AMOEBIASIS

A common parasitic infection of the gastrointestinal system acquired through oral-faecal transmission.

Causes

  • Protozoan Entamoeba histolytica

Clinical features

It may present as:

Amoebic dysentery

  • Persistent mucoid/bloody diarrhoea
  • Abdominal pain, tenesmus
  • Chronic carriers are symptomless

Amoebic abscess (as a result of spread via the blood stream):

  • Liver abscess: swelling/pain in the right sub-costal area, fever, chills, sweating, weight loss
  • Brain: presenting as space-occupying lesion
  • Lungs: cough and blood stained sputum
  • Amoeboma: swelling anywhere in the abdomen, especially ascending colon
  • Anal ulceration: may occur by direct extension from the intestinal infection

Differential diagnosis

  • Bacillary dysentery
  • Any other cause of bloody diarrhoea
  • Cancer of the liver
  • Other causes of swelling in the liver
  • Carcinoma colon

Investigations

  • Stool: Microscopy for cysts and motile organisms
  • Ultrasound

Management

  • Correct any dehydration (section 1.1.3)
  • Metronidazole 800 mg every 8 hours for 10 days
    Child: 10 mg/kg per dose
  • Or tinidazole 2 g daily for 5 days
    Child: 50 mg/kg per dose
Caution
  • Metronidazole/tinidazole: do not use in 1st trimester of pregnancy; avoid alcohol during treatment and for 48
    hours thereafter
  • Metronidazole: Take after food

Prevention

  • Educate the public on personal and food hygiene (washing hands before eating), proper faecal disposal
  • Ensure proper management of carriers and patients
  • Promote use of clean drinking water