Benign and cramping fasciculations syndrome: causes, symptoms, treatment

By Cristiano Antonino On Aug 9, 2022

The benign fasciculations syndrome (often abbreviated to ‘SFB’, in English ‘benign fasciculation syndrome’) and the variant of cramps-fasciculations syndrome (‘SCF’, in English ‘cramps-fasciculations syndrome’), are chronic syndromes caused by factors that are not yet fully clarified, characterised mainly by fasciculations, i.e. slight, spontaneous, rapid and regularly intermittent contractions of one or more motor units, without motor outcome, visible and perceived by the subject as sudden twitching or trembling of a part of any muscle (often those of the upper or lower limbs or those of the upper eyelid of the eye), sometimes associated with cramps, spasms, in general peripheral neuromuscular hyperexcitability with myoclonias, i.e. spontaneous movements of the muscles, sometimes with slight pain, stiffness and asthenia

Unless other independent problems occur, benign fasciculations syndrome generally does not worsen with time, except in some cases where it may become cramps and fasciculations syndrome, also benign but with more severe symptoms than benign fasciculations syndrome.

Benign fasciculations syndrome and the variant of cramps and fasciculations syndrome belong to the group of ‘peripheral nerve hyperexcitability’ disorders.

Benign fasciculations syndrome is often associated with chronic fatigue syndrome

According to some theories, at least 25% of the world’s population has experienced episodes of fasciculation at least once in their lifetime.

Benign fasciculations syndrome affects about 3% of the population.

The exact cause of benign fasciculations syndrome is currently unknown.

Perhaps its aetiology involves the motor neuron, muscles, areas of the brain or the neuromuscular junction, or all of these structures simultaneously.

Hereditary cases have been identified.

Possible diseases or conditions that could cause or favour benign fasciculations syndrome are:

anxiety;
hypokalaemia (magnesium deficiency) due to exertional sweating, anxiety, heat or other causes;
magnesium and calcium malabsorption (spasmophilia);
physiological calcium and potassium deficiency;
hypoglycaemia;
familiarity;
other syndromes belonging to the group of ‘peripheral nerve hyperexcitability’;
coeliac disease (hypersensitivity to gluten);
post-infection syndrome;
autoimmune diseases;
Guillain-Barré syndrome;
neuropathies;
myelopathies;
hypothyroidism;
hyperthyroidism;
incorrect diet;
malnutrition by default;
vitamin-poor diet;
fibromyalgia;
systemic lupus erythematosus;
sarcoidosis;
HIV infection;
Lyme disease;
excessive intake of stimulants such as caffeine, coke, cigarette smoke or drugs;
high sugar intake;
contractures due to cold and draughts;
excessive intake of phosphoric acid from soft drinks,
chronic anxiety;
psycho-physical stress;
panic attacks;
post-traumatic stress disorder;
food intolerances;
neurogenic inflammation;
insomnia;
irritable bowel syndrome;
hypersomnia;
interstitial cystitis;
multiple chemical sensitivity syndrome (a syndrome whose existence has not yet been fully ascertained);
restless legs syndrome;
depression;
manic-depressive bipolar disorder;
allergies;
electrosensitivity (not ascertained by the scientific community);
vitiligo;
psoriasis;
side effects of medication;
chronic hyperventilation syndrome;
obsessive-compulsive disorder;
infections caused by influenza viruses, Epstein-Barr virus and Streptococcus pyogenes.

In 40% of patients, benign fasciculations syndrome is idiopathic, i.e. no cause or risk factor for the syndrome can be identified.

The symptoms and signs of benign fasciculations syndrome are:

muscle fasciculations;
myokymia;
anxiety;
itching;
discomfort when swallowing food or liquids.

In addition to these symptoms and signs, cramps and fasciculations syndrome also includes

paresthesias;
cramps and spasms;
hypereflexia (excessive muscle reflexes);
tremor;
asthenia;
mild hyposthenia;
muscle rigidity.

Some symptoms are also very similar to the more severe chronic fatigue syndrome or CFS (whose main symptom is asthenia) and fibromyalgia (diffuse pain as a prominent sign), and others characterised by idiopathic peripheral nerve hyperexcitability (e.g. spasmophilia) (or PNH), but with fasciculations as a fundamental symptom.

Many fibromyalgia patients have SFB and about 70 % of them also manifest CFS symptoms.

Some patients have a moderate and slight increase in creatine phosphokinase (CPK) in the blood, without reaching pathological levels.

Since the syndrome presents some mild neurological symptoms, this often increases the sufferer’s anxiety (resulting in temporarily worsening symptoms), sometimes to the point of hypochondria and the thought of having contracted a motor neuron disease, which in this case are ruled out as the origin (all the various causes of fasciculations, such as trauma, neuropathies, myasthenia gravis, deficiencies, etc., are included in the differential diagnosis), by means of a neurological examination and possibly electromyography (EMG).

