1/10. A case of ocular neuromyotonia with tonic pupil.A 48-year old woman with hypertension experienced painful oculomotor nerve palsy. After surgery for a giant aneurysm of the internal carotid artery in the cavernous sinus, phasic constrictions of the pupil developed. Two years later, this phenomenon disappeared and was replaced by intermittent involuntary cyclic spasms elevating the ptosed lid. These cyclic lid movements were not elicited with any eye movement or by increased accommodation. The pupil now manifested the pharmacologic features of a tonic pupil. The explanation for this unique case of ocular neuromyotonia is based on a misdirection phenomenon, possibly caused by ephaptic transmission.- - - - - - - - - - ranking = 1keywords = ocular, eye (Clic here for more details about this article) |
2/10. Neuromyotonia of the abducens nerve after hypophysectomy and radiation.The clinical signs of the rarely encountered ocular neuromyotonia consist of transient involuntary tonic contraction and delayed relaxation of single or multiple extraocular muscles, resulting in episodic diplopia. With a mean time delay of 3.5 years, this motility disorder frequently follows tumor excision or adjuvant radiation near the skull base. Ocular neuromyotonia may reflect inappropriate discharge from oculomotor neurons with unstable cell membranes because of segmental demyelinization by tumor compression and radiation-induced microangiopathy. In the present paper, the authors present the case of a 53-year-old patient with a history of transsphenoidal hypophysectomy and adjuvant radiotherapy, who underwent strabismus surgery for abducens palsy.- - - - - - - - - - ranking = 0.3999188772613keywords = ocular (Clic here for more details about this article) |
3/10. adult-onset acquired oculomotor nerve paresis with cyclic spasms: relationship to ocular neuromyotonia.PURPOSE: To describe the characteristics and significance of acquired oculomotor nerve paresis with cyclic spasm. METHOD: Retrospective case series of two patients with a history of previous skull base irradiation for intracranial tumor who developed double vision and were found to have oculomotor nerve paresis with cyclic spasm. Both patients underwent a complete neuroophthalmologic assessment, including testing of eyelid position, pupillary size and reactivity, and ocular motility and alignment during both the paretic and spastic phases of the condition. RESULTS: Both patients developed unilateral lid retraction and ipsilateral esotropia with limitation of abduction during the spastic phase of the cycle, with ipsilateral ptosis, exotropia, and variable limitation of adduction during the paretic phase. The cycles were continuous and were not induced or altered by eccentric gaze. CONCLUSIONS: Cyclic oculomotor nerve paresis with spasms may occur years after irradiation of the skull base. This condition is different from the more common ocular motor disturbance that occurs in this setting-ocular neuromyotonia. However, in view of the similarity between these two disorders, it seems likely that they are caused by a similar peripheral mechanism.- - - - - - - - - - ranking = 1.3999188772613keywords = ocular, eye (Clic here for more details about this article) |
4/10. Gaze-induced strabismus.A 20-year-old woman with a past history of a sinonasal undifferentiated carcinoma involving the skull base and cavernous sinus, previously treated with surgery and radiation therapy, presented with intermittent horizontal diplopia induced by gaze to the right side. The gaze in the direction of the action of the right VI nerve produced sustained contraction of the right lateral rectus and an exodeviation increasing on left gaze. Ocular neuromyotonia involving the right VI nerve was believed to be secondary to the patient's previous radiation therapy. The discussants review the prior literature regarding ocular neuromyotonia involving the III, IV and VI cranial nerves, its relationship to prior radiation therapy, and possible modes of therapy including the use of carbamazepine.- - - - - - - - - - ranking = 0.19995943863065keywords = ocular (Clic here for more details about this article) |
5/10. Ocular neuromyotonia.AIMS/BACKGROUND: Ocular neuromyotonia is characterised by spontaneous spasm of extraocular muscles and has been described in only 14 patients. Three further cases, two with unique features, are described, and the underlying mechanism reviewed in the light of recent experimental evidence implicating extracellular potassium concentration in causing spontaneous firing in normal and demyelinated axons. methods: Two patients had third nerve neuromyotonia, one due to compression by an internal carotid artery aneurysm, which has not been reported previously, while the other followed irradiation of a pituitary tumour, a common association in the published reports. Selective activation occurred in both, where neuromyotonic activity was triggered by prolonged voluntary activation of specific extraocular muscles with or without spread of activity to other third nerve muscles. The other patient had fourth nerve involvement, where spasms of the superior oblique muscle were induced only by alcohol, a phenomenon which has not been described. RESULTS: The two patients with third nerve involvement responded to carbamazepine and in one, an improvement in a chronic partial third nerve paresis occurred. The other has not required treatment and remains asymptomatic by refraining from alcohol. CONCLUSIONS: A careful examination, including the effects of prolonged voluntary muscle action is required to initiate episodes and to demonstrate selective activation. Imaging is mandatory to exclude compressive intracranial lesions, particularly where there is no history of pituitary fossa irradiation. A trial of anticonvulsants should be considered in all patients. Extracellular potassium may play a role in spontaneous firing and ephatic transmission in ocular neuromyotonia.- - - - - - - - - - ranking = 0.59987831589194keywords = ocular (Clic here for more details about this article) |
