A 38-year-old woman from rural Odisha presents with a 3-month history of progressive abdominal distension, intermittent colicky pain, and passage of worm segments in stool. On examination, she has mild malnutrition and a palpable abdominal mass in the right iliac fossa. Stool microscopy reveals eggs with a polar plug at both ends. She is otherwise systemically well. Which anthelmintic is the drug of choice for this infection?

## Clinical Diagnosis The patient's presentation is classic for **Ascaris lumbricoides** infection: - Passage of worm segments in stool (adult worms) - Abdominal distension and colicky pain (mechanical obstruction from worm burden) - Eggs with polar plugs (pathognomonic feature of Ascaris) - Rural endemic area (Odisha is a high-prevalence zone) ## Drug of Choice **Key Point:** Albendazole is the first-line anthelmintic for Ascaris lumbricoides and most intestinal nematodes. ### Mechanism of Albendazole Albendazole is a **benzimidazole** that: 1. Inhibits microtubule polymerization in the worm's intestinal epithelium 2. Causes impaired glucose uptake and energy depletion 3. Leads to paralysis and expulsion of the worm ### Dosing & Efficacy | Parameter | Details | |-----------|----------| | **Dose** | 400 mg once daily for 3 days (or single dose 400 mg) | | **Efficacy** | >95% cure rate for Ascaris | | **Onset** | Worms expelled within 24–72 hours | | **Advantage** | Broad-spectrum (works against most intestinal helminths) | ## Why Albendazole Over Alternatives **High-Yield:** Albendazole is preferred because it: - Has the highest efficacy for Ascaris - Is safe in pregnancy (second/third trimester) - Has low cost and wide availability in India - Covers mixed infections (Ascaris + Trichuris + hookworm) ## Clinical Pearl **Warning:** In heavy Ascaris infections with impending obstruction, **piperazine** (a paralytic agent) is sometimes used first to paralyze worms *before* using albendazole, to prevent bolus obstruction. However, in uncomplicated cases like this, albendazole alone is standard. [cite:KD Tripathi 8e Ch 52]