Orthostatic Hypacusis in a Patient with CSF Hypovolaemia

Abstract

The syndrome of CSF hypovolaemia has been a recognized cause of orthostatic headache (a headache in the upright position relieved by recumbancy) (1-3). Among other clinical manifestations, a change in hearing has also been described in this syndrome (1,2,4,5). However, the pathogenesis of hearing changes in CSF hypovolaemia is unclear.We report a patient with CSF hypovolaemia who had orthostatic hypacusis (hearing impairment in the upright position relieved by recumbancy) that was clearly demonstrated by pure tone audiometry. The anatomical and physiological relationship between CSF space and inner ear structure may explain the pathogenesis of orthostatic hypacusis in CSF hypovolaemia. Case reportA 34-year-old previously healthy man presented with severe headache. The headache consistently occurred within 1 min of assuming the upright posture, and was relieved within 2 min of lying flat. The headache was pressing in nature, and was associated with posterior neck pain. Two days after the onset of his symptoms, he developed a change in hearing that was provoked by standing or sitting, and relieved by lying down. The patient's hearing change was described as 'muffled' or 'distant'. This orthostatic change in hearing had gradually worsened, and was severe enough to impede his daily life.Neurological examination 5 days after the onset of headache was unremarkable. He continued to develop the orthostatic change in hearing 5-10 min after he assumed an upright position. The orthostatic hypacusis of both ears was clearly demonstrated with pure tone audiometry. When he assumed an upright position for 10 min, the average hearing intensity thresholds at lower frequencies (250, 500 and 1000 Hz) were 26.7 dBHL in the right ear and 23.3 dBHL in the left (Fig. 1A). Upon lying flat, average hearing intensity thresholds normalized: 10.0 dBHL in the right ear and 11.7 dBHL in the left (Fig. 1B). The hearings at higher frequencies were stable. The summating potential to action potential ratio (SP/AP) of electrocochleography (ECoG), performed only in the supine position, was 0.36 in the left ear and 0.25 in the right ear.On CSF examination, the opening pressure was unmeasurably low and other CSF composition was normal. A brain T1-weighted gadolinium-enhanced MRI showed diffuse pachymeningeal enhancement but no evidence of brain sagging or subdural fluid collection. A spine MRI revealed extradural fluid collection at the level of thoracic spine, and engorgement of the epidural venous plexus at the level of cervical spine. MR myelography showed multiple hyperintense lesions along the bilateral paradural space at the level of upper thoracic spine ( Fig. 2A). Radioisotope cisternography demonstrated multiple paradural uptakes of tracer at the level of the thoracic spine. The orthostatic headache and orthostatic hypacusis were simultaneously resolved after treatment of four epidural blood patches. MR myelography, performed 1 month after treatment, showed the resolution of multiple hyperintense lesions along the bilateral paradural space a...

Audiovestibular impairments associated with intracranial hypotension

“…Our patients mostly had unilateral low-frequency SNHL while one showed bilateral low-and high-frequencies SNHL. These are consistent with the findings of earlier case reports on intracranial hypotension, which described unilateral or bilateral low-frequency SNHL with occasional progression to downsloping mild-to-profound SNHL [6][7][8][9][10][11][12][13][14][15][16][17]. In contrast, the caloric tests were normal in all.…”

“…Thus, the irritation of the vestibular and cochlear nerves may be an alternative mechanism. Stretching of the vestibulocochlear nerve due to brain sagging may be another possibility [9]. However, this can hardly explain isolated auditory symptoms without vertigo and other cranial or cervical nerve dysfunctions in some patients.…”

“…Several mechanisms have been proposed for the neurotological dysfunction in intracranial hypotension, which have converged on irritation or hypofunction of the peripheral labyrinth or vestibulocochlear nerve [7][8][9]. Under normal condition, there is a balance of pressure between the CSF and perilymph via the cochlear aqueduct (if permeable) [19].…”

“…A study of 30 consecutive patients with intracranial hypotension has described neurotological symptoms including dizziness (30%), tinnitus (20%), aural fullness (20%), and hearing loss (3%) [1], while another reported auditory symptoms in approximately 70% of the patients [6]. Earlier reports have also documented unilateral or bilateral low-frequency sensorineural hearing loss on audiometry with or without vertigo, likewise in Meniere's disease (MD) [6][7][8][9][10][11][12][13][14][15][16][17]. However, previous studies have mostly focused on auditory dysfunction, and no study has attempted objective documentation of vestibular dysfunction in intracranial hypotension.…”

Detection of CSF Leak in Spinal CSF Leak Syndrome Using MR Myelography: Correlation with Radioisotope Cisternography

“…There have been sporadic case reports in which MRM was used for the detection of a CSF leak. 6 We tested to see if MRM could detect the leakage site in 15 consecutive patients with spinal CSF leak syndrome and compared the results of MRM with those of RIC. For comparison, we performed MRM in 15 subjects without symptoms of spinal CSF leak syndrome.…”