This hypochondria can also become a serious psychiatric problem (this does not mean, however, that the fasciculations are not real), given the superficial similarity of the symptoms of SFB with those of the early phase of amyotrophic lateral sclerosis (ALS), the main motor neuron disease.

Fasciculations may pass in some cases, in others they remain, but do not degenerate; the cramps and fasciculations syndrome only has fasciculations in common with ALS (the initial fatigue is less obvious, there is no progressive denervation atrophy above all, and the drops in strength are transient, if they occur at all); nor does it have anything in common with multiple sclerosis; they are totally different diseases, involving different structures of neurons: those who have BFS have no alteration of myelin and motor neurons, and no drastic weight loss of the muscles, which is evident in electromyography, if performed.

The only correlation between the two diseases is the apparently similar symptoms, although that in ALS the drop in strength is much more evident, months before the fasciculations.

Diagnosis

Diagnosis is based on anamnesis, physical examination and neurological, orthopaedic and other examinations such as electromyography or magnetic resonance imaging, if necessary.

Often the diagnosis of benign cramps and fasciculations syndrome is reached by exclusion of other pathologies that cause the same symptoms (see next section).

Generally speaking, tests that may be useful in diagnosing the cause of fasciculations are:

blood tests;
laboratory tests;
magnetic resonance imaging;
computed tomography (CT) scan;
radiography;
myelography;
electrocardiogram;
ultrasound with colordoppler
biopsies;
postural analysis;
vestibular examination;
electromyography;
electroencephalogram;
lumbar puncture.

IMPORTANT: Not all of the listed examinations are always necessary, usually history, physical examination, imaging and sometimes electromyography are sufficient to reach a diagnosis.

The diagnosis (and treatment) of a condition that causes frequent fasciculations may require the intervention of various professional figures, including a neurologist, neurosurgeon, orthopaedist, otolaryngologist, posturologist, vascular surgeon; radiologist, haematologist, cardiologist, physiotherapist and others.

Differential diagnosis

Some symptoms and signs present in benign fasciculations syndrome and cramps and fasciculations syndrome are also present in other pathologies, which must be excluded by the physician, including:

myelopathies;
Lyme disease with neuroborreliosis;
multiple sclerosis;
congenital sodium paramyotonia;
acquired neuromyotonia or Isaacs syndrome;
motor neuron diseases (such as amyotrophic lateral sclerosis);
fibromyalgia;
chronic fatigue syndrome;
drug addiction;
alcoholism;
side effects of drugs;
hypothyroidism;
hyperthyroidism;
allergies;
particular mineral deficiencies; celiac disease and avitaminosis;
severe hyperventilation.

When to go to the doctor?

Generally speaking, a single episode of fasciculation occurring during a stressful period (e.g. in the office or at work) or after excessive exertion and not associated with other symptoms, although annoying, should not be a sign of particular seriousness and does not require a medical examination: benign fasciculations involve few muscle fibres and are not accompanied by muscular atrophy and asthenia, so they are easily ‘manageable’ by the patient and often diminish or disappear with psycho-physical rest.

If, on the other hand, the fasciculation occurs in more than one place on the body, often even at rest and is associated with other symptoms (e.g. lack of strength, pain, motor and/or sensory deficits), then it is important to seek medical advice because ‘malignant’ fasciculations could be an indication of even a serious illness.

Therapies

As it is often difficult to identify the presumed cause or risk factor behind the syndrome, there is no specific treatment that treats it upstream.

However, there are symptomatic therapies, used when (rarely) the fasciculations become so bothersome that they lead to a decline in the patient’s quality of life, for example by interfering with work, if the latter requires the ability to concentrate and make fine, precise movements.

In some more severe cases, the same drugs used in essential tremor (beta-blockers, anticonvulsants) may be used, or attempts may be made to treat the possible causes.

Sometimes, as proof of some connection with spasmophilia, supplementation with mineral salts on a massive scale may be helpful.

Prognosis

The prognosis, both of the milder form and of the cramps and fasciculations syndrome, is benign and generally, having reached a peak of symptoms and signs, the syndromes tend to remain stable over time, neither worsening nor, however, improving.

In some cases, syndromes may have periods of remission.

The condition itself, while annoying, is not harmful in the long term and often the patient learns to live with it and ‘ignore’ it when it occurs.

Sometimes in anxious individuals or those with other illnesses, the feeling of weakness and the worry that they may be suffering from a serious or neurodegenerative disease may increase.

In some rare cases there may be coexistence or degeneration into fibromyalgia or chronic fatigue syndrome, which are, however, pathologies that can be kept under control.

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