Variation in Evolving Optic Neuritis.

BACKGROUND: The typical natural history of optic neuritis is subjected to important exceptions. Recognition of these exceptions has led to valuable insights regarding specific etiologies of optic neuritis. Exceptions to the natural history of recovering optic neuritis are well-defined (e.g., chronic relapsing inflammatory optic neuropathy), but exceptions to the natural history of evolving optic neuritis are less so. METHODS: Medical records of patients illustrating an atypical course of evolving optic neuritis were reviewed in a retrospective manner. Each patient was treated by at least one of the authors. RESULTS: Four patients were identified who illustrated an atypical natural history of incipient optic neuritis. Diagnoses included idiopathic optic neuritis, seropositive neuromyelitis optica spectrum disease, anti-myelin oligodendrocyte glycoprotein antibody disease, and multiple sclerosis in 1 patient each. Features of interest included an atypical temporal relationship between development of pain and onset of clinical optic neuropathy, an unusually protracted duration of pain, and an unusually long duration of worsening optic neuropathy before stabilization. CONCLUSIONS: This case series illustrates the substantial clinical heterogeneity which may be observed in the evolution of optic neuritis. The temporal relationship between development of pain and onset of clinical optic neuropathy, the duration of pain, and duration of worsening optic neuropathy before stabilization are all subjected to significant variability. Although most patients with optic neuritis present with painful vision loss which progresses over 1 week or less, careful attention to the exceptions described herein may facilitate earlier recognition of diagnostically challenging cases.

Utility of Magnetic Resonance Imaging Features for Improving the Diagnosis of Idiopathic Intracranial Hypertension Without Papilledema.

OBJECTIVE: Revised diagnostic criteria for idiopathic intracranial hypertension (IIH) were proposed in part to reduce misdiagnosis of intracranial hypertension without papilledema (WOP) by using 3 or 4 MRI features of intracranial hypertension when a sixth nerve palsy is absent. This study was undertaken to evaluate the sensitivity and specificity of the MRI criteria and to validate their utility for diagnosing IIH in patients with chronic headaches and elevated opening pressure (CH + EOP), but WOP. METHODS: Brain MRIs from 80 patients with IIH with papilledema (WP), 33 patients with CH + EOP, and 70 control patients with infrequent episodic migraine were assessed in a masked fashion for MRI features of intracranial hypertension. RESULTS: Reduced pituitary gland height was moderately sensitive for IIH WP (80%) but had low specificity (64%). Increased optic nerve sheath diameter was less sensitive (51%) and only moderately specific (83%). Flattening of the posterior globe was highly specific (97%) but had low sensitivity (57%). Transverse venous sinus stenosis was moderately sensitive for IIH WP (78%) but of undetermined specificity. A combination of any 3 of 4 MRI features was nearly 100% specific, while maintaining a sensitivity of 64%. Of patients with CH + EOP, 30% had 3 or more MRI features, suggesting IIH WOP in those patients. CONCLUSION: A combination of any 3 of 4 MRI features is highly specific for intracranial hypertension and suggests IIH WOP when present in patients with chronic headache and no papilledema.

Headache and the pseudotumor cerebri syndrome.

Pseudotumor cerebri syndrome (PTCS) refers to the primary and secondary disorders that cause elevated intracranial pressure without an intracranial mass lesion, ventriculomegaly, or central nervous system infection or malignancy. Headache is the most frequent symptom of PTCS, but there is considerable overlap between the headache features of raised intracranial pressure and the headache features of primary headache disorders. We review headache subtypes that occur in PTCS, non-headache features that help distinguish PTCS from other headache types, changes to the diagnostic criteria for PTCS with and without papilledema, and headache treatment strategies as they apply to PTCS.

Neuroimaging of the afferent visual system.

Neuroimaging studies provide a useful tool for the clinician evaluating a patient with visual loss. In this review, we discuss the use of magnetic resonance imaging (MRI), computed tomography (CT), orbital ultrasound, and optical coherence tomography (OCT) for evaluating causes of visual loss affecting the afferent visual system. The imaging characteristics of diseases affecting the optic nerve, orbit, sellar and parasellar region, optic tracts, and retrogeniculate visual pathways will be discussed.

