A 'fasciculation' (or "muscle
twitch") is a small, local, involuntary
muscle contraction (twitching) visible under the skin arising from the spontaneous discharge of a bundle of
skeletal muscle fibers. Fasciculations have a variety of causes, the majority of which are
benign, but can also be due to disease of the motor neurons.
Causes and risk factors
Conditions
★ The origin of most cases is at present unknown and has therefore been given the title
benign fasciculation syndrome[1].
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Werdnig-Hoffman disease
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Amyotrophic lateral sclerosis (rare)
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Organophosphate poisoning
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Benzodiazepine withdrawal
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Magnesium deficiency (which can be caused by stress)
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Dehydration
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Fatigue
Medications
Other risk factors may include the use of
anticholinergic drugs over long periods, in particular
ethanolamines such as
Benadryl, used as an antihistamine and sleep aid, and
Dramamine for nausea and motion sickness. Persons with
Benign fasciculation syndrome (BFS) may experience
paraesthesia shortly after taking such medication; hours later as it wears off (especially upon awaking), fasciculation episodes begin.
Stimulants can cause fasciculations directly. These include
caffeine,
pseudoephedrine (Sudafed®), and the
asthma bronchodilators
albuterol/salbutamol (e.g. Proventil®, Combivent®, Ventolin®). Medications used to treat
attention deficit disorder often contain stimulants as well, and are common causes of benign fasciculations.
Treatment
Inadequate
magnesium intake can cause fasciculations, especially after a magnesium loss due to severe
diarrhea. Over-exertion is another risk factor for magnesium loss. As much as 80% of the population does not get the recommended daily amount of magnesium; this may be a common cause. Treatment is with supplements or increased intake of foods rich in magnesium, especially almonds & other nuts, and bananas. Ironically, magnesium supplements may result in diarrhea and more magnesium loss, so
dosage and timing (i.e. with meals) are important.
Fasciculation also often occurs during a rest period after sustained stress, such as that brought on by unconsciously tense muscles. Reducing stress and anxiety is therefore another useful treatment.
References
1. Long-term follow-up of 121 patients with benign fasciculations, Blexrud MD, Windebank AJ, Daube JR, , , Ann. Neurol., 1993
External links
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