Granulomatous amoebic encephalitis

Source: Wikipedia, the free encyclopedia.
Granulomatous amoebic encephalitis
seizures, coma, risk of death
CausesAcanthamoeba spp., Balamuthia mandrillaris, and Sappinia pedata
TreatmentNitroxoline, miltefosine
T1-weighted
MRI showing expansion of the brain infection 4 days later

Granulomatous amoebic encephalitis (GAE)[2] is a rare, often fatal, subacute-to-chronic central nervous system disease caused by certain species of free-living amoebae[3] of the genera Acanthamoeba, Balamuthia and Sappinia.[4][5] The term is most commonly used with Acanthamoeba. In more modern references, the term "balamuthia amoebic encephalitis" (BAE) is commonly used when Balamuthia mandrillaris is the cause.[6][7][8][9]

Symptoms and signs

GAE starts slowly, with symptoms like headache, nausea, dizziness, irritability and a low-grade fever. The CNS symptoms depend on the part of the brain that is infected. Changes in behavior are an important sign. Other CNS signs may include

cranial nerve palsies, ataxia, confusion, and personality changes.[1]

Some of the symptoms may mimic glioma (especially brainstem glioma), or other brain diseases, which may hamper timely diagnosis. The symptoms are caused by inflammatory necrosis of brain tissue brought on by compounds released from the organisms.[citation needed]

Diagnosis

The condition can be difficult for doctors to diagnose, because it is a rare disease.

trophozoites will be visible.[11]

Treatment

Acanthamoeba

5-flucytosine and pentamidine have been shown to be effective against Acanthamoeba in vitro.[12]

Balamuthia

See also: Balamuthia mandrillaris § Treatment

Like with Acanthamoeba, infection of the brain with this organism rapidly turns fatal in most cases.[13] However some survivors have been reported:

Two patients survived after being successfully treated with a therapy consisting of flucytosine, pentamidine, fluconazole, sulfadiazine, and azithromycin. Thioridazine or trifluoperazine was also given. Successful treatment in these cases was credited to "awareness of Balamuthia as the causative agent of encephalitis and early initiation of antimicrobial therapy."[14]

In one case, cloxacillin, ceftriaxone, and amphotericin B were tried, but this treatment protocol did not prove effective.[15]

In 2018 a metagenomic sequencing analysis identified

amoebicidal agent against the Balamuthia mandrillaris.[16]

In 2021 a patient recovered after treatment with

amoebicidal agent against Balamuthia mandrillaris.[16]
The brain abscess shrank only one week later and the man later recovered.

Prognosis

Even with treatment, CNS infection with Acanthamoeba is often fatal, and there are very few recorded survivors, almost all of whom had permanent

neurocognitive deficits.[12] The prognosis is largely influenced by the time of diagnosis, how virulent and sensitive the Acanthamoeba strain is, and, most crucially, the immune status of the affected person. Due to it commonly being an opportunistic infection, the prognosis is generally poor, with a mortality rate approaching 90%.[1]

Sappinia pedata can cause GAE, however only one case of GAE due to S. pedata infection has ever been reported, and the patient survived without any long-term consequences.[19]

See also

  • Naegleriasis, an almost invariably fatal infection of the brain by the percolozoan Naegleria fowleri

References

  1. ^ a b c Duggal SD, Rongpharpi SR, Duggal AK, Kumar A, Biswal I (2018-01-22). "Role of Acanthamoeba in Granulomatous Encephalitis: A Review". Journal of Infectious Diseases & Immune Therapies. 2017.
  2. PMID 19621290
    .
  3. ^ Nguyen L, Perloff S (2018-07-24). Steele RW (ed.). "Amebic Meningoencephalitis: Overview". EMedicine.
  4. PMID 17932496
    .
  5. PMID 15358823
    .
  6. PMID 19657454
    .
  7. PMID 17644721
    .
  8. PMID 17913450
    .
  9. PMID 19236272
    .
  10. PMID 29747695
    .
  11. PMID 34133896
    .
  12. ^ a b Wang J, Nichols L, Martinez AJ. "Final Diagnosis -- Granulomatous Amoebic Encephalitis Due to Acanthamoeba castellanii". Department of Pathology. University of Pittsburgh.
  13. S2CID 31162954
    .
  14. PMID 14583863
    .
  15. PMID 15211011
    .
  16. ^
    PMID 30377287
    .
  17. doi:10.1126/science.adh0048
    . Retrieved 10 February 2023.
  18. PMID 36573629
    .
  19. ^ "Sappinia - Frequently Asked Questions (FAQs)". U.S. Centers for Disease Control and Prevention. Archived from the original on 2011-10-18.

External links

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