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Pathogenic free-living amoebic encephalitis from 48 cases in China: A systematic review
Xiang-Ting Chen1, Qian Zhang1, Si-Yuan Wen1
1Department of Neurology, Bishan Hospital of Chongqing Medical University, Chongqing, China.
Background:
Free-living amoebae (FLA) including Naegleria fowleri, Acanthamoeba spp., and Balamuthia mandrillaris can become pathogenic and cause severe cerebral infections, named primary amoebic meningoencephalitis (PAM), granulomatous amoebic encephalitis (GAE), and balamuthia amoebic encephalitis (BAE), respectively. FLA encephalitis has been reported across China, but the clinical data descriptions and analytical results of these different reports vary widely. Currently, no consensus treatment has been established. We conduct a systematic review to evaluate the exposure location, clinical symptoms, diagnosis, treatment, and prognosis of three FLA encephalitis and aim to reveal the differences between three FLA encephalitis in China.
Methods:
We used MEDLINE (PubMed interface), EMBASE, China National Knowledge Infrastructure (CNKI), Wanfang database, and China Biology Medicine disc (CBMdisc) databases for literatures published and manually retrieve the hospital records of our hospital. The search time was up to August 30, 2022, with no language restrictions.
Results:
After excluding possible duplicate cases, a total of 48 patients of three FLA encephalitis were collected. One from the medical records of our hospital and 47 patients from 31 different studies. There were 11 patients of PAM, 10 patients of GAE, and 27 patients of BAE. The onset of PAM is mostly acute or subacute, and the clinical symptoms are acute and fulminant hemorrhagic meningoencephalitis. Most patients with GAE and BAE have an insidious onset and a chronic course. A total of 21 BAE patients (77.8%) had skin lesions before onset of symptoms. Additionally, 37 cases (77.1%) were diagnosed with FLA encephalitis before death. And there were 4 of PAM, 2 of GAE, and 10 of BAE diagnosed using next generation sequencing. No single agent can be proposed as the ideal therapy by itself. Only 6 cases were successfully treated.
Conclusions:
This review provides an overview of the available data and studies of FLA encephalitis in China and identify some potential differences. FLA encephalitis is a rare but pathogenic infection, and physicians should early identify this encephalitis to improve survival.
Insights
Free-living amoebae (FLA) can cause severe brain infections like primary amoebic meningoencephalitis (PAM), granulomatous amoebic encephalitis (GAE), and balamuthia amoebic encephalitis (BAE). This review highlights differences in FLA encephalitis in China to improve early identification and survival.
Area of Science:
- Neurology
- Infectious Diseases
- Parasitology
Background:
- Free-living amoebae (FLA) such as *Naegleria fowleri*, *Acanthamoeba* spp., and *Balamuthia mandrillaris* can cause fatal encephalitis.
- Reported cases of FLA encephalitis in China show varied clinical data, with no established treatment consensus.
- This systematic review focuses on primary amoebic meningoencephalitis (PAM), granulomatous amoebic encephalitis (GAE), and balamuthia amoebic encephalitis (BAE) in China.
Purpose of the Study:
- To systematically review and analyze exposure, symptoms, diagnosis, treatment, and prognosis of PAM, GAE, and BAE in China.
- To identify and highlight key differences between these three types of FLA encephalitis.
- To inform clinical practice and improve patient outcomes for rare but severe amoebic brain infections.
Main Methods:
- Searched multiple databases (MEDLINE, EMBASE, CNKI, Wanfang, CBMdisc) and hospital records up to August 30, 2022.
- Included literature and hospital records with no language restrictions.
- Collected and analyzed data from 48 confirmed cases of FLA encephalitis (11 PAM, 10 GAE, 27 BAE).
Main Results:
- PAM typically presents with acute onset and fulminant meningoencephalitis, while GAE and BAE have insidious onset and chronic courses.
- Skin lesions preceded symptoms in 77.8% of BAE cases. Overall, 77.1% of FLA encephalitis cases were diagnosed before death.
- Next-generation sequencing aided diagnosis in some cases. Treatment success was low, with only 6 out of 48 patients successfully treated.
Conclusions:
- FLA encephalitis represents a rare but significant cause of severe neurological infection in China.
- Understanding the distinct clinical presentations and diagnostic patterns of PAM, GAE, and BAE is crucial.
- Early identification by physicians is essential to improve the survival rate of patients with FLA encephalitis.
