Case Studies

 Case 9.2 Membranous glomerulonephritis

A 38-year-old man presented with a 3-month history of intermittent swelling of his ankles and puffiness of his face. There were no urinary symptoms and no family history of renal disease. On examination, he was pale and thin with ankle oedema and a blood pressure of 130/80. Investigations showed a normal haemoglobin and white cell count and an erythrocyte sedimentation rate (ESR) of 32mm/h. His blood urea was 9.1mmol/l (NR 2.5-7.5), serum albumin 26g/l with a urinary protein loss of 7.8g/day and a creatinine clearance of 106ml/min. His serum immunoglobulin IgM and IgA, C3 and C4 levels were normal, but his IgG was low at 5.1g/l (NR 7.2-19.0). Antinuclear antibodies and hepatitis B surface antigen were not detected, and the antistreptolysin O titre was not raised. There were no free light chains in his urine.

A renal biopsy was done to find the cause of his nephrotic syndrome; this showed no obvious increase in cellularity. However, the basement membrane of all glomeruli showed marked but uniform thickening with numerous subepithelial 'spikes'. Immunofluorescent examination showed granular deposits of IgG and C3 along all the glomerular capillary walls. The biopsy appearances were typical of membranous glomerulonephritis (Fig. 9.9). No specific treatment was given. One year later, he is asymptomatic but still has severe, non-selective proteinuria of 14g/day.