The Pseudotumor Cerebri Syndrome: A Unifying Pathophysiological Concept for Patients with Isolated Intracranial Hypertension with Neither Mass Lesion Nor Ventriculomegaly.

In 1991 we proposed that while the syndrome of isolated intracranial hypertension might have many definite and probable causes, it has nonetheless a single unifying pathophysiological mechanism: namely, impairment of cerebrospinal fluid (CSF) reabsorption. For that reason, we also proposed then that it is best described by a single, unifying, inclusive term, namely, pseudotumor cerebri syndrome. Although it appears that there is, as far as nomenclature is concerned, now international agreement, there is as yet no agreement on pathophysiology and classification. Herein we outline our views on these matters and give our reasons.

Transverse sinus stenting for pseudotumor cerebri: a cost comparison with CSF shunting.

BACKGROUND AND PURPOSE: Transverse sinus venous stent placement has been shown to lower intracranial pressure in patients with venogenic pseudotumor cerebri and to reverse, or at least stabilize, its symptoms and signs. There have been no studies comparing the cost of venous stenting with the time-honored treatment for pseudotumor cerebri-CSF shunting. The purpose of this study was to compare the cost of trasverse sinus stenting versus CSF shunting for the treatment of pseudotumor cerebri. MATERIALS AND METHODS: This work was a retrospective cost analysis of individual resource use in 86 adults who were stented for pseudotumor cerebri during a 12-year period compared with resource use in 110 children who were shunted for hydrocephalus during a 3-year period. RESULTS: There was no significant difference between the cost of inserting an initial venous stent ($13,863 ± 4890) versus inserting an initial CSF shunt ($15,797 ± 5442) (P = .6337) or between inserting an additional venous stent ($9421 ± 69) versus revising a CSF shunt ($10,470 ± 1245) (P = .4996). There were far fewer additional venous stent insertions per patient than there were subsequent CSF shunt revisions; 87% of stents placed required just 1 stent procedure, whereas only 45% of shunts required 1 shunt procedure. The main cause of the cost difference was the need for repeated revisions of the shunts, especially when they became infected-24 instances of a total 143 shunt procedures (16.8%) at an average cost of $84,729, approximately 5 times the cost of an initial shunt insertion. CONCLUSIONS: Venous stenting costs significantly less per 100 procedures than does CSF shunting, due largely to the high cost of treating shunt infections and the need for repeated shunt revisions.

Malignant meningitis presenting as pseudotumor cerebri.

Malignant leptomeningitis can present as the clinical syndrome of pseudotumor cerebri due to infiltration of arachnoid villi in the superior sagittal sinus. We show that malignant pachymeningitis can also present with pseudotumor cerebri, likely due to cerebral venous hypertension from transverse sinus compression. We present 3 cases of pseudotumor cerebri due to pachymeningeal or leptomeningeal metastases and discuss the mechanism of intracranial hypertension in such cases, its diagnosis and treatment.

Posterior semicircular canal occlusion for intractable benign positional vertigo: outcome in 55 ears in 53 patients operated upon over 20 years.

OBJECTIVE: To report the outcome of posterior semicircular canal occlusion surgery for intractable benign positional vertigo, regarding vertigo cure rate and hearing and balance outcomes. METHODS: Retrospective review of 53 patients presenting with benign positional vertigo, unresponsive to repositioning manoeuvres, who eventually underwent posterior canal occlusion, over a 20 year period. RESULTS: From 1991 to 2011, 5364 benign positional vertigo patients were treated in our balance disorders clinic; 53 of those who failed to respond to repositioning underwent posterior canal occlusion. All 53 were cured of their benign positional vertigo. Nine suffered some symptomatic permanent hearing loss (>20 dB at low and >25 dB at high frequencies). Ten patients suffered caloric vestibular function deterioration, with mild but permanent subjective imbalance in five; a further 10 patients with no post-operative caloric test changes also had some permanent imbalance. Benign positional vertigo later developed in the operated ear lateral canal in two patients and in the opposite ear posterior canal in eight patients. Two patients needed bilateral sequential posterior canal occlusion. CONCLUSION: Posterior canal occlusion is a highly effective treatment for intractable benign positional vertigo, with what is probably an acceptable risk to hearing and balance: five of six patients will have no hearing problem and nine of 10 no balance problem after surgery.

Isolated reversible hypoglossal nerve palsy as the initial manifestation of pre-eclampsia.

Isolated hypoglossal nerve lesions often reflect sinister neoplastic or vascular pathology. Rarely, reversible lesions occur, perhaps via mechanisms similar to Bell's palsy. We report a patient with reversible isolated hypoglossal nerve palsy as the first and predominant early manifestation of pre-eclampsia and speculate on the pathogenesis behind this abnormality.

