Elevated lumbar puncture opening pressure in aseptic meningitis

Elevated lumbar puncture opening pressure (ELPOP) is a reported but understudied phenomenon in aseptic meningitis. This study aimed to characterize the features of ELPOP in aseptic meningitis patients.

An observational, retrospective, single-center study was conducted. We included all adult patients diagnosed with aseptic meningitis or meningoencephalitis from October 2015 to May 2017, for whom lumbar puncture opening pressure (LP OP) was measured. OP > 25 cm H₂O was documented as ELPOP. Patients' demographic characteristics, clinical data, laboratory and cerebrospinal fluid (CSF) results, as well as optic disc appearance were analyzed.

Among 116 patients (61 males) included, 16 patients (14 %) had ELPOP (11 males). The average age of those patients was 32.4 years (SD = 9.8), and the mean OP was 31.7 cm H₂O (SD = 6.02) as opposed to the mean normal LPOP (NLPOP) of16.13 cm H₂O (SD = 4.15). Body mass index (BMI) was significantly higher in the ELPOP group (p = 0.0081). Funduscopic examination was documented in 15/16 patients in the ELPOP group and revealed swollen optic discs in 6 (40 %) patients. Fundus examination was performed in 62 patients in the NLPOP group, of whom 2 (3.2 %) had a swollen disc. There was no difference in CSF content between groups.

This study fills the void of information lacking on the frequency of ELPOP in aseptic meningitis. Its association with increased BMI may be related to the pathogenesis. LP OP should be measured in all patients with aseptic meningitis. Additional research is needed to determine the threshold of tolerated intracranial pressure (ICP).