A patient with amebic colitis may present with nonspecific findings. The diagnosis can be made with endoscopy provided appropriate studies are performed.
Patient selection: endoscopy on a patient with colitis
Endoscopic features of the colonic mucosa:
(1) erythema
(2) edema
(3) mucosal erosions
(4) white exudates
(5) mucosal ulcers
Biopsies should be taken and intestinal fluid over the colitis collected.
Intestinal fluid should be tested for:
(1) bacterial pathogens
(2) acid fast bacilli
(3) ova and parasites
Entamoeba can be seen in biopsies using the periodic acid-Schiff (PAS) stain or other stain including immunoperoxidase staining (if available). Trophozoies of E. histolytica will show hemophagocytosis.
The diagnosis is supported by
(1) a positive clinical response to metronidazole.
(2) exclusion of other diagnoses (but a patient may have more than one cause for colitis)
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