important factors contributing to successful treatment outcome over both the short and the long term.