Isolated sixth nerve palsy from hemorrhage of a pontine cavernous malformation.

A 32-year-old woman who developed binocular horizontal diplopia was found to have an isolated fascicular sixth nerve palsy secondary to hemorrhage of a cavernous malformation within the left pontine tegmentum. There was sparing of the paramedian pontine reticular formation and absence of a horizontal gaze palsy. The natural history of cavernous malformations and a mechanism by which hemorrhage of these vascular lesions may produce minimal neurologic signs, including isolated ocular motor cranial nerve palsies, is discussed. Magnetic resonance imaging (MRI) that includes susceptibility-weighted sequences leads to their accurate diagnosis.

Human discrimination of rotational velocities.

Vestibular reflexes are critically important for stabilizing gaze and maintaining posture, but comparatively little is known about conscious perceptions of vestibular stimuli and how they may relate to balance function. We used psychophysical methods to determine the ability of normal subjects and a vestibular-deficient subject to discriminate among velocities of earth-vertical sinusoidal rotations. Discrimination thresholds in normal subjects rose from 2.26 deg/s at a peak velocity of 20 deg/s up to 5.16 deg/s at 150 deg/s. The relationship between threshold and peak angular velocity was well described by the power law function DeltaI = 0.88I(0.37), where I is the magnitude of the stimulus and DeltaI is the discrimination threshold. The subject with bilateral vestibular hypofunction had thresholds more than an order of magnitude worse than normals. The performance of normal subjects is much better than that predicted by Weber's Law, which states that discrimination thresholds increase proportionally with stimulus magnitude (i.e., DeltaI/I = C, where C is the "Weber fraction"). This represents a remarkable exception to other sensory systems and may reflect the vestibular system's ability to stabilize gaze and maintain posture even at high stimulus intensities. Quantifying this relationship may help elucidate the role of higher-level processes in maintaining balance and provide information to diagnose and guide therapy of patients with central causes for imbalance.

Bilateral occipital metastases: Visual deficits and management considerations.

BACKGROUND: Metastases to the bilateral occipital lobes pose a difficult clinical scenario due to risk of debilitating visual loss. We sought to characterize clinical outcomes following different treatment modalities to help guide management in this challenging situation. METHODS: We retrospectively reviewed brain metastases patients treated at a single institution between 2008 and 2017 and assessed visual symptoms before and after treatment, the tumor and peritumoral edema volumes before treatment, and clinical outcomes including mortality. RESULTS: Eighteen patients with metastases affecting both occipital lobes were identified. Lung cancer represented the most common primary (n = 10). Visual deficits were present in 12 patients at the time of diagnosis of bilateral occipital metastases (67%). Patients received radiotherapy (n = 5) or combined surgical resection and radiotherapy (n = 13). Among symptomatic patients, two received radiation and 10 received combined surgery and radiation. Nine patients had improved visual symptoms after treatment with no new visual deficits reported as a result of treatment. Among asymptomatic patients, three were treated with radiation alone and three with resection and radiation. Three of these patients developed new visual symptoms following treatment, including one patient with Balint's syndrome. CONCLUSION: Patients with symptomatic bilateral occipital lobe metastases may experience visual improvement following intervention, especially if symptoms stem from compression or edema. Those without visual symptoms are at risk of developing new visual deficits during treatment, which should be included in the decision-making process and when counseling patients. Visual deficits improved after surgery in the majority of patients, with no cases of immediate visual deterioration.

Neuro-Ophthalmic Disorders in Pregnancy.

The physiologic changes that accompany pregnancy can have important implications for neuro-ophthalmic disease. This article discusses pregnancy-related considerations for meningioma, pituitary disorders, demyelinating disease, myasthenia gravis, thyroid eye disease, idiopathic intracranial hypertension, cerebral venous sinus thrombosis, stroke, migraine, and cranial neuropathies. The article also details the potential neuro-ophthalmic complications of preeclampsia and eclampsia and reviews the use of common diagnostic studies during pregnancy.

Response to Olaparib in a Patient with Germline BRCA2 Mutation and Breast Cancer Leptomeningeal Carcinomatosis.

