Benign fasciculation syndrome
   HOME

TheInfoList



OR:

Benign fasciculation syndrome (BFS) is characterized by
fasciculation A fasciculation, or muscle twitch, is a spontaneous, involuntary muscle contraction and relaxation, involving fine muscle fibers. They are common, with as many as 70% of people experiencing them. They can be benign, or associated with more serio ...
(twitching) of
voluntary muscle Skeletal muscles (commonly referred to as muscles) are organs of the vertebrate muscular system and typically are attached by tendons to bones of a skeleton. The muscle cells of skeletal muscles are much longer than in the other types of muscle ...
s in the body. The twitching can occur in any voluntary muscle group but is most common in the
eyelid An eyelid is a thin fold of skin that covers and protects an eye. The levator palpebrae superioris muscle retracts the eyelid, exposing the cornea to the outside, giving vision. This can be either voluntarily or involuntarily. The human eyel ...
s, arms, hands, fingers, legs, and feet. The tongue can also be affected. The twitching may be occasional to continuous. BFS must be distinguished from other conditions that include muscle twitches.


Signs and symptoms

The main symptom of benign fasciculation syndrome is focal or widespread involuntary muscle activity (
fasciculation A fasciculation, or muscle twitch, is a spontaneous, involuntary muscle contraction and relaxation, involving fine muscle fibers. They are common, with as many as 70% of people experiencing them. They can be benign, or associated with more serio ...
). The benign twitches usually have a constant location. Other common symptoms are generalized
fatigue Fatigue describes a state of tiredness that does not resolve with rest or sleep. In general usage, fatigue is synonymous with extreme tiredness or exhaustion that normally follows prolonged physical or mental activity. When it does not resolve ...
or weakness,
paraesthesia Paresthesia is an abnormal sensation of the skin (tingling, pricking, chilling, burning, numbness) with no apparent physical cause. Paresthesia may be transient or chronic, and may have any of dozens of possible underlying causes. Paresthesias ar ...
or numbness, and
muscle cramp A cramp is a sudden, involuntary, painful skeletal muscle contraction or overshortening associated with electrical activity; while generally temporary and non-damaging, they can cause significant pain and a paralysis-like immobility of the aff ...
ing or spasms.
Anxiety Anxiety is an emotion which is characterized by an unpleasant state of inner turmoil and includes feelings of dread over anticipated events. Anxiety is different than fear in that the former is defined as the anticipation of a future threat wh ...
and
somatic symptom disorder A somatic symptom disorder, formerly known as a somatoform disorder,(2013) dsm5.org. Retrieved April 8, 2014. is any mental disorder that manifests as physical symptoms that suggest illness or injury, but cannot be explained fully by a general ...
s and symptoms are commonly reported.
Muscle stiffness Delayed onset muscle soreness (DOMS) is the pain and stiffness felt in muscles after unaccustomed or strenuous exercise. The soreness is felt most strongly 24 to 72 hours after the exercise. It is thought to be caused by eccentric (lengthening) e ...
may also be present; if muscle weakness is not also present, and cramps are more severe, the stiffness may be categorized instead as
cramp fasciculation syndrome Cramp fasciculation syndrome (CFS) is a rare peripheral nerve hyperexcitability disorder. It is more severe than the related (and common) disorder known as benign fasciculation syndrome; it causes fasciculations, cramps, pain, fatigue, and muscle s ...
. Cramp fasciculation is a variant of BFS which presents with muscle pain and
exercise intolerance Exercise intolerance is a condition of inability or decreased ability to perform physical exercise at the normally expected level or duration for people of that age, size, sex, and muscle mass. It also includes experiences of unusually severe post ...
. BFS symptoms are typically not accompanied by severe muscle weakness, and are typically present when the muscle is at rest. Individuals with BFS may have perceived weakness which is the sensation of a fatigued limb, but is not true clinical weakness. Fasciculations can move from one part of the body to another.


Causes

The precise cause of BFS is unknown. It is not known if it is a disease of the
motor nerve A motor nerve is a nerve that transmits motor signals from the central nervous system (CNS) to the muscles of the body. This is different from the motor neuron, which includes a cell body and branching of dendrites, while the nerve is made up of ...
s, the muscles, or the
neuromuscular junction A neuromuscular junction (or myoneural junction) is a chemical synapse between a motor neuron and a muscle fiber. It allows the motor neuron to transmit a signal to the muscle fiber, causing muscle contraction. Muscles require innervation to ...
. Health anxiety disorder may be a cause among individuals who become concerned they have a
motor neuron disease Amyotrophic lateral sclerosis (ALS), also known as motor neuron disease (MND) or Lou Gehrig's disease, is a neurodegenerative disease that results in the progressive loss of motor neurons that control voluntary muscles. ALS is the most comm ...
; this persistent concern is a psychiatric condition mostly noted among healthcare professionals and doctors. An association with anxiety level is established; BFS is reportedly found among "anxious medical students" and clinicians under the age of 40, and this phenomenon known as "fasciculation anxiety syndrome" is reinforced by access to information on the internet. Fasciculations can be caused or worsened by intense and long periods of daily exercise. BFS can also be caused by long-term use of
anticholinergics Anticholinergics (anticholinergic agents) are substances that block the action of the neurotransmitter called acetylcholine (ACh) at synapses in the central and peripheral nervous system. These agents inhibit the parasympathetic nervous system ...
, and fasciculations may be caused by other drug use or exposure to steroids, nicotine, caffeine, alcohol, insecticides and pesticides. Thyroid disease may also cause similar symptoms. Fasciculations can also be caused by deficiencies of magnesium and/or calcium.


