What is the Difference Between Myokymia and Fasciculations

The key difference between myokymia and fasciculations is that myokymia is rhythmic and slower contractions in muscles at the same place, while fasciculation is the non-rhythmic and faster contractions in muscles at the same place or in different places.

Muscle twitches are fine movements in the muscles that are caused by muscle contraction in the area. Muscle twitches are often considered minor medical conditions. They are also common and normal. However, some are signs of a nervous system disorder. Muscle twitches can be caused due to autoimmune disorders, drug overdose, lack of sleep, side effects of drugs, exercise, nutritional deficiency, stress, medical conditions that cause metabolic disorders such as low potassium, kidney disease, and uremia and nervous system conditions (amyotrophic lateral sclerosis, neuropathy, spinal muscular atrophy, and myopathy). Myokymia and fasciculations are two different types of muscle twitches.

CONTENTS

1. Overview and Key Difference
2. What is Myokymia  
3. What is Fasciculation
4. Similarities – Myokymia and Fasciculations
5. Myokymia vs Fasciculations in Tabular Form
6. Summary – Myokymia vs Fasciculations

What is Myokymia?

Myokymia is an involuntary spontaneous twitching of muscles or bundles within a muscle. It is commonly used to describe involuntary eyelid contraction. Myokymia in the eyelid typically involves the lower eyelid than the upper eyelid. It can also be observed in the face and limbs. Myokymia usually occurs in normal people. It starts and disappears spontaneously. Sometimes, it can last up to three weeks. Doctors do not consider myokymia as a serious condition. Therefore, it is not a cause for concern. The causes of myokymia may include drinking too much caffeine, high levels of anxiety, stress, fatigue, dehydration, overwork, lack of sleep, use of certain drugs or alcohol, magnesium deficiency, and multiple sclerosis.

Myokymia can be diagnosed through medical history, physical examination, complete blood count, CT scan, MRI, nerve conduction velocity (NCV) and EMG studies, and lumbar puncture with an examination of cerebrospinal fluid (CSF). Furthermore, treatment options for myokymia include a warm compress applied to the eyelid, face, or limbs, a small dose of antihistamine, increased bed rest, decreased exposure to computer screens, televisions, and harsh lighting, and decreased caffeine intake.

What is Fasciculation?

Fasciculation is defined as the visible, fast, fine, involuntary, spontaneous, and intermittent contraction of the muscle fibers. Fasciculation is very common, and 70% of people may experience it. Fasciculation can be benign or associated with more serious medical conditions. This condition can be mainly observed in areas such as limbs and the tongue. Fasciculation is caused by anxiety, caffeine or alcohol, thyroid disease, magnesium deficiency, long time usage of anticholinergic drugs.

Moreover, fasciculation can be diagnosed through physical examination, blood tests, surface electromyography (EMG), and electromyography (EMG) testing. Furthermore, treatment options for fasciculation may include medicines that decrease the excitability of nerves, such as carbamazepine, gabapentin, Ianotrigine, and pregabalin, medicines used to treat depression and anxiety, such as selective serotonin reuptake inhibitors, treating for underlying conditions like amyotrophic lateral sclerosis (ALS), counselling, stretching exercise, massage, and immunosuppressive therapy with prednisone to reduce cramps.

What are the Similarities Between Myokymia and Fasciculation?

• Myokymia and fasciculations are two different types of muscle twitches.
• Both conditions may be normal or benign.
• They can be observed in similar areas of the body, such as limbs.
• Both conditions can be caused due to excessive intake of caffeine or alcohol and stress.
• Both conditions can be diagnosed through physical examination, blood test, and nerve conduction test.
• They are treated through taking rest, and medicines reduce stress or anxiety.

What is the Difference Between Myokymia and Fasciculations?

Myokymia is rhythmic and slower contractions in muscles at the same place, while fasciculation is non-rhythmic and faster contractions in muscles at the same place or in different places. Thus, this is the key difference between myokymia and fasciculations. Furthermore, myokymia mainly occurs in areas of the body such as the eyelid, face, and limbs. On the other hand, fasciculation mainly occurs in areas of the body such as limbs and the tongue. Thus, this is also a difference between myokymia and fasciculations.

The below infographic presents the differences between myokymia and fasciculations in tabular form for side-by-side comparison.

Summary – Myokymia vs Fasciculations

Myokymia and fasciculations are two different types of muscle twitching conditions. Both these conditions can be observed in normal people. Myokymia is rhythmic and slower contractions in muscles at the same place. In contrast, fasciculation is the non-rhythmic and faster contractions in muscles at the same place or different places. So, this summarizes the difference between myokymia and fasciculations.

Reference:

1. Suying L Song, MD. “Myokymia Clinical Presentation.” History, Physical, Causes, Medscape.
2. “Fasciculation.” An Overview | ScienceDirect Topics.

Image Courtesy:

1. “Day 077” By Ernesto Andrade (CC BY-ND 2.0) via Flickr
2. “Interscutularis connectome Nerve Fasciculation Pattern and Its Relationship to Axonal Branching” By Lu J, Tapia JC, White OL, Lichtman JW – The Interscutularis Muscle Connectome (CC BY 2.5) via Commons Wikimedia