Clinical characterization of idiopathic intracranial hypertension at the Detroit Medical Center

BACKGROUND: Idiopathic intracranial hypertension (IIH), also known as pseudotumor cerebri (PTC), is a condition characterized by increased intracranial pressure without clinical, laboratory or radiologic evidence of an intracranial space-occupying lesion, meningeal inflammation or venous outflow obstruction. Previous population-based studies evaluated the presenting clinical features of IIH in North-Eastern Libya, Iowa, Louisiana, Minnesota, Northern Ireland, Israel and Western Turkey. However, we report the demographic patterns of a metropolitan North American city. METHODS: We performed a retrospective study of all patients with an initial IIH diagnosis and follow-up at the Detroit Medical Center (DMC), Michigan from 1985 to 2002. Medical records of 174 patients were reviewed, with 77 patients fitting the diagnostic criteria. RESULTS: Seventy-seven patients, 71 females (92.2%) and 6 males (7.8%) were identified. Age ranged from 10 to 50 years, with a mean of 34 years. Fifty patients (65%) were African-American and 24 patients (31%) were Caucasian. The most common presentation was isolated headache (28.6%). Nineteen patients (24.7%) were asymptomatic. Obesity was described in 65 of 74 patients (87.8%) evaluated for body dimensions. CONCLUSIONS: We report an increased number of asymptomatic patients after routine ophthalmic examination. Obese females in metropolitan Detroit would benefit from routine eye evaluations to avoid potential visual loss related to papilledema.     

Spinal cord astrocytoma presenting as "idiopathic" intracranial hypertension

Increased intracranial pressure is rarely seen in association with spinal tumors. We describe a young, non-obese man who presented with increased intracranial pressure, papilledema and visual obscuration. Multiple cerebrospinal fluid (CSF) examinations with normal or minimally elevated CSF protein lead to the initial diagnosis of idiopathic intracranial hypertension. After a lumboperitoneal shunt placement a progressive thoracic myelopathy developed 7 months after onset of symptoms. The spinal MRI showed a low cervical-upper thoracic intramedullary tumor. Open biopsy confirmed a grade 3 fibrillary astrocytoma. The suspected mechanisms of spinal tumors causing increased intracranial pressure are reviewed as well as three other cases of spinal astrocytomas previously reported in the literature that presented with papilledema and increased intracranial pressure without hydrocephalus. This case illustrates that increased intracranial pressure may in exceptional cases of spinal tumors precede the more typical myelopathic presentation by months and mimic idiopathic intracranial hypertension.     

Venous obstruction and jugular valve insufficiency in idiopathic intracranial hypertension

The pathophysiology of elevated intracranial pressure in idiopathic intracranial hypertension (IIH) is unclear. Cerebral venous outflow obstruction and elevated intracranial venous pressure may play an etiological role. We examined jugular valve insufficiency as a potential factor contributing to intracranial hypertension. Jugular venous valve function was assessed bilaterally by duplex sonography in 20 consecutive patients with diagnosis of IIH and in 20 healthy controls matched for age, gender and body mass index. Diagnosis of valvular insufficiency was based on reflux duration during a controlled Valsalva maneuver. Intracranial venous outflow was evaluated in 11 patients (MR venography in 10, digital subtraction angiography (DSA) in two cases). As a principle result, valvular insufficiency was significantly more frequent in patients with IIH (70 vs. 30%; p < 0.05). This finding was associated with irregular leaflet structures on B-mode imaging (p < 0.01). Bilateral insufficiency was more frequent in the patient group which, however, was not significant (p = 0.08). In addition, sinovenous outflow obstruction was found in five of six patients that had undergone contrast-enhanced MR venography and DSA. The detection rate was inferior in phase-contrast MR imaging (one of five patients). In conclusion, this study gives evidence that valvular insufficiency may play a causal role in IIH. Obesity is a major risk factor for the disease and weight reduction leads to improvement of symptoms. Possibly, increased intra-abdominal pressure is transmitted into the intracranial venous system, causing intracranial hypertension. Jugular valve insufficiency may facilitate pressure transmission. As transverse sinus stenosis was a concomitant finding, these factors may be complementary.     

