Patient Presentation
A 19-year-old male came to clinic with a 2 month history of tremor in both hands. He first noticed it when doing homework late at night, but now notices it more throughout the day. There are times when it is better (after sleeping) but also worse (when sleep deprived or stressful times). It generally does not bother him, but he has noticed that his homework is somewhat messier but still more than legible and functional to use in his college classes. He denies any new drugs (prescribed, illicit or complimentary/alternative), but did notice that the tremor gets worse with increased caffeine and is better after drinking a beer. He says otherwise he feels fine but this was making him nervous. The past medical history was non-contributory. The family history is positive for a paternal grandfather with hand tremors. The review of systems showed no fevers, chills, weight loss/gain, night sweats, changes in hair or nails, or rashes.

The pertinent physical exam showed a healthy male with normal vital signs. HEENT showed normal hair texture and no thyroid enlargement or nodules. His neurological examination showed a rest tremor in both hands that had moderate frequency and low amplitude. The tremor continued in different positions but did not increase in frequency or amplitude. If he put one hand on top of the other, this decreased the tremor. He said that he noticed that he just did this instinctively sometimes when he was working on handwritten homework at different times. The work-up included a normal complete blood count, electrolytes, calcium, magnesium, phosphorus, glucose and thyroid stimulating hormone and T4. A ceruloplasmin level was later negative. The diagnosis of a probable essential tremor was made. Because of the recent onset and that he was living out-of-state from his family who were also concerned, a neurology appointment was made. The neurologist confirmed the diagnosis of an essential tremor and he was offered functional recommendations. He was to re-contact the neurologist if his symptoms worsened and were interfering with his life and work.

Discussion
Tremor is one of several movement disorders in childhood including tics, dystonia, chorea, myoclonus, and sterotypy. Tremors are a rhythmic oscillating involuntary movement across a joint axis. They are the result of normal or accentuated postural or muscular processes. They are categorized as follows:

• Rest tremor – occurs during rest and stops with movement
• Action tremor- occurs during a voluntary activity
  • Kinetic tremor- occurs when limb is moving
  • Postural tremor – occurs when the limb is stationary but held against gravity
  • Isometric tremor – occurs when limb is stationary but is exerting a force against a stationary object

Causes of tremors including those that are benign (jitteriness, shuddering attacks, spasmus nutans), hereditary (fragile X premutation, essential), neurological (brain lesions, strokes, mitochondrial encephalopathy, peripheral neuropathy), endocrinopathies (hyperthyroid, hyperadrenergic states), metabolic (low calcium, glucose, or magnesium, B12 deficiency and inborn errors of metabolism), drugs (many including anti-epileptic, asthma, nicotine, alcohol, caffeine) and psychogenic.

Essential tremor (ET) is the most common movement disorder in adults. Up to 50% of adults report onset of their tremor in childhood and it appears to be the most common movement disorder in children. ET is a hereditary action tremor that is autosomal dominant with variable penetrance. Penetrance appears to increase with increasing age. Young children may not report it as it does not functionally cause problems, but adolescents may report tremor more as it affects their school, social and personal habits than younger children. Most children present with a high frequency tremor of the upper limbs that is postural or kinetic and only rarely causing disability. Usually difficulties are with eating and handwriting. Assuming an otherwise normal child with hand tremor as the only problem, then the child most likely has ET. A moderate amount of alcohol also improves ET in some families (i.e. ET is alcohol responsive). The differential diagnosis for ET mainly includes drugs and medication, hyperthyroidism, Wilson disease and psychogenic tremor.

Psychogenic tremor occurs suddenly but is inconsistent regarding the frequency and amplitude of the tremor as well as the affected muscle groups. Unusual combinations of rest and action tremors occur. Although psychological stressors and psychiatric disease may be more common, up to 30% of subjects with psychogenic movement disorders have no psychiatric diagnosis.

Most patients with ET do not need treatment. Primodone and propranolol are usual first-line choices but benzodiazepines are also used. In adults other more invasive treatments are also being used such as botulinum A toxin injections or vagal nerve or brain stimulation. Other interventions such as weighting of wrists or other occupational therapy interventions may also assist patients.

Learning Point
Tremor commonly occurs as part of movement disorders in children (10-20% of children with movement disorders). Tremor prevalence studies in children are not common. Two studies evaluated tremor using Archimedes spiral test scoring, which asks the person to draw a spiral shape starting at the center and spiraling outward.

In a cross-section study in Spain of school aged children in 2011, mild tremor in one hand was common (51%) and was less likely in both hands (10.7%). More severe tremor was uncommon. Boys were slightly more affected than girls, the left hand was more affected than the right, and there was an increase in tremor with age.

In a population-based cohort of New York City children ages 9-15 in 2014, mild tremor was seen in 33.1% in one hand and was less common in both hands (9.1%). The dominant hand was affected in 12.6% and non-dominant hand in 29.7%. Boys were more affected than girls. Age was inversely correlated (in the dominant hand) tremor. The authors believe this may be the result of improved motor performance with increasing age because of development and practice. Children using psychiatric medication more often had tremor but interestingly, asthma medication did not appear associated with tremor. Tremor was also associated with poor motor dexterity.

Questions for Further Discussion
1. How is tremor different from other childhood movement disorders?
2. What are indications for evaluation by a neurologist?
3. What are indications for neuroimaging?

Related Cases

Disease: Tremor | Movement Disorders

Symptom/Presentation: Extremity Problems

Specialty: Neurology / Neurosurgery

Age: Young Adult

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 SearchingPediatrics.com, the National Guideline Clearinghouse and the Cochrane Database of Systematic Reviews.

Information prescriptions for patients can be found at MedlinePlus for these topics: Tremor and Movement 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.

Keller S, Dure LS. Tremor in childhood. Semin Pediatr Neurol. 2009 Jun;16(2):60-70.

Louis ED, Cubo E, Trejo-Gabriel-Galan JM, Villaverde VA, Benito VD, Velasco SS, Vicente JM, Guevara JC, Benito-Leon J. Tremor in school-aged children: a cross-sectional study of tremor in 819 boys and girls in Burgos, Spain. Neuroepidemiology. 2011;37(2):90-5.

Cardoso F. Movement disorders in childhood. Parkinsonism Relat Disord. 2014 Jan;20 Suppl 1:S13-6.

Louis ED, Garcia WE, Rauh VA. Tremor in a population-based cohort of children in New York City. Pediatr Neurol. 2015 Feb;52(2):187-91.

Author

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

Date
May 11, 2015