IgA-Dominant Postinfectious Glomerulonephritis (IgA-PIGN) Is Frequent in Non-Diabetic Patients with Staphylococcus Aureus (SA) Infection
S Worawichawong, L Girard, K Trpkov, J Gough, D Gregson, H Benediktsson. University of Calgary, Calgary, Canada
Background: IgA-PIGN was first associated with methicillin-resistant Staphylococcus aureus (MRSA) infections in studies from Japan. Recent North American studies found an association with diabetic nephropathy, but it was also documented in non-diabetic patients.
Design: We identified 6 patients with dominant or co-dominant IgA-PIGN, representing 1% of 608 renal biopsies examined in our institution from 07/2007 to 08/2009, in a population-based practice. We reviewed the clinical presentation, the biopsy and microbiology findings, and we obtained patient follow-up.
Results: All patients (4 males, 2 females) presented with acute renal failure (creatinine range, 527-1086 µmol/L), hematuria, proteinuria and hypertension. Median age was 62 years (range, 46 to 86). Only one patient had diabetes mellitus, but no biopsy-proven diabetic nephropathy. Complements C3 and C4 were normal in 4 of 5 patients with available data; low C3 and C4 were seen in one patient each. All 6 patients had documented infections at the time of the biopsy. Three of 6 patients had SA infections confirmed within two weeks before renal biopsy; two were MRSA. CMRSA-10 (equivalent to USA-300), clone responsible for the ongoing communitywide MRSA epidemic was identified in one patient. On biopsy, diffuse proliferative endocapillary GN was found in 5 patients and membranoproliferative GN in one. Diffuse proliferative crescentic GN was seen only in one patient, but no crescents were found in the other patients. On immunofluorescence, IgA subepithelial and mesangial immune complexes were dominant in 4 patients and co-dominant with IgG in the remaining 2 patients. On electron microscopy, large subepithelial deposits (“humps”) measuring from 360-4100 nm, were found in all patients. Temporary hemodialysis was performed in 5 of 6 patients; only the diabetic patient remained on dialysis after 6 months. All non-diabetic patients improved their renal function (creatinine range, 99-155 µmol/L; mean follow-up 6 months). Creatinine however remained well above the previous baseline range of 65-77 µmol/L.
Conclusions: IgA-PIGN was mostly found in non-diabetic patients in this study, in contrast with some previous studies showing strong association with diabetic nephropathy. We confirm that IgA-PIGN is often associated with SA and MRSA infections and for the first time we found an association with CMRSA-10. Although renal function improved in all non-diabetic patients, full recovery was not seen in any of the patients during the follow-up.
Category: Kidney (does not include tumors)
Wednesday, March 24, 2010 1:00 PM
Poster Session VI # 237, Wednesday Afternoon