Clinical features of amebic appendicitis are similar to acute appendicitis from other causes. The diagnosis may first be suspected during histologic examination of the resected appendix.
Reasons to suspect amebic appendicitis:
(1) ulcerations in the appendiceal mucosa
(2) absence of fecalith or other explanation
(3) person who has lived or traveled to an endemic area
(4) HIV or other immunosuppression
(5) history of amebiasis
(6) presence of large histiocytes-like cells or cysts in the inflammatory exudate
Diagnostic tests that can aid in the diagnosis:
(1) PAS stain (will stain amebae and histiocytes pink to red, with distinction based on nuclear appearance)
(2) methenamine silver
(3) immunohistologic stain
(4) serology (false positive in past exposure; false negative in immunodeficiency; may be negative in the absence of extraintestinal infection)
(5) stool for ova and parasites
