A 28-year-old woman from coastal Odisha presents with abdominal pain, diarrhea, and eosinophilia (18%). Stool examination reveals barrel-shaped embryonated eggs. What is the drug of choice for this helminthic infection?

Explanation

## Diagnosis: Ascaris lumbricoides Infection The clinical and laboratory findings are diagnostic of ascariasis: - Barrel-shaped (lemon-shaped) embryonated eggs are pathognomonic for *Ascaris lumbricoides* - Abdominal pain and diarrhea are typical GI symptoms - Eosinophilia reflects parasitic infection and immune response - Coastal region in India (high endemicity) ## Drug of Choice: Albendazole **Key Point:** Albendazole is the WHO-recommended and first-line treatment for ascariasis in India. It is a broad-spectrum benzimidazole that paralyzes and eliminates adult worms. **High-Yield:** Albendazole is preferred because: 1. Single dose (400 mg) is highly effective (>95% cure rate) 2. Broad-spectrum activity against multiple helminths 3. Safe in pregnancy (second and third trimester) 4. Minimal side effects 5. Cost-effective and widely available in India **Mnemonic:** **ALBENDAZOLE for ASCARIS** — both start with 'A'; albendazole is the gold standard. **Clinical Pearl:** In endemic areas, mass drug administration programs use albendazole as the drug of choice for school-age children and pregnant women (after first trimester). ## Anthelmintic Drug Selection for Common Parasites | Parasite | Drug of Choice | Alternative | |----------|----------------|-------------| | *Ascaris lumbricoides* | **Albendazole** | Mebendazole, Pyrantel pamoate | | *Trichuris trichiura* | **Albendazole** | Mebendazole | | *Hookworm* | **Albendazole** | Mebendazole, Pyrantel pamoate | | *Strongyloides stercoralis* | **Ivermectin** | Albendazole | | *Schistosoma* species | **Praziquantel** | — | | *Filaria* (*W. bancrofti*) | **Diethylcarbamazine** | Albendazole (microfilaricide) | ## Why Not Other Options? ```mermaid flowchart TD A["Barrel-shaped eggs in stool"]:::outcome --> B{"Which parasite?"}:::decision B -->|"Ascaris lumbricoides"|C["Albendazole 400 mg single dose"]:::action B -->|"Schistosoma (miracidia)"|D["Praziquantel"]:::action B -->|"Filaria (microfilariae)"|E["Diethylcarbamazine"]:::action B -->|"Strongyloides (rhabditiform larvae)"|F["Ivermectin"]:::action ``` **Warning:** Praziquantel is NOT effective against intestinal nematodes; it is used for trematodes and cestodes (schistosomiasis, tapeworms). Ivermectin is the drug of choice for *Strongyloides* and filarial infections, not ascariasis. Diethylcarbamazine is used for lymphatic filariasis, not intestinal helminths.