Pulmonary complications of amebiasis; a report of six cases.

Amebiasis is typically an infection of the colon by the protozoan, Endamoeba histolytica. It may be acute or chronic and presents a varied clinical course. The most frequent symptom is diarrhea with small amounts of blood-streaked mucus, but stubborn constipation is not unusual. Often, constipation may alternate with diarrhea accompanied by tenesmus, lassitude, and a generalized vague abdominal discomfort. Due to the variety of symptoms, it may be confused with chronic cholecystitis, pancreatitis, chronic appendicitis, diverticulitis of the colon, regional ileitis, mucous colitis, and spastic colon. Pulmonary and hepatic involvement are believed to be secondary to intestinal infestation in all cases. Pulmonary amebiasis is usually secondary to hepatic involvement. There may be contiguous spread through the diaphragm, trans-diaphragmatic lymphatic extension, or embolic spread through the circulation.2 About 75 per cent of cases occur by a rupture of a liver abscess directly through the diaphragm.’#{176} Batson1 has described a mode of metastases through the vertebral venous system network to the cerebral and pulmonary areas without passage through the liver. The primary form of pulmonary amebiasis caused by amoebae reaching the respiratory tract by direct embolism from the intestinal tract is considered to be rare.5 However, pulmonary amebiasis in people without other symptoms or signs of amebiasis are on record.’1 Such a case is reported by Chaudhuri and Chaudhuri3 in which there is no history of dysentery, hepatic involvement, or Endamoeba histolytica in the feces. Sodeman#{176} points out that there may be hepatic infection by amoebae without pulmonary involvement and yet suggesting lung disease. This is found in cases of hepatic abscess where the pain is referred to the right shoulder area and aggravated by inspiration. Such cases often complain of stabbing pain in the region of the right costal margin. Here the diaphragm may be immobilized and the right base of the lung fixed. In this case an apparent increased density in the lower right pulmonary area may be mistaken for pneumonitis. Extension through the diaphragm from hepatic abscess below may give rise to pleural reaction resulting in pleural effusion which appears clear and sterile. However, amoebae may be isolated in the pleural fluid. Radke’ reports the isolation of End,amoeba histolytica from the pleural fluid and the successful treatment with quinacrine (atabrine) and carbarsone. Fibrinous exudate may attach the lung to the diaphragm, causing adhesions to develop, thus producing a fixation. Hepatic abscess may rupture into the lung, producing bronchopleural or