Is This a Fasciculation?

Patient Presentation
A 17-year-old male came to clinic with a two week history of eye twitching. It occurred fairly often throughout the day and would last only for a very brief time. He said it only occurred in his right upper eyelid and did not progress to other areas. He denied actual eye blinking or any other muscle twitching. He also denied any other neurological symptoms such as visual or auditory changes, headache, muscle aches, or changes in mental status or mood. He also denied any drugs or chemical exposures. “It’s the end of the school year and I have a lot of tests. So I’ve been noticing it more I think because I am studying so much,” he stated.
The past medical and family history were non-contributory.

The pertinent physical exam showed a healthy male with normal vital signs and what appeared to be normal mood. His vision screening was 20/25 for both eyes. He did have a brief right eye twitch during the examination that lasted 2-3 seconds at the most. His complete eye and neurological examinations were normal.

The diagnosis of benign muscle fasciculations was made. “Are you drinking a lot of caffeine?” asked the pediatrician. “Yes, with all the studying I’m drinking a lot of Mountain Dew® and Red Bull®,” he answered. “I think that your eye twitching will get better if you cut back on the caffeine and also get some good sleep. These usually are worse when people are stressed and not sleeping well,” he said. I’ll go over the things you should come back for, but I think this will get better once your exams are done and you are sleeping better,” he continued. At the teenager’s well child examination later that summer, the eye twitching had ceased.

Benign fasciculations are very common and occur in up to 70% of the general population. They occur at different points in people’s lives. They can be brought out by stress, poor sleep hygiene and caffeine.

Caffeine has numerous uses especially for regulating sleep and attention. However too much can cause restlessness, jitteriness and sleep deprivation too. The recommended amount of caffeine for a teenager is < 2.5 mg/kg or 100-175 mg/day. A Red Bull® beverage has 80 mg of caffeine /12 ounces, while Mountain Dew® has 55 mg caffeine/12 ounces. A review of caffeine can be found here.

Adolescents, if left alone without external influences, will sleep slightly more than 9 hours. However, often they will not achieve 9 hours for many external causes. There are many health problems associated with inadequate sleep and they can be reviewed here.

A new onset of simple partial seizures could also be a consideration for the patient above. Simple partial seizures can occur with or without consciousness being impaired. Those without consciousness impairment are classified according to other symptoms such as motor, sensory, autonomic or psychic symptoms or signs.

Simple tics are also common and can get worse in times of stress too. A review can be found here.

Learning Point
Benign fasciculations occur in a single muscle group and are not multifocal or continuous. They are felt to not progress to other neurological problems, but in very rare cases have been reported to precede motor neuron disease. Amyotrophic lateral sclerosis, a progressive motor neuron degenerative disease, is associated with fasciculations and muscle weakness. Because of this association, there can be anxiety associated with benign fasciculations especially in men working in health care.

Questions for Further Discussion
1. How are seizures classified? A review can be found here
2. What causes muscle cramps? A review can be found here
3. What causes nystagmus?
4. What is a tremor?

Related Cases

To Learn More
To view pediatric review articles on this topic from the past year check PubMed.

Evidence-based medicine information on this topic can be found at and the Cochrane Database of Systematic Reviews.

Information prescriptions for patients can be found at MedlinePlus for these topics: Neuromuscular Disorders and Muscle Disorders.

To view current news articles on this topic check Google News.

To view images related to this topic check Google Images.

To view videos related to this topic check YouTube Videos.

Filippakis A, Jara J, Ventura N, et al. A prospective study of benign fasciculation syndrome and anxiety. Muscle Nerve. 2018;58(6):852-854. doi:10.1002/mus.26193

de Carvalho M, Turkman A, Swash M. Sensory modulation of fasciculation discharge frequency. Muscle Nerve. 2019;59(6):688-693. doi:10.1002/mus.26456

How Much Caffeine in Drinks — Coffee, Tea, Soft Drinks — Caffeine Content. Accessed June 25, 2019.

Donna M. D’Alessandro, MD
Professor of Pediatrics, University of Iowa