#6722 A RARE CASE OF ACUTE KIDNEY INJURY IN A PATIENT GRANULOMATOSIS WITH POLYANGIITIS, MONOCLONAL GAMMOPATHY WITH RENAL SIGNIFICANCE AND AMYLOIDOSIS
Authors: Nikolova Radina , Bogov Boris , Cankova Mila 
Published: June 2023

Abstract

Introduction
Anti - neutrophil cytoplasmic antibody /ANCA/- associated vasculitis is a small vessel vasculitis. It is a rare, autoimmune, inflammatory disease, with undetermined etiology, including granulomatosis with polyangiitis, microscopic polyangiitis, eosinophilic granulomatosis with polyangiitis. It could lead to pauci - immune necrotizing and crescentic glomerulonephritis and rapidly progressive glomerulonephritis. Monoclonal gammopathy of renal significance /MGRS/ is a plasma cell or B-cell disorder that could lead to renal impairment due to production of monoclonal protein, which do not meet the criteria for myeloma multiplex. There is a significant higher risk in progression to end stage renal disease/ESRD/ in groups with renal vasculitis and concomitant disease due to nonrenal factors.

Clinical case
We present a rare clinical case of a patient with combination of ANCA -vasculitis, MGRS and amyloidosis. A 60 year-old male patient with deteriorated renal function was presented to the clinic. Chronic congestive heart failure, arterial hypertension, situs inversus, anemic syndrome, hepatosplenomegaly were reported as concomitant diseases. Due to progressive worsening of renal function emergency hemodialysis treatment was initiated through temporary vascular access. Against the background of several chronic diseases, which could lead to chronic kidney failure, the echographic image of the kidneys stands out. Both kidneys are enlarged, with increased echogenicity of the parenchyma as in a diffuse renal process. The performed immunological tests confirm the diagnosis of granulomatosis with polyangiitis /formerly called Wegener's/, PR3-105,7. The results for the screened viral infections was negative. An episode of severe pulmonary edema was registered in the context of obstruction of the hemodialysis catheter due to coagulation disorders. The renal biopsy supports the diagnosis of vasculitis, crescentic glomerulonephritis - in advanced stage of development, probably a morphological manifestation of secondary nephropathy. An interesting finding is the presence of amyloidosis /AL/. The immunofixation blood test identify monoclonal IgG kappa type component. A sternal puncture, SPECT/CT was performed and diagnosis of multiple myeloma was excluded. Pathogenic treatment with corticosteroids and cyclophosphamide was initiated. In addition a short-term change in vision is observed in the context of the underlying disease. A consultation with ophthalmologist and neurologist was held, confirming cerebral arteritis. At this stage the recovery of renal function is incomplete. High flux membrane were used during dialysis treatment to reduce large and middle sized molecules. In addition, for the treatment of light chain amyloidisis, bortezomib was considered.

Conclusion
This clinical case emphasizes on the need to precisely clarify the cause that led to acute kidney injury. A thorough search for the underlying disease causing the deterioration of kidney function is critical for the renal outcome. The reasons for incomplete recovery of renal function during active treatment of vasculitis should be sought in underlying diseases-arterial hypertension, chronic heart failure, amyloidosis.

Discussion
Younger patients with lower eGFR at the onset of ANCA-associated vasculitis and no concomitant disease show significant improvement in renal function by the end of the first year regardless the need of dialysis treatment. Patients with severe accompanying disease have slow and insufficient improvement in renal function due to the prevalence of higher percentage of globally sclerotic glomeruli. Considering the severe prognosis of ANCA-associated vasculitis it is crucial to start early treatment. The state of the renal function at the first year of pathogenic treatment along with the pathological findings of the renal biopsy could be a predictors for the renal function course.