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Continuous muscle fiber activity (Isaacs syndrome)

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Continuous muscle fiber activity (Isaacs syndrome)

This 35-year-old man presented with a 1-year history of stiffness and cramps in lower limbs. Myokymia was present in muscles of the lower limbs with severe involvement of the gastrocnemius muscle. This phenomenon resembled a bag of worms. (Contributed by Dr. Ravindra Kumar Garg.)

Associated Disorders

  • Acute inflammatory demyelinating polyneuropathy
  • Bell palsy
  • Brainstem encephalitis (Rhombencephalopathy)
  • Central pontine myelinolysis
  • Chronic inflammatory demyelinating polyneuropathy
  • Episodic ataxia type 1 (Ataxia)
  • Episodic ataxia with myokymia (EA1)
  • Familial paroxysmal kinesigenic ataxia (Paroxysmal dyskinesias)
  • Focal neuropathies
  • Guillain-Barre syndrome (AIDP)
  • Heavy metal poisoning (Metal neurotoxicity)
  • Hereditary neuropathies
  • Inflammatory meningoradiculitis
  • Multifocal motor neuropathy
  • Multiple sclerosis:clinical aspects
  • Myasthenia gravis
  • Neoplastic meningoradiculitis (Leptomeningeal metastasis)
  • Neurovascular cranial nerve compression (Trigeminal neuralgia and other cranial neuralgias)
  • Normocalcemic tetany
  • Paraneoplastic limbic encephalitis
  • Peripheral neuropathies (Clinical evaluation of peripheral neuropathies)
  • Radiation plexopathy
  • Radiculopathies
  • Schwartz-Jampel syndrome
  • Syringobulbia (Syringomyelia)
  • Thyrotoxicosis
  • complication of cranial radiation treatment