Question:easy
Flask-shaped ulcers in the intestine are caused by which of the following?
Flask-shaped ulcers in the intestine are caused by which of the following?
Show Hint
The parasite seen with ingested red blood cells in stool causes this classic ulcer.
Updated On: Jun 23, 2026
- Giardia lamblia
- Entamoeba histolytica
- Helicobacter pylori (H. pylori)
- E. vermicularis
Show Solution
The Correct Option is B
Solution and Explanation
Step 1: The phrase flask-shaped ulcer is a buzzword pointing to invasive intestinal amoebiasis, whose agent is Entamoeba histolytica.
Step 2: The trophozoite adheres to the colonic epithelium and releases lytic enzymes that dissolve cell membranes and proteins, allowing it to burrow through the mucosa.
Step 3: Because invasion is widest below a small mucosal opening, the resulting ulcer looks like a flask - narrow neck, wide base.
Step 4: Confirmation in stool comes from seeing trophozoites containing ingested red cells (erythrophagocytosis). Giardia (malabsorption), pinworm and H. pylori do not produce this lesion.
\[\boxed{\text{Entamoeba histolytica}}\]
Step 2: The trophozoite adheres to the colonic epithelium and releases lytic enzymes that dissolve cell membranes and proteins, allowing it to burrow through the mucosa.
Step 3: Because invasion is widest below a small mucosal opening, the resulting ulcer looks like a flask - narrow neck, wide base.
Step 4: Confirmation in stool comes from seeing trophozoites containing ingested red cells (erythrophagocytosis). Giardia (malabsorption), pinworm and H. pylori do not produce this lesion.
\[\boxed{\text{Entamoeba histolytica}}\]
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