What is the treatment for amoebiasis?

Treatment of Amoebiasis

Diagnostic Confirmation Before Treatment

Do not initiate treatment for amoebiasis unless microscopic examination of fresh feces demonstrates Entamoeba histolytica trophozoites, or two different antibiotics for shigellosis have failed after 4 days total. 1

• Fresh stool microscopy must be performed within 15-30 minutes of passage to identify motile trophozoites 2
• At least 3 stool samples should be examined on different days, as organism shedding can be intermittent 2
• Care must be taken to distinguish large white cells (nonspecific indicator of dysentery) from actual trophozoites, as amebic dysentery tends to be misdiagnosed 1
• If dysentery is present but microscopy is unavailable or trophozoites are not definitively identified, treat for shigellosis first with ampicillin or TMP-SMX before considering amoebiasis 1

For suspected amoebic liver abscess:

• Perform indirect hemagglutination testing (>90% sensitivity) 1
• Ultrasound should be performed in all suspected cases; consider CT scan if ultrasound is negative but clinical suspicion remains high 1

Primary Treatment Regimen

Metronidazole is the first-line treatment for both intestinal amoebiasis and amoebic liver abscess. 1, 3

Adults:

• Metronidazole 750 mg orally three times daily for 5-10 days 1
• Alternative: Tinidazole 2 g once daily for 3 days (FDA-approved for amebiasis) 4

Children (>3 years):

• Metronidazole 30 mg/kg/day divided into three doses for 5-10 days 1, 2
• Alternative: Tinidazole (if metronidazole unavailable) 2, 4

Expected Response:

• Most patients respond within 72-96 hours of treatment initiation 1, 2
• If no improvement occurs within 2 days, consider alternative diagnoses or drug resistance 1
• For amoebic liver abscess, expect response within 72-96 hours 1

Essential Follow-Up Treatment (Critical to Prevent Relapse)

After completion of metronidazole or tinidazole, ALL patients must receive a luminal amebicide to eliminate intestinal cysts and prevent relapse. 1

Failure to provide a luminal agent after metronidazole/tinidazole therapy is the most common cause of relapse. 1

Luminal Amebicide Options:

• Paromomycin 30 mg/kg/day orally in 3 divided doses for 10 days (preferred) 1, 5
• Alternative: Diloxanide furoate 500 mg orally three times daily for 10 days 1

Note: Paromomycin is FDA-approved for intestinal amebiasis but is NOT effective in extraintestinal amebiasis 5. It must be given after tissue amebicide treatment is complete.

Special Clinical Situations

Amoebic Liver Abscess:

• Use the same metronidazole regimen as intestinal amoebiasis 1
• Surgical or percutaneous drainage is rarely required 1
• Consider drainage only if: diagnostic uncertainty exists, persistent symptoms after 4 days of treatment, or risk of imminent rupture 1
• Follow with luminal amebicide after metronidazole completion 1

Severe Acute Ulcerative Colitis with Travel History:

• For patients with recent travel to endemic areas, consider adding metronidazole pending stool microscopy if amoebiasis is suspected 1

Asymptomatic Cyst Passage:

• Tinidazole is NOT indicated for asymptomatic cyst passage 4
• Use luminal agents only (paromomycin or diloxanide furoate) 5

Common Pitfalls to Avoid

• Never skip the luminal amebicide after metronidazole/tinidazole - this is the leading cause of treatment failure and relapse 1
• Do not confuse bacterial dysentery with amebic dysentery - misdiagnosis leads to inappropriate treatment 1
• Do not use paromomycin alone for invasive disease - it is only effective for luminal infection 5
• Avoid antimotility agents in young children with severe disease 2

Monitoring and Follow-Up

• If fever persists or systemic inflammatory response develops despite treatment, consider amoebic liver abscess or other extraintestinal disease 2
• Perform abdominal ultrasound if hepatic involvement is suspected 2
• If symptoms persist beyond 4 days despite appropriate treatment, consider alternative diagnoses or complications 2

Prevention Counseling

• 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