Wall-Eyed Bilateral Internuclear Ophthalmoplegia From Lesions at Different Levels in the Brainstem

Keyhole Aqueduct Syndrome

Keyhole aqueduct syndrome is a rare progressive neurodegenerative disorder describing a unique set of neuro-ophthalmologic, neuroimaging, and histopathological findings on autopsy. A midline mesencephalic cleft communicating with the cerebral aqueduct resembling syrinx is seen on imaging and histopathology. There are 9 cases published in the literature. We encountered a patient with vertical nystagmus, internuclear ophthalmoplegia, and progressive ataxia who has a midline cleft connecting the cerebral aqueduct with the interpeduncular cistern highlighting a distinguishing feature of this syndrome.

Case report: A variant of wall-eyed bilateral internuclear ophthalmoplegia from unilateral pons infarction

Wall-eyed bilateral internuclear ophthalmoplegia (WEBINO) is an uncommon ocular motility disorder that encompasses the following clinical signs: bilateral adduction deficits, bilateral abducting nystagmus, convergence lost, and a large angle exotropia in primary gaze. Here we report a case of a 55-year-old man presenting with atypical WEBINO syndrome with unilateral exotropia. The coverage test was used to record the patient's alternating exotropia. The patient experienced diplopia and ophthalmoplegia and was admitted to our hospital 3 days after the onset of the double vision. Neurologic examination showed left eye exotropia and bilateral internuclear ophthalmoplegia with impaired convergence. Vertical saccades of the left eye were also limited. Consequently, an MRI scan suggested an acute infarction in the left of the pontine tegmentum. The patient was finally diagnosed with pons infarction and was treated with anticoagulation and anti-platelet aggregation therapy.

[A case of cardioembloic stroke with wall-eyed bilateral internuclear ophthalmoplegia (WEBINO) syndrome]

Here, we report a case of an 85-year-old man who presented sudden onset of diplopia, dysarthria, and gait disturbance. On admission, he exhibited bilateral adduction palsy, convergence palsy, and binocular exotropia in the forward gaze showing wall-eyed bilateral internuclear ophthalmoplegia (WEBINO) syndrome. He had a history of chronic nonvalvular atrial fibrillation. DWI-MRI revealed acute ischemic lesions in the paramedian pontine tegmentum, lower midbrain, both cerebellar hemispheres, and left frontal cortex. He was thus diagnosed with an acute phase of cardioembolic stroke. Subsequently, the right eye adduction palsy in the forward gaze was slightly improved, but other eye movement disorders persisted during discharge from the hospital. The pathology was suspected to involve bilateral damages to both medial longitudinal fasciculus and the paramedian pontine reticular formation. WEBINO syndrome was not only ascribed to lacunar infarction and large artery atherosclerosis but also cardioembolic stroke. The presence of other non-eye symptoms and multiple ischemic lesions could be the characteristics of WEBINO syndrome following cardioembolic stroke.

Wall-Eyed Bilateral Internuclear Ophthalmoplegia by Ischemic Stroke: Case Report and Literature Review

INTRODUCTION

Wall-eyed bilateral internuclear ophthalmoplegia (WEBINO) is a rare symptom. Several studies have reported that a small brainstem lesion could cause WEBINO.

CASE REPORT

The authors present the case of an 88-year-old female individual who developed sudden-onset diplopia and gait disturbance. Neurological examination revealed WEBINO with convergence impairment, gaze-evoked upward nystagmus on upward gaze, and bilateral limb ataxia. Brain magnetic resonance imaging revealed a small paramedian pontine tegmentum infarction, responsible for the symptoms. A literature review of WEBINO in ischemic stroke revealed that most patients exhibited impaired convergence and other neurological symptoms.

CONCLUSION

Gaze-evoked upward nystagmus on upward gaze and bilateral limb ataxia accompanied by WEBINO due to a small brainstem lesion were the characteristic findings of our case.

An Anatomic, Imaging, and Clinical Review of the Medial Longitudinal Fasciculus

The medial longitudinal fasciculus (MLF) is a paired, highly specialized, and heavily myelinated nerve bundle responsible for extraocular muscle movements, including the oculomotor reflex, saccadic eye movements an smooth pursuit, and the vestibular ocular reflex. Clinically, lesions of the MLF are classically associated with internuclear ophthalmoplegia. However, clinical manifestations of a lesion in the MLF may be more complex and variable. We provide an overview of the neuroanatomy, neurologic manifestations, and correlative examples of the imaging findings on brain MRI of MLF lesions to provide the clinician and radiologist with a more comprehensive understanding of the MLF and potential clinical manifestations for an MLF lesion.