Sonographic assessment of the optic nerve and the central retinal artery in idiopathic intracranial hypertension

PurposeTransorbital sonography easily detects papilledema and enlarged optic nerve sheath diameters (ONSD) in IIH (idiopathic intracranial hypertension) patients. As the central retinal artery is located within the optic nerve, its hemodynamic properties might be affected by the increased pressure. In this study we assessed the diagnostic usefulness of transorbital sonography in IIH with a special focus on color Doppler imaging of the central retinal artery. IIH patients presented papilledema and enlarged ONSD. ONSD accurately predicted an increased intracranial pressure in IIH (cut-off: 5.8 mm, 81% sensitivity, 80% specificity). 24 h following therapeutic lumbar puncture ONSD diminished significantly, whereas papilledema was not changed. PSV (peak systolic velocity) and Vmean (mean flow velocity) of the central retinal artery were increased in IIH patients compared to controls. PSV accurately predicted an increase of intracranial pressure (cut-off: 11.0 cm/s, 70% sensitivity, 69% specificity). PI (pulsatility index), PSV and Vmean decreased following lumbar puncture. PSV and Vmean decreases were statistically significant for right eyes only in which the values changed to normal. In summary, besides ONSD enlargement and papilledema transbulbar sonography demonstrated an alteration of central retinal artery blood flow in IIH patients. Especially PSV might serve as valuable surrogate marker for intracranial pressure in IIH. Furthermore, the change of intra-individual central retinal arteries PI might be a valuable parameter to demonstrate response to lumbar puncture in IIH patients.     

Visual evoked potentials study in chronic idiopathic inflammatory demyelinating polyneuropathy.

BACKGROUND: The frequency of the association between chronic demyelinating inflammatory polyneuropathy (CIDP) and central nervous system (CNS) demyelinating lesions is probably underestimated. OBJECTIVE: To investigate the occurrence of combined central and peripheral demyelination in CIDP patients and to correlate visual evoked potential (VEP) abnormalities with CNS demyelinating lesions, observed on brain magnetic resonance imaging, and antibodies against glycolipids. METHODS: Nerve conduction studies, brain MRI and antibodies against glycolipids were prospectively studied in 17 patients who fulfilled the diagnostic criteria proposed for CIDP (Cornblath DR, Asbury AK, Albers JW, Feasby TE, Hahn AF, McLeod JG, Mendell JR, Parry GJ, Pollard JD, Thomas PK. Ad Hoc Subcommittee of the American Academy of Neurology AIDS Task Force. Research criteria for diagnosis of chronic inflammatory demyelinating polyneuropathy. Neurology, 1991;41:617-618). VEPs were performed in each case before and after 6 months treatment with either intravenous immunoglobulins (IVIG) or steroids. RESULTS: Eight patients (47%) had increased latencies in at least one eye or showed increased interocular latency difference. Four patients (23%) presented a significant high signal intensity on T2-weighted brain MRI images. Of these 4 patients, 3 had prolonged VEP latency. Two patients with delayed VEP latency had antibodies against GM1, and SGLPG and anti-sulfatides, respectively. One patient with normal VEPs also had antibodies to GM1. VEP results were not significantly modified after treatment, either with steroids or IVIG. CONCLUSION: This study confirmed the high frequency of abnormal VEPs in CIDP patients, and found that they are poorly correlated with CNS demyelinating lesions and antibodies against glycolipids. The VEP abnormalities of these patients may be explained by the susceptibility to immune-mediated damage of both the peripheral nervous system and the optic nerve.     

Dural venous sinus stenting for idiopathic intracranial hypertension: An updated review

Background

Dural venous sinus stenting (DVSS) is an accepted treatment option in selected patients with medically refractory idiopathic intracranial hypertension and obstructive venous outflow physiology prior to cerebrospinal flow diversion (CSFD) surgery. There are no randomized controlled studies focusing on outcomes and complication rates for dural venous sinus stenting.

The light-flash-evoked response as a possible indicator of increased intracranial pressure in hydrocephalus

Surgical treatment of infantile hydrocephalus by shunt implantation may result in suboptimal intracranial pressure. Major neurological impairments and death are usually prevented by shunt treatment, but minor sequelae may persist or develop. The introduction of adjustable shunts has improved the possibilities of optimizing shunt function and minimizing the risk of such impairments. However, it is still impossible to determine the intracranial pressure without invasive measurements. Clinical findings and procedures such as computed tomography (CT) are not always enough to allow a conclusion as to whether a child's signs and symptoms are the result of suboptimal intracranial pressure (shunt dysfunction) or are of another etiology. With the aim of reducing the number of invasive pressure measurements and CT scans, we investigated the effect of increased intracranial pressure on the visual evoked response (VER). Binocular light flash stimuli of supramaximal intensity were used and VER recordings were performed from Oz and Cz. The VER results from a group of 31 infants and children with hydrocephalus and 2 children with pseudotumor cerebri were compared with responses from a control group of 35 healthy children. The results show that a subpotential, P (P-prime), usually just preceding P1 (P100), has an increased latency (>96 ms) in all hydrocephalic children before surgery. The P latency in this group was usually even above 110 ms. The latencies of other VER potentials were also increased but not as consistently as P. After surgical intervention the VER latencies decreased and usually normalized. The P latency in four children in the control group was just above the borderline latency, but was less than 110 ms. In the remaining 31 children the VER P latency was 96 ms or below. The VER provides information about the physiological condition of the visual system and seems to be related to intracranial pressure. The method was found to be useful in the clinical examination of hydrocephalic children. In addition, the VER may be used to monitor patients' clinical condition and the effect of treatment, e.g., in cases of pseudotumor cerebri or traumatic brain injury.     

