Severe Delayed-Onset Meningitis Developed One Year After a Basilar Skull Fracture Without a Cerebrospinal Fluid Leak: A Case Report.

Traumatic cerebrospinal fluid (CSF) leakage from skull base fractures increases the risk of bacterial meningitis, which is associated with a high mortality rate in adults, and commonly results in severe neurological outcomes. While most cases of CSF leakage occur within three months post-injury and generally resolve spontaneously, delayed-onset meningitis remains a challenging complication. Herein, we report a rare case of severe bacterial meningitis with an intraventricular abscess one year following a frontal skull base fracture, despite no CSF leak. A 68-year-old man with a history of a frontal skull base fracture due to a motor vehicle accident presented with seizures, fever, and altered consciousness. Imaging revealed ventriculitis, while laboratory findings confirmed bacterial meningitis caused by Streptococcus pneumoniae. Following initial antibiotic therapy, imaging revealed a new abscess near the fracture site, indicating potential bacterial entry due to a dural injury. Surgical repair was performed using a periosteal pedicle flap to close the intracranial space from the paranasal sinus. Postoperatively, antibiotic treatment resolved the abscesses, and the patient was subsequently treated for postmeningitis hydrocephalus. This case underscores the risk of delayed-onset meningitis in patients with large skull base fractures, even those without CSF leaks. In cases of skull base trauma with bone defects, a potential occult dural injury should be considered. If meningitis develops, surgical dural repair should be evaluated in addition to antibiotic treatment, regardless of the presence of a CSF leak, to effectively manage the infection and prevent a poor prognosis.