Diagnosis, inclusion and exclusion criteria

The symptoms and results of the subjects meet the diagnostic criteria for purulent meningitis (Supplementary Table I). Diagnostic criteria: in the light of the diagnostic criteria of refractory purulent meningitis in children in Zhu Futang Practical Pediatrics [4]: pediatric patients who meet one or more of the following criteria are classified as refractory purulent meningitis: (i) the main clinical symptoms are acute fever, convulsions, depressed mood, lethargy, irritability, etc. (ii) with bregma bulge, meningeal irritation sign and other signs; (iii) Abnormal tabular brain parenchymal areas on CT or MRI of the head; (iv) Accompanying persistent complications such as subdural effusion, ependymitis, and hydrocephalus; (v) Sequela during death or late follow- up period, such as secondary epilepsy, cranial nerve injury, and psychomotor delay; (vi) After one week of conventional treatment (penicillin ceftriaxone and cefotaxime), there are still symptoms of fever or other recurrent purulent meningitis. (vii) Recurrent purulent intracranial infection of unknown origin.

Inclusion criteria: complete clinical data; no previous treatment with dexamethasone; aging 1–7 years; all children's guardians gave informed consent and signed an informed consent form.

Exclusion criteria: combined with other organ dysfunction symptoms; immunodeficiency, systemic infection; septic shock; fungal meningitis, tuberculous meningitis and other non-bacterial central nervous system infections; intracranial hemorrhage, craniocerebral trauma, brain tumor and other diseases; the children whose guardians are unwilling to participate in this research.