Diagnosis

Benign fasciculation syndrome is a
diagnosis of exclusion A diagnosis of exclusion or by exclusion (''per exclusionem'') is a diagnosis of a medical condition reached by a process of elimination, which may be necessary if presence cannot be established with complete confidence from history, examination or ...
; that is, other potential causes for the twitching must be ruled out before BFS can be diagnosed. Diagnosis includes blood tests, a neurological exam, and
electromyography Electromyography (EMG) is a technique for evaluating and recording the electrical activity produced by skeletal muscles. EMG is performed using an instrument called an electromyograph to produce a record called an electromyogram. An electromyog ...
(EMG). Another step in diagnosing BFS is checking for clinical weakness or wasting, which are found in more serious conditions. Lack of clinical weakness along with normal EMG results (in those with only fasciculations) largely eliminates more serious disorders from potential diagnosis. In younger people with only
lower motor neuron Lower motor neurons (LMNs) are motor neurons located in either the anterior grey column, anterior nerve roots (spinal lower motor neurons) or the cranial nerve nuclei of the brainstem and cranial nerves with motor function (cranial nerve lower mo ...
(LMN) fasciculations, no muscle weakness, and no thyroid abnormalities, Turner and Talbot (2013) state that "individuals under 40 years can be reassured without resorting to electromyography (EMG) to avoid the small but highly damaging possibility of false-positives". According to Kincaid (1997), the diagnosis is made when there is no clinical finding of neurogenic disease; he first reassures patients that no "ominous disease seems to be present", and says, "I suggest that patients like this be followed for a year or longer with clinical and electromyographic exams at about 6-month intervals before one becomes secure in the diagnosis that the fasciculations are truly benign." Other publications recommend followups for four or five years before ruling the condition benign, although the percentage of individuals who progress to a more serious condition is very low.


Classification

Benign fasciculation syndrome and the variant cramp fasciculation syndrome "can be regarded as part of a larger spectrum of disease that also incorporates acquired auto-immune neuromyotonia.


Differential

Other serious diseases that must be distinguished include
motor neuron disease Amyotrophic lateral sclerosis (ALS), also known as motor neuron disease (MND) or Lou Gehrig's disease, is a neurodegenerative disease that results in the progressive loss of motor neurons that control voluntary muscles. ALS is the most comm ...
s (MND) such as
amyotrophic lateral sclerosis Amyotrophic lateral sclerosis (ALS), also known as motor neuron disease (MND) or Lou Gehrig's disease, is a neurodegenerative disease that results in the progressive loss of motor neurons that control voluntary muscles. ALS is the most comm ...
(ALS),
neuropathy Peripheral neuropathy, often shortened to neuropathy, is a general term describing disease affecting the peripheral nerves, meaning nerves beyond the brain and spinal cord. Damage to peripheral nerves may impair sensation, movement, gland, or o ...
, and
spinal cord disease Myelopathy describes any neurologic deficit related to the spinal cord. The most common form of myelopathy in humans, '' cervical spondylotic myelopathy (CSM)'', also called ''degenerative cervical myelopathy'', results from narrowing of the spina ...
s. According to Turner and Talbot (2013), "the fasciculations of MND are often abrupt and widespread at onset in an individual previously unaffected by fasciculations in youth. The site of the fasciculations, for example, those in the calves versus abdomen, has not been shown to be discriminatory for a benign disorder. There is conflicting evidence as to whether the character of fasciculations differs neurophysiologically in MND." It is "exceptionally rare for patients later diagnosed with ALS to present with fasciculations alone", and ALS is ruled out with a normal EMG and no evidence of muscle wasting.


Treatment

There is support for treating any accompanying anxiety using
cognitive behavioral therapy Cognitive behavioral therapy (CBT) is a psycho-social intervention that aims to reduce symptoms of various mental health conditions, primarily depression and anxiety disorders. CBT focuses on challenging and changing cognitive distortions (suc ...
or antidepressants.
Quinine Quinine is a medication used to treat malaria and babesiosis. This includes the treatment of malaria due to ''Plasmodium falciparum'' that is resistant to chloroquine when artesunate is not available. While sometimes used for nocturnal leg cr ...
is effective, but not recommended because of the potential for serious side effects.
Calcium channel blocker Calcium channel blockers (CCB), calcium channel antagonists or calcium antagonists are a group of medications that disrupt the movement of calcium () through calcium channels. Calcium channel blockers are used as antihypertensive drugs, i.e., as ...
s may be effective, although the evidence for their use is weak. There is little evidence supporting other therapies. In cases caused by magnesium or calcium deficiencies, curing the deficiency through diet or supplementation is effective.


Prognosis

The prognosis for those with BFS is good to excellent. The syndrome causes no known long-term physical damage. Some individuals remain anxious even after being diagnosed with the benign condition and are often directed towards professionals who can assist with understanding stress and anxiety, or those who can prescribe medication to help manage anxiety. Spontaneous remission has been known to occur, and in cases where anxiety is thought to be a major contributor, symptoms are typically lessened after the underlying anxiety is treated.


Research

There may be an association between widespread fasciculations or
paresthesia Paresthesia is an abnormal sensation of the skin (tingling, pricking, chilling, burning, numbness) with no apparent physical cause. Paresthesia may be transient or chronic, and may have any of dozens of possible underlying causes. Paresthesias ar ...
s with small fiber neuropathy.


References

{{DEFAULTSORT:Benign Fasciculation Syndrome Neurological disorders Ailments of unknown cause Syndromes affecting muscles Syndromes affecting the nervous system