Fasciculations and muscle twitching: causes and treatment

Fasciculations and muscle twitching – causes and treatment

Fasciculations are brief, involuntary twitches of individual bundles of muscle fibres, visible as “twitching under the skin” – the most common and usually benign form of muscle twitching. An eyelid muscle twitches for several days in a row. A calf “jumps” on its own in the evening in bed. An arm muscle twitches although the arm is still. Muscle twitching – in medical terminology most often referred to as fasciculations – is one of the most common benign neurological phenomena in the population. In a twenty-year study by Blexrud and colleagues at the Mayo Clinic, it was shown that benign fasciculations in people with no other neurological symptoms do not progress to motor neurone disease, even though they can persist for years (Blexrud et al., 1993). Even so, muscle twitching can cause intense anxiety – especially in people who have read online about amyotrophic lateral sclerosis. In this article we explain what fasciculations are, when they are harmless, when they call for a visit to a neurologist, and how to work on their anxiety-related background.

Important medical disclaimer: this article is educational and does not replace a medical consultation. Any twitching accompanied by muscle weakness, muscle wasting, paresis or gait disturbances requires urgent assessment by a neurologist.

What is muscle twitching? Fasciculations, tremor, myoclonus – the differences

In everyday speech, “muscle twitching” covers very different neurological phenomena. In medicine, several separate disorders are distinguished:

Fasciculations are spontaneous, irregular, short-lived contractions of single motor units – a group of muscle fibres supplied by one motor neurone. They are visible as quick, local “twitches under the skin” that do not cause movement at a joint. These are the “jumps” of the eyelid, calf or arm that appear for no apparent reason.

Tremor is involuntary, rhythmic oscillating movement caused by alternating contraction of agonist and antagonist muscles. It produces visible movement of a part of the body – the hand shakes, the head nods, the voice trembles. We describe it in detail in our article on hand tremor – causes (anxiety disorder vs. diseases) and treatment.

Myoclonus refers to sudden, brief, jerking contractions resembling an “electric shock”. The best-known physiological form is hypnagogic myoclonus – sudden jerks when falling asleep. Pathological myoclonus can be a symptom of epilepsy or metabolic disorders.

Cramps are painful, long-lasting (seconds to minutes) contractions of a whole muscle – a classic example is a painful calf cramp at night.

The most common reason patients report “muscle twitching” is fasciculations – so we devote the main part of the article to them.

Why do muscles twitch on their own? The physiology of fasciculations

Every skeletal muscle is supplied by hundreds of motor neurones located in the anterior horns of the spinal cord. Each motor neurone supplies anywhere from a few to several thousand fibres – together they form what is called a motor unit. A fasciculation arises when a single motor unit fires spontaneously, without a command from the central nervous system. Most often the generator is the nerve endings within a peripheral nerve.

What throws nerve endings off balance:

• Electrolyte disturbances – magnesium, potassium and calcium are key to the polarisation of nerve membranes
• Metabolic fatigue – after exertion, prolonged tension, sleep deprivation
• Sympathetic arousal – a high level of catecholamines increases the excitability of motor neurones
• Stimulants – caffeine, nicotine, some medicines
• Nerve microdamage – chronic compression, neuropathies

Fasciculations are an extremely common phenomenon. A survey by Filippakis and colleagues among healthy medical students showed that as many as 70% of young adults with no neurological disease had experienced fasciculations at some point (Filippakis et al., 2018). In most of them they were occasional and were not linked to any danger.

The most common causes of muscle twitching

Electrolyte deficiencies

• Magnesium deficiency – a classic cause of twitching of the eyelid, calves and facial muscles. Magnesium stabilises cell membranes. Deficiency results from a diet low in leafy green vegetables and nuts, from chronic stress (cortisol increases Mg excretion), or from the use of diuretics and proton pump inhibitors
• Potassium deficiency – disrupts neuromuscular conduction; common after diarrhoea, vomiting and diuretic overuse
• Calcium deficiency – can cause tetany and more pronounced twitching; linked to vitamin D levels and blood pH

Caffeine and stimulants

Excess coffee (more than 4–5 cups a day), energy drinks, black tea and nicotine can significantly worsen twitching. Caffeine blocks adenosine receptors and raises the excitability of motor neurones. In sensitive people even 2–3 cups of coffee can trigger eyelid twitching for a day.

