A 35-year-old woman from Jharkhand presents with a 6-month history of fever, weight loss, and abdominal swelling. Clinical examination reveals massive splenomegaly (12 cm below costal margin) and mild hepatomegaly. Laboratory investigations show Hb 7.5 g/dL, WBC 1,800/μL, platelets 60,000/μL, and elevated serum creatinine (2.1 mg/dL). Bone marrow examination confirms *Leishmania donovani* amastigotes. She has been on sodium stibogluconate 20 mg/kg/day for 45 days with persistent fever and no clinical improvement. What is the most appropriate next step?

Explanation

## Management of Antimony-Resistant Visceral Leishmaniasis ### Clinical Scenario: Treatment Failure **Key Point:** Failure to achieve clinical response (defervescence) and parasitological cure (bone marrow clearance) after 60 days of sodium stibogluconate indicates antimony-resistant *L. donovani*. **High-Yield:** Antimony resistance is endemic in parts of Bihar and Jharkhand, with reported failure rates of 20–60% in some regions. The patient has: - No clinical improvement after 45 days (expected response by day 5–7) - Persistent parasitemia on bone marrow - Renal impairment (Cr 2.1 mg/dL) — a risk factor for antimonial toxicity ### Treatment Algorithm for Resistant Kala-azar ```mermaid flowchart TD A[Visceral Leishmaniasis Confirmed]:::outcome --> B[Start Sodium Stibogluconate<br/>20 mg/kg/day × 28 days]:::action B --> C{Clinical Response<br/>by Day 5-7?}:::decision C -->|Yes| D[Continue to Day 28<br/>Cure rate ~95%]:::action C -->|No| E{Renal Function<br/>Impaired?}:::decision E -->|Yes| F[Switch to Liposomal<br/>Amphotericin B]:::action E -->|No| G[Continue Stibogluconate<br/>Reassess at Day 60]:::action G --> H{Parasites Cleared?}:::decision H -->|Yes| I[Cure]:::outcome H -->|No| F F --> J[3 mg/kg/day IV<br/>× 10 days]:::action J --> K[Cure rate ~95%<br/>in resistant cases]:::outcome ``` ### Second-Line Agents for Resistant Disease | Agent | Dose | Duration | Advantage | Limitation | |-------|------|----------|-----------|------------| | **Liposomal Amphotericin B** | 3 mg/kg/day | 10 days | **Best efficacy in resistance**; renal-sparing | Cost; IV only | | Amphotericin B deoxycholate | 1 mg/kg/day | 15 days | Effective; cheaper | Nephrotoxic | | Miltefosine | 2.5 mg/kg/day | 28 days | Oral; no resistance | Teratogenic; slower response | **Clinical Pearl:** Liposomal amphotericin B is the gold standard for antimony-resistant visceral leishmaniasis because: 1. Cure rate >95% even in resistant strains 2. Minimal nephrotoxicity (critical in this patient with Cr 2.1 mg/dL) 3. Rapid clinical response (defervescence within 3–5 days) 4. WHO-recommended second-line agent **Key Point:** The patient's renal impairment (Cr 2.1 mg/dL) is a contraindication to continuing or escalating antimonial therapy, as pentavalent antimonials are nephrotoxic and can precipitate acute kidney injury. **Mnemonic:** **LAMP** for second-line agents in resistant kala-azar: - **L**iposomal amphotericin B (first choice) - **A**mphotericin B deoxycholate (if LAMB unavailable) - **M**iltefosine (oral alternative) - **P**entamidine (rarely used; high toxicity) ### Why Liposomal Amphotericin B Here? - Proven efficacy in antimony-resistant disease - Renal-sparing formulation (safe despite elevated creatinine) - Rapid parasitological cure - WHO and Indian guidelines recommend for resistant cases