P0257CLINICOPATHOLOGICAL SPECTRUM OF KIDNEY INVOLVEMENT IN MONOCLONAL GAMMOPATGY

Abstract Background and Aims The occurrence of kidney diseases associated with a monoclonal gammopathy is increasingly recognized.Renal biopsy and evaluation by light microscopy, electron microscopy and immunofluorescence,in association with adequate clinical examination are essential in accurate diagnosis. The objective of our study is to describe the types of kidney damage secodary to monoclonal gammopathies and to study its renal prognosis. Method It is a monocentric RETOSPECTIVE DESCRIPTIVE STUDY carried out in the nephrology department of CHU FATTOUMA BOURGUIBA MONASTIR spread over a period of 7 years from January 2012 to December 2018. Results we collected 40 cases of monoclonal gammopathies. The median age was 61 years.The sex ratio was 0,9. the circumstances of discovery were dominated by renal failure. it revealed the diagnosis in 77.5% of cases. the renal presentation proteinuria in 70%, microscopic hematuria in 12.5%, edematous syndrome in 27.5% and nephrotic syndrome in 37,5%. The mean creatinine level was 500 umol / L and proteinuria at 4,3 g / 24 h with a maximum rate of 17.5 g / 24h. the electrophoresis of serum proteins showed the presence of a monoclonal peak in 90% of the cases in the gamma zone. The plasmocytosis was less than 10% in 15% of cases and more than 60% in 22,5% of the cases. Radiology showed bone localizations in 32,5% of cases. These gammopathies were classified as Multiple myeloma in34 patients, POEMS in one case and 5 MGRS. Kidney biopsy was performed in 10 patients showing cast nephropathy, AL amyloidosis and vasculites(endocapillary glomerulonephritis with hyaline thrombi in all vessels and double contour appearance of the glomerular basement membrane) in respectively 12,5%, 7,5% and 2,5% of cases. the main indications were rapidly progressive renal failure, unexplained acute renal failure and nephrotic syndrome. The renal involvement retained was a myeloma tubulopathy in 28 patients, 3 of whom were confirmed histologically . AL amyloidosis was found in 5 patients and the confirmation was histological. Type 1 cryoglobulinemia was diagnosed in only one patient. Glomerular nephropathy remained undetermined in 6 patients whose PBR was indicated but not made in the presence of hemostasis disorders. The chemotherapy was started in 34 patients based on bortezomide-thalidomide-dexamethasone in 30% of cases. An autograft of the bone marrow was done in one patient. Hemodialysis was required in 15 patients. The renal function was improved in 42.5% of the cases and a passage on chronic hemodialysis in 10% of cases. 10% of patients have achieved complete hematological remission. Conclusion Patients with MG can develop a large variety of related renal lesions.Renal involvement darkens the prognosis hence the need for adequate care .