A 28-year-old male farmer from rural Maharashtra presents with a 5-day history of high-grade fever, severe headache, myalgia, and conjunctival suffusion without exudate. On day 6, he develops jaundice, acute kidney injury (creatinine 3.2 mg/dL), and thrombocytopenia (platelets 45,000/μL). Blood culture and urine culture are sent. PCR on blood is positive for Leptospira interrogans. What is the most appropriate immediate management?

Explanation

## Clinical Presentation and Diagnosis **Key Point:** This patient presents with Weil's disease (severe leptospirosis), characterized by the biphasic illness with immune phase manifestations: jaundice, renal failure, thrombocytopenia, and hemorrhage. **High-Yield:** The clinical triad of fever + conjunctival suffusion (without exudate) + myalgia in a farmer with occupational exposure to contaminated water is pathognomonic for leptospirosis. ## Antibiotic Selection in Severe Leptospirosis | Feature | Penicillin G | Doxycycline | Ceftriaxone | Amoxicillin | |---------|---|---|---|---| | **Efficacy in severe disease** | ✓ First-line | ✗ For mild-moderate only | ✗ Second-line | ✗ Inadequate | | **Timing** | Early + late phases | Early phase only | Alternative | Not recommended | | **Renal penetration** | Excellent | Good | Moderate | Poor | | **Dosing in severe disease** | 18 MU/day IV | 100 mg PO BD | 1 g daily | 500 mg TDS | **Clinical Pearl:** Penicillin G is the gold standard for severe leptospirosis (Weil's disease) because it achieves excellent CSF and renal tissue penetration and is effective in both the immune phase and late complications. Doxycycline is reserved for mild-to-moderate disease in the first week. **Mnemonic: WEIL = Weil's disease needs Early Intensive Leptospirosis treatment** — use IV penicillin G for systemic manifestations (jaundice, renal failure, hemorrhage). ## Why Penicillin G Here 1. **Severe phenotype**: Jaundice + AKI + thrombocytopenia = immune phase = needs penicillin 2. **Timing**: Day 6 of illness = late immune phase, when doxycycline is ineffective 3. **Guideline standard**: WHO and Indian guidelines recommend IV penicillin G (or ceftriaxone as alternative) for severe leptospirosis [cite:Harrison 21e Ch 181]