Question
Weil’s disease
Answer
Weil’s disease is the severe, icteric (jaundiced) form of leptospirosis, caused by pathogenic strains of Leptospira interrogans, representing the most life-threatening presentation of the disease.
Pathogenesis: after entry through cuts/abrasions or intact mucosa during contact with water/soil contaminated by infected animal urine, the organism disseminates haematogenously, its outer-membrane components directly damaging vascular endothelium and producing widespread vasculitis and capillary leak.
Clinical features (classical triad plus haemorrhage): jaundice (often disproportionately severe relative to hepatocellular necrosis, canalicular cholestasis predominates); acute kidney injury (interstitial nephritis, acute tubular necrosis); haemorrhagic manifestations (petechiae/purpura to pulmonary haemorrhage in severe cases); additional features include myocarditis, aseptic meningitis (later immune phase), and myalgia.
Laboratory diagnosis: dark-field microscopy/culture (Fletcher’s/EMJH medium) or PCR early in illness; Microscopic Agglutination Test (MAT) — the serological gold standard — and IgM-ELISA from the second week; supportive findings include deranged LFTs, raised renal parameters, thrombocytopenia, and raised CPK.
Treatment: IV penicillin or ceftriaxone for severe disease, with supportive management of renal failure and haemorrhage; doxycycline chemoprophylaxis for high-risk exposure.