Long-term visual outcome in idiopathic intracranial hypertension

Objective:

To characterize the course, outcome, and risk of relapse or late worsening in a clearly defined cohort of idiopathic intracranial hypertension (IIH) over a long period of follow-up.

Materials and Methods:

Retrospective chart review of patients with definite IIH was evaluated at the Sree Chitra Tirunal Institute for Medical Sciences and Technology between 1998 and 2006. Patients’ demographic data, clinical, neuro-ophthalmic examinations, and treatment details were abstracted. Patients were further categorized into three groups based on whether they improved, worsened, or relapsed on follow-up. Final visual outcome of each patient was defined according to grading of the worse eye at the last visit. Statistical analysis included t test to compare group means and chi-square test to compare proportions.

Results:

Of the 43 women included, visual impairment was observed in 80 eyes (93%) at presentation and it was moderate to severe in 14%. The mean CSF opening pressure at presentation did not differ significantly in those with visual impairment compared to those with normal vision. Those having early severe visual impairment had significantly higher (P = 0.015) likelihood of severe visual impairment on last follow-up. Of the total, 34 patients (79%) improved, 4 (9.3%) relapsed on follow-up after period of stability, and 5 (11.6%) worsened over 56 months follow-up (range, 26-132 months). The groups were comparable, except those who improved were younger (P<0.05). At last examination, 9% had significant vision loss.

Conclusion:

IIH patients can have delayed worsening or relapses and about tenth of patients can have permanent visual loss early or late in the course of the disease. All patients with IIH need to be kept under long-term follow-up, with regular monitoring of visual functions.     

Visual evoked potentials after optic neuritis

Visual evoked potentials (VEPs) were compared among six groups of patients tested at various times after an episode of acute unilateral optic neuritis (ON). The incidence of abnormalities ranged from above 90% in patients tested during the first 6 months to about 70% when more than 2 years had elapsed. Compared with the acute stage (1–8 weeks), latency prolongation was almost 50% less in patients tested after 2–19 years. In the latter group, latencies were significantly correlated with the patients' age at the time of the attack. The findings confirm and extend the evidence of serial studies which shows that the shortening of VEP latency is a general phenomenon which proceeds for up to 2 years and possibly for longer in younger patients. When the patients with clinically isolated ON were compared with those who had a history of additional neurological episodes suggestive of multiple sclerosis (MS), up to 4 weeks after ON latencies were more prolonged in the MS group but between 4 and 8 weeks amplitudes were larger and between 8 weeks and 2 years latencies were significantly shorter. No significant differences were found in patients tested after more than 2 years. It is suggested that the electrophysiological deficit may initially be more severe in patients with disseminated disease, but that recovery may occur faster.     

Is there a difference in outcomes of patients with idiopathic intracranial hypertension with the choice of cerebrospinal fluid diversion site: a single centre experience

The visual and headache outcomes in patients with idiopathic intracranial hypertension (IIH) undergoing cerebrospinal fluid diversion with a lumboperitoneal (LPS) or ventriculoperitoneal shunting (VPS) have not been well reported. The aims of this study were to: (a) to assess outcomes of CSF diversion in IIH, (b) to understand influence of the type of shunt in outcomes, and (c) to understand factors predisposing in shunt failure.

Methods

The medical records of 34 patients who underwent cerebrospinal fluid diversion (CSFD) between 1996 and 2007 were retrieved and epidemiological and clinical data was collected.

Results

The mean age was 35 (±7.9) years. Thirty-four patients underwent 63 shunt placements in total. 85% follow-up was achieved. The mean follow-up for the entire group was 28.9 (±31.8) months. Headaches improved more than visual disturbances. There was no significant difference between the groups that received a VPS and those receiving an LPS in both headache and visual outcomes. The rate of complications was 20.5% and the need for revision was 35% for the whole group. Patients with LPS suffered more complications and first time revisions than patients with VPS. No factor recorded could predict the need for revision or final outcomes. The shunts of patients receiving a VPS tend to survive longer than those receiving primarily an LPS, however the difference is not statistically significant.

