A comparison of amebic and pyogenic abscess of the liver

We evaluated the clinical features of 96 cases of amebic liver abscess and 48 of pyogenic hepatic abscess. Most patients with amebic abscess were young Hispanic males. Those with pyogenic abscess were older, without any ethnic predominance. Symptoms tended to be acute and localized to the right upper quadrant in amebic infection. In pyogenic disease, symptoms were often nonspecific and chronic in nature. A marked shift to the left of the leukocyte count occurred more frequently in pyogenic abscess, as did markedly abnormal values of the serum albumin, direct bilirubin, lactic dehydrogenase and aspartate aminotransferase. Sonography detected all cases of amebic abscess and missed the lesions in 2 of 39 patients with pyogenic abscess. Abscess cultures yielded pathogens in 90% of cases of pyogenic disease, while blood cultures were positive in 50%. Five of 20 patients with positive blood cultures had additional organisms isolated from the abscess that would have required adjustment of antibiotics for optimal coverage. We believe that all pyogenic abscesses should be aspirated to guide antibiotic therapy. In amebic abscess, the diagnosis was usually based on clinical and sonographic findings, aspiration being performed in only 14% of cases. Ninety-eight percent of patients were treated with amebicidal agents alone, and all responded to therapy. Therapeutic needle aspiration is rarely necessary. In pyogenic abscess, prolonged fever was common during medical therapy. Even in those eventually cured without surgery, the median time to defervescence was 8 days. Though 19 patients underwent surgical drainage, only 2 clearly did not benefit from medical treatment, having high fevers after more than 2 weeks on a regimen of appropriate antibiotics. Surgery is often performed prematurely because physicians expect fever to resolve quickly, but persistent fever of less than 2 weeks' duration should not constitute an indication for surgical drainage. Seven patients with pyogenic abscess died, 5 as a result of hepatic abscess. In 3 of these cases, the diagnosis was unsuspected till autopsy. Improved awareness of this disease may decrease morbidity and mortality from this treatable condition.