Amoebic Infection (Amebiasis)

Amoebic Infection (Amebiasis) – Treatment Overview

Introduction
Amoebic infection, or amebiasis, is caused by the protozoan parasite Entamoeba histolytica, transmitted via the fecal–oral route through contaminated food or water. It can present as:

• Asymptomatic intestinal colonization (cyst carriers).

• Intestinal disease: Amebic colitis, dysentery.

• Extraintestinal disease: Most commonly liver abscess, but also pleuropulmonary or brain involvement in severe cases.

Management depends on the clinical form of disease. Successful treatment requires both tissue-active agents (for invasive forms) and luminal agents (to eradicate intraluminal cysts and prevent relapse/transmission).

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Treatment Options and Doses

1. Asymptomatic Cyst Carriers (Luminal Amebiasis)

• Paromomycin: 25–35 mg/kg/day orally in 3 divided doses for 7 days.

• Iodoquinol: 650 mg orally three times daily for 20 days.

• Diloxanide furoate: 500 mg orally three times daily for 10 days (where available).

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2. Intestinal Amebiasis (Amebic Colitis / Dysentery)

• Metronidazole: 750 mg orally three times daily for 7–10 days.

  • Children: 35–50 mg/kg/day in 3 divided doses (max 2.25 g/day).

• Tinidazole (alternative): 2 g orally once daily for 3–5 days.

• Followed by a luminal agent (paromomycin, iodoquinol, or diloxanide).

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3. Amebic Liver Abscess (ALA)

• Metronidazole: 750 mg orally or IV three times daily for 7–10 days.

• Tinidazole: 2 g orally once daily for 5 days.

• Follow with luminal therapy (paromomycin, iodoquinol, or diloxanide).

• Drainage: Reserved for:

  • Very large abscesses at risk of rupture (especially in the left lobe).

  • No clinical improvement after 5–7 days of therapy.

  • Diagnostic uncertainty (to rule out pyogenic abscess).

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4. Severe / Complicated Amebiasis

• Hospitalization.

• IV metronidazole if oral therapy not possible.

• IV fluids and electrolyte correction.

• Broad-spectrum antibiotics if secondary bacterial infection suspected.

• Surgical intervention only for perforation, peritonitis, or uncontrolled colitis.

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Supportive Measures

• Adequate hydration and nutrition.

• Avoid corticosteroids (can worsen fulminant colitis).

• Monitor for complications (toxic megacolon, rupture of abscess).