Conclusions

Predicting which patients will improve is not possible at present. The influence of site diversion is not critical but patients with VPS have less complications and revisions than those receiving a LPS.     

Static and pulsatile intracranial pressure in idiopathic intracranial hypertension

Objective

The aim of this observational study was to characterize the static and pulsatile intracranial pressure (ICP) in conservatively (medically) treated idiopathic intracranial hypertension (IIH) patients in need of shunt surgery, and also in patients with chronic daily headache (CDH) without visual disturbances.

Methods

The material includes 14 IIH patients and 7 CDH patients in whom ICP was monitored continuously over-night. Static ICP was characterized by mean ICP, pulsatile ICP was characterized by the wave amplitude, rise time, and rise time coefficient.

Results

In the IIH group all 14 had headache and visual disturbances. Mean ICP was high (>15 mmHg) in only 7 patients (50%), while mean ICP wave amplitude was high (≥4 mmHg) in all 14 (100%). All IIH patients were shunted and improved clinically thereafter (i.e., relief from visual disturbances and/or headache). None in the CDH group had high mean ICP or mean ICP wave amplitude, and none were shunted.

Conclusions

In this cohort of 14 conservatively treated IIH patients with lasting and shunt-responsive headache and visual disturbances, the mean ICP wave amplitude was elevated (≥4 mmHg) in all patients despite normal mean ICP (<15 mmHg) in 7 patients (all but one on medication). Therefore, the pulsatile ICP may be more relevant than the static ICP in the diagnostic setting for patients with IIH. Further prospective standardized approaches are warranted.     

Intraoperative subcortico-cortical evoked potentials of the visual pathway under general anesthesia

ObjectiveTo assess whether intraoperative subcortical mapping of the visual pathways during brain surgeries was feasible.MethodsSubcortico-cortical evoked potentials (SCEPs: 30 stimulations/site, biphasic single pulse, 1.3 Hz, 0.2 ms/phase, maximum 10 mA; bipolar probe) were measured in 12 patients for stimulation of the optic radiation, Meyer’s loop or optic nerve. Recorded sites were bilateral central, parietal, parieto-occipital, occipital (subdermal scalp electrodes, 5–4000 Hz). The minimum distances from the stimulation locations, i.e. the closest border of the resection cavity to the diffusion tensor imaging based visual pathways, were evaluated postoperatively (smallest distance across coronal, sagittal and axial planes).ResultsStimulation elicited SCEPs when the visual tracts were close (≤4.5 mm). The responses consisted of a short (P1, 3.0–5.6 ms; 8/8 patients) and of a middle (P2, 15–21.6 ms; 3/8 patients) latency waveforms. In agreement with the neuroanatomy, ipsilateral occipital responses were obtained for temporal or parietal stimulations, and bi-occipital responses for optic nerve stimulations.ConclusionsFor the first time to our knowledge, intraoperative SCEPs were observed for stimulations of the optic radiation and of Meyer’s loop. Short latency responses were found in agreement with fast conduction of the visual pathway’s connecting myelinated fibers.SignificanceThe mapping of the visual pathways was found feasible for neurosurgeries under general anesthesia.     

Paroxysmal intracranial hypertension

We present the case of a man who presented with headache and severe papilloedema which was caused not by chronic intracranial hypertension but by paroxysms of raised intracranial pressure, and we speculate what relationship this disorder has to idiopathic intracranial hypertension.     

Asymptomatic idiopathic intracranial hypertension in children

Objective – To define characteristics of pediatric asymptomatic idiopathic intracranial hypertension (IIH). Patients and methods – We retrospectively reviewed our Neuro‐Ophthalmology database (2000–2006) for all cases of symptomatic and asymptomatic pediatric IIH. Results – Out of 45 IIH cases, 14 (31.1%) were asymptomatic (incidental examination). When compared with children with symptomatic IIH, asymptomatic cases were younger [5.6 (1.8–15) vs 11.0 (5–17) years, P = 0.007], had lower percentage of obesity (14.3% vs 48.4%, P = 0.046), and had male predominance (71.4% vs 38.7%, P = 0.06). Asymptomatic cases required shorter duration of acetazolamide treatment [3 (0–8), vs 6 (0–20) months, P = 0.021], and resulted in complete resolution of swollen discs. Conclusions – We speculate that asymptomatic IIH may be more common in young children and could represent a milder form or a presymptomatic phase before evolving into classic symptomatic IIH. Further studies to assess the clinical significance of asymptomatic IIH are warranted.     

