Treatment of Amoebic Sinusitis
Amoebic sinusitis requires immediate treatment with metronidazole 800 mg three times daily, along with surgical drainage of infected areas and removal of any foreign material for optimal outcomes. 1
Diagnosis and Etiology
Amoebic sinusitis is a rare parasitic infection of the sinuses that can be caused by:
- Entamoeba histolytica (causing amoebiasis cutis)
- Acanthamoeba species (particularly concerning in immunocompromised patients)
Diagnosis requires a high index of clinical suspicion and is confirmed by:
- Demonstration of amoebic trophozoites in wet-drop preparations from lesion margins
- Visualization of trophozoites in H&E and periodic acid Schiff-stained histological sections 1
Treatment Protocol
First-line Treatment
- Metronidazole 800 mg three times daily for at least 2 weeks 1
- Surgical intervention including drainage of infected areas and removal of any foreign material 2
For Immunocompromised Patients
- More aggressive multidisciplinary approach is required
- Extended course of metronidazole may be necessary
- Close monitoring for disseminated infection 3
Adjunctive Treatments
- Saline nasal irrigation to help clear mucus and reduce inflammation 2
- Intranasal corticosteroids to reduce inflammation 2
- Adequate hydration to maintain mucus flow 2
Monitoring and Follow-up
- Assess for clinical improvement within 72 hours of starting treatment
- Consider immediate specialist referral (otolaryngologist) if:
- No improvement after appropriate therapy
- Signs of complications (orbital involvement, severe pain, persistent fever)
- Immunocompromised status 2
Important Considerations
Clinical Pearls
- Amoebic sinusitis is rare but potentially fatal, especially in immunocompromised patients
- Only a few cases of Acanthamoebic rhinosinusitis have been reported in literature, with high mortality 3
- HIV status should be evaluated in patients with confirmed amoebic infections, as there is a strong association 3
Pitfalls to Avoid
- Misdiagnosis is common due to rarity of the condition
- Amoebic sinusitis can be misdiagnosed as bacterial sinusitis or even malignancy 3
- Delayed treatment can lead to significant morbidity and mortality
- Standard antibiotic regimens for bacterial sinusitis (amoxicillin, cephalosporins) are ineffective against amoebic infections 2, 4
Unlike bacterial sinusitis which can often be treated with amoxicillin or amoxicillin-clavulanate 2, 4, amoebic sinusitis requires specific antiparasitic therapy with metronidazole and often surgical intervention to achieve resolution 1.