Muscle twitching

Category: Brain & Nerves · All brain & nerves symptoms

What it can feel like

Muscle twitching (fasciculations) is the visible flickering of small muscle bundles under the skin — most people know it as an eyelid twitch that comes with tiredness and caffeine. Widespread benign twitching is common and usually harmless; twitching earns neurological attention when it arrives with weakness and wasting.

Possible causes

A symptom can have many causes, and most are not serious. The lists below group conditions this symptom can be associated with — common causes first. They are possibilities to discuss with a clinician, not a diagnosis.

Common causes

Twitching can be associated with fatigue, stress, caffeine, exercise, and an entirely benign pattern (benign fasciculation syndrome) in which twitching occurs without weakness, often in calves and eyelids, in otherwise healthy people.

Other possible causes

Twitching can also be associated with nerve root irritation, peripheral nerve damage, electrolyte disturbance, and motor neurone disease — where the key company it keeps is progressive painless weakness and muscle wasting, without numbness.

Red flags — when to seek help promptly

Twitching with progressive weakness or shrinking muscles
Twitching with slurred speech, swallowing difficulty or tongue twitching
Twitching after starting a new medicine, with severe muscle pain or dark urine
Twitching in one limb with numbness in a root pattern and neck or back pain

What a clinician may do

A clinician will examine for wasting, weakness and reflex changes — their absence is reassuring — and review medicines and caffeine. Blood tests cover salts and thyroid; electrical studies of nerves and muscles (EMG) are used when weakness or wasting is present or suspicion persists.

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Frequently asked questions

Is twitching a sign of motor neurone disease?

By itself, usually not — MND twitching comes with weakness and wasting, because the twitching reflects dying motor nerves whose muscles are failing. Twitching with normal strength, normal muscle bulk and normal reflexes is overwhelmingly benign, and time (no progression) confirms it.

Why do eyelids twitch?

Eyelid twitching (myokymia) is a benign, local overactivity of the eyelid muscle fibres, driven by fatigue, stress, caffeine and dry eyes. It settles over days to weeks. Twitching affecting one whole side of the face, or persisting for months, takes a different pathway.

Related symptoms — Brain & Nerves

Burning feet Clumsiness and dropping things Confusion Dizziness Fainting Memory problems

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Please note: This page is educational information about a symptom. A symptom alone cannot diagnose any condition, and the causes listed here are possibilities, not a diagnosis. If you are worried about a symptom — especially one that is new, severe, getting worse or not going away — please see your own clinician, who can examine you and arrange tests. In an emergency, call your local emergency number.