Visual evoked potentials follow-up in idiopathic intracranial hypertension

Objectives:To demonstrate the importance of visual evoked potential (VEP) in determining the severity and prognosis of the disease and in monitoring the clinical course in patients with idiopathic intracranial hypertension (IIH).Methods:This is a prospective cross-sectional study conducted covering the period between March 2014 and January 2015. The study included 32 patients recently diagnosed with IIH and 30 healthy volunteers. The initial VEP values of the IIH patients were compared to the VEP values of the healthy control group. Furthermore, the initial VEP values of the IIH patients were compared with their VEP values after one month of treatment.Results:The mean age of the IIH patients was 37.8±12.02 years. Of the IIH patients, 27 (84%) were females and 5 (16%) were males. There was a statistically significant association of the initial VEP values with the visual field findings (p=0.011) and visual acuity (p=0.040). Moreover, a statistically significant difference was found between the control group and IIH patients in terms of right (p<0.001) and left P100 values (p<0.001). While 18 (56%) of the initial VEPs of IIH patients were pathological, 14 (44%) of the second VEPs were pathological, and this difference was not statistically significant (p=0.125).Conclusion:A relationship between the VEP P100 values and the severity of the disease was detected, while the importance of monitoring VEP values in the follow-up of IIH patients was not demonstrated.

Idiopathic intracranial hypertension can be defined as raised intracranial pressure with a normal cerebrospinal fluid (CSF).1,2 The overall incidence of IIH is 2.4/100,000; however, the incidence is 22/100,000 in obese women.3 Indeed, the female gender and a high body mass index (BMI) are important risk factors for the disease and female patients account for 90% of the cases.4,5The visual field is commonly affected in IIH patients.6 Although the visual field is currently the most sensitive method to monitor visual disturbances during the course of the disease, its specificity and sensitivity is not 100%.6,7 However, an early diagnosis, determination of the disease severity, and follow-up of the patients with IIH are critical as IIH can cause serious and irreversible visual field defects and even vision loss during the course of the disease.7-9The number of patients with IIH is on the rise globally as the number of patients with obesity increases day by day.10 There is a paucity of precisely sensitive and objective indicators of the disease for monitoring relapses and remission.11,12 Moreover, no sensitive and objective methods have been established yet to determine the disease severity in order to decide whether surgery should be performed in these patients.12-14Despite the potential of IIH to cause visual morbidity, only a limited number of studies are available in the literature to predict the potential impact of IIH on the vision.13 The findings obtained by VEP reflect the functions of the visual pathways extending from the retina to the occipital cortex. The test is particularly sensitive to demonstrate conduction disturbances in the anterior (pre-chiasmatic) visual pathway.15,16 A few studies have shown abnormal findings in VEP tests in patients with IIH, indicating the importance of VEP in the evaluation of the visual functions.17 In the literature, we found only one study evaluating the value of VEP values in the follow-up of patients with IIH.17This study aimed to demonstrate the importance of VEP testing in determining the severity and prognosis of the disease and in monitoring the clinical course of the patients with IIH as the number of studies evaluating this subject is limited in the literature.     

Pseudotumor cerebri/idiopathic intracranial hypertension in children: An experience of a tertiary care hospital

Objective: Pseudotumor cerebri (PTC) is diagnosed at increasing rates probably due to the increase in obesity prevalence all over the world and awareness about the disease. Our aim in this study was to evaluate the PTC clinical picture and etiological factors in children at the present time. Method: The records of 53 patients with 32 females, who were diagnosed with PTC in a child neurology department between the years of 2005 and 2012 were retrospectively analyzed. Results: The mean age at presentation was 10.9 years (3–17 years) and approximately half of patients were aged of 11 years or less. While more than half of prepubertal patients were male, girls rate reaches 74% at puberty. An etiological factor such as venous sinus thrombosis, infections, anemia, steroid discontinuation, drugs, slit ventricle syndrome and minor head injury causing the PTC was identified in 43% of the patients. The mean duration of treatment was 6.4 months (3–24 months) and the mean follow-up duration 16.5 months (3–52 months). Visual field constriction was moderate in only two pubertal and obese female patients and mild in four patients. Conclusions: PTC is seen in prepubertal children as often as in puberty. An etiological factor causing PTC is present in about half the patients in childhood. The main etiological factors of the disease currently consist of cranial venous thrombosis, infections, anemia and drugs. Malnutrition, renutrition and related vitamin deficiencies or excesses commonly seen previously have become less important in PTC etiology. PTC is a disease that requires long-term treatment and follow-up but the prognosis is good in patients who are diagnosed early, receive appropriate treatment and show good compliance with the treatment.