although symptomatic intracranial hypertension is a well - recognized complication of bacterial meningoencephalitis , in aseptic meningoencephalitis it is a rather uncommon phenomenon and has been systematically assessed in children only . we report a case of aseptic meningitis complicated by severe intracranial hypertension and accompanied by a distinct leptomeningeal contrast enhancement on fluid - attenuated inversion recovery ( flair ) magnetic resonance imaging ( mri ) . a 19-year - old woman presented with a 10-day history of continuous headache , mild photophobia and nausea ; her medical and recent travel history were unremarkable as was the clinical examination . cerebrospinal fluid ( csf ) analysis ( 120 cells/l ; 85% lymphocytic and 15% monocytic cells ; protein 1,031.6 mg / l ; glucose and lactate within the normal range ) was consistent with aseptic meningitis . treatment with acyclovir was given until proof of negative csf pcr for herpes simplex virus . one week after admission , the patient 's condition worsened with a decline in cognitive functions and a generalized epileptic seizure . a prominent sulcal and leptomeningeal enhancement was noted on flair mri after contrast involving both hemispheres and the cerebellum in the absence of focal parenchymal lesions . 1 ) . repetitive broad serologic examinations ( herpesviridae , hiv , enterovirus , adenovirus , respiratory syncytial virus , measles , mumps , rubella , tick - borne encephalitis virus , influenza , borreliosis , leptospirosis , chlamydia pneumoniae and trachomatis , listeria monocytogenes , legionella pneumophila , mycobacterium tuberculosis , treponema pallidum , mycoplasma pneumoniae , bartonella henselae and haemophilus influenzae ) and viral full - genome sequencing could not identify a pathogen . in the absence of any eosinophilia , a fungal or parasitic etiology was unlikely , neither was there any hint at a systemic autoimmune disease . the patient complained about a progressive headache intensity with continuous nausea and repeated vomiting ( an overview of the clinical course is given in fig . a csf opening pressure of > 60 cm h2o was documented . in the further course follow - up mri demonstrated prominent optical nerves and an empty sella compatible with intracranial hypertension ; venous thrombosis was ruled out . at this time , transcranial dopp - ler indicated vasospasms of the middle cerebral artery , which gradually resolved on nimodipine . in repetitive lumbar punctures , an opening pressure of > 60 cm h2o was measured ; after drainage of 30 ml csf and under oral therapy with acetazolamide , a rapid but short - lasting symptom improvement was achieved after each lumbar puncture . over the course of 14 days , a maximum csf cell count of 314/l and a protein level > 2,000 mg / l were found . cytology varied between 80 and 97% of lymphocytes and between 3 and 20% of monocytes in the csf . increased blood - brain barrier ( bbb ) permeability was repeatedly demonstrated as illustrated in the reibergram ( fig . 3 ) . we decided to place a temporary external lumbar drainage to reduce intracranial pressure ( icp ) and to avoid further punctures . subsequently , the patient became gradually headache free , and the sixth nerve palsy and the visual disturbances gradually resolved . after 7 days , the drain was removed , and another 10 days later , the patient was discharged and fully recovered over the course of the following 4 weeks . a follow - up csf analysis including opening pressure and mri findings returned to normal . this case of aseptic meningoencephalitis has several unusual features : a rather severe complication of intracranial hypertension  requiring temporary placement of an external lumbar drainage  and a persisting almost generalized bbb dysfunction as demonstrated on postcontrast flair mri and by csf analysis for an extended period . reports on peri - infectious intracranial hypertension ( icht ) are much less frequent in aseptic meningitis compared to purulent meningitis . in a small case series of 3 patients between 14 and 28 years of age with aseptic meningitis , a course with papilledema and sixth nerve palsy has been described , and an elevated csf pressure ( 30 cm h2o ) has been reported in 1 of these patients . a presentation with headache , papilledema and an elevated csf opening pressure of 46 cm h2o requiring 3 additional lumbar punctures was reported in a 16-year - old female with cytomegalovirus - positive meningitis . another benign course with elevated icp has been reported in a patient with acute toscana virus meningoencephalitis . despite a favorable clinical course after repetitive lumbar punctures , elevated icp was associated with a hydrocephalus on imaging . in an 8-year - old girl , chronic epstein - barr virus infection was complicated by cerebral involvement and elevated icp but again with concomitant parenchymal abnormalities and , this time , without csf pleocytosis . on the other hand , elevated icp in the absence of hydrocephalus on imaging is the leading criterion of idiopathic icht . secondary intracranial hypertension has been described in a postinfectious context , e.g. in lyme disease   and in peri - infectious aseptic meningitis in leptospirosis . however , these patients presented with isolated symptoms of icht rather than meningitis . in the context of viral infections , intracranial hypertension has been reported in an 8-year - old child after measles but without csf pleocytosis . secondary and severe icht treated by repetitive lumbar punctures was reported in a 15-year - old obese girl with chronic aseptic meningitis . we faced a prolonged course of viral meningoencephalitis complicated by a continuously elevated icp requiring repetitive lumbar punctures over a 2-month period . since the patient showed a strong benefit from repetitive lumbar punctures , we chose to perform a continuous lumbar drainage for 1 week according to beneficial reports in bacterial meningitis . this proved to be an effective symptomatic treatment and might be a useful means to treat icp complications in meningitis patients . the elevated icp could either be due to disturbed csf reabsorption or leptomeningeal transudation due to leptomeningeal bbb dysfunction . despite the absence of parenchymal lesions and , furthermore , the absence of a hydrocephalus , mri provided important information by revealing contrast enhancement in the sulcal space in a leptomeningeal pattern on postcontrast flair mri . this phenomenon has been recently reported in several leptomeningeal pathologies including subarachnoid hemorrhage , meningitis or meningeal carcinomatosis [ 12 , 13 ] . mainly due to the suppression of the csf signal , postcontrast flair images show a higher sensitivity in the delineation of meningeal pathologies . leakage from damaged pial vessels , leading to focal extravasation of the contrast agent into the csf adjacent to the brain , is the most likely pathophysiological explanation for leptomeningeal enhancement on flair images , indicating blood - csf barrier disruption and matching the finding of an increased albumin csf / serum ratio in the csf analysis . csf and mri results suggest that a bbb disturbance , as frequently seen in aseptic meningitis , may cause raised icp . since we did not identify a pathogen , we can only speculate about the mechanism of such a prolonged bbb disturbance , e.g. a bbb - toxic agent , activation of chemoattractants or an overwhelming immune reaction . written informed consent was obtained from the patient for publication of this case report and any accompanying images .
we report a case of a 19-year - old woman who developed intracranial hypertension as an unusual clinical complication of severe aseptic meningoencephalitis probably due to a diminished cerebrospinal fluid reabsorption capacity or leptomeningeal transudation as a consequence of blood - brain barrier dysfunction . 
 these severe inflammatory changes were accompanied by prominent leptomeningeal contrast enhancement best visualized on fluid - attenuated inversion recovery magnetic resonance imaging . in such a prolonged course , a continuous lumbar drainage might be a temporary option to provide rapid symptom relief to the patient .