Review of Clinical Presentations in Thai Patients With Primary Amoebic Meningoencephalitis

Viroj Wiwanitkit, MD

In This Article

Abstract and Introduction

Context: Primary amoebic meningoencephalitis (PAM) is a very rare but deadly infection of the central nervous system. Since the disease was first identified in 1965, fewer than 200 cases have been observed worldwide.
Objective: The author performed a literature review of the reports of PAM in Thailand in order to study the clinical summary of PAM among Thai patients.
Design: This study was designed as a descriptive retrospective study. A literature review of the papers concerning PAM in Thailand was performed.
Results: According to this study, there have been at least 12 reports of PAM in Thailand, of which 2 cases were nonlethal. The mean age was 15.2 ± 16.1 years with a male:female ratio of about 2:1. History of risk behaviors such as suffocation of surface water during swimming was demonstrated in 6 cases. Also, 2 interesting cases involved possible water contact according to the Thai tradition and culture. Concerning the patients' clinical features, fever, headache, impaired consciousness, and stiff neck were seen in all cases. However, some unusual presentations such as intermittent abdominal pain and convulsion were also seen in this series. Similar to worldwide findings, most cases occurred during the summer months. Most of the cases involved young males from rural provinces in various regions of Thailand. Concerning the laboratory investigation, the cerebrospinal fluid (CSF) profile presented the polymorphonuclear (PMN) pleomorphic with hypoglycorhachia pattern. Trophozoite could be identified in all but 2 cases in this series.
Conclusion: PAM is sporadically reported in Thailand but remains a public health issue. The clinical diagnosis of PAM is usually difficult as many clinicians are unfamiliar with the disease. The prognosis outcome is usually grave although broad medications are prescribed.

PAM is a very rare disease of the brain.[1] Naegleria fowleri is the principal protozoa, commonly referred to as pathogenic free-living amoebae, that causes PAM.[2] PAM occurs very rarely but is usually fatal. Since the disease was first identified in 1965,[3] fewer than 200 cases have been identified worldwide.[1,2,4] N fowleri are ubiquitous in the environment, in soil, water, and air.[5] Infections in humans are rare and are acquired through water entering the nasal passages (usually during swimming) and by inhalation.

Most human victims of PAM are exposed to free-living amoebae while swimming in warm surface water. This may include ponds, lakes, streams, rivers, and improperly maintained swimming pools. The risk of acquiring PAM increases as water temperatures rise.[1,5] Transmission to humans occurs when the organism gains access to brain tissues through the nasal passages. The organism can enter the nasal passages when water containing the organism is forced up the nose through activities such as diving, jumping into water, and underwater swimming. Luckily, PAM is not transmitted from person to person.[1,2,4]

In Thailand, the first case report of PAM was published in 1983 by Jariya and colleagues.[6] Since the first case report, there have been sporadic reports of PAM in Thailand. Here, the author performed a literature review on the reports of PAM in Thailand in order to study the clinical summary of PAM among Thai patients.


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