Bilateral oculomotor ocular neuromyotonia: a case report
Abstract Background Ocular neuromyotonia (ONM) is characterized by episodic diplopia, which is usually triggered by prolonged eccentric gaze of the affected extraocular muscles. The spell is characterized by involuntary, occasionally painful, sustained contraction of one or more extraocular muscles...
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| Format: | Article |
| Language: | English |
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BMC
2018-09-01
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| Series: | BMC Neurology |
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| Online Access: | http://link.springer.com/article/10.1186/s12883-018-1142-0 |
| _version_ | 1817988759153541120 |
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| author | Tanyatuth Padungkiatsagul Panitha Jindahra Anuchit Poonyathalang Narong Samipak Kavin Vanikieti |
| author_facet | Tanyatuth Padungkiatsagul Panitha Jindahra Anuchit Poonyathalang Narong Samipak Kavin Vanikieti |
| author_sort | Tanyatuth Padungkiatsagul |
| collection | DOAJ |
| description | Abstract Background Ocular neuromyotonia (ONM) is characterized by episodic diplopia, which is usually triggered by prolonged eccentric gaze of the affected extraocular muscles. The spell is characterized by involuntary, occasionally painful, sustained contraction of one or more extraocular muscles innervated by the oculomotor, trochlear, or abducens nerve. ONM usually occurs as a late consequence of radiotherapy around the parasellar area, although idiopathic cases have been reported. Most cases are unilateral; however, bilateral ONM has occasionally been described. Case presentation A 60-year-old woman presented with a 4-month history of episodic, painful, horizontal binocular diplopia. She underwent external beam radiotherapy to the skull base for treatment of nasopharyngeal carcinoma. The tumor was well controlled. General neurological examination findings were unremarkable. Neuro-ophthalmic examination revealed normal visual acuity, visual fields, pupils, and fundi. Ocular alignment showed orthotropia with normal ocular motility. Myasthenic eyelid signs were absent. However, she developed episodes of involuntary sustained contraction of the medial rectus muscle following prolonged eccentric gaze toward the affected medial rectus muscle, which resulted in esotropia upon returning to the primary position. The esotropic episodes spontaneously resolved after approximately 2 min. These spells affected both medial rectus muscles. Both pupils remained normal throughout the examination. Magnetic resonance imaging revealed neither brain parenchyma/brain stem lesions nor tumor recurrence. Her symptoms were successfully treated with carbamazepine. Conclusions Episodic esotropia in the adducting eye following prolonged horizontal eccentric gaze is a significant characteristic of ONM affecting the bilateral medial rectus muscles (i.e., bilateral oculomotor ONM). In spite of its extreme rarity, ONM should be considered as a differential diagnosis of episodic diplopia, especially in patients with a history of radiotherapy around the parasellar area. Careful examination with prolonged eccentric gaze should be performed to achieve a correct diagnosis and avoid an extensive unnecessary workup. |
| first_indexed | 2024-04-14T00:38:23Z |
| format | Article |
| id | doaj.art-1a266765ba284ffda139c75b47431272 |
| institution | Directory Open Access Journal |
| issn | 1471-2377 |
| language | English |
| last_indexed | 2024-04-14T00:38:23Z |
| publishDate | 2018-09-01 |
| publisher | BMC |
| record_format | Article |
| series | BMC Neurology |
| spelling | doaj.art-1a266765ba284ffda139c75b474312722022-12-22T02:22:16ZengBMCBMC Neurology1471-23772018-09-011811410.1186/s12883-018-1142-0Bilateral oculomotor ocular neuromyotonia: a case reportTanyatuth Padungkiatsagul0Panitha Jindahra1Anuchit Poonyathalang2Narong Samipak3Kavin Vanikieti4Department of Ophthalmology, Faculty of Medicine Ramathibodi Hospital, Mahidol UniversityDepartment of Medicine, Faculty of Medicine Ramathibodi Hospital, Mahidol UniversityDepartment of Ophthalmology, Faculty of Medicine Ramathibodi Hospital, Mahidol UniversityChakri Nareubodindra Medical Institute, Faculty of Medicine Ramathibodi Hospital, Mahidol UniversityDepartment of Ophthalmology, Faculty of Medicine Ramathibodi Hospital, Mahidol UniversityAbstract Background Ocular neuromyotonia (ONM) is characterized by episodic diplopia, which is usually triggered by prolonged eccentric gaze of the affected extraocular muscles. The spell is characterized by involuntary, occasionally painful, sustained contraction of one or more extraocular muscles innervated by the oculomotor, trochlear, or abducens nerve. ONM usually occurs as a late consequence of radiotherapy around the parasellar area, although idiopathic cases have been reported. Most cases are unilateral; however, bilateral ONM has occasionally been described. Case presentation A 60-year-old woman presented with a 4-month history of episodic, painful, horizontal binocular diplopia. She underwent external beam radiotherapy to the skull base for treatment of nasopharyngeal carcinoma. The tumor was well controlled. General neurological examination findings were unremarkable. Neuro-ophthalmic examination revealed normal visual acuity, visual fields, pupils, and fundi. Ocular alignment showed orthotropia with normal ocular motility. Myasthenic eyelid signs were absent. However, she developed episodes of involuntary sustained contraction of the medial rectus muscle following prolonged eccentric gaze toward the affected medial rectus muscle, which resulted in esotropia upon returning to the primary position. The esotropic episodes spontaneously resolved after approximately 2 min. These spells affected both medial rectus muscles. Both pupils remained normal throughout the examination. Magnetic resonance imaging revealed neither brain parenchyma/brain stem lesions nor tumor recurrence. Her symptoms were successfully treated with carbamazepine. Conclusions Episodic esotropia in the adducting eye following prolonged horizontal eccentric gaze is a significant characteristic of ONM affecting the bilateral medial rectus muscles (i.e., bilateral oculomotor ONM). In spite of its extreme rarity, ONM should be considered as a differential diagnosis of episodic diplopia, especially in patients with a history of radiotherapy around the parasellar area. Careful examination with prolonged eccentric gaze should be performed to achieve a correct diagnosis and avoid an extensive unnecessary workup.http://link.springer.com/article/10.1186/s12883-018-1142-0BilateralOculomotorOcular neuromyotoniaEpisodic esotropia |
| spellingShingle | Tanyatuth Padungkiatsagul Panitha Jindahra Anuchit Poonyathalang Narong Samipak Kavin Vanikieti Bilateral oculomotor ocular neuromyotonia: a case report BMC Neurology Bilateral Oculomotor Ocular neuromyotonia Episodic esotropia |
| title | Bilateral oculomotor ocular neuromyotonia: a case report |
| title_full | Bilateral oculomotor ocular neuromyotonia: a case report |
| title_fullStr | Bilateral oculomotor ocular neuromyotonia: a case report |
| title_full_unstemmed | Bilateral oculomotor ocular neuromyotonia: a case report |
| title_short | Bilateral oculomotor ocular neuromyotonia: a case report |
| title_sort | bilateral oculomotor ocular neuromyotonia a case report |
| topic | Bilateral Oculomotor Ocular neuromyotonia Episodic esotropia |
| url | http://link.springer.com/article/10.1186/s12883-018-1142-0 |
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