The Medial Longitudinal Fasciculus and Internuclear Opthalmoparesis: There's More Than Meets the Eye

Background and purpose

The classic sign of a lesion in the medial longitudinal fasciculus is internuclear opthalmoplegia. However, clinical presentation may vary depending on the type of pathology and the lesion location. The purpose of this study was to identify and classify the different lesions of the medial longitudinal fasciculus on MRI and review their clinical presentations. We also offer an overview of the pertinent imaging anatomy of the medial longitudinal fasciculus.

Materials and methods

Patients with an abnormality affecting the medial longitudinal fasciculus were identified retrospectively using the keyword ‘medial longitudinal fasciculus’ included in radiology reports between 2010 and 2018 using the Nuance mPower software (Nuance Communications, Burlington, MA). The brain MRI examinations of these patients were reviewed by two neuroradiolgists. Detailed description of lesion location within the medial longitudinal fasciculus, pathology type, additional lesions, and clinical presentations were recorded along with pertinent demographic information.

Results

Five men and four women were identified with lesions in the medial longitudinal fasciculus on brain MRI. Five patients demonstrated demyelination in the medial longitudinal fasiculus and four patients demonstrated findings of an acute cerebrovascular accident. Two-thirds of medial longitudinal fasiculus lesions were located in the upper, mid, or lower pons with the remaining located in the midbrain. Of the patients presenting with a cerebrovascular accident, there was little to no additional evidence of acute stroke elsewhere in the brain. All patients were clinically symptomatic with 89% of patients demonstrating extraocular muscle dysfunction at presentation and 78% of patients experiencing dizziness. Additional symptoms included headache, weakness, and gait instability.

Conclusions 

Lesions involving the medial longitudinal fasiculus may not always present with the classic sign of internuclear opthalmoplegia. Variations in lesion location may result in diplopia rather than internuclear opthalmoplegia, and additional brain lesions may produce clinical symptoms that confound extraocular muscle dysfunction. Lesions affecting the often-overlooked vestibular and otolithic reflexes, which run in the medial longitudinal fasiculus, may result in dizziness/weakness and mask the classic internuclear opthalmoplegia symptoms. The radiologist should carefully inspect the medial longitudinal fasiculus in all patients regardless of the supportive clinical history of extraocular muscle dysfunction since symptoms may be more general than classically described. 

Non-Paralytic Pontine Exotropia as a Predominant Sign of Brainstem Infarction - A Case Report

The association of internuclear ophthalmoplegia (INO) with exotropia in the contralateral eye is a rare finding, known as non-paralytic pontine exotropia (NPPE). We report a case of an 80-year-old woman with acute onset of diplopia on admission who presented with left eye exotropia with left-beating nystagmus whilst fixating with the right eye and inability to adduct the right eye on left gaze. Brain magnetic resonance imaging showed two small areas of vertebrobasilar territory ischaemic stroke, one beneath the inferior portion of the aqueduct and another in the right occipital lobe. Our case highlights an interesting clinical manifestation of brainstem infarction that, along with ocular motility examination, allowed us to review its pathophysiology, including the influence of the contralateral paramedian pontine reticular formation stimulation in the mechanism of contralateral exotropia in NPPE. The fast clinical resolution of these cases can explain the scarcity of NPPE reports.

Vertical diplopia and oscillopsia due to midbrain keyhole aqueduct syndrome associated with severe cough

Purpose

Midline structural defects in the neural axis can give rise to neuro-ophthalmic symptoms. We report a rare case of keyhole aqueduct syndrome presenting after two years of severe cough due to gastroesophageal reflux disease.

Observations

A 58-year-old woman with a 2-year history of daily, severe cough presented to the neuro-ophthalmology clinic with progressive diplopia and oscillopsia. Examination revealed a 1-2 Hz down-beating nystagmus in primary gaze that worsened with left, right, and down gazes. Gaze evoked nystagmus and mild paresis were also seen with up gaze. There was an incomitant left hypertropia due to skew deviation that worsened with right and up gazes and improved with down gaze. She also had a right-sided ptosis and a 3 mm anisocoria not due to cranial nerve 3 paresis or Horner's syndrome. Brain magnetic resonance imaging showed a 1.5 mm × 11.7 mm × 6 mm midline cleft in the ventral midbrain communicating with the cerebral aqueduct, consistent with keyhole aqueduct syndrome. Her nystagmus and diplopia improved with oral acetazolamide treatment, at high doses of 2500-3000 mg per day.

