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

Abstract

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 (<80 ml/min) in 49% (n = 26/53) and increased microalbuminuria (>20 microg/min) in 22% (n = 11/51). Compared to the evaluation carried out 3 years before, the number of cases with creatinine clearance lower than 80 ml/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.