Acanthamoeba species
From IDWiki
Background
Microbiology
- One of the free-living amoebae
- Seventeen genotypes (T1-T17), of which 10 have caused disease in humans
- Most common is Acanthamoeba castellanii complex (T4)
Life Cycle
- Cysts and trophozoites can cause disease
Epidemiology
- More common in immunocompromised patients, with risk factors including AIDS, liver disease, diabetes, organ transplantation, corticosteroid use, chemotherapy, and rituximab
Clinical Manifestations
Granulomatous amebic encephalitis
- Subacute presentation of encephalitis (fever, headache, nuchal rigidity, behaviour changes, altered level of conciousness, focal neurological deficiets)
- Often preceded by cutaneous lesions by months
- May include ulcers, nodules, and subcutaneous abscesses
- Amoebic granulomas on biopsy
Non-neurological disseminated acanthamoebiasis
- Rarely, patients may have disseminated disease without evidence of CNS involvement
- Mostly seen in patients with AIDS, transplant, or prolonged corticosteroid use
- Most commonly involves skin, but can involve liver, lungs, and bones
Amoebic keratitis
- Sight- and eye-threatening infection
- Often secondary to corneal trauma or improper contact lens hygiene
- Present with severe pain, photophobia, tearing
- May see dendiform epitheliopathy or stromal ring
Management
Granulomatous amebic encephalitis
- Can consider a combinaction of pentamidine, azoles, flucytosine, sulfadiazine, miltefosine, amikacin, and voriconazole
Amoebic keratitis
- Can be treated with any of:
- PHMB
- Chlorhexadine
- Topical and oral voriconazole
- Propamidine
- Hexamidine
