- Due to infection with the protozoan parasite Entamoeba histolytica
- Found in the stool of carriers in the cystic or trophozoite form
- Transmitted by the faecal-oral route
- The liver is the commonest extraintestinal site of infection
- 10% of affected patients develop liver abscesses
- Liver abscesses can be solitary or multiple
- 80% of abscess develop in right lobe of the liver
- Can present several years after intestinal infection
Clinical features
- Presents with malaise pyrexia and weight loss
- Right hypochondrial pain is often mild
- Less than 20% of patients present with diarrhoea
- Jaundice is uncommon
- Complications can arise as a result of abscess rupture or extension of infection
- Complications occur in 5% patients and include:
- Amoebic empyema
- Hepato-bronchial fistula
- Lung abscess
- Pericarditis
- Peritonitis
Investigations
- Serology shows raised WCC and ESR
- Latex agglutination assay positive in more than 90%
- Sigmoidoscopy, stool microscopy and rectal biopsy may identify the organism
- Chest x-ray may show a raised right hemidiaphragm, atelectasis or abscess
- The abscess can often be identified on ultrasound
- Aspiration produces a typical 'anchovy sauce' appearing pus
- Pus is odourless and sterile on routine culture
Management
- Metronidazole is the antibiotic of choice
- If ineffective chloroquine and dihydrometine may be considered
- Ultrasound guided aspiration may be useful
- Surgery is only rarely required
- Prognosis in uncomplicated cases is good (<1%)
- If pulmonary complications occur mortality cab as high as 20%
Bibliography
Greenstein A J, Barth J, Dicker A et al. Amebic liver abscess: a study of 11 cases compared with
a series of 38 patients with pyogenic liver abscess. Am J Gastroenterol 1985; 80: 472-475. |