Leptomeningeal carcinomatosis (LC) is a devastating complication of metastatic cancer that disproportionately affects patients with advanced breast cancer. Moreover, those with BRCA1/2-mutated disease more often experience leptomeningeal metastasis. Treatment options for LC are limited and often include significant toxicities. PARP inhibitors offer an important potential treatment for patients with BRCA1/2-mutated breast and ovarian cancers, but clinical studies excluded patients with central nervous system (CNS) metastases, including LC. Efficacy data in this area are therefore limited, although a phase I study of olaparib in glioblastoma did show CNS penetration. Here we report a case of a patient with BRCA2-mutated breast cancer and solitary recurrence in the leptomeninges with ongoing complete response to treatment with the PARP inhibitor olaparib. PARP inhibitors may be an important treatment option for patients with BRCA-mutated disease and LC, and warrant further study.

Magnetic Resonance Imaging Findings in Pediatric Pseudotumor Cerebri Syndrome.

BACKGROUND: Revised diagnostic criteria for pseudotumor cerebri syndrome require three of four neuroimaging findings in the absence of papilledema. We examined the sensitivity and specificity of three or more of four of these magnetic resonance imaging (MRI) findings for pseudotumor cerebri syndrome in children. METHODS: As part of clinical care, patients in whom there was suspicion for pseudotumor cerebri syndrome underwent neurological and fundoscopic examinations, lumbar puncture, MRI, or magnetic resonance venogram. For this retrospective study, we used this information to classify 119 subjects into definite (n = 66) or probable pseudotumor cerebri syndrome (n = 12), elevated opening pressure without papilledema (n = 23), or controls who had normal opening pressure without papilledema (n = 24). A neuroradiologist, unaware of the clinical findings or original MRI report, reviewed MRIs for pituitary gland flattening, flattening of the posterior sclera, optic nerve sheath distention, and transverse venous sinus stenosis. RESULTS: The presence of three or more MRI findings has a sensitivity of 62% (95% confidence interval: 47% to 75%) and a specificity of 95% (95% confidence interval: 77% to 100%), compared with controls. Two of three (transverse venous sinus stenosis, pituitary gland flattening, flattening of the posterior sclera) had a similar sensitivity and specificity. Transverse venous sinus stenosis alone had a slightly higher sensitivity (74%, 95% confidence interval: 60% to 85%) and specificity (100%, 95% confidence interval: 80% to 100%). CONCLUSIONS: In children, three of four of the proposed neuroimaging criteria and transverse venous sinus stenosis alone have a moderate sensitivity and robust specificity for pseudotumor cerebri syndrome. MRIs should be reviewed for these criteria, and their presence should raise suspicion for pseudotumor cerebri syndrome in children, particularly if the presence of papilledema is uncertain.

Utility of optical coherence tomography in the evaluation of sellar and parasellar mass lesions.

PURPOSE OF REVIEW: Anterior visual pathway compression is a common feature of sellar region masses. We review the visual pathway neuroanatomy pertaining to sellar and parasellar lesions and describe recent advances in optical coherence tomography (OCT) imaging that have provided a novel quantitative perspective in the evaluation and management of such patients. RECENT FINDINGS: Ultrastructural measurements of optic nerve integrity using OCT, namely peripapillary retinal nerve fiber layer (pRNFL) and the ganglion cell and inner plexiform layer (GCIPL) thicknesses, have been shown to correlate with visual acuity and visual field deficits on perimetry in patients with compressive sellar region masses. In some cases, OCT can visualize early signs of anterior visual pathway involvement in the absence of clinically evident visual field loss or optic disc pallor. OCT is particularly useful when assessing patients who demonstrate less reliable visual field testing. Furthermore, there is growing awareness that pRNFL and GCIPL thinning preoperatively correlate with worse visual recovery following chiasmal decompression, highlighting the prognostic utility of OCT in this patient population. SUMMARY: OCT provides a complimentary, yet critical, role in quantitatively assessing ultrastructural retinal injury in patients with sellar and parasellar lesions compressing the anterior visual pathway and should be incorporated into routine evaluation.

Visual Fixation Instability in Multiple Sclerosis Measured Using SLO-OCT.

