Introduction: Lumbar puncture (LP) is routinely performed as part of the workup evaluation of suspected acute disseminated encephalomyelitis (ADEM). Though, the cerebrospinal fluid (CSF) can be normal, studies have shown that mild pleocytosis and/or increased CSF protein concentration are common findings in ADEM. However, the opening pressure of the spinal fluid tap, reflecting the intracranial pressure (ICP), has not been acknowledged to date in the literature.
Methods: Chart reviews of pediatric patients hospitalized in the Tel-Aviv Sourasky medical center, between 2005-2013, that were diagnosed with ADEM, were identified retrospectively. Patients with definite diagnosis of ADEM and documented CSF opening pressure were included in the analysis.
Results: Among 35 children diagnosed with ADEM, 20 who had documented CSF opening pressure comprised the study group. The mean age was 5.3±4.1 years, ten males (50%); Mean CSF opening pressure was 27.8±12.4 cmH2O, range 10-55 cmH2O. Considering the upper normal limit of CSF opening pressure in this age group (18 cmH2O), 15/20 (75%) patients had elevated pressure. One sample t-test comparison showed significant elevated CSF opening pressure among patients with ADEM (pv=0.0023, 95%CI 3.9-15.6). Minimal pleocytosis was present in seven samples (median=2 cells/mm2). Eighteen out of twenty (90%) patients had clinical complaints/signs that can be explained by increased ICP (drowsiness/encephalopathy n=18, vomiting n=8, headache n=8).
Discussion: The study results indicate that increased ICP should be considered in the patho-physiological changes occurring in the CNS of patients diagnosed with ADEM. In our cohort, this was the most common CSF abnormal finding, independent of pleocytosis level. These findings may explain, in part, the common non-focal neurological signs and symptoms, the beneficial effect of steroid treatment and the possible effect of other treatments for increased ICP. A multi-center study with larger numbers of patients is currently being carried out to validate our results.
