患者，男，26岁，自由职业者，广东惠州人。2024年7月27日出现头痛，7月30日出现低热，分别按“感冒”“上呼吸道感染”治疗，效果不佳，8月5日因“头痛10天，发热7天”在惠州市中心人民医院住院治疗。发病前1月余有食用鱼生（草鱼）和生腌（淡水虾、蟹）史。查体有双眼向左凝视时可见水平方向眼球震颤。胸部CT示双肺有感染病灶，头颅平扫CT未见异常，颅脑MRI显示右侧额叶白质区少许缺血变性灶。外周血嗜酸粒细胞数升高（1.677 × 10⁹/L），嗜酸粒细胞百分数升高（16%），ELISA检测血清广州管圆线虫IgG抗体阴性。脑脊液常规示脑脊液压力240 mmH₂O（1 mmH₂O = 0.0098 kPa），脑脊液宏基因组二代测序检出广州管圆线虫特异序列7条，相对丰度8.1%，8月6日予甘露醇（连续18 d）降颅压，8月9日开始予阿苯达唑口服（0.4 g/次，3次/d，连续20 d），8月17日加用地塞米松磷酸钠静脉推注（10 mg/d，连续10 d），8月27日停用地塞米松，予醋酸泼尼松片口服，后续23 d按60、30、20、10、5 mg依次减量至停用。入院第9天头痛基本缓解，出院前复查外周血嗜酸粒细胞数恢复正常，肺部病灶较前吸收，脑脊液压力降低，脑脊液宏基因组二代测序示广州管圆线虫特异序列数逐渐升高。9月4日患者好转出院；10月8日电话随访，患者无不适。

A 26-year-old male patient, a freelancer hailing from Huizhou, Guangdong Province, started to experience headaches on July 27, 2024, and developed a low-grade fever on July 30. Treatments targeting “cold” and “upper respiratory tract infections” yielded unsatisfactory outcomes. On August 5, he was admitted to Huizhou Central People’s Hospital for hospitalization due to “10 days of headache and 7 days of fever”, and he reported a history of consuming raw fish (grass carp) and raw-pickled food (freshwater shrimp and crabs) over one month prior to disease onset. Physical examination showed horizontal nystagmus when he gazed toward the left with both eyes. A chest computed tomography (CT) scan displayed infectious lesions in bilateral lungs, and a plain cranial CT scan showed no abnormalities, while a cranial magnetic resonance imaging (MRI) scan displayed a few ischemic and degenerative foci in the white matter area of the right frontal lobe. His peripheral blood eosinophil count was elevated (1.677 × 10⁹/L), as was the percentage of eosinophils (16%). However, enzyme-linked immunosorbent assay (ELISA) detected negative serum IgG antibodies against Angiostrongylus cantonensis. Routine cerebrospinal fluid tests showed a cerebrospinal fluid pressure of 240 mmH₂O (1 mmH₂O = 0.0098 kPa), and metagenomic next-generation sequencing (mNGS) of cerebrospinal fluid specimens detected 7 specific sequences of A. cantonensis, with a relative abundance of 8.1%. Mannitol was administered to reduce intracranial pressure for 18 consecutive days since August 6, and albendazole was orally administered at a single dose of 0.4 g by three times a day, for 20 consecutive days since August 9. Dexamethasone sodium phosphate injection was additionally given at a daily dose of 10 mg for 10 consecutive days since August 17, and dexamethasone was discontinued on August 27, when the patient was switched to oral prednisone acetate tablets, with the dose gradually tapered down to discontinuation over the subsequent 23 days in the sequence of 60 mg, 30 mg, 20 mg, 10 mg and 5 mg. His headache was almost relieved on day 9 post-admission, and a follow-up test showed that the peripheral blood eosinophil counts had returned to normal before discharge, the pulmonary lesions had been absorbed to some extent compared with the previous state, the cerebrospinal fluid pressure had decreased, and mNGS of cerebrospinal fluid specimens indicated a gradual increase in the number of specific sequences of A. cantonensis. The patient improved and was discharged on September 4, and a follow-up phone call on October 8 revealed that the patient was free of discomfort.