Vasculitis affecting the kidney: presentation, histopathology and long-term outcome

Fifty-three patients who by clinical and/or histological criteria were judged to have vasculitis affecting the kidney were reviewed. Patients with systemic lupus or Sch?nlein-Henoch purpura were excluded. Segmental necrotising glomerulitis was taken as a manifestation of vasculitis ('microscopic polyarteritis'). Those patients in whom vasculitis was confined to glomerular capillaries were compared with those who in addition had vascular lesions outside the glomeruli. The two groups were found to have identical clinical features. Clinical presentation was predominantly extrarenal, and exclusively renal in only two. Three patients were classified histologically as Wegener's granulomatosis, four had malignant tumours and two relapsing polychondritis. Hepatitis B surface antigen was absent in all of 37 patients tested. Renal disease presented with microscopic haematuria and minor proteinuria in the majority (32) but 16 patients presented with rapid deterioration of renal function, including seven with anuria. Histologically 42 patients showed segmental necrotising glomerulitis ('microscopic polyarteritis'), six diffuse proliferative glomerulonephritis,and in five only minor or ischaemic glomerular changes were present. Crescents were found in 41/42 of those with segmental necrotising glomerulitis, nd involved more than 50 per cent of glomeruli in 15 patients. Immunohistochemical studies were generally negative except the fibrin. Electron microscopy showed no evidence of immune deposits in necrotising glomerulitis, but these were present in 2/6 patients with diffuse proliferative glomerulonephritis. Overall prognosis was poor, 35 patients having died, 20 early in the course of the disease and 15 later. Oligoanuria and extensive crescent formation were adverse signs. Survivals were 54, 38 and 34 per cent at one, five and 10 years respectively. Of those who survived the initial illness, 12 were stable with apparently inactive disease, whilst 16 continued to show clinical signs of activity and required treatment. A variety of treatments was employed including oral and intravenous corticosteroids, immunosuppressive agents, anticoagulants; only one patient was treated by plasmapheresis. It is difficult to draw any firm conclusions as to the efficacy of treatment and survival rates remain unsatisfactory.