Abstract:

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.

Key words: Angiostrongylus cantonensis, Eosinophilic pulmonary disease, Metagenomic next-generation sequencing, Central nervous system infection