Transverse sinus stenting for idiopathic intracranial hypertension: a review of 52 patients and of model predictions.

BACKGROUND AND PURPOSE: Transverse sinus stenosis is common in patients with IIH. While the role of transverse sinus stenosis in IIH pathogenesis remains controversial, modeling studies suggest that stent placement within a transverse sinus stenosis with a significant pressure gradient should decrease cerebral venous pressure, improve CSF resorption in the venous system, and thereby reduce intracranial (CSF) pressure, improving the symptoms of IIH and reducing papilledema. We aimed to determine if IIH could be reliably treated by stent placement in transverse sinus stenosis. MATERIALS AND METHODS: We reviewed the clinical, venographic, and intracranial pressure data before and after stent placement in transverse sinus stenosis in 52 of our own patients with IIH unresponsive to maximum acceptable medical treatment, treated since 2001 and followed between 2 months and 9 years. RESULTS: Before stent placement, the mean superior sagittal sinus pressure was 34 mm Hg (462 mm H(2)0) with a mean transverse sinus stenosis gradient of 20 mm Hg. The mean lumbar CSF pressure before stent placement was 322 mm H(2)O. In all 52 patients, stent placement immediately eliminated the TSS pressure gradient, rapidly improved IIH symptoms, and abolished papilledema. In 6 patients, symptom relapse (headache) was associated with increased venous pressure and recurrent stenosis adjacent to the previous stent. In these cases, placement of another stent again removed the transverse sinus stenosis pressure gradient and improved symptoms. Of the 52 patients, 49 have been cured of all IIH symptoms. CONCLUSIONS: These findings indicate a role for transverse sinus stent placement in the management of selected patients with IIH.

Tumour necrosis factor (TNF) inhibitor therapy in Susac's syndrome.

Susac's syndrome is the clinical triad of encephalopathy, branch retinal artery occlusions and sensorineural hearing loss (Susac 1994) [1]. It occurs predominantly in young females and is believed to be an immune-mediated endotheliopathy of small vessels of the brain, retina and cochlea (Neumayer et al. 2009) [2]. Early, aggressive, and sustained immunosuppressive therapy has been recommended for Susac's syndrome and anecdotal evidence has suggested a therapeutic role for monoclonal antibodies (Rennebohm et al. 2008, Lee and Amezcua 2009) [3,4]. We report a case of Susac's syndrome in which the patient improved immediately after tumour necrosis factor (TNF) inhibition with the monoclonal antibody, infliximab.

Carotid endarterectomy for symptomatic, but "haemodynamically insignificant" carotid stenosis.

OBJECTIVE: Carotid endarterectomy (CEA) guidelines in symptomatic carotid stenosis are based on NASCET and ECST criteria with 70% or greater carotid stenosis as estimated from a catheter angiogram the major indication. This has several problems: (1) lack of reliable correlation between non-invasive imaging and catheter angiography, which has been largely superseded by non-invasive imaging in investigating carotid stenosis; (2) errors inherent in estimating the degree of stenosis from catheter angiography; (3) disregard for the fact that stroke risk also depends on plaque stability, and number of ischaemic events. METHODS: A retrospective review of ischaemic events, imaging results, operative findings, surgical complications and stroke-free follow-up in 31 patients presenting over a 23 year period with TIA/stroke (symptoms lasting > 24 h and/or imaging evidence of infarction) who had 70% or less carotid stenosis (on non-invasive imaging), but nonetheless underwent CEA. RESULTS: Nineteen patients had small strokes, 7 had TIAs and 5 had ocular events; 28 patients had features of unstable plaque on imaging; 19 patients experienced multiple events before CEA. All had haemorrhagic, ruptured plaque at CEA. One patient suffered an intra-operative stroke, only 1 patient suffered a further stroke/TIA (mean follow-up 4.2 years). CONCLUSION: To predict the likelihood of major stroke in symptomatic carotid stenosis and the benefit of CEA, plaque stability and the number of ischaemic events might be as important as an estimate of the degree of stenosis.

Ocular vestibular evoked myogenic potentials in response to bone-conducted vibration of the midline forehead at Fz. A new indicator of unilateral otolithic loss.

If a patient, who is lying supine and looking upward, is given bone-conducted vibration (BCV) of the forehead at the hairline in the midline (Fz) with a clinical reflex hammer or a powerful bone conduction vibrator, short-latency surface potentials called ocular vestibular evoked myogenic potentials (oVEMP) can be recorded from just beneath the eyes. The early negative (excitatory) component (n10) is approximately equal in amplitude for both eyes in healthy subjects, but in patients with unilateral vestibular loss, the n10 component is significantly asymmetrical under the 2 eyes - the n10 component is small or absent under the eye on the side contralateral to the prior unilateral vestibular nerve removal, but of normal amplitude under the eye on the side contralateral to the healthy ear. The n10 component of the oVEMP response to BCV at Fz stimuli reflects vestibular and probably mainly otolithic function via crossed otolithic-ocular pathways, and so n10 asymmetry is a new way of identifying the affected side in patients with unilateral otolithic loss.

