Characteristics of meningitis following transsphenoidal endoscopic surgery: a case series and a systematic literature review

Background: Meningitis occurs in 0.8–1.5% of patients undergoing neurosurgery. The aim of the study was to evaluate the characteristics of meningitis after endoscopic endonasal transsphenoidal surgery (EETS) comparing the findings retrieved to those highlighted by literature search. Materials and methods: Patients treated by EETS during an 18-year period in the Department of Neurosurgery of ‘Federico II’ University of Naples were evaluated and included in the study if they fulfilled criteria for meningitis. Epidemiological, demographic, laboratory, and microbiological findings were evaluated. A literature research according to PRISMA methodology completed the study. Results: EETS was performed on 1450 patients, 8 of them (0.6%) had meningitis [median age 46 years (range 33–73)]. Endoscopic surgery was performed 1–15 days (median 4 days) before diagnosis. Meningeal signs were always present. CSF examination revealed elevated cells [median 501 cells/μL (range 30–5728)], high protein [median 445 mg/dL (range 230–1210)], and low glucose [median 10 mg/dL (range 1–39)]. CSF culture revealed Gram-negative bacteria in four cases (Klebsiella pneumoniae, Escherichia coli, Alcaligenes spp., and Haemophilus influenzae), Streptococcus pneumoniae in two cases, Aspergillus fumigatus in one case. An abscess occupying the surgical site was observed in two cases. Six cases reported a favorable outcome; two died. Incidence of meningitis approached to 2%, as assessed by the literature search. Conclusions: Incidence of meningitis after EETS is low despite endoscope goes through non-sterile structures; microorganisms retrieved are those present within sinus microenvironment. Meningitis must be suspected in patients with persistent fever and impaired conscience status after EETS.