Purpose: Precise measurements of visual fixation and its instability were recorded during optical coherence tomography (OCT) as a marker of neural network dysfunction in multiple sclerosis (MS), which could be used to monitor disease progression or response to treatment. Methods: A total of 16 MS patients and 26 normal subjects underwent 30 seconds of scanning laser ophthalmoscope (SLO)-based eye tracking during OCT scanning of retinal layer thickness. Study groups consisted of normal eyes, MS eyes without prior optic neuritis (MS wo ON), and MS eyes with prior optic neuritis (MS + ON). Kernel density estimation quantified fixation instability from the distribution of fixation points on the retina. In MS wo ON eyes, fixation instability was compared to other measures of visual and neurologic function. Results: Fixation instability was increased in MS wo ON eyes (0.062 deg2) compared to normal eyes (0.030 deg2, P = 0.015). A further increase was seen for MS + ON eyes (0.11 deg2) compared to MS wo ON (P = 0.04) and normal (P = 0.006) eyes. Fixation instability correlated weakly with ganglion cell layer (GCL) volume and showed no correlation with low-contrast letter acuity, EDSS score, or SDMT score. Conclusions: Fixation instability reflects the integrity of a widespread neural network germane to visual processing and ocular motor control, and is disturbed in MS. Further study of visual fixation, including the contribution of microsaccades to fixation instability, may provide insight into the localization of fixation abnormalities in MS and introduce innovative and easily measured outcomes for monitoring progression and treatment response.

The Pattern of Visual Fixation Eccentricity and Instability in Optic Neuropathy and Its Spatial Relationship to Retinal Ganglion Cell Layer Thickness.

PURPOSE: The purpose of this study was to assess whether clinically useful measures of fixation instability and eccentricity can be derived from retinal tracking data obtained during optical coherence tomography (OCT) in patients with optic neuropathy (ON) and to develop a method for relating fixation to the retinal ganglion cell complex (GCC) thickness. METHODS: Twenty-nine patients with ON underwent macular volume OCT with 30 seconds of confocal scanning laser ophthalmoscope (cSLO)-based eye tracking during fixation. Kernel density estimation quantified fixation instability and fixation eccentricity from the distribution of fixation points on the retina. Preferred ganglion cell layer loci (PGCL) and their relationship to the GCC thickness map were derived, accounting for radial displacement of retinal ganglion cell soma from their corresponding cones. RESULTS: Fixation instability was increased in ON eyes (0.21 deg2) compared with normal eyes (0.06982 deg2; P < 0.001), and fixation eccentricity was increased in ON eyes (0.48°) compared with normal eyes (0.24°; P = 0.03). Fixation instability and eccentricity each correlated moderately with logMAR acuity and were highly predictive of central visual field loss. Twenty-six of 35 ON eyes had PGCL skewed toward local maxima of the GCC thickness map. Patients with bilateral dense central scotomas had PGCL in homonymous retinal locations with respect to the fovea. CONCLUSIONS: Fixation instability and eccentricity measures obtained during cSLO-OCT assess the function of perifoveal retinal elements and predict central visual field loss in patients with ON. A model relating fixation to the GCC thickness map offers a method to assess the structure-function relationship between fixation and areas of preserved GCC in patients with ON.

Cauda equina involvement in Susac's syndrome.

Susac's syndrome is a rare autoimmune microangiopathy characterized by the clinical triad of encephalopathy, branch retinal artery occlusions, and sensorineural hearing loss. In many cases, the clinical triad is not fully present at the onset of symptoms. MRI studies often show characteristic punched out lesions of the central fibers of the corpus callosum, and leptomeningeal enhancement and deep gray matter lesions may also be seen. Here we present a case of Susac's syndrome in a middle aged man with the unique clinical finding of cauda equina syndrome and spinal MRI showing diffuse lumbosacral nerve root enhancement. Biopsy specimens of the brain, leptomeninges, and skin showed evidence of a pauci-immune endotheliopathy, consistent with pathology described in previous cases of Susac's syndrome. This case is important not only because it expands the clinical features of Susac's syndrome but also because it clarifies the mechanism of a disorder of the endothelium, an important target for many disorders of the nervous system.