Stress, anxiety and chronic tension

Chronic stress sustains a state of sympathetic nervous system hyperactivation – high levels of adrenaline and noradrenaline increase the excitability of motor neurones. In people going through intense stress, twitching worsens dramatically.

Sleep deprivation, dehydration, exertion

Sleep of under 6 hours for several days is enough to trigger persistent eyelid or calf twitching in healthy people. After a long workout, especially in a hot climate, fasciculations can persist for 24–72 hours – a natural physiological reaction to electrolyte loss and microdamage to fibres.

Medicines

Twitching can be caused by, among others: beta-agonists (salbutamol), some antibiotics (quinolones), statins, corticosteroids, psychiatric medicines (SSRIs, lithium) in the initiation phase, and ADHD medicines (methylphenidate). If twitching appeared after starting a new medicine – discuss it with your doctor, but never stop medicines on your own.

Anxiety disorder and muscle twitching – the hyperarousal mechanism

In people with anxiety disorders, muscle twitching is one of the most common somatic symptoms. The mechanism is based on persistently raised activity of the sympathetic nervous system. In health, this system is activated briefly, in response to a real threat. In anxiety disorders it remains chronically elevated – which is described by the term hyperarousal.

A constantly raised level of catecholamines leads to:

• A lowered excitability threshold of motor neurones – motor units discharge “spontaneously”
• Constant, low muscle tension – muscles never fully relax
• Increased loss of magnesium in the urine (mediated by cortisol)
• Shallower breathing – subtle hyperventilation that disturbs blood pH
• Sleep disturbances – which further worsen the symptom

In a person with chronic anxiety, muscles can twitch for weeks, “wandering” from the eyelid to the calf to the arm. This is a very characteristic picture of somatic anxiety.

Benign fasciculation syndrome (BFS)

In some people with chronic tension, a syndrome known as benign fasciculation syndrome (BFS) develops. It is defined as persistent, daily fasciculations affecting different muscle groups, lasting for months, without loss of strength, without muscle wasting, with normal electrophysiological test results. The groundbreaking twenty-year study by Blexrud and colleagues showed that among 121 patients with isolated benign fasciculations, none developed motor neurone disease after an average of 7 years of follow-up – which gave a strong basis for regarding BFS as a functional, non-progressive disorder (Blexrud et al., 1993).

BFS very often co-occurs with health anxiety and excessive somatic vigilance. Patients who have once noticed a fasciculation begin to monitor their body – and naturally find more. A vicious circle forms: anxiety → hypervigilance → more twitches noticed → greater anxiety → increased sympathetic activation → objectively more fasciculations.

Fear of ALS – the classic scenario

One of the most common reasons for consultation is patients whose fasciculations set off an avalanche of searching online, ending in the conviction that they have amyotrophic lateral sclerosis. The patient examines their muscles daily, presses on them, checks their strength – which paradoxically worsens both the anxiety and the twitching. It is worth knowing that in ALS, fasciculations almost always appear together with symptoms of weakness and progressive muscle wasting – isolated fasciculations, without weakening, are extremely rarely the first and only manifestation of motor neurone disease.

When to see a doctor? Red flags

Repeated medical note: the symptoms below require urgent neurological consultation. Do not delay a visit on the assumption that it is “surely anxiety”.

See a doctor if any of the following occurs together with muscle twitching:

• Progressive loss of muscle strength – difficulty opening jars, getting up from a chair, raising an arm above your head
• Visible muscle wasting (atrophy) – one muscle has clearly become thinner compared with the other side
• Paresis – foot drop, wrist drop, facial asymmetry
• Gait disturbances – tripping, instability, “dragging” a leg
• Speech or swallowing problems – slurred speech, choking when eating
• Sensory disturbances accompanying the twitching (suggesting neuropathy; more in the article on paraesthesia – what it is, symptoms, causes and treatment)
• Tongue twitching at rest with accompanying thinning
• Neck stiffness, headache, fever – urgent, suspected meningitis

The most serious diseases to be distinguished are: amyotrophic lateral sclerosis (ALS), spinal muscular atrophy (SMA), peripheral neuropathies (diabetic, alcoholic, due to B12 deficiency), and myopathies (inflammatory, drug-induced).

