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|LETTER TO EDITOR
|Year : 2015 | Volume
| Issue : 3 | Page : 444-446
Wall-eyed bilateral internuclear ophthalmoplegia
Abhishek Agarwal, Sony Vyas, Subodh Banzal, Rajesh Kumar Jha
Department of Medicine, Sri Aurobindo Medical College and PG Institute, Indore, Madhya Pradesh, India
|Date of Web Publication||5-Jun-2015|
Department of Medicine, Sri Aurobindo Medical College and PG Institute, Indore, Madhya Pradesh
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Agarwal A, Vyas S, Banzal S, Jha RK. Wall-eyed bilateral internuclear ophthalmoplegia. Neurol India 2015;63:444-6
The introduction of the term 'wall-eyed bilateral internuclear ophthalmoplegia' (WEBINO) is attributed to Lubow, according to Hoyt and Daroff in 1971. It is a rare neuro-ophthalmic condition describing a disorder of ocular motility and characterized by large angle exotropia in primary gaze and internuclear ophthalmoplegia (INO) bilaterally.  The etiology of the lesion differs greatly and includes inflammatory, toxic, infectious, degenerative, traumatic, postsurgical, demyelinating and neoplastic conditions, but midbrain infarction and autoimmune diseases (e.g., multiple sclerosis) are the most frequently reported lesion. 
A 19-year-old lady with no previous comorbidities presented to the emergency department with complaints of tingling sensation in the left upper limb, vomiting, uneasiness, stuttering speech, and painless diplopia on vertical gaze that had commenced a day earlier. The patient had no previous history of any systemic disease.
On general examination, she was conscious and following commands and her vitals parameters were stable with a pulse rate of 100/min and a blood pressure of 150/80 mmHg. Her neurological examination revealed a left-sided upper motor neuron type of facial palsy. There was no motor weakness. However, all her reflexes were exaggerated with bilateral extensor plantars. The ocular motility examination showed bilateral exotropia (i.e. "wall-eyed") in the primary position. Attempted horizontal saccades revealed bilateral INO (i.e., bilateral adduction palsy with dissociative abducting eye nystagmus). Down gaze was intact, but up gaze and convergence were defective. The patient also developed skew deviation of the eyes with up beating nystagmus. The pupils measured 4 mm in dim illumination and constricted normally to direct light. There was no ptosis [Figure 1]. Her routine laboratory parameters (complete blood count, random blood sugar, coagulation profile, fasting lipid profile, liver, renal and thyroid function tests), were within normal range. However, her plasma homocysteine levels were found to be raised (15.92 μmol/L [normal range: 3.7-13.9 μmol/L]). The brain magnetic resonance imaging demonstrated an irregular-shaped acute infarct in the midline of mesencephalic tegmentum involving bilateral medial longitudinal fasciculus (MLF), the periaqueductal gray matter, and the oculomotor nuclei [Figure 2].
|Figure 1: Ocular motility of the patients in all the directions (a) primary gaze; (b) left gaze; (c) upward gaze; (d) right gaze; and, (e) downward gaze|
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|Figure 2: (a-c) Magnetic resonance imaging of the brain revealed areas of diffusion restriction seen in caudal midbrain involving the central region of the midbrain and right crus of the pons. This area appears bright on the diffusion-weighted image with low apparent diffusion coefficient value (yellow arrow). (d and e) Magnetic resonance angiography showed the thrombosed basilar artery (yellow arrow)|
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On the clinical examination and neuroimaging, the diagnosis of a midbrain infarct secondary to basilar artery thrombosis leading to WEBINO syndrome was made. The patient was managed conservatively with antiplatelet therapy and ocular motility exercises. After 6 weeks of treatment, her dizziness and diplopia subsided, and vertical gaze restriction improved, but the right-sided ocular adduction palsy persisted.
The oculomotor alterations exhibited by the patient correspond to a clinical condition described only occasionally in the literature and known by the acronym WEBINO. This peculiar form of bilateral INO is characterized by a restriction of adduction in both the eyes with accompanying contralateral abducting nystagmus, exotropia in primary gaze position, and impairement of convergence. It may also be associated with vertical gaze palsy, up-beat nystagmus, and skew deviation. 
The pathogenesis of WEBINO syndrome is still a matter of debate. Bilateral MLF damage producing bilateral INO, in conjunction with abnormalities of the medial rectus subnuclei (MRSN) of the ventral oculomotor nuclear complex, culminating in bilateral exotropia and bilateral convergence impairment, may be considered as the possible cause of WEBINO syndrome. Since MRSN neurons are scattered within the MLF at the level of the ponto-mesencephalic junction, an injury at this level could affect both these structures. Variable degree of vertical gaze abnormalities in WEBINO is explained by the frequent concomitant involvement of rostral interstitial nucleus of MLF or the interstitial nucleus of Cajal in the midbrain-thalamic region. ,
Hyperhomocysteinemia is one of the causes of thrombus formation.  The present case had hyperhomocysteinemia. There was also thrombus formation within the mid and distal basilar artery, which could have led to the WEBINO syndrome.
Management of WEBINO is centered on eliminating diplopia, which is one of the most common complaints reported by patients. So far, the top two modalities for managing diplopia are surgery for strabismus and botulinum toxin injections. 
| » References|| |
Hoyt WF, Daroff RB. Supranuclear disorders of ocular control systems in man: Clinical, anatomical, and physiological correlations. In: Bach-Y-Rita P, Colins CC, editors. The Control of Eye Movements. New York: Academic Press; 1971. p. 223-6.
Wu YT, Cafiero-Chin M, Marques C. Wall-eyed bilateral inter nuclear ophthalmoplegia: Review of pathogenesis, diagnosis, prognosis and management. Clin Exp Optom 2015;98:25-30.
Chakravarthi S, Kesav P, Khurana D. Wall-eyed bilateral inter nuclear ophthalmoplegia with vertical gaze palsy. QJM 2014;107:165.
Beh SC, Frohman EM. WEBINO and the return of the King′s Speech. J Neurol Sci 2012;315:153-5.
Undas A, Brozek J, Szczeklik A. Homocysteine and thrombosis: From basic science to clinical evidence. Thromb Haemost 2005;94:907-15.
[Figure 1], [Figure 2]