Leptospirosis and dengue fever: a predictive model for early differentiation based on clinical and biochemical parameters.

Leptospirosis and dengue fever are increasingly seen as causes of tropical febrile illness and often are clinically indistinguishable. This two-year prospective study from a tertiary care centre comprised 200 patients including 68 men (mean 34.8 years) with dengue and 73 (mean 46.19 years) with leptospirosis. Oliguria, icterus, muscle tenderness, anaemia, leukocytopenia, thrombocytopenia, elevated erythrocyte sedimentation rate (ESR), acute renal failure (ARF) and hypoalbuminaemia appeared more commonly in leptospirosis in comparison to dengue. Eighteen per cent mortality was observed in leptospirosis compared to one per cent in dengue. ARF, hyperbilirubinaemia, acute respiratory distress syndrome (ARDS), creatine kinase (CK) elevation and thrombocytopenia were predictors of death in leptospirosis and thrombocytopenia, ARDS and ARF predictors of death in dengue. On receiver operating characteristics (ROC) analysis, leucocytosis >11000/mm(3), ESR >40 mm, serum creatinine >2 mg/dL, total serum bilirubin >2 mg/dL, CK >500 U/L and serum albumin <3 mg/dL were more likely to be an indication of leptospirosis at presentation compared to dengue.