Muscle twitching is also known as muscle fasciculations. Muscle fasciculations are rapid, fine, acute and intermittent involuntary muscle contractions that occur in in a single muscle or in a group of muscles.1 These are very subtle muscle contractions which can be felt or seen, it is a sudden jerk in the muscle. Unlike muscle spasm you will not feel any pain or a hardened area in the muscle. The skeletal muscles or a motor unit contracts when they get a signal from the nervous system thorough the nerves e.g. if you think you need to raise your leg at a second speed the signal is carried to the muscles that are needed to raise the leg. Muscle twitching occurs when the muscle contracts without a signal from the nervous system on their own. You did not think this action and it is totally unexpected.
What Is Muscle Twitching A Sign Of?
Muscle twitching is not an abnormal thing always. Most of you have experienced muscle twitching at some point. Eye twitching is very common, even leg twitching, these are normal and there is nothing to worry about. There are so many causes for muscle twitching and some of them are normal and some are serious. If you continue to get muscle twitching with increased frequency and if you have other symptoms such as weakness, abnormal movements and pain then you need to see a doctor.
Muscle twitching in healthy individuals
- Stress 1
- Exhausting physical activities
- Cramp syndrome
- Benign fasciculations
Muscle twitching associated with movement disorders
- Parkinsonism (multiple system atrophy, amyotrophic lateral sclerosis plus syndrome)2
- Espinocerebellar degeneration-type 3
- Espinocerebellar degeneration-type 36
- Motor neuron disease
- Amyotrophic lateral sclerosis
Progressive spinal muscular atrophy
- Benign monomelic amyotrophy
- Post-polio syndrome
- Kennedy syndrome
- Systemic disease
Calcium disorders secondary to hyperparathyroidism
- Hyperthyroidism; syndrome of inappropriate secretion of thyrotropin (Ohba)
- Drugs and heavy metals
- Elemental mercury intoxication
Association of lithium and nortriptyline
Muscle Twitching With Movement Disorders
Muscle twitching is not categorized as one of the movement disorders however, there are some cases of movement disorders with muscle twitching.
The atypical form of Parkinson which is called multiple system atrophy (MSA) which was called Shy-Drager syndrome earlier has some cases reported with Parkinson features, cerebellar features, muscle twitching and other features. There were 5 patients with muscle twitching and amyotrophy, examination and investigations suggested of an MSA. Another case study reported about a 68-year-old man with had muscle weakness, fasciculations, tremors, amyotrophy and cerebellar syndrome.
Electroneuromyography (ENMG) and MRI both confirmed it’s one type of SMA. This patient’s muscle twitching was mainly seen in the face.
Another atypical form of Parkinson Disease (PD) is amyotrophic lateral sclerosis (ALS) plus syndrome. A case study reported a 48-year-old man who had muscle weakness, muscle twitching in various body parts, rigidity, tremor and imbalance, died one year after the manifestations of symptoms. The autopsy revealed ALS and PD. One of the symptoms in ALS is muscle twitching. A multicenter study done with recruiting 6,471 ALS patients, 314 Parkinson disease patients with 7668 control patients revealed that ALS and PD are related at gene level and sometimes signs of ALS preceded PD and sometimes the opposite.
Muscle twitches are also known as muscle fasciculations. Muscle fasciculations are rapid, fine, acute and intermittent involuntary muscle contractions that occur in in a single muscle or in a group of muscles. These are very subtle muscle contractions which can be felt or seen, it is a sudden jerk in the muscle. Muscle twitching is not categorized as one of the movement disorders however; there are some cases of movement disorders with muscle twitching. The atypical forms of Parkinson which are multiple system atrophy (MSA) and amyotrophic lateral sclerosis (ALS) plus syndrome are associated with muscle twitching. MSA is mostly associated with facial twitching, ALS muscle twitching does not have any specific area. There is not enough evidence to prove muscle twitching is one of the signs of movement disorders yet, but it can be present in some atypical forms of movement disorders.