Makindo Medical Notes

🐀 Leptospirosis is transmitted via the urine of infected animals (especially rats, mice, cows, pigs, and dogs). 💡 Start antibiotics based on clinical suspicion — do not wait for cultures.

🔎 About

• Zoonotic infection caused by Leptospira interrogans.
• Incubation period: typically 1–2 weeks.
• Globally widespread; more common in tropical and subtropical regions.

🧫 Pathology

• Leptospires live in the renal tubules of asymptomatic carriers.
• Excreted in urine → survive for weeks in shaded, warm, humid environments.
• Entry via mucous membranes or broken skin.

⚠️ Risk Factors

• Occupational: abattoir, farm, and sewage workers.
• Recreational: swimming, kayaking, water sports in contaminated rivers/lakes.
• Pets and bites = rare sources.
• Human-to-human transmission = extremely rare.

🧬 Aetiology

• Leptospira = Gram-negative, coiled, motile bacteria with hooked ends.
• Major reservoir host: rat (Rattus norvegicus).

🩺 Clinical Presentation

• Fever, headache, myalgia (especially calf tenderness).
• Conjunctival suffusion = classical sign.
• Renal: oliguria, proteinuria, haematuria.
• Hepatic: jaundice + hepatosplenomegaly (without frank liver failure).
• Pulmonary: ARDS, pulmonary haemorrhage (severe cases, esp. Asia).
• Bleeding: bruising, epistaxis, GI bleeding, effusions.
• Neurological: aseptic meningitis, encephalitis.
• Cardiac: myocarditis, arrhythmias.

📌 Classical Presentations

• Mild flu-like illness.
• Weil’s Syndrome: Jaundice + renal failure + haemorrhage + myocarditis.
• Meningoencephalitis.
• Pulmonary haemorrhage with respiratory failure.

🔍 Differentials

• Dengue, Typhoid fever, Malaria, Scrub typhus, Hantavirus.

🧪 Investigations

• FBC: Thrombocytopenia, neutrophilia.
• U&E: AKI with raised creatinine, proteinuria, haematuria.
• LFTs: ↑ AST/ALT, ↑ bilirubin, prolonged PT.
• CSF: Aseptic (↑ protein, normal glucose).
• Culture: Blood positive early (≤10 days); urine positive after day 7.
• Serology: IgM detectable after 1 week.
• PCR: Detects leptospiral DNA in blood/urine (most useful day 8+).

🛡️ Prevention

• Good hygiene: wash hands after animal contact, cover wounds.
• Protective clothing for at-risk occupations.
• Avoid contaminated water; shower after exposure.
• Vaccinate dogs 🐶 (no human vaccine available).
• Boil untreated water before use.

⚠️ Complications

• Oliguric AKI → dialysis may be required.
• Severe pulmonary haemorrhage → high mortality, often ICU care.
• Aseptic meningitis, ARDS, Guillain-Barré syndrome, DIC, shock.

💊 Management

• Supportive care = cornerstone (hydration, renal replacement, transfusions if needed).
• Severe disease:
  • IV Benzylpenicillin 1.5 MU q6h × 7 days OR Ceftriaxone 1 g daily × 7 days.
• Mild disease: Doxycycline 100 mg PO BD × 7 days.
• Jarisch–Herxheimer reaction may occur with penicillin therapy.
• Mortality >10% in severe forms.

🛡️ Prophylaxis (High-Risk Exposure)

• Doxycycline 200 mg weekly can reduce risk in high-risk groups.

💡 Key Exam Pearl: Weil’s disease = jaundice + renal failure + haemorrhage. Always ask about occupational/recreational water exposure in febrile patients with jaundice + AKI.