Myokymia.

Myokymia is one of the involuntary movements, which is characterized by undulatory muscle spasm, similar to the worm's crawl. Sometimes muscle pain, itchy sensation, dysautonomia and other symptoms are associated with it. Cases showing normal neurological findings are rare. Myokymia is caused by various diseases, such as, multiple sclerosis, hypothyroidism, Guillan-Barre syndrome and so on. Generally myokymia is classified into two types, i.e. limb myokymia and facial myokymia according to the site. On the other hand, myokymia with hyperhidrosis is known as Issacs syndrome. There are many opinions about the pathogenesis and mechanism in the myoneural junction, peripheral nerve or spinal cord, however these are not established. Further investigation of myokymia is expected.