What is the recommended treatment for amoebic dysentery?

Treatment of Amoebic Dysentery

Metronidazole 750 mg three times daily for 5-10 days is the recommended treatment for amoebic dysentery, followed by a luminal amoebicide such as diloxanide furoate or paromomycin to prevent relapse. 1

Diagnostic Approach

• Microscopic confirmation is essential before initiating treatment for amebiasis, as amebic dysentery tends to be misdiagnosed 1
• Stool specimens should be examined by microscopy to identify Entamoeba histolytica trophozoites 1
• Care must be taken to distinguish large white blood cells (nonspecific indicators of dysentery) from actual amebic trophozoites 1
• Treatment for amebiasis should not be considered unless microscopic examination shows amebic trophozoites OR two different antibiotics for shigellosis have failed 1

Treatment Algorithm

First-Line Therapy: Tissue Amoebicide

Metronidazole 1, 2:

• Adults: 750 mg orally three times daily for 5-10 days
• Children: 30 mg/kg/day for 5-10 days
• Cure rates exceed 90% 1
• Most patients respond within 72-96 hours 1

Alternative: Tinidazole 1, 3:

• Adults: 2 g daily for 3 days
• Results in less nausea compared to metronidazole 1
• Indicated for intestinal amebiasis and amebic liver abscess 3
• Superior efficacy and tolerability compared to metronidazole in some studies 4, 5

Critical Second Step: Luminal Amoebicide

All patients must receive a luminal amoebicide after completing metronidazole or tinidazole to reduce relapse risk, even with negative stool microscopy 1:

• Diloxanide furoate: 500 mg orally three times daily for 10 days 1
• Paromomycin: 30 mg/kg per day orally in 3 divided doses for 10 days 1

Clinical Context and Pitfalls

When Microscopy is Unavailable

• If microscopy is unavailable or definite trophozoites are not seen, patients with bloody diarrhea should be treated initially for shigellosis 1
• Only after failure of two different antibiotics for shigellosis should amebiasis treatment be considered 1
• At this stage, resistant shigellosis remains more likely than amebiasis 1

Common Diagnostic Pitfall

• Amebic dysentery is frequently misdiagnosed 1
• The tendency to overdiagnose amebiasis leads to inappropriate treatment and delays proper management of bacterial dysentery
• Only 20% of patients with amebic liver abscess have a history of dysentery, and only 10% have diarrhea at diagnosis 1

Treatment Considerations

• Metronidazole alone does NOT eradicate intestinal cysts 1
• Failure to follow tissue amoebicide with luminal amoebicide results in treatment failure and relapse 1
• In severe cases where oral administration is impossible, metronidazole retention enema (2 g in 200 mL normal saline) achieves rapid absorption and high serum levels 6
• For amebic liver abscess, metronidazole therapy does not obviate the need for aspiration or drainage of pus when clinically indicated 2