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.

Central nystagmus in progressive supranuclear palsy: A neglected clinical feature?

BACKGROUND

Progressive supranuclear palsy (PSP) features parkinsonism characterized by early postural instability, falls and prominent eye movement abnormalities that consist of saccadic slowing, followed by gaze limitation. Nystagmus is not considered typical for PSP, being more commonly associated with multiple system atrophy.

OBJECTIVES

To describe the prevalence and phenomenology of nystagmus in patients with PSP.

METHODS

42 patients with probable PSP underwent detailed clinical eye movement examination. Patients with nystagmus performed video-nystagmography. T-test, Chi-Square test and Wilcoxon signed-rank test were used to test differences in demographic data, disease duration and PSP subtype between patients with and without nystagmus, and for analysis of video-nystagmographic data.

RESULTS

Among 42 patients with PSP, we identified 15 patients (35,7%) with gaze-evoked nystagmus, predominantly horizontal. Clinically, 10/15 patients had symmetrical or asymmetrical gaze - evoked nystagmus (Type 1), while 5/15 patients had dissociated gaze-evoked nystagmus related to internuclear ophthalmoplegia (Type 2). Nystagmus and eye movement abnormalities were further characterized by video-nystagmography. There was no significant difference in age, disease duration or PSP subtypes between patients with and without nystagmus.

CONCLUSION

Central nystagmus is present in more than a third of patients with progressive supranuclear palsy. It may present as symmetrical or asymmetrical gaze-evoked nystagmus or as dissociated gaze-evoked nystagmus related to internuclear ophthalmoplegia and probably arises from neurodegeneration of the neural integrator. Nystagmus in PSP has been a hitherto under-described feature and its presence should not deter clinicians from a diagnosis of PSP.

Progressive Supranuclear Palsy with Wall-Eyed Bilateral Internuclear Ophthalmoplegia Syndrome: Authors' Second Case

Wall-eyed bilateral internuclear ophthalmoplegia (WEBINO) syndrome has previously been reported in only 2 patients with progressive supranuclear palsy (PSP). Herein, we report a third case of WEBINO syndrome with PSP. The patient was an 81-year-old man who had experienced gradually increasing gait disturbance and occasional falls since the age of 78 years. At 80 years of age, he presented with cognitive impairment, parkinsonism, and oculomotor abnormalities. The oculomotor abnormalities consisted of vertical gaze palsy and loss of eye convergence. Brain magnetic resonance imaging demonstrated marked atrophy of the midbrain. He was diagnosed with PSP. At the age of 81 years, he presented with alternating extropia in his forward gaze and adduction paresis and outward nystagmus of the abducted eye in his horizontal gaze, both of which were compatible with WEBINO syndrome. Previously, we reported the first case of PSP with WEBINO syndrome, and another group recently reported a second case. In light of the previous cases and the present case, WEBINO syndrome in PSP should not be considered extremely rare. Furthermore, WEBINO syndrome has not been reported in other neurodegenerative disorders, which suggests that it might be a useful and specific diagnostic finding in PSP.

[Case of wall-eyed bilateral internuclear ophthalmoplegia (WEBINO) syndrome with cerebellar ataxia and facial dysesthesia]

We report an 85-year-old man presenting with wall-eyed bilateral internuclear ophthalmoplegia (WEBINO) syndrome with cerebellar ataxia and facial dysesthesia. He experienced an abrupt onset of double vision and exotropia of the right eye with unsteady gait and dysesthesia around upper lip. He was admitted to our hospital ten days after the onset of the double vision. On admission, he presented with WEBINO, left limb ataxia, and dysesthesia around upper lip on the right side. His exotropia was prominent on the right side. Diffusion weighted images of MRI revealed a high intensity lesion in the paramedian pontine tegmentum involving bilateral medial longitudinal fasciculus (MLF), consistent with acute ischemic lesion. Four months after the onset, the WEBINO persisted, without cerebellar ataxia and facial dysesthesia. Putative lesions of the WEBINO, cerebellar ataxia and facial dysesthesia were bilateral MLF, left superior cerebellar peduncle and trigeminothalamic tract, respectively, which were broader than the MRI lesion. Neurological examination is critical for evaluation of accurate ischemic area.

[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.

Visual signs and symptoms of progressive supranuclear palsy

Progressive supranuclear palsy is a rare, degenerative brain disorder and the second most common syndrome in which the patient exhibits 'parkinsonism', that is, a variety of symptoms involving problems with movement. General symptoms include difficulties with gait and balance; the patient walking clumsily and often falling backwards. The syndrome can be difficult to diagnose and visual signs and symptoms can help to separate it from closely related movement disorders such as Parkinson's disease, multiple system atrophy, dementia with Lewy bodies and corticobasal degeneration. A combination of the presence of vertical supranuclear gaze palsy, fixation instability, lid retraction, blepharospasm and apraxia of eyelid opening and closing may be useful visual signs in the identification of progressive supranuclear palsy. As primary eye-care practitioners, optometrists should be able to identify the visual problems of patients with this disorder and be expected to work with patients and their carers to manage their visual welfare.

Visual aspects of neurologic protein misfolding disorders

PURPOSE OF REVIEW

This article reviews topics of interest to the ophthalmologist relating to the most common neurologic protein misfolding disorders.

RECENT FINDINGS

Many neurodegenerative diseases are pathologically associated with misfolded proteins. These diseases cause a profound impact of disability to the individual and society. Alzheimer's disease costs alone are estimated to be over US$225 billion annually in the USA. The ophthalmologist is often asked to provide an opinion regarding the cause of visual symptoms in patients with these unique disorders.

SUMMARY

The categorization of neurodegenerative diseases has evolved based on advances in genetic, molecular and pathological research. In many neurodegenerative diseases, aggregation of a misfolded protein is responsible for the development of pathologic inclusions. When the misfolded protein is tau or synuclein, these diseases are called tauopathies or synucleinopathies, respectively. This article focuses on ophthalmic findings in some of the most common tauopathies and synucleinopathies: Alzheimer's disease, progressive supranuclear palsy, Parkinson's disease, dementia with Lewy bodies and multisystem atrophy.

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.

[Case of multiple sclerosis with WEBINO syndrome]

We report a 50-year-old man presenting with wall-eyed bilateral internuclear opthalmoplegia (WEBINO) syndrome. He had suffered from progressive double vision and tetraparesis, and been diagnosed as secondary progressive multiple sclerosis (MS). On admission, he presented with bilateral facial nerve palsy, pseudobulber palsy, and spastic tetraparesis, predominantly on the right side. Bilateral adduction deficits were noted on horizontal gaze, together with nystagmus of abducting eyes. On primary eye position, the right eye was fixed in the midposition, while the left eye was exotropic. The right eye was deviated outward on fixation with the left eye. Vertical gaze and convergence were preserved. These ocular findings were compatible with WEBINO and considered to result from impairment of bilateral medial longitudinal fasciculus and imbalance of paramedian pontine reticular formation on both sides. T2-weighted images of MRI revealed a high signal lesion in the paramedian pontine tegmentum without enhancement. He underwent steroid pulse therapy, followed by mild improvement in adduction of both eyes. Although WEBINO tends to be observed in the acute stage of stroke, this patient suggests that demyelinative lesions of MS can cause persistent WEBINO, involving the paramedian pontine tegmentum.