Differential diagnosis of muscle twitching

History and neurological examination

The most important test. The neurologist assesses muscle strength in all groups (MRC scale), tendon reflexes, sensation, coordination, gait, cranial nerves, and the presence or absence of wasting. A normal neurological examination in a person with isolated fasciculations practically rules out motor neurone disease at that point in time.

Laboratory tests

• Electrolytes: magnesium, potassium, calcium, sodium
• TSH, fT3, fT4 – to rule out an overactive thyroid
• Vitamin B12, folic acid, vitamin D
• Fasting glucose, HbA1c – diabetes
• Creatine kinase (CK) – raised in myopathies
• Full blood count, ESR, CRP – assessment of inflammation

EMG (electromyography)

EMG is the gold standard in diagnosing neurologically based muscle twitching. It makes it possible to distinguish benign fasciculations (with normal discharge morphology) from pathological ones (with additional denervation activity – fibrillations and positive sharp waves). In patients with BFS, EMG is normal or shows only fasciculations, without signs of denervation. EMG is ordered by a neurologist – it is not a test to “check” on your own.

How to help yourself – lifestyle, supplementation, breathing

Sleep

The absolute foundation. Aim for 7–9 hours of regular sleep at fixed times. Sleep deprivation is one of the strongest triggers of fasciculations.

Magnesium supplementation

Organic forms are absorbed best – magnesium citrate, malate, glycinate – at a dose of 200–400 mg of magnesium ions a day, ideally in the evening. Magnesium oxide is poorly absorbed. If you take other supplements or medicines, check the dose with a pharmacist.

Reducing caffeine

Gradually (not suddenly) cut coffee down to 1–2 cups a day, ideally in the morning. Eliminate energy drinks and strong teas. In sensitive people, this change alone stops eyelid twitching within a few days.

Hydration and electrolytes

2–2.5 litres of water a day, and more in hot weather and during intense exertion, ideally with added electrolytes.

Breathing and regulation of the autonomic nervous system

• 4–6 diaphragmatic breathing – breathe in for 4 seconds, out for 6 seconds, for 5–10 minutes a day. It activates the vagus nerve and lowers sympathetic tension
• Coherent breathing – 5 breaths a minute – shown to reduce sympathetic activation
• Jacobson’s progressive relaxation – alternately tensing and relaxing muscle groups
• Mindfulness – observing the twitching without reacting, without trying to control it

Physical activity

Regular, moderate activity (walking, swimming, yoga, cycling) is one of the strongest non-pharmacological interventions for lowering anxiety and tension.

Cutting down on body checking

For patients with health anxiety, the key is to refrain from compulsively touching, pressing and “testing” the muscles. Each check brings relief in the short term, but in the long term it entrenches the anxiety and the twitching itself by increasing hypervigilance.

Psychotherapy for somatic anxiety

If the twitching persists for weeks, is accompanied by intense health anxiety and does not go away after lifestyle changes – it is worth considering psychotherapy. The best-documented approach in treating anxiety disorders with somatic symptoms is cognitive behavioural therapy (CBT).

The meta-analysis by Hofmann and colleagues published in Cognitive Therapy and Research covered 269 clinical studies. It showed that cognitive behavioural therapy has a strong, documented effect in treating anxiety disorders and medically unexplained somatic symptoms, with a significant reduction in both anxiety symptoms and the somatic discomfort itself (Hofmann et al., 2012). It is the first-choice method for patients with BFS co-occurring with health anxiety, generalised anxiety, panic attacks and somatisation disorder.

