Muscle Twitch: Causes, Treatment, and Prevention – Verywell Health

Kristen Gasnick, PT, DPT, is a health writer and a physical therapist at Holy Name Medical Center in New Jersey.
Oluseun Olufade, MD, is a board-certified orthopedist. He teaches as an Assistant Professor of Orthopedics at Emory School of Medicine in Atlanta, Georgia.
Muscle twitches, also called fasciculations, are fast, spontaneous contractions of muscle fibers that can be seen on the surface of the skin. Muscle twitches are different from muscle spasms, which are sudden, involuntary contractions of muscles, or muscle jerks (myoclonus), which are sudden spasms that involve an entire muscle group, such as leg jerks when falling asleep. 
Muscle twitches commonly occur in people with healthy neuromuscular systems—up to 70% of healthy people get them—but they can also be a sign of a more serious condition.
Peter Dazeley / Getty Images
Nerve cells, called neurons, generate and conduct electrical signals through the transfer of ions in and out of cell walls. Cell walls contain pumps that transfer sodium ions into cells while transporting potassium ions out of cells. This transfer of ions causes a change in the neuron’s electrical charge, allowing an electrical signal to travel through the nerve.
In order for neurons to transfer signals to other neurons and other cells in the body, they release small chemicals called neurotransmitters. The space where the end of one neuron meets another cell is called a synapse. This is where neurotransmitters are transferred from one neuron to another cell through its receptors.
The area where a neuron transmits a signal to a muscle cell is called the neuromuscular junction. When muscles contract and movement occurs, the neurotransmitter acetylcholine is released from neurons at the neuromuscular junction and received by receptors of muscle cells. Muscle cells use acetylcholine to generate a muscular contraction by releasing calcium ions from storage within a membrane-bound structure in muscle cells called the sarcoplasmic reticulum. This process happens all in a matter of mere fractions of a second.
A motor unit refers to a motor neuron, the nerve cell that controls muscular activity, and the muscle fibers that it controls. Whenever a motor unit is active, the motor neuron releases acetylcholine into the neuromuscular junction and all of the muscle fibers controlled by that motor neuron contract. Muscle twitches occur due to excessive stimulation of the motor unit and the subsequent release of acetylcholine for a variety of reasons, including those in the list that follows.
Sodium, potassium, and calcium are all important electrolytes involved in nervous system function and muscle contractions. When electrolytes are imbalanced due to diet, dehydration, hormonal disruptions, illnesses, or certain medications, abnormal muscle contractions can result, causing muscle twitching.
Caffeine is a stimulant known to increase energy and alertness. Too much caffeine, however, can cause the release of too many calcium ions from the sarcoplasmic reticulum within muscles. This increased concentration can result in muscle fibers contracting and twitching.
Dehydration, which can result from not drinking enough water or from too much water loss from sweating, urinating, vomiting, and diarrhea, can cause electrolyte imbalances that lead to muscle twitching. Poor hydration also increases the concentration of sodium within the body since the body does not have enough water to remove sodium ions through excretions like sweat and urine. This buildup of excess sodium stimulates repetitive nerve signaling that can lead to muscle twitching.
Physical exhaustion can result in bodily stress, which can make the nervous system more sensitive. This increased activation of the sympathetic nervous system and the increased likelihood of spontaneous nerve firing can cause muscle contracture and muscle twitching.
A pinched nerve, which occurs when a nerve is compressed, can cause repetitive stimulation to the nerve and the muscle fibers that it controls. This compression can cause ongoing muscle contraction and twitching.
The receptors on the muscle fibers within the neuromuscular junction that uptake the neurotransmitter acetylcholine are called nicotinic receptors. Nicotinic receptors are activated by binding to acetylcholine and initiating muscle contraction.
Nicotinic receptors, as their name implies, are also activated by nicotine, the compound found in tobacco products like cigarettes and cigars. Smoking or using other tobacco products containing nicotine can lead to muscle twitching due to an overstimulation of the nicotinic receptors.
Muscle fibers become fatigued from the overstimulation of their motor neurons during physical activity. Even after you stop exercising and your muscle fibers no longer need to contract as quickly and repetitively, the neurons still may remain stimulated. This can result in muscle twitching for a short period of time after exercising until the motor neurons return to normal.
Neuropathy, a condition characterized by nerve damage and malfunction, can cause signals to continually be sent along the motor nerves to muscle fibers. This malfunctioning of the nervous system can cause repetitive involuntary muscle contractions and twitching.
Certain medications, such as diuretics that increase the loss of water from the body through urination, can cause muscle twitching, a side effect from electrolyte imbalance.
Beta-2 agonists such as Symbicort, Albuterol, and Brethine, a class of asthma medications, can also cause muscle twitching. They enhance the activity of beta receptors on muscles and increase the activity of nearby nicotinic receptors, resulting in an uptake of acetylcholine.
Most of the time, muscle twitches are benign and not a reason for concern. However, prolonged and repetitive muscle twitching that has been ongoing for several weeks or months may be indicative of a more serious neurological condition, including:
A visit with a doctor can help confirm the cause of your muscle twitching. Your doctor will ask several questions about your symptoms, including:
If your muscle twitching occurs frequently and interferes with your daily life, you may undergo electromyography (EMG) testing to record and assess the electrical activity of your muscle fibers.
If you have been experiencing other neurological symptoms, such as muscle weakness, fatigue, slurred speech, weakened grip strength, and difficulty walking, you will likely be referred to a neurologist. This specialist will perform further assessments, such as blood work, nerve conduction tests, and, possibly, muscle biopsies to determine if a neurological condition is causing your muscle twitching. 
Treatment for muscle twitching depends on its underlying cause. Lifestyle changes can help decrease the likelihood of spontaneous muscle twitching in healthy people.
For more serious causes of muscle twitching such as ALS, muscular dystrophy, or Isaac’s syndrome, you may be prescribed medications to help reduce symptoms. You may also need physical therapy to maintain proper muscle function and to prevent symptom progression.
Lifestyle changes can help prevent muscle twitching from occurring. These include:
Make sure to let your physician know of all medications and supplements that you are taking to avoid potentially dangerous drug interactions and to decrease your risk of developing serotonin syndrome. 
Muscle twitches are not necessarily a cause for concern since they often affect healthy people. However, if you have had muscle twitches for a long time, an underlying condition could be the cause. In that case, you should talk to your doctor to get an accurate diagnosis.
Most muscle twitching occurs naturally from various lifestyle factors and should not be a reason to worry unless your muscle twitching is frequently occurring over several weeks or months. Staying adequately hydrated, getting enough sleep, and avoiding caffeine and nicotine can help decrease the occurrence of muscle twitches.
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