6/10. Intermittent diplopia and strabismus caused by ocular neuromyotonia.PURPOSE: Two cases illustrate the symptoms, signs, etiologies, and treatment of ocular neuromyotonia (ONM). methods: The histories, neuroradiologic tests, and/or biopsy revealed the etiologies of ONM in both patients. Clinical observations, videotaping, and electronic eye movement recordings documented the eye movements. RESULTS: A 72-year-old man with chronic arachnoiditis following myelography with thorium dioxide (Thorotrast) developed intermittent diplopia and a partial right third nerve palsy. Left gaze induced spasm of the right medial rectus. Right gaze produced right lateral rectus spasm. A 66-year-old woman, who had radiation treatment for a pituitary tumor and acromegaly, had intermittent spasm of the left medial rectus muscle and left esotropia. The episodes occurred spontaneously and were induced by right gaze. A left internuclear ophthalmoplegia was also found. carbamazepine (Tegretol) abolished the ONM in both patients. CONCLUSIONS: Although ONM is an unusual cause of intermittent diplopia and strabismus, its distinctive clinical features identify it. Injury to the peripheral cranial nerves probably leads to segmental demyelination, axonal hyperexcitability, and a self-perpetuating, reverberating circuit, which causes spasms of the extraocular muscles.- - - - - - - - - - ranking = 1.2001622454774keywords = ocular, eye (Clic here for more details about this article) |
7/10. Ocular neuromyotonia in Graves dysthyroid orbitopathy.OBJECTIVES: To describe 2 patients with ocular neuromyotonia in association with Graves orbitopathy and to consider the possible underlying mechanisms. DESIGN: Description of the clinical findings in 2 patients with these conditions. SETTING: Neuro-ophthalmology referral centers. patients: Two patients, aged 55 and 52 years, had episodic, involuntary periods of vertical diplopia and dysthyroid orbitopathy. INTERVENTION: Treatment with carbamazepine in one patient and external beam radiation therapy in the second patient. MAIN OUTCOME MEASURES: Frequency and duration of episodic spasms of the extraocular muscles. RESULTS: Although radiation therapy is the most common association with ocular neuromyotonia, it cannot explain the involuntary contractions of extraocular muscles in all affected patients. Other mechanisms must be involved, such as those discussed in this article. CONCLUSION: Ocular neuromyotonia is described in 2 patients with dysthyroid orbitopathy, confirming previous findings. Possible mechanisms are given.- - - - - - - - - - ranking = 0.79983775452259keywords = ocular (Clic here for more details about this article) |
8/10. Ocular neuromyotonia in a patient with cavernous sinus thrombosis secondary to mucormycosis.PURPOSE: To report a case of ocular neuromyotonia occurring after cavernous sinus thrombosis secondary to mucormycosis. methods: Case report. We performed serial comprehensive neuro-ophthalmologic examinations. RESULTS: Fifteen months after initial total ophthalmoplegia of the right eye and complete right upper eyelid ptosis, isolated ocular neuromyotonia, characterized by episodic upward jerking movements of the right upper eyelid, was noted. CONCLUSION: Ocular neuromyotonia, which usually manifests in patients with a history of intracranial tumors and cranial radiation, may also be secondary to infectious cavernous sinus thrombosis.- - - - - - - - - - ranking = 0.40052729780157keywords = ocular, eye (Clic here for more details about this article) |
9/10. Ocular neuromyotonia: three case reports with eye movement recordings.The objective of this article was to evaluate the etiologies, findings, and treatment of ocular neuromyotonia (ONM) in three case reports. The etiologies of ONM were determined by the histories, neuroradiologic tests, or biopsies. Clinical observations, videotaping, and electronic eye movement recordings documented the eye movement abnormalities. Intermittent diplopia developed several years after myelography with thorium dioxide (Thorotrast), radiation treatment for a pituitary tumor, and radiotherapy for medulloblastoma of the posterior fossa. All of the patients had intermittent, variable tropias that occurred spontaneously or were induced by eccentric gaze. One patient had a partial third nerve palsy, and another had a unilateral internuclear ophthalmoplegia (INO). ONM involved the paretic third nerve, extraocular muscles, and ipsilateral lateral rectus muscle in one patient, the paretic medial rectus muscle (INO) in one patient, a lateral rectus muscle (INO) in one patient, and a lateral rectus muscle in the last patient. Eye movement recordings were consistent with spasms of the involved muscles. carbamazepine (Tegretol) abolished the ONM in two patients. The other patient had been taking carbamazepine for seizures and developed ONM when the dose was decreased. Increasing the dose abolished the ONM. ONM is an unusual cause of intermittent diplopia and strabismus, but its distinctive history and signs identify it easily. Damage to the peripheral cranial nerves might produce segmental demyelination, axonal hyperexcitability, and a self-perpetuating, reverberating circuit that causes spasms of the extraocular muscles.- - - - - - - - - - ranking = 0.6010951569725keywords = ocular, eye (Clic here for more details about this article) |
10/10. Terminating attacks of ocular neuromyotonia.We examined a 30-year-old woman who, for 6 months, had suffered from ocular neuromyotonia, which consisted of episodic ocular depression. Apart from the ocular complaint, her medical history and the clinical findings were unremarkable. The patient discovered that she could terminate each episode of tonic ocular depression instantly by forcefully directing her gaze upward. Stretching the affected muscle might also prove to be an effective way of ending attacks of neuromyotonia in other patients suffering from this condition.- - - - - - - - - - ranking = 1.5996755090452keywords = ocular (Clic here for more details about this article) |
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