Tuberculous cranial pachymeningitis.

We describe two immunocompetent patients with tuberculous cranial pachymeningitis. Both patients underwent biopsy after focal dural thickening was identified on MRI. Histopathologic examination of tissue revealed necrotizing granulomatous inflammation. PCR for Mycobacterium tuberculosis DNA was negative on CSF but positive on tissue. Both patients responded to antituberculous therapy. Although uncommon as a cause of cranial pachymeningitis, tuberculosis should be considered, since it responds well to treatment.

Cranial venous outflow obstruction and pseudotumor Cerebri syndrome.

The pathophysiology of PTS including idiopathic intracranial hypertension or 'BIH', remains controversial. The older literature frequently referred to pathology in the cerebral venous drainage but more modern imaging techniques (CT and early MR) failed to reveal gross venous pathology. The role of impaired cranial venous outflow has recently been re-examined in the light of new methods of investigation (advanced MR venography and direct microcatheter venography with manometry) and of treatment (venous sinus stenting). Venous sinus obstruction in PTS is a more common factor in the pathogenesis of the condition than previously recognised. Venous obstruction may be primary, that is, it is the underlying aetiological factor in PTS. Venous sinus obstruction may also be secondary to raised CSF pressure which may exacerbate problems with intracranial compliance and raised CSF pressure. Early experience with venous stenting suggests that it may be a helpful treatment for patients with PTS but more experience and longer follow-up is required to define the subgroups of patients for whom it is most appropriate.

Syringomyelia with Chiari malformation; 3 unusual cases with implications for pathogenesis.

Syringomyelia is an important cause of neurological deficit. Most cases of non-traumatic syringomyelia occur in association with a Chiari malformation. We present three unusual examples of syringomyelia with such an association. The first case is that of syringomyelia in a young woman with Marfan's syndrome, a spontaneous CSF leak and intractable intracranial hypotension. The second is a woman with long-standing lumbo-peritoneal shunt for pseudotumour cerebri who developed an acquired Chiari malformation. A young woman with a Dandy-Walker cyst that herniated into the upper cervical canal is the third case. These cases provide a basis for discussion of the pathogenesis and management of syringomyelia and the Chiari malformation in such cases.

Dural arteriovenous fistulae causing pseudotumour cerebri syndrome in an elderly man.

The clinical presentation of dural arteriovenous fistulae (DAVF) is dependent on their location and the nature of their venous drainage. The latter plays a critical part in determining whether or not the fistula gives rise to intracranial hypertension, which is present in only a minority of cases. We present a case of the pseudotumour cerebri syndrome in an elderly man with bilateral intracranial DAVF supplied by the occipital arteries. Cerebral angiography was required for definitive diagnosis, and to characterise the abnormal venous drainage. The pathophysiology of intracranial hypertension in DAVF is discussed.

Effects of unilateral vestibular deafferentation on the linear vestibulo-ocular reflex evoked by impulsive eccentric roll rotation.

The effects of unilateral vestibular deafferentation (UVD) on the linear vestibulo-ocular reflex (LVOR) were studied by measuring three-dimensional eye movements in seven UVD subjects evoked by impulsive eccentric roll rotation while viewing an earth-fixed target at 200, 300, or 600 mm and comparing their responses to 11 normal subjects. The stimulus, a whole-body roll of approximately 1 degrees, with the eye positioned 815 mm eccentric to the rotation axis, produced an inter-aural linear acceleration of approximately 0.5 g and a roll acceleration of approximately 360 degrees /s(2). The responses generated by the LVOR comprise horizontal eye rotations. Horizontal eye velocity at 100 ms from stimulus onset in UVD subjects was significantly lower than in normal subjects for all viewing distances, with no significant difference between ipsilesional and contralesional responses. LVOR acceleration gain, defined as the slope of actual horizontal eye velocity divided by the slope of ideal horizontal eye velocity during a 30-ms period starting 70 ms from stimulus onset, was bilaterally significantly reduced in UVD subjects at all viewing distances. Acceleration gain from all viewing distances was 1.04 +/- 0.28 in normal subjects, and in UVD subjects was 0.49 +/- 0.23 for ipsilesional and 0.63 +/- 0.27 for contralesional acceleration. LVOR enhancement in the first 100 ms by near viewing was still present in UVD subjects. LVOR latency in UVD subjects (approximately 39 ms) was not significantly different from normal subjects (approximately 36 ms). After UVD, LVOR is bilaterally and largely symmetrically reduced, but latency remains unchanged and modulation by viewing distance is still present.

