1/18. Continuous facial myokymia in multiple sclerosis: treatment with botulinum toxin. Continuous facial myokymia (CFM) is an involuntary undulating, vermicular movement that spreads across facial muscles and is associated with a characteristic electromyographic pattern. It is an infrequent clinical sign that almost always occurs in intrinsic brainstem lesions, particularly in multiple sclerosis (MS). It is usually present for only a few weeks, but it may persist for long periods of time being very troublesome for patients. We report 2 cases with MS and continuous hemifacial myokymia persisting for up to 1 month which disappeared after injection of botulinum toxin. Botulinum toxin A (BTX-A) has been used successfully to treat a variety of focal dystonias and occasionally in orbicularis myokymia, but its use has not been reported in continuous hemifacial myokymia. BTX-A appears to be effective and safe for treating persistent facial myokymia in MS patients. ( info) |
2/18. A case of superior oblique myokymia observed by an image-analysis system. Superior oblique myokymia is a microtremor of the eye that causes monocular torsional oscillopsia. A modified Harada-Ito procedure was used to treat a case of the disease in a 20-year-old woman. The authors used video-image analysis pre- and postoperatively to evaluate the effect of the surgery on abnormal torsional eye movements. This analysis revealed that before surgery, the abnormal torsional movement had a very regular cycle (duration of attack, 8.0 /- 0.5 s; time interval between attacks, 18.7 /- 3.2 s; n = 9). After the surgery, amplitude of the abnormal torsional eye movement was reduced, and the oscillopsia had subjectively improved, although the movement cycle remained unchanged. The authors' video-image analysis, which used iris striation, proved to be a useful method for clinical measurement of torsional eye movements. ( info) |
3/18. Remission of superior oblique myokymia after microvascular decompression. Superior oblique myokymia (SOM) is an ocular motility disorder characterized by oscillopsia, vertical or torsional diplopia, sometimes combined with pressure sensation. Although the pathophysiological basis is unclear, isolated case reports have documented its association with intracranial pathological processes. We present a case of SOM associated with a vascular compression of the fourth nerve at the root exit zone. Following microneurosurgical decompression, SOM completely resolved and paralysis of the fourth nerve occurred. This was less disturbing. ( info) |
4/18. Functional changes and adverse reactions after successful treatment of hereditary myokymia: a case report. myokymia is a vermiform motion of muscle that can be found in conditions in which there is pathology to the peripheral nerve to that muscle. There are inherited syndromes that can present with muscle cramping and myokymia that have been described, but little information exists on long-term follow-up. In this case study, a 12-year-old girl had an inherited form of myokymia, as determined by clinical examination, electromyographic findings, and family history. The mode of inheritance appeared to be autosomal dominant with reduced penetrance. carbamazepine was used successfully to treat this disorder. Measurements were made of strength and endurance before and after treatment; significant improvement was seen in endurance with little effect on strength. The patient was able to discontinue carbamazepine without return of symptoms and subsequently was not limited in her activities. Return of symptoms was seen with prednisone treatment for exacerbated asthma. The symptoms resolved with restarting the carbamazepine and weaning of the prednisone. Discussion is presented on the possible mechanism by which anticonvulsant and steroid therapy exert their effects on myokymia. ( info) |
5/18. Vascular compression as a cause of superior oblique myokymia disclosed by thin-slice magnetic resonance imaging. PURPOSE: To describe a case of superior oblique myokymia in which thin-slice magnetic resonance imaging (MRI) appeared to show vascular compression of the trochlear nerve. methods: A 50-year-old woman presented with episodic monocular oscillopsia. Neuro-ophthalmologic examinations showed intermittent intorsional microtremor of her right eye, diagnosed as right superior oblique myokymia. Thin-slice (1.6 mm) MRI, using spoiled gradient recalled acquisition in the steady state, was employed to examine the trochlear nerve in its course through the ambient cistern. RESULTS: Imaging disclosed a branch of the posterior cerebral artery immediately adjacent to the right trochlear nerve. CONCLUSION: These magnetic resonance findings suggest that a cause of superior oblique myokymia may be vascular compression of the trunk of the trochlear nerve. ( info) |
6/18. myokymia and neonatal epilepsy caused by a mutation in the voltage sensor of the KCNQ2 K channel. KCNQ2 and KCNQ3 are two homologous K( ) channel subunits that can combine to form heterotetrameric channels with properties of neuronal M channels. Loss-of-function mutations in either subunit can lead to benign familial neonatal convulsions (BFNC), a generalized, idiopathic epilepsy of the newborn. We now describe a syndrome in which BFNC is followed later in life by myokymia, involuntary contractions of skeletal muscles. All affected members of the myokymia/BFNC family carried a mutation (R207W) that neutralized a charged amino acid in the S4 voltage-sensor segment of KCNQ2. This substitution led to a shift of voltage-dependent activation of KCNQ2 and a dramatic slowing of activation upon depolarization. myokymia is thought to result from hyperexcitability of the lower motoneuron, and indeed both KCNQ2 and KCNQ3 mRNAs were detected in the anterior horn of the spinal cord where the cells of the lower motoneurons arise. We propose that a difference in firing patterns between motoneurons and central neurons, combined with the drastically slowed voltage activation of the R207W mutant, explains why this particular KCNQ2 mutant causes myokymia in addition to BFNC. ( info) |
