What is myoclonus?

Myoclonus describes a symptom and not a diagnosis of a disease. It refers to sudden, involuntary jerking of a muscle or group of muscles. Myoclonic twitches or jerks usually are caused by sudden muscle contractions, called positive myoclonus, or by muscle relaxation, called negative myoclonus. Myoclonic jerks may occur alone or in sequence, in a pattern or without pattern. They may occur infrequently or many times each minute. Myoclonus sometimes occurs in response to an external event or when a person attempts to make a movement. The twitching cannot be controlled by the person experiencing it.
In its simplest form, myoclonus consists of a muscle twitch followed by relaxation. A hiccup is an example of this type of myoclonus. Other familiar examples of myoclonus are the jerks or "sleep starts" that some people experience while drifting off to sleep. These simple forms of myoclonus occur in normal, healthy persons and cause no difficulties. When more widespread, myoclonus may involve persistent, shock-like contractions in a group of muscles. In some cases, myoclonus begins in one region of the body and spreads to muscles in other areas. More severe cases of myoclonus can distort movement and severely limit a person's ability to eat, talk, or walk. These types of myoclonus may indicate an underlying disorder in the brain or nerves.

What are the causes of myoclonus?

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. For example, myoclonic jerking may develop in patients with multiple sclerosis, Parkinson's disease, Alzheimer's disease, or Creutzfeldt-Jakob disease. Myoclonic jerks commonly occur in persons with epilepsy, a disorder in which the electrical activity in the brain becomes disordered leading to seizures.

I don't get the twitches, but I get very painful spasms/cramping that last @ 20-30 seconds. They are so painful that it takes my breath away. The only thing I can do when I'm having one is just try to ride it out. Does anyone know why I get those? Does anyone else get them. They are mostly in my middle torso area.

it makes sense to be neurtopathy as the nervous system is affected by fibro, that makes sense thank you x

It seems that I read somewhere that cramping and twitching are symptoms of fibromyalgia, or maybe neuropathy. Sorry, my brain fog has taken on a new life and my memory seems to be failing quickly. so, I can't remember which it was.

i have involuntary jerking sometimes, , its like a sudden jumping like you do at a scary movie, feels strange, often wondered what the hell is this? x thanks for the info, Notice it desnt say it can be firbo related in the article?