Purpose or Case Report: Aseptic or chemical meningitis is an inflammation of the meninges without an infectious cause. It is a diagnosis of exclusion which is reached only in the appropriate clinical context after a careful search for bacterial or viral pathogens is negative. Aseptic meningitis following transsphenoidal resection of craniopharyngioma has been reported in the neurosurgical literature with an incidence of up to 3%; however, it remains unfamiliar in the radiology literature and there have been only a few case reports describing associated imaging findings. The chemical meningitis is thought to be caused by the release of craniopharyngioma fluid which contains inflammatory cholesterol crystals. Clinical and CSF findings can be identical to bacterial meningitis except for the absence of identifiable bacterial or viral pathogens. Complications can include vasospasm, stroke, and death. The purpose of this report is to describe two cases of aseptic meningitis following craniopharyngioma resection with the hope of improving awareness among pediatric radiologists.
Methods & Materials: Two patients (8 and 12 years old) underwent transsphenoidal resection of craniopharyngioma. Because of clinical concern for infection, both patients had post-operative MRIs which demonstrated leptomeningeal enhancement concerning for infectious meningitis. Both patients had elevated CSF neutrophils and protein, consistent with bacterial meningitis; however, CSF abnormalities persisted despite antibiotic treatment and CSF cultures remained negative. Follow-up MRI demonstrated resolution of leptomeningeal enhancement by 6 weeks with associated clinical improvement in both patients.
Results:
Conclusions: Craniopharyngiomas are relatively frequent tumors in children and aseptic meningitis should be included in the differential when a child presents with imaging findings concerning for meningitis following transsphenoidal craniopharyngioma resection, especially if CSF cultures are negative. It is possible that this entity is being underdiagnosed because patients are being treated for presumed infectious meningitis.