Long term outcome of acute kidney injury due to leptospirosis? A longitudinal study in Sri Lanka

BACKGROUND: Leptospirosis is an important zoonotic disease of variable severity and is a common cause of acute kidney injury (AKI) in tropics. However the knowledge on long term renal outcome in leptospirosis is scarce. This study aims to assess the long-term renal outcome of AKI caused by leptospirosis. FINDINGS: Hospital records of patients who had developed AKI following leptospirosis (Serologically confirmed) presented to two Teaching Hospitals in Kandy district over 3 years from 2007 were studied. A total of 44 patients were included and they had been followed up at least for one year in out patient clinics with regular assessment including renal status. Renal histology was studied in two patients. The primary outcome measure was normalization of renal function at one year. Of the 44 patients, 31 were in the risk and injury stage (Group 1), and the rest of them were in the failure stage (Group 2) under RIFLE criteria. Of group 2 patients, 11 had abnormal renal functions on discharge. Their mean serum creatinine and GFR values on discharge were 392 mmol/l and 20 ml/min/1.73 m(2). Other two patients had full renal recovery whilst in the hospital. Nine in the group 2 required renal replacement therapy by means of peritoneal dialysis, intermittent haemodialysis or haemofiltration. Seventeen out of the total had persistently abnormal renal functions on discharge. Of them 13 recovered their renal functions to normal. Four patients (9%) who belonged to group 2, had persistently abnormal renal functions after first year compatible with stage 3 chronic kidney disease (CKD). Renal histology of two patients showed tubulointerstitial lymphocyte infiltrate, tubular atrophy and interstitial fibrosis. CONCLUSION: The long term renal outcome of AKI following leptospirosis is satisfactory as only 9% of patients had abnormal renal functions compatible with early stage of CKD. Even among them, advanced CKD or dialysis dependency had not been observed.