Myoclonus may develop in response to infection, head or spinal cord injury, stroke, brain tumors, kidney or liver
failure, lipid storage disease, chemical or drug
poisoning, or other disorders. Prolonged oxygen deprivation to the brain, called hypoxia, may result in posthypoxic myoclonus. Myoclonus can occur by itself, but most often it is one of several symptoms associated with a wide variety of nervous system disorders.