Conclusions and importance

We report the first case of midbrain keyhole aqueduct syndrome with ocular motor and other neuro-ophthalmic manifestations associated with severe cough. Although her cough was effectively treated and intracranial pressure measurement was normal, her ophthalmic symptoms continued to progress, which is common in previous cases reported. Treatment with acetazolamide led to significant improvement, supporting the use of acetazolamide in this rare condition.

Ocular Motor Manifestations of Multiple Sclerosis

BACKGROUND

Multiple sclerosis (MS) is a demyelinating disease of the central nervous system leading to disability, especially in young patients. Acute or chronic lesions of MS within the brainstem and the cerebellum frequently result in ocular motor disorders.

EVIDENCE ACQUISITION

This review encompasses the spectrum of ocular motor disorders in patients with MS emphasizing prevalence, examination findings, diagnostic features, functional consequences, classification of MS course, and management of these disturbances of ocular motility.

RESULTS

Ocular motor manifestations of MS can occur acutely in relapse or chronically, the latter as a consequence of previous relapses or as a chronic course of the disease. The most frequent and specific acute ocular motor manifestation is uni- or bilateral internuclear ophthalmoplegia (INO). The most frequent chronic manifestations include INO and cerebellar ocular motor disorders such as gaze-evoked nystagmus, saccadic hypermetria, and lack of vestibulo-ocular reflex inhibition. The most disabling syndrome is pendular nystagmus.

CONCLUSIONS

The high prevalence of ocular motor manifestations emphasizes the importance of neuro-ophthalmological examination among patients with MS. Because chronic manifestations may cause minimal or no symptoms, a systematic investigation of the most common manifestations should be performed in daily practice. Appropriate treatment may improve visual outcome in some of these ocular motor disorders.

[Webino syndrome caused by meningovascular syphilis. A rare entity with an unexpected cause]

CASE REPORT

The patient is a 57-year-old obese and hypertensive male. His chief complaints were double vision and dizziness, with mild exodeviation in both eyes in primary gaze position in the ocular motility examination, but more predominant in the left eye. The exotropia was noticeably more evident on the attempted upgaze. On horizontal gaze, the abducting eye deviated fully, but the adducting eye did not cross the midline. Nystagmus in the abducting eye and convergence impairment were found. Pupil size and testing were normal. Ataxia and areflexia were also present. Bilateral internuclear ophthalmoplegia was suspected and imaging and laboratory tests were performed. The CAT scan showed a right occipital hypo-attenuated lesion. In the MRI scan, a mesencephalic subacute ischemic lesion was found, involving the medial rectus sub-nuclei. Blood and cerebrospinal fluid test for syphilis were positive.

DISCUSSION

Bilateral internuclear ophthalmoplegia is a very uncommon -and difficult to diagnose- condition. In the reported case the lesion involved the medial rectus sub-nuclei. This fact could explain the exotropia in the primary gaze position, and supports that is not possible to exclude the involvement of the medial rectus sub-nuclei in the webino syndrome. The rapid identification of the pathology contributed to the better prognosis of the patient.

Bilateral internuclear ophthalmoplegia associated with pediatric brain tumor progression: a case series and review of the literature

Internuclear ophthalmoplegia (INO) is a rare disorder of conjugate lateral gaze that has been described in a number of neurologic conditions including multiple sclerosis, stroke and less commonly brain tumors. We describe a series of 3 boys (11, 12, 15 years) diagnosed with primary central nervous system tumors (pilomyxoid variant astrocytoma, anaplastic oligoastrocytoma, gliomatosis cerebri) who developed bilateral INO as a manifestation of progressive disease. Time from diagnosis to development of bilateral INO ranged from 13-36 months. All children died of their disease 1-9 months following diagnosis of bilateral INO and had significant dorsal pontine invasion on magnetic resonance imaging at progression. Only one child had brainstem involvement at diagnosis. Our case series highlights this rare ophthalmologic syndrome of bilateral INO in association with tumor progression and provides a literature review of brain tumor associations with INO.

