Diseases of Muscle and the Neuromuscular Junction
John W. Scadding, Nicholas A. Losseff in Clinical Neurology, 2011
Symptoms may begin at any age but occur most often in late childhood or early adulthood. Muscle stiffness is usually the first symptom and appears in distal limb muscles, slowly spreading over months or years to involve the axial and cranial muscles. Movement becomes slow. Myokymia can be seen in overactive muscles. Muscle relaxation after contraction is slow and percussion myotonia is absent. Increased sweating and muscle weakness with hyporeflexia is seen in some patients. Examination demonstrates mild weakness, which can be proximal, distal or both. Hallucinations, insomnia, seizures and intellectual impairment have been reported in some patients in conjunction with neuromyotonia, a polyneuropathy and sometimes an underlying thymoma (Morvan’s syndrome).
Diseases of the Peripheral Nerve and Mononeuropathies
Philip B. Gorelick, Fernando D. Testai, Graeme J. Hankey, Joanna M. Wardlaw in Hankey's Clinical Neurology, 2020
Myokymic discharges originate from the peripheral nerve and result from ephaptic transmission between damaged contiguous axons. These discharges are often seen clinically and described as a bag of worms. These can occur in a variety of nerve disorders including Isaac's syndrome (acquired neuromyotonia) and Morvan's syndrome (limbic encephalitis with peripheral nerve hyperexcitability) due to anti–voltage-gated potassium channel complex antibodies and episodic ataxia type 1 due to mutations in the neuronal potassium channel Kv1.1 but are most commonly associated with radiation-induced nerve injury and other demyelinating disorders.3 Facial myokymia may be seen in multiple sclerosis, pontine glioma, and spinal and bulbar muscular atrophy. Eyelid myokymia is a common and generally benign occurrence.
Discussions (D)
Terence R. Anthoney in Neuroanatomy and the Neurologic Exam, 2017
Another probable reason for inconsistencies in the movements listed as involuntary is stated clearly by Fahn at the beginning of his section entitled “Involuntary Movements”: “Although convulsions, fasciculations, and myokymia are involuntary movements, these disorders have special characteristics and are not classified with the types of abnormal involuntary movements to be described in this section.” (in Rowl, p. 38)3
Swallow-Induced Eyelid Myokymia: A Novel Synkinesis Syndrome
Published in Neuro-Ophthalmology, 2020
Amrita-Amanda D. Vuppala, Gregory J. Griepentrog, Ryan D. Walsh
Myokymia is a disorder of involuntary, fine, undulating, non-synchronous striated muscle fibre contractions resulting in a visible rippling of the overlying skin.1 Eyelid myokymia is the most common type of focal facial myokymia and involves the orbicularis oculi muscle.2 Clinically, eyelid myokymia is typically described by patients as small annoying twitches of the upper or lower eyelids.3 It may be triggered by fatigue, stress, excessive caffeine, or physical exertion and is most often a benign and self-limited condition.2 Other reported aetiologies include topiramate,4-6 autoimmune diseases,7,8 multiple sclerosis,1,9–11 brainstem pathology (such as pontine glioma),12 and repetitive sessions of anodal transcranial direct current stimulation.13 In this report, we describe a novel case of eyelid myokymia triggered by swallowing.
Ocular Neuromyotonia: Case Reports and Literature Review
Published in Strabismus, 2018
Anne-Catherine Stockman, Maria Dieltiëns, Hilde Janssens, Maria Van Lammeren, Liesbet Beelen, Veerle Van Bellinghen, Catherine Cassiman
Peripheral neuromyotonia, also known as Isaacs syndrome and not limited to ONM, is a state of involuntary sustained muscle hyperactivity, which can be triggered by a voluntary muscle contraction. This is due to abnormal excitability of peripheral motor nerve axons of the affected muscle. The clinical presentation varies, as well as the associated electrophysiological abnormalities. Patients may present with myokymia, fasciculations, muscle cramps, stiffness, fatigue, and other related symptoms.
Polysubstance use disorder as a probable self-medication in Isaacs’ syndrome
Published in Psychiatry and Clinical Psychopharmacology, 2018
Yasin Hasan Balcioglu, Simge Seren Kirlioglu, Pinar Cetinay Aydin
Index patient was a 31-year-old man, who was single, high school graduated, and unemployed. Preceding complaints were spontaneous, continuous, visible muscle twitching with undulations especially in lower limbs 15 years ago. He also complained of weakness in both lower limbs, which worsened on walking long distances or exertion. Severe calf pain, paresthaesia, stiffness, and fasciculations in his lower limbs with increased sweating had also been noted. Electromyography revealed continuous muscle fibre activities and myokymia, particularly in bilateral gastrocnemius. According to clinical findings and thorough examination, he had been diagnosed with IS at the age of 16 by the neurology outpatient department he was admitted to. The diagnosis was confirmed by the presence of serum VGPC autoantibodies. The treatment had been initiated with carbamazepine 400 mg/daily; however, he discontinued medication after a short notice. He started using psychoactive substances (primarily opioids) 10 years ago and added cannabis – including synthetic forms, ecstasy, and alcohol. He kept up substance use in spite of four attempts of addictology treatment. He referred us because of behavioural disturbance and polysubstance use intoxication, particularly with opioids and cannabinoids. He admitted regular use of synthetic cannabinoids every day for four years. He stated that his complaints of muscle pain and stiffness had been relieved while using opioids and cannabinoids over the past six years. He also told that he had been suffering from muscle stiffness, cramping, and pain when not using synthetic cannabinoids for two or three days. In his current psychiatric examination, he appeared his age and his self-care was normal. No psychotic nor affective symptom was determined. In the neurological examination, myokymia and stiffness were observed in his lower limbs. Motor examination revealed average muscle status with no wasting and sensory examination was normal. His plantar reflexes were flexor bilaterally. 35/100 of pain score was recorded according to the Visual Analog Scale administration. Spasticity was rated at 1/4 (slight increase in muscle tone) according to Modified Ashworth Scale. There was no abnormality in his hemogram and wide biochemical panel. We initiated the treatment with carbamazepine 200 mg/daily and potentiated to 400 mg in light of routine screening of blood carbamazepine levels. He was discharged with the improvement of his behavioural disturbance and impulsivity.
Related Knowledge Centers
- Brainstem
- Brainstem Glioma
- Demyelinating Disease
- Eyelid
- Polyneuropathy
- Joint
- Neoplasm
- Multiple Sclerosis
- Superior Oblique Myokymia
- Guillain–Barré Syndrome