Paraneoplastic brain stem encephalitis in a woman with anti-Ma2 antibody.

A woman developed brain stem encephalopathy in association with serum anti-Ma2 antibodies and left upper lobe lung mass. T2 weighted MRI of the brain showed abnormalities involving the pons, left middle and superior cerebellar peduncles, and bilateral basal ganglia. Immunohistochemical analysis for serum antineuronal antibodies was confounded by the presence of a non-neuronal specific antinuclear antibody. Immunoblot studies showed the presence of anti-Ma2 antibodies. A premortem tissue diagnosis of the lung mass could not be established despite two CT guided needle biopsies, and the patient died as a result of rapid neurological deterioration. The necropsy showed that the lung lesion was an adenocarcinoma which expressed Ma2 immunoreactive protein. Neuropathological findings included prominent perivascular inflammatory infiltrates, glial nodules, and neuronophagia involving the brain stem, basal ganglia, hippocampus and the dentate nucleus of the cerebellum. Ma2 is an autoantigen previously identified in patients with germ cell tumours of the testis and paraneoplastic brain stem and limbic encephalitis. Our patient's clinical and immunopathological findings indicate that this disorder can affect women with lung adenocarcinoma, and that the encephalitic changes predominate in those regions of the brain known to express high concentrations of Ma proteins.

Sudden unilateral hearing loss with simultaneous ipsilateral posterior semicircular canal benign paroxysmal positional vertigo: a variant of vestibulo-cochlear neurolabyrinthitis?

We describe 4 patients who all simultaneously developed a sudden total or partial unilateral sensorineural hearing loss and an unusual acute peripheral vestibulopathy in the same ear characterized by posterior semicircular canal benign paroxysmal positional vertigo with intact lateral semicircular canal function. Two patients also had ipsilateral loss of otolith function. The vertigo resolved in all 4 patients after particle-repositioning maneuvers. The findings of audiometry and vestibular tests indicated that the lesion responsible for this syndrome was probably located within the labyrinth itself rather than within the vestibulocochlear nerve and that it was more likely a viral vestibulocochlear neurolabyrinthitis than a labyrinthine infarction.

Pseudotumour cerebri syndrome due to cryptococcal meningitis.

Three cases are reported of the pseudotumour cerebri syndrome-that is, intracranial hypertension without mass lesion or enlarged ventricles, due to cryptococcal meningitis. In these patients the papilloedema was successfully treated with optic nerve sheath decompression, and the intracranial hypertension with lumboperitoneal CSF shunting. These cases support the concept that pseudotumour cerebri is a syndrome of intracranial hypertension that can be due to any disorder producing obstruction of the CSF pathways at the level of the arachnoid villi. This concept is important because it directs therapy to normalise the intracranial pressure and preserve vision.

Absent vestibular evoked myogenic potentials in vestibular neurolabyrinthitis. An indicator of inferior vestibular nerve involvement?

BACKGROUND: Benign paroxysmal positioning vertigo (BPPV) is generally thought to be caused by canalolithiasis in the posterior semicircular canal, an organ that is innervated by the inferior vestibular nerve. We hypothesized that absent vestibular evoked myogenic potentials (VEMPs) would indicate involvement of the inferior vestibular nerve and that posterior semicircular canal-type BPPV could not develop after vestibular neurolabyrinthitis (VNL) in patients with absent VEMPs. OBJECTIVE: To find out if VEMPs could be helpful in evaluating involvement of the inferior vestibular nerve in acute VNL. DESIGN: We reviewed the VEMP findings in 47 patients (34 men and 13 women) with acute VNL, 10 of whom had then developed posterior semicircular canal-type BPPV. RESULTS: While p13-n23, the first positive-negative peak of the VEMP, was ipsilaterally present on stimulation of the unaffected side in all patients, it was absent on the affected side in 16 patients (34%). The absence or presence of p13-n23 was independent of the results of caloric tests, pure tone audiometry, and auditory brain-stem responses. Typical posterior semicircular canal BPPV developed in 10 of the 47 patients after the acute attack of VNL, always on the same side as the neurolabyrinthitis. The p13-n23 potentials were preserved on stimulation of the affected ear in all 10 patients with BPPV. CONCLUSIONS: These results suggest that if VEMPs are absent from an ear that has suffered acute VNL, then posterior semicircular canal BPPV is unlikely to develop as a consequence of the VNL. The reason for this appears to be that the absence of VEMPs is due to involvement of the inferior vestibular nerve or involvement of the structures that it innervates.