Acute onset of upbeat nystagmus, exotropia, and internuclear ophthalmoplegia--a tell-tale of ponto-mesencephalic infarct

Two patients were assessed for acute onset of diplopia. Clinical examination revealed upbeat nystagmus, exotropia, and internuclear ophthalmoplegia (INO). Both patients had vascular risk factors; acute ischemic stroke affecting ponto-mesencephalic junction was suspected. Magnetic resonance imaging confirmed strategic location of the acute infarct affecting the medial longitudinal fasciculus, adjacent occulomotor nuclei, and paramedian tract. We propose that constellation of acute onset of upbeat nystagmus, INO, and exotropia in patients with vascular risk factors might be unequivocal manifestation of the ponto-mesencephalic stroke.

Wall-eyed bilateral internuclear ophthalmoplegia (WEBINO) syndrome in a patient with neuromyelitis optica spectrum disorder and anti-aquaporin-4 antibody

This report describes, for the first time, an occurrence of wall-eyed bilateral internuclear ophthalmoplegia (WEBINO) in a 19-year-old female with neuromyelitis optica (NMO) spectrum disorder, who had anti-aquaporin-4 (AQP4) antibody. A high signal intensity lesion on T2-weighted MRI was detected in the midbrain tegmentum adjacent to the aqueduct, and presumably involved the medial longitudinal fasciculus bilaterally at the caudal levels. Plasma exchange resolved both WEBINO syndrome and the midbrain lesion. Although WEBINO syndrome is occasionally reported in multiple sclerosis patients, diagnosis of NMO should not be excluded in patients with WEBINO syndrome, because AQP4 is expressed abundantly around the periaqueductal region.

Midbrain cleft as a cause of chronic internuclear ophthalmoplegia, progressive ataxia, and facial weakness

A 44-year-old man with progressive ataxia, facial weakness, bilateral adduction deficits, and abducting nystagmus was initially misdiagnosed and treated for multiple sclerosis because a midbrain anatomic cleft had been overlooked on brain MRI. Six cases of "midbrain (or mesencephalic) cleft" or "keyhole aqueduct syndrome" have been previously reported. This developmental anatomic abnormality always manifests bilateral internuclear ophthalmoplegia (INO), often together with ataxia, which may be progressive and debilitating. Because the INO is chronic, patients may have no visual symptoms. The cause of a midbrain cleft is uncertain, but it may be the midbrain version of a syrinx. There is no known effective treatment.

Internuclear and supranuclear disorders of eye movements: clinical features and causes

Eye movements bring visual stimuli to the fovea and also maintain foveal fixation on a moving target and during head movements. These movements are performed by the ocular motor system that consists of ocular motor nerves and nuclei in the brainstem originating in the cerebral cortex, cerebellum, vestibular structures, and the extraocular muscles. The ocular motor system is divided according to anatomic location into infranuclear, nuclear, internuclear, and supranuclear components. It is important to distinguish supranuclear and internuclear from nuclear and infranuclear disturbances affecting cranial nerves III, IV, and VI, because the disturbances are of highly varied causes and present different clinical pictures. Internuclear ophthalmoplegia is due to a lesion of the medial longitudinal fasciculus, caused by multiple sclerosis in younger patients, particularly when the ophthalmoplegia is bilateral, and usually of vascular origin in the elderly. Eye movement abnormalities of supranuclear origin are characterized by gaze palsies, tonic gaze deviation, saccadic and smooth pursuit disorders, vergence abnormalities, nystagmus, and ocular oscillations. Supranuclear disorders result from lesions above the level of the ocular motor nerve nuclei. If oculocephalic maneuvers move the eyes appropriately, the lesion causing the gaze palsy is supranuclear. Supranuclear disorders account for almost 10% of all patients with disorders of eye movements.

Wall-eyed bilateral internuclear ophthalmoplegia in a patient with progressive supranuclear palsy

Wall-eyed bilateral internuclear ophthalmoplegia (WEBINO) is a rare disorder consisting of a bilateral adduction deficit and primary gaze position exotropia. Associated with bilateral medial longitudinal fasciculus lesions, it has been mostly reported in patients with multiple sclerosis and brainstem stroke. A 72-year-old man with characteristic clinical features of progressive supranuclear palsy (PSP) later developed WEBINO. Brain MRI revealed atrophy of the midbrain tegmentum. Caloric irrigation revealed intact horizontal eye movements in both eyes. We believe this to be the first report of WEBINO in PSP. The preservation of vestibulo-ocular horizontal eye movements supports the notion that the WEBINO in this condition was caused by a supranuclear rather than a nuclear lesion and suggests the possibility that even in other causes of WEBINO, the lesion is supranuclear and not in the medial rectus subnucleus as is often suggested.