What happens in therapy:

• Psychoeducation – a detailed explanation of the mechanism of fasciculations, BFS and hyperarousal. Simply knowing that the symptom is harmless significantly reduces anxiety
• Cognitive restructuring – identifying and working through catastrophic thoughts (“I have ALS”)
• Interoceptive exposure – deliberately inducing bodily sensations in safe conditions. It shows the brain that somatic sensations are not threatening
• Work on safety behaviours – gradually reducing compulsive body checking and googling symptoms
• Relaxation and autonomic nervous system regulation – breathing training, mindfulness, progressive relaxation

A standard CBT protocol includes 12–20 sessions, usually weekly. In many patients, noticeable improvement appears after just 4–8 sessions – the twitching becomes less frequent and shorter, and, more importantly, stops being a source of paralysing anxiety.

If you do not know whether your twitching needs neurological diagnostics first and foremost, or rather work on anxiety – it is worth starting with a psychological consultation. A psychologist will help assess whether the symptom fits the picture of an anxiety disorder, and will recommend further steps, including a referral to a neurologist if indicated. Psychotherapy in the cognitive behavioural approach is effective in treating established anxiety disorders with somatic symptoms.

FAQ – frequently asked questions

Is eyelid twitching a sign of illness?

In the vast majority of cases, no. Eyelid twitching (myokymia) is one of the most common benign neurological phenomena – it most often results from sleep deprivation, excess caffeine, stress or magnesium deficiency. It usually resolves on its own within a few days to two weeks. See a doctor if the twitching lasts longer than 3 weeks, affects the whole half of the face, or is accompanied by a drooping eyelid or vision problems.

How long can fasciculations last?

In people with benign fasciculation syndrome (BFS), they can persist for months or even years, “wandering” across different muscle groups. This does not mean the disease is progressing – long-term studies have shown that BFS does not progress to motor neurone disease.

Are fasciculations the beginning of ALS?

Practically never – as long as no other symptoms accompany them. In ALS, fasciculations appear together with progressive loss of muscle strength and visible muscle wasting. Isolated fasciculations, without weakening, with a normal neurological examination – are in the overwhelming majority of cases benign fasciculation syndrome or a somatic symptom of anxiety. Fear of ALS is in itself a common clinical pattern and calls for psychotherapeutic work, not more tests.

Does magnesium really help with muscle twitching?

Yes, if there is a genuine deficiency – which affects a considerable part of the population, especially people under chronic stress. Supplementation (citrate, malate or glycinate, 200–400 mg of ions a day, in the evening) often reduces fasciculations within 2–4 weeks. If there is no improvement after 6–8 weeks – it is worth extending the diagnostics.

Can twitching be caused by psychiatric medicines?

Yes, some medicines – SSRIs (sertraline, escitalopram), SNRIs, lithium, antiepileptic medicines – can cause twitching, especially in the first weeks of treatment. Usually the symptom gradually subsides. If the twitching is troublesome or persists longer, discuss it with your doctor – never stop psychiatric medicines on your own.

Is muscle twitching in pregnancy dangerous?

Most often it results from an increased need for magnesium, calcium and vitamin D, as well as from fatigue and hormonal changes. It is usually harmless and goes away after childbirth. Any new twitching in pregnancy is worth discussing with your doctor – to rule out eclampsia and deficiencies that require supplementation.

Muscle twitching does not always mean illness – but it is always worth checking

Most cases of muscle twitching have benign causes – magnesium deficiency, excess caffeine, stress, sleep deprivation, benign fasciculation syndrome. Some cases, however, require neurological assessment. The rule is simple: twitching combined with loss of strength, muscle atrophy, paresis, or disturbances of gait, speech or sensation – see a neurologist. Twitching that is bilateral, “wandering”, situational, worsening under stress, without other neurological symptoms – after organic causes have been ruled out – see a psychologist.

If muscle twitching has persisted for a long time, is accompanied by intense health anxiety, and neurological tests have shown no pathology – it may be a somatic symptom of anxiety or of benign fasciculation syndrome reinforced by chronic tension. At the Centrum Psychologiczne Sztuka Harmonii in Gdańsk and Gdynia, we work with people experiencing somatic symptoms of anxiety. We use cognitive behavioural therapy, which has proven effectiveness in treating anxiety disorders with somatic symptoms.

Call and book an appointment: 732 059 980