Aseptic meningitis as initial presentation of acute disseminated encephalomyelitis

Abstract

Background It is well known that upper respiratory infections or vaccinations are etiologic factors in the majority of acute disseminated encephalomyelitis (ADEM) cases. However, it is less well known that aseptic meningitis may be an initial manifestation of ADEM. Objectives To compare the clinical and laboratory findings between aseptic meningitis associated with ADEM (AM-ADEM) and isolated aseptic meningitis (AM-alone), and to determine possible predictive factors for progression to ADEM. Methods Twenty-five adults initially diagnosed as having aseptic meningitis were included in the present study. Clinical features, CSF, and laboratory parameters were retrospectively analyzed and compared between those with AM-alone and those who went on to develop AM-ADEM. Results Twenty patients were diagnosed as AM-alone, whereas five were AM-ADEM. Neurological features associated with ADEM including somnolence, diplopia, ataxia, paresis, and bladder disturbance developed 5–19 days after the first symptoms of aseptic meningitis. Sustained high fever > 38 °C and hyponatremia < 135 mEq/l were seen more frequently in cases with AM-ADEM compared with those with AM-alone. Conclusions Patients with an initial diagnosis of aseptic meningitis may develop ADEM during hospitalization. Sustained high fever and hyponatremia upon admission might be useful predictive factors for the subsequent development of ADEM in patients with aseptic meningitis.