Fatal Primary Amoebic Meningoencephalitis in Coastal Areas of North China in an Immunocompetent Patient: A Case Report and Literature Review

Qian Li Wang,1,* Sheng Nan Teng,1,* Xiao Jing Zhang,2 Yu Xin Guo,2 Yang Kong,1 Xing Han Tian,1 Yi Zhang1,3 1Department of Critical Care Medicine, Yantai Yuhuangding Hospital Affiliated to Qingdao University, Yantai, Shandong, People’s Republic of China; 2WillingMed Technology (Beijing) Co., Ltd, Beijing, People’s Republic of China; 3The Second Affiliated Hospital of Anhui Medical University, Hefei, People’s Republic of China*These authors contributed equally to this workCorrespondence: Xing Han Tian, Department of Critical Care Medicine, Yantai Yuhuangding Hospital Affiliated to Qingdao University, Yantai, Shandong, People’s Republic of China, Email tianfenger987@sina.com Yi Zhang, Department of Critical Care Medicine, Yantai Yuhuangding Hospital Affiliated to Qingdao University, Yantai, Shandong, People’s Republic of China, Email 853169163@qq.comPurpose: Primary amoebic meningoencephalitis (PAM) is a rapidly fatal infection caused by Naegleria fowleri (N. fowleri) with a mortality rate exceeding 95%. This study presented the clinical course, diagnosis, treatment, and outcome of a confirmed PAM case in an adult female. Additionally, we analyzed the epidemiology of PAM in China and review the therapeutic regimens of surviving cases worldwide, aiming to enhance disease awareness and improve clinical outcomes.Case Presentation: The patient was a 50-year-old immunocompetent woman with a history of hot spring bathing before symptom onset, which was not initially disclosed. Moreover, her early infectious symptoms, particularly fever following a tick bite in an orchard, directed clinical suspicion toward tick-borne disease. Four days later, she was hospitalized with generalized convulsions and coma. Clinical examination suggested a bacterial intracranial infection, and treatment with meropenem and vancomycin was initiated. However, her condition deteriorated rapidly. The presence of N. fowleri was identified by cerebrospinal fluid (CSF) metagenomic next-generation sequencing (mNGS) and smear. The etiology was clarified only after retrospective confirmation of hot spring contact, which was later confirmed by blood mNGS. Despite intensive therapy with amphotericin B (AmB), the patient unfortunately died. To provide insights into PAM management in China, we also conducted a systematic analysis of 15 domestic cases and 18 global survivors.Conclusion: PAM is characterized by rapid progression, underscoring the importance of early diagnosis. In cases of rapidly advancing meningoencephalitis, clinicians should maintain a high index of suspicion for rare pathogens such as N. fowleri, with thorough and repeated assessment of recent environmental exposures such as hot spring immersion or freshwater swimming. Early application of mNGS is essential for timely pathogen identification. While AmB remains the first-line therapy, its dosing and duration should be tailored to individual patient factors, and combination therapy should be considered to enhance efficacy. Overall, improved clinical vigilance, advanced pathogen diagnostics, and standardized anti-amoebic therapy form the cornerstone of enhancing outcomes in PAM. As the first documented PAM case in Shandong Province, China, this report highlights the need for heightened awareness in coastal regions while contributing valuable epidemiological insights into this devastating disease.Keywords: Naegleria fowleri, primary amoebic meningoencephalitis, metagenomic next-generation sequencing, diagnosis, coastal areas of North China