Amoebic colitis
Amoebic colitis • Infection of the colon with Entamoeba histolytica Morphology • Sites: • Ascending colon –the most common • Sigmoid colon • Rectum • appendix
• Flask shaped ulcers: • Early intestinal lesion is microulceration of mucosa which slowly enlarges. • Small ulcer with heaped up margin but extends below the surface n apperars as flaskshaped.
• Numerous trophozoites can be seen at the margin of dead n viable tissue. • Large ulcers show extensive liquefactive necrosis with shaggy appearance.
• Ameboma: ameobic infection grossly appears as a mass. The mucosa becomes thin n ulcerated.Below this is inflammed n thickened wall of intestine, which is edematous and hemorrhagic with exuberant granulation tissue formation.
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Complications 1) liver abscess 2) effusion;;pleural 3) Hepatobronchial fistula 4) pericardial effusion
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Clinical picture: Pain abdomen with cramp Diarrhoea, sometimes with blood. Diagnosis: PAS stain: trophozoites of E.Histolytica are stained by PAS and iron haematoxylin.
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