Renal amyloidosis is characterized by progressive deposition of extracellular material, most commonly in the glomeruli. Most often, patients present with nephrotic range proteinuria and the disease progresses gradually to renal failure. We report a case of crescentic glomerulonephritis superimposed on amyloidosis, clinically presenting as rapidly progressive renal failure, and present a review of the literature. Glomeruli are involved in 75 90% of cases, clinical correlate of which is nephrotic range proteinuria and slow progression to chronic kidney disease. It is seldom appreciated that extracapillary glomerulonephritis may be superimposed on amyloidosis in such cases. A 50 year old man presented with the complaint of swelling of feet and facial puffiness of 1 month duration accompanied by oliguria. He was not a diabetic or hypertensive and had no significant illness in the past.

Abdominal examination showed the presence of ascites without any evidence of organomegaly. Laboratory examination showed hemoglobin of 10 mg/ dl, total leukocyte count of 14.4 x0d7 10 9 /l with 76% of polymorphs in differential count. Biochemical parameters were as follows: random blood sugar 127 mg/dl, serum creatinine 1.4 mg/dl, blood urea 34 mg/dl, and serum albumin 0.9 g/dl. Urine analysis showed 3+ protein, 2 x02013 3 pus cells/hpf, and inactive sediments.

Abdominal sonogram showed moderate ascites with bilateral pleural effusion and bilateral normal sized kidneys. X0201d renal biopsy was carried out to ascertain the nature of glomerular pathology. Light microscopy showed 24 glomeruli, all of which showed pale, eosinophilic, acellular, weakly periodic acid schiff pas positive material in the mesangium and basement membrane, focally forming nodules figure 1 . Minimal amount of amyloid material was seen in the wall of interlobular arteries. Immunofluorescence showed ten viable glomeruli that were negative for igg, iga, igm, c3c, c1q, and fibrin. Immunohistochemical studies were positive for amyloid a protein in the deposits figure 2 .

A diagnosis of renal amyloid a aa amyloidosis causing secondary nephrotic syndrome was reached and the patient was put on enalapril, atorvastatin, and diuretics. Rapidly progressive glomerulonephritis rpgn is a disease of the kidney characterized clinically by a rapid decrease in the glomerular filtration rate gfr of at least 50% over a short period, from a few days to 3 months. The ubiquitous pathological feature of crescentic glomerulonephritis is a focal rupture of glomerular capillary walls that can be seen by light microscopy and electron microscopy. The term rapidly progressive glomerulonephritis was first used to describe a group of patients who had an unusually fulminant poststreptococcal glomerulonephritis and a poor clinical outcome. Several years later, the antiglomerular basement membrane anti gbm antibody was discovered to produce a crescentic glomerulonephritis in sheep, and, following this discovery, the role of anti gbm antibody in goodpasture syndrome was elucidated. Soon afterward, the role of the anti gbm antibody in rapidly progressive glomerulonephritis associated with goodpasture disease was established.

In the mid 1970s, a group of patients was described who fit the clinical criteria for rapidly progressive glomerulonephritis but in whom no cause could be established. Many of these cases were associated with systemic signs of vascular inflammation systemic vasculitis , but some cases were characterized only by renal disease. A distinct feature of these cases was the virtual absence of antibody deposition after immunofluorescence staining of the biopsy specimens, which led to the label pauci immune rapidly progressive glomerulonephritis. More than 80% of patients with pauci immune rapidly progressive glomerulonephritis were subsequently found to have circulating antineutrophil cytoplasmic antibodies ancas , and, thus, this form of rapidly progressive glomerulonephritis is now termed anca associated vasculitis. Rapidly progressive glomerulonephritis is classified pathologically into three categories, as follows: 1 anti gbm antibody disease approximately 3% of cases , 2 immune complex disease 45% of cases , and 3 pauci immune disease 50% of cases. A classification based on pathology, with the clinical syndromes and the anca status described under each pathological description, is outlined below.

Michael berger 1 and thomas petrusick 1 1 departments of pediatrics and pathology, divisions of nephrology and renal immunopathology, the university of texas medical branch, galveston, texas usa 77550 correspondence: r. Department of pediatrics, division of nephrology, the university of texas medical branch. Galveston, tx 77550 usa summary: the clinical course and outcome of rapidly progressive glomerulonephritis rpgn of variable etiology are not well defined in children. The present investigation reports on the clinical characteristics, the course and outcome, as well as the results of treatment of 13 children with apparent postinfectious rpgn.