Internal Medicine

P1: SBT

0521779407-03 CUNY1086/Karliner 0 521 77940 7 June 7, 2007 19:6

106 Amebiasis

Amebiasis..........................................

J. GORDON FRIERSON, MD

history & physical

History

■Exposure: ingestion of food or water contaminated by cysts of Enta-

moeba histolytica, direct fecal-oral contamination (seen in mental

institutions and day care centers), oral-anal sexual practices. Insects

may contaminate food. Entamoeba dispar is identical to E. histolyt-

ica in appearance but does not cause disease.

Signs & Symptoms

■Intestinal amebiasis: gradual onset of diarrhea which varies from

mild to severe, sometimes with blood and pus (dysentery), abdomi-

nal pain. Fever, weight loss, dehydration seen in severe cases. Perfo-

ration and stricture can occur. Ameboma is a proliferative response

to the amebae, resulting in a mass effect in colon wall. Some patients

have no symptoms.

■Systemic amebiasis:

➣a) hepatic: presents as liver abscess, with fever, weight loss, right

upper quadrant pain. Course can be acute or chronic. Rupture

can produce empyema, peritonitis, pericarditis.

➣b) Pericardial amebiasis: usually due to rupture of liver abscess

into pericardium. Presents as chest pain, dyspnea, tachycardia,

pulsus paradoxicus, hypotension.

➣c) Amebic brain abscess: acute illness resembling pyogenic

abscess with headache, fever, neurologic signs indicating mass

➣d) Cutaneous amebiasis: usually seen near anus or on genitals.

Presents as painful skin ulcerations.

tests

■Basic tests: blood: Intestinal disease: CBC may show anemia, some-

times elevated neutrophils.

➣Systemic disease: CBC shows anemia, elevated WBC. LFTs

altered, usually with elevated alkaline phosphatase and transam-

inases.

■Basic tests: urine: not helpful

■Specific tests: Intestinal disease: Stool examination for O&P demon-

strates trophozoites and cysts. May need up to 3, rarely more, stools