What is the recommended treatment for amoebiasis (infection with Entamoeba histolytica)?

Treatment of Amoebiasis

The recommended treatment for amoebiasis (Entamoeba histolytica infection) is metronidazole 750 mg three times daily for 5-10 days in adults, followed by a luminal amebicide to eliminate intestinal cysts and prevent relapse. 1

Diagnosis

• Diagnosis should be confirmed through microscopic examination of fresh feces showing amebic trophozoites or after two different antibiotics for shigellosis have failed to produce clinical improvement 1
• Indirect hemagglutination testing has over 90% sensitivity for amoebic liver abscess and should be performed in suspected cases 1
• Ultrasound should be performed in all patients with suspected amoebic liver abscess; consider CT scan if ultrasound is negative but clinical suspicion remains high 1

Treatment Regimens

Intestinal Amoebiasis

First-line therapy:

• Adults: Metronidazole 750 mg orally three times daily for 5-10 days 1, 2
• Children: Metronidazole 30 mg/kg/day divided in three doses for 5-10 days 1, 2
• Alternative: Tinidazole 2 g once daily for 3 consecutive days (higher cure rates and better tolerated than metronidazole) 3, 4

Follow-up treatment (essential):

• After completion of metronidazole or tinidazole, all patients must receive a luminal amebicide to eliminate intestinal cysts and prevent relapse 1, 5
• Options for luminal amebicides include:
  • Diloxanide furoate: 500 mg orally three times daily for 10 days 1
  • Paromomycin: 30 mg/kg/day orally in 3 divided doses for 10 days 1, 6

Amoebic Liver Abscess

• Same drug regimens as intestinal amoebiasis 1
• Most patients will respond within 72-96 hours of treatment initiation 1
• Surgical or percutaneous drainage is rarely required and should only be considered in cases of:
  • Diagnostic uncertainty
  • Persistent symptoms after 4 days of treatment
  • Risk of imminent rupture 1

Special Considerations

• For patients who cannot take oral medications, metronidazole can be administered rectally as a retention enema (2 g in 200 ml normal saline) 7
• Metronidazole is active against most obligate anaerobes but does not possess clinically relevant activity against facultative anaerobes or obligate aerobes 2
• Nitazoxanide has shown promising results as a broad-spectrum antiparasitic with activity against both luminal and invasive forms of E. histolytica 6
• Amebiasis is increasingly prevalent among men who have sex with men who engage in oral-anal sex, requiring particular attention to this risk group 5

Prevention

• Emphasize hand washing after using the bathroom and before preparing or eating food 1
• Avoid consuming untreated water or uncooked food in endemic areas 1
• Partners of infected patients should be treated simultaneously to prevent reinfection, especially in cases of sexual transmission 5
• Improvement of water purification systems and hygiene practices could decrease disease incidence 8

Treatment Monitoring

• Clinical response should be evident within 72-96 hours of treatment initiation 1
• If no improvement occurs within 2 days, consider alternative diagnoses or drug resistance 9
• Follow-up stool examination may be necessary to confirm parasitological cure 4