Muscle twitches and cramps

This fact sheet provides information on muscle twitches and cramps, when you should seek advice and what treatment is available.

Please note this fact sheet is only designed as a brief summary of management.

Muscle twitching and cramps are common normal symptoms, occasionally they may indicate an underlying neurological condition but are nearly always benign. In one study over 50% of the population had muscle fasciculation and 37% of had muscle cramps in a single year.

Blepharospasm

This is bilateral repeated eye closure (blinking) due to overactivity of the orbicularis oculi muscle. Benign, and can cause effective blindness in more severe cases.

Hemifacial spasm

Unilateral eye blinking with upwards twitching of the corner of the mouth.

Muscle cramps

The sudden involuntary painful contraction of an isolated muscle cramp is usually benign and commonly worsened by exercise, dehydration, or pregnancy, and especially sleep in the elderly (sleeping with feet plantarflexed). Occasionally, when profound and/or associated with other symptoms such as weakness, they may indicate underlying neuromuscular disease. Metabolic disorders may also cause cramp.

Muscle fasciculation

Usually seen or felt, most commonly in the calves and after exercise, but may be more widespread. They can be associated with cramps and, in the absence of weakness, are usually “benign cramp/fasciculation syndrome”. Nearly always benign. Health-related anxiety (Motor Neurone Disease (MND) specifically) can amplify them.

Myokymia

Painless repetitive muscle fibre twitching, commonly seen around the eye or first dorsal interosseous muscle. Nearly always benign.

Myotonia

Described by patients as muscle stiffness or discomfort rather than visible twitching with an inability to relax a muscle. It’s rare and suggests underlying neuromuscular disease (e.g. myotonic dystrophy or neuromyotonia).

• Is there any weakness? – if so, this would suggest referral appropriate.
• Is there a family history (common in benign cramp-fasciculation syndrome)?
• Are they on medications that might cause the symptoms of electrolyte imbalance (e.g. diuretics, methylphenidate etc)?
• Is it nocturnal only – if so, any symptoms to suggest restless legs syndrome?
• What are they concerned about? Most people will be reassured with careful explanation that isolated fasciculation is common, but occasionally this can evolve into health-related anxiety which in turn can amplify fasciculation. Health anxiety, especially common in health professionals, requires explicit explanation and avoidance of repeated reassurance.

• Biochemical screen including Urea and Electrolytes (U&Es), calcium and Thyroid Function Tests (TFTs).
• Creatine kinase (trivial increase about reference range rarely relevant).

Cramps

Treatment: Calf muscle stretches before bed. Reduce diuretics / caffeine. Vitamin B complex, diltiazem, quinine (recommended short course).

When to seek advice from neurology: Unusually profound / debilitating and / or associated symptoms, notably weakness.

Myokymia

Treatment: Explanation and reassurance

When to seek advice from neurology: Any neurological symptoms other than myokymia

Fasciculation

Treatment: Explanation and reassurance. If severe then treatment of health anxiety

When to seek advice from neurology: Any wasting / weakness, or very florid or widespread, or with severe cramp

Blepharospasm/hemifacial spasm

Treatment: Conservative or botulinum toxin

When to seek advice from neurology: If causing problems

1. Dijkstra JN, Boon E, Kruijt N, et al. Pract Neurol 2023;23:23–34. DOI: 10.1136/pn-2022-003574
2. Erogu M. The perils of being your own doctor. Guardian 4 Aug 2016 (article about benign fasciculation). Full text Accessed 28/01/2025