Long-term clinical and morphological evaluation of primary membranoproliferative glomerulonephritis.

BACKGROUND

Membranoproliferative glomerulonephritis (MPGN) is a relatively rare primary glomerulonephritis (GN). Its incidence has decreased progressively in the past two decades. To improve knowledge of this rare GN, a retrospective review of 22 patients during a 12-year period was undertaken.

METHODS

From November 1982 to December 1994, from a total 814 cases of primary GN, 22 patients with primary MPGN were diagnosed. Clinical data, medical records, renal pathology and outcome were reviewed.

RESULTS

Patients included 15 male and 7 females, aged from 11 to 67 years. The average follow-up period was 46.3 months, with a range of 1 to 140 months. Tissue was available for electromicroscopic study in 11 cases; of which 9 cases fulfilled morphologic criteria of Type I MPGN; the other 2 cases were Type II MPGN. The clinical presentations at diagnosis included nephrotic syndrome (86.4%), impaired renal function (63.6%), microhematuria (50%), gross hematuria (31.8%) and hypertension (50%). Low serum C3 was found in 40.9% cases, 44.4% in Type I and 50% in Type III MPGN. The positive rate of hepatitis B virus infection was 22.7% with 33.3% in Type I and none in Type III MPGN. All 22 patients received various combined antihypertensive agents, immunosuppressant, anticoagulant and antiplatelet agents at diagnosis, but 17 had progressive disease, 4 maintained normal renal function with proteinuria and only 1 had complete remission. Fifteen patients, including six Type I and no Type III MPGN, progressed to end-stage renal failure. Both patients with Type III MPGN maintained normal renal function and responded to treatment. The 5 and 10 year actuarial renal survival rates were 33.3% and 16.7% respectively. The median kidney survival time was 51.2 months.

CONCLUSIONS

A majority of cases with MPGN presenting with impaired renal function (86.7%) and hypertension (85%) at diagnosis progressed to end-stage renal failure. Delayed diagnosis and poor compliance were possible reasons for compared with for worse prognosis previous reports. But two patients with Type III MPGN had favorable prognosis previously described. Treatments generally failed to halt disease progression. Since at least five cases (22.7%) maintained normal renal function after treatments, a course of immunosuppressant is probably indicated if there is no contraindication. Further study with a larger population is warranted to clarify this issue.