| Morvan's 'fibrillary chorea' or Morvan's syndrome is characterized by neuromyotonia (NMT), pain, hyperhydrosis, weight loss, severe insomnia and hallucinations. We describe a man aged 76 years with NMT, dysautonomia, cardiac arrhythmia, lack of slow-wave sleep and abnormal rapid eye movement sleep. He had raised serum antibodies to voltage-gated K( ) channels (VGKC), oligoclonal bands in his CSF, markedly increased serum norepinephrine, increased serum cortisol and reduced levels and absent circadian rhythms of prolactin and melatonin. The neurohormonal findings and many of the clinical features were very similar to those in fatal familial insomnia, a hereditary prion disease that is associated with thalamic degenerative changes. Strikingly, however, all symptoms in our MFC patient improved with plasma exchange. The patient died unexpectedly 11 months later. At autopsy, there was a pulmonary adenocarcinoma, but brain pathology showed only a microinfarct in the hippocampus and no thalamic changes. The NMT and some of the autonomic features are likely to be directly related to the VGKC antibodies acting in the periphery. The central symptoms might also be due to the direct effects of VGKC antibodies, or perhaps of other autoantibodies still to be defined, on the limbic system with secondary effects on neurohormone levels. Alternatively, changes in secretion of neurohormones in the periphery might contribute to the central disturbance. The relationship between VGKC antibodies, neurohormonal levels, autonomic, limbic and sleep disorders requires further study. ( info) |
8/18. Superior oblique myokymia: magnetic resonance imaging support for the neurovascular compression hypothesis. Superior oblique myokymia is a rare movement disorder thought to be caused by vascular compression of the trochlear nerve. Direct display of such neurovascular compression by magnetic resonance imaging has been lacking. The goal of this study was to assess the presence of neurovascular contacts in patients with superior oblique myokymia, using a specific magnetic resonance imaging protocol. A total of 6 patients suffering from right superior oblique myokymia underwent detailed neuro-ophthalmological examination, which showed tonic or phasic eye movement. All patients underwent magnetic resonance imaging, using a magnetic resonance imaging Fourier transform constructive interference in steady-state sequence in combination with magnetic resonance imaging time of flight magnetic resonance arteriography both before and after the administration of Gd-DTPA. With this protocol, the trochlear nerve could be visualized on 11 of 12 sides (92%). Arterial contact was detected at the root exit zone of the symptomatic right trochlear nerve in all 6 patients (100%). No arterial contact was identified at the root exit zone of the asymptomatic left trochlear nerve in any of the 5 left nerves visualized. In conclusion, superior oblique myokymia can result from neurovascular contact at the root exit zone of trochlear nerve, and therefore should be considered among the neurovascular compression syndromes. ( info) |
9/18. An unusual case of electromyographic recorded myokymic potentials: a case report. Abnormal spontaneous potentials, specifically myokymia, can occur from various causes. We present the case of a 64-year-old woman with a 12-month history of left leg weakness and difficulty descending stairs. The patients' medical history was significant for breast carcinoma (no node involvement), hypercholesterolemia, and vitamin B(12) deficiency. She previously had a modified radical mastectomy and received chemotherapy (5-flurouracil, methotrexate, Cytoxan [cyclophosphamide]), but received no radiation. She took simvastatin for hypercholesterolemia and received vitamin B(12) injections for her B(12) deficiency. She initially noticed her symptoms when she began taking simvastatin, and they were exacerbated when her dose was increased from 10 to 20mg/d. Electrodiagnostic studies were performed twice at a 6-month interval. Nerve conduction studies were normal, but the initial needle electromyography showed significant myokymic discharges in bilateral iliopsoas, adductor magnus, and left deltoid muscles. The second electromyograph had similar findings, except for the absence of myokymic discharges in the left deltoid muscle. The possible origins of these myokymic discharges are discussed. ( info) |
10/18. Segmental neurogenic muscle hypertrophy associated with radiation injury. A 48-year-old man presented with painless left trapezius hypertrophy 20 years after radiotherapy for nasopharyngeal carcinoma. EMG sampling showed myokymic discharges, reduced polyphasic motor unit recruitment and no signs of active denervation. The relationship between radiotherapy, brachial plexopathy and neurogenic muscle hypertrophy is discussed. ( info) |