A 10-year-old boy presents with recurrent foul-smelling, greasy stools and abdominal distension after a school trip to a hill station. Duodenal aspirate examination shows pear-shaped trophozoites with two nuclei, four pairs of flagella, and two median axostyles giving an 'old man with spectacles' appearance. The drug of choice for this infection is:
- A Albendazole
- B Metronidazole ✓
- C Ivermectin
- D Praziquantel
Correct answer: B. Metronidazole
Explanation
The findings describe Giardia lamblia trophozoites. Nitroimidazoles such as metronidazole, tinidazole and secnidazole are the standard first-line drugs; tinidazole achieves cure with a single dose. Albendazole is used in mass deworming programmes and as an alternative but is not the classic answer. Praziquantel acts on trematodes and cestodes, and ivermectin on nematodes, so neither covers a luminal protozoan like Giardia.
Reference: Paniker's Textbook of Medical Parasitology, 8th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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