Persistent kidney dysfunction after leptospirosis-associated acute kidney injury: a case series from coastal Karnataka, India.

backgroundLeptospirosis has been infrequently associated with persistent kidney dysfunction fulfilling the criteria for chronic kidney disease (CKD). However, the entity remains poorly characterised. This study aimed to describe the clinical profile, laboratory findings, treatment requirements, and kidney outcomes of patients without recognised CKD risk factors who had persistent kidney dysfunction fulfilling CKD criteria at three-month follow-up after leptospirosis-associated Acute Kidney Injury (AKI).

methodsThis descriptive case series was nested within a prospective cohort of hospitalised patients with leptospirosis admitted to a tertiary care hospital in coastal Karnataka, India, between April 2025 and March 2026. Patients with leptospirosis-associated AKI who fulfilled Kidney Disease: Improving Global Outcomes (KDIGO) criteria for CKD at three-month follow-up were included. Leptospirosis was confirmed by immunoglobulin M (IgM) enzyme-linked immunosorbent assay or polymerase chain reaction (PCR). Patients with known CKD or recognised clinical risk factors for CKD, including diabetes mellitus, hypertension, family history of kidney disease, structural renal abnormalities, or other identifiable causes of kidney disease, were excluded. Clinical features, laboratory parameters, treatment details, organ support requirements, and kidney outcomes were recorded.

resultsAmong 101 hospitalised patients with leptospirosis, 67 (66.3%) developed AKI. Of these, 7 (10.4%) died in hospital, and 17 (28.3%) of the 60 survivors did not undergo serum creatinine testing at three-month follow-up. Among the remaining 43 evaluable survivors without known CKD or recognised CKD risk factors, 6 (14.0%) fulfilled criteria for CKD at three-month follow-up. All six patients had KDIGO Stage 3 AKI during admission. Admission serum creatinine ranged from 3.19 to 8.63 mg/dL, while peak serum creatinine ranged from 4.92 to 11.84 mg/dL. Jaundice was present in 4/6, 66.7%, of patients, leukocytosis was observed in all patients, and thrombocytopenia was present in all patients. Pulmonary complications were common, with pleural effusion in 4/6, 66.7%, patients, acute respiratory distress syndrome in 1/6, 16.7%, and diffuse alveolar haemorrhage in 1/6, 16.7%. Myocarditis was noted in 2/6, 33.3%, of patients. Three patients required haemodialysis, and three required mechanical ventilation. At discharge, serum creatinine remained elevated in all six patients, ranging from 1.85 to 5.15 mg/dL. At three-month follow-up, estimated glomerular filtration rate (eGFR) ranged from 44 to 59 mL/min/1.73 m

conclusionsSevere leptospirosis-associated AKI may be followed by persistent kidney dysfunction at three months despite improvement in serum creatinine from peak values. Persistent creatinine elevation at discharge may be an important clinical warning sign. Patients with severe leptospiral AKI, particularly those with KDIGO Stage 3 AKI, dialysis requirement, persistent discharge creatinine elevation, or multiorgan involvement, may benefit from structured post-discharge kidney follow-up, including eGFR reassessment, urinalysis, proteinuria assessment, blood pressure monitoring, and, where feasible, tubular function testing.