Extraintestinal manifestations of invasive amebic disease, although far less common than amebic colitis, are still a significant cause of morbidity and mortality worldwide, accounting for approximately 50 000 deaths annually. The most common presentation, amebic liver abscess, can be diagnosed clinically by its characteristic presentation in conjugation with appropriate epidemiologic risks and supported by several serologic or antigen-based detection tests. Without treatment, amebic liver abscess is almost always fatal, but with prompt and appropriate treatment, the chance of a cure is nearly universal. Other, more rare, manifestations of invasive amebiasis also occur and will be discussed as well. The foundation of successful invasive amebiasis treatment has been metronidazole and the related nitroimidazole, tinidazole, which recently gained U.S. Food and Drug Administration (FDA) approval.

AMEBIC LIVER ABSCESS

In addition to amebic colitis and its complications, extraintestinal manifestations of invasive Entameba histolytica infections can occur, led in frequency by amebic liver abscesses. An estimated 10% of the worldwide 40 to 50 million symptomatic amebic infections will either present as or be complicated by amebic liver abscess. Adult men are 7 to 10 times more likely to have amebic liver abscess than women, but there is no difference between the sexes in children. It has been suggested that the different gender rates in adults may have to do with protective effects of estrogen in women and the role of alcohol in men with hepatocellular damage setting up a nidus for infection during portal drainage from an infected colon.