Five-year follow-up of patients with epidemic glomerulonephritis due to Streptococcus zooepidemicus

Background. In 1998 there was a large outbreak of acute glomerulonephritis in Nova Serrana, Brazil, caused by group C Streptococcus zooepidemicus. This study describes the follow-up of these patients, after a mean time of 5.4 years of the acute episode. Methods. Of 135 cases identified in 1998, 56 were re-examined in a prospective study and had measurements of blood pressure, creatinine clearance (estimated by the Cockcroft and Gault formula), microalbuminuria (radioimmunoassay), urine sediment analysis and a protein dipstick test. Results. Of the original group of 135 subjects, 3 died in the acute phase and 5 (3.7 %) required chronic dialysis. Of the 56 cases re-evaluated, 54 (96 %) were adults (mean +/- SD age, 43 +/- 17 years) and 36 (64 %) females. At the follow-up examination, we found arterial hypertension in 30 % (n = 17/56) of the subjects, reduced creatinine clearance (<80ml/min) in 49 % (n = 26/53) and increased microalbuminuria (> 20 mu g/min) in 22 % (n=11/51). Compared to the evaluation carried out 3 years before, the number of cases with creatinine clearance lower than 80ml/min increased from 20 to 26 (of 53 cases). Increased microalbuminuria and/or reduced creatinine clearance were detected in 57 % (n = 32/56) of the subjects. Patients with reduced creatinine clearance were older than those without reduced renal function (54 +/- 15 vs 34 +/- 12 years, P < 0.001). Conclusions. After a mean time of 5.4 years, a relatively high proportion of patients with epidemic poststreptococcal glomerulonephritis due to S.zooepidemicus present hypertension, reduced renal function and increased microalbuminuria.