This complex scenario describes a progression from intestinal to extraintestinal disease by an invasive protozoan. The initial presentation with dysentery and large, ciliated trophozoites is classic for Balantidium coli infection, not Entamoeba histolytica (which has amoeboid trophozoites). B. coli is an opportunistic pathogen that can cause severe disease in debilitated hosts (alcoholism, malnutrition). While it primarily causes colonic ulceration, it can rarely invade the bloodstream and disseminate. The most likely sequence is: 1) B. coli trophozoites invade the colonic mucosa, causing ulcers and dysentery. 2) From these colonic ulcers, trophozoites enter the portal venous circulation. 3) They are carried to the liver, where they cause focal necrosis, leading to a liver abscess. This mirrors the pathogenesis of amebic liver abscess but is caused by a different organism. The key is recognizing B. coli's potential for extraintestinal spread in immunocompromised hosts. Option A incorrectly identifies the parasite as E. histolytica. Option C describes biliary obstruction, not typical for these parasites. Option D suggests contiguous spread from colon to liver, which is anatomically unlikely.

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Zambia

• ivwananji siwale – 29 pts

• Visual Pathway Lesions
• Positive and Negative Symptoms
• Hallucinations and Delusions
• Antipsychotic Medications
• Emergency: Environmental Emergencies