Tremors: Essential Tremor and Beyond

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Tremor is a fairly common movement disorder presenting to an outpatient pediatric neurology practice. Tremors can be primary or secondary to underlying neurologic or systemic diseases. When assessing a child with tremor, it is paramount to evaluate the phenomenology of the tremor, determine the presence or absence of other neurologic signs and symptoms, and the possible modifying influence of medications. Proper classification is essential for specific diagnosis and prompt adequate management. Treatment considerations should take into account objective assessment of tremor severity and the degree of disability or impairment experienced by the child. Overall effectiveness of pharmacologic treatments of tremor is unfortunately disappointing. In this article we review the clinical examination, classification, and diagnosis of tremor. The pathophysiology of the different forms of tremor is outlined, and treatment options are discussed.

Introduction

Tremor is a common symptom encountered by pediatric neurologists. Although not life threatening, chronic tremor can negatively impact the quality of life of a child. Tremor can interfere with a developing child′s fine motor skills such a hand-writing or even participation in some sports activities. It may represent an important source of distress for the child and the family.

As with most neurologic conditions, a thorough history and physical examination is essential to appropriately diagnose and treat tremor. It is important to characterize the type, duration, and time course of tremor symptoms, as this can help to include or exclude specific diagnoses. Other significant symptoms or physical examination findings such as focal weakness or ataxia should be considered to better localize potential lesion causing the tremor. Family history can also be critical when considering inherited causes of tremor in the child.

Etiologies vary widely and differ much between children and adults. While Parkinson disease (PD) is not an uncommon encounter in older patients, “benign” essential tremor (ET) and enhanced physiological tremor are by far the most common diagnoses in children who do not have other underlying neurologic conditions. Medication induced tremor is also frequently seen and a matter of concern for families.

In most patients, tremor has little clinical significance, needing no further diagnostic testing or medical treatment. However, in many cases, it may be a sign of a more ominous neurologic problem. Evaluation tools include brain imaging studies to investigate the possibility of a structural lesion (cerebral ischemia, brain tumor, or neurodegenerative process). Genetic testing, although expensive, can be diagnostic when no structural lesion is found, especially in the setting of a significant family history of tremor or a suspected neurodegenerative disorder. Laboratory testing for thyroid and parathyroid disease, hypoglycemia, vitamin deficiencies (vitamin B12), and heavy metal toxicity should be considered since these are potentially treatable causes of tremor.1, 2, 3, 4, 5, 6

Section snippets

Pathophysiology

We have made progress in understanding the anatomical regions in the central nervous system (CNS) as well as specific pathways involved in the generation of tremor, however, the pathophysiology of tremogenesis is still incompletely defined. Two sets of neuronal networks appear to be particularly important (Fig. 1).7 One is the cortico-striato-thalamo-cortical loop, whose physiological task is to integrate different muscle groups for complex movement programs and to ensure that an ongoing

Classification

Tremor is defined as an involuntary, rhythmic, oscillatory movement of a body part. Using phenomenology, tremor can be classified according to is clinical features and activation conditions (Table 1).18 Tremor can also be classified along 2 axes, taking into consideration clinical features, diagnostic testing, and etiology (Fig. 2).19

Axis 1—clinical features, including historical data (age at onset, family history, and temporal evolution), tremor characteristics (body distribution, activation

Tremor Syndromes

A tremor syndrome can be isolated (consisting only of tremor) or combined (tremor associated with other systemic or neurologic signs). Both common and rare tremor syndromes are described below.

Conclusion

Tremor, although not life threatening, can negatively impact the quality of life of a child. A thorough history and physical examination is essential to appropriately characterize and treat. Secondary underlying neurologic conditions need to be excluded. Brain imaging studies and genetic testing may be indicated in select cases. Management is highly dependent on the degree of functional impairment. Treatment should include a multidisciplinary approach in which comprehensive rehabilitation

References (75)

  • R. Saunders-Pullman et al.

    Pediatric movement disorders

    Child Adolesc Psychiatr Clin N Am

    (1999)
  • H. Tan et al.

    Rubral tremor after thalamic infarction in childhood

    Pediatr Neurol

    (2001)
  • K.S. Carvalho et al.

    Deep brain stimulation of the globus pallidus suppresses post-traumatic dystonic tremor

    J Clin Neurosci

    (2014)
  • S. Bose-O’Reilly et al.

    Signs and symptoms of mercury-exposed gold miners

    Int J Occup Med Environ Health

    (2017)
  • A. de Souza et al.

    Involuntary movements due to vitamin B12 deficiency

    Neurol Res

    (2014)
  • G. Linazasoro et al.

    Three in one: Case report supporting different origins of essential and parkinsonian tremors

    Eur Neurol

    (2006)
  • M.G. Vega et al.

    [Extrapyramidal syndrome and hypoparathyroidism. On the identity of Fahr disease]

    Arq Neuropsiquiatr

    (1994)
  • L.S. Boylan

    Hypoglycaemic injury spares thalamus, spoils striatum and leaves only a rest tremor

    BMJ Case Rep

    (2016)
  • A. Puschmann et al.

    Diagnosis and treatment of common forms of tremor

    Semin Neurol

    (2011)
  • U. Bonuccelli

    Essential tremor is a neurodegenerative disease

    J Neural Transm (Vienna)

    (2012)
  • G. Deuschl et al.

    Essential tremor—Neurodegenerative or nondegenerative disease towards a working definition of ET

    Mov Disord

    (2009)
  • A. Cerasa et al.

    Linking essential tremor to the cerebellum-neuroimaging evidence. Cerebellum

    (2016)
  • J.H. McAuley et al.

    Physiological and pathological tremors and rhythmic central motor control

    Brain

    (2000)
  • R.J. Elble et al.

    Motor-unit activity responsible for 8- to 12-Hz component of human physiological finger tremor

    J Neurophysiol

    (1976)
  • D. Claus et al.

    Long latency muscle responses in cerebellar diseases

    Eur Arch Psychiatry Neurol Sci

    (1986)
  • M. Vidailhet et al.

    Pathology of symptomatic tremors

    Mov Disord

    (1998)
  • H. Miwa et al.

    Thalamic tremor: Case reports and implications of the tremor-generating mechanism

    Neurology

    (1996)
  • H. Singer et al.

    Tremor

    Movement Disorders in Childhood

    (2015)
  • K.P. Bhatia et al.

    Consensus statement on the classification of tremors, from the task force on tremor of the International Parkinson and Movement Disorder Society

    Mov Disord

    (2018)
  • H.J. Wharrad et al.

    The influence of fasting and of caffeine intake on finger tremor

    Eur J Clin Pharmacol

    (1985)
  • J.J. Pilcher et al.

    Effects of sleep deprivation on performance: A meta-analysis

    Sleep

    (1996)
  • G. Deuschl et al.

    Consensus statement of the Movement Disorder Society on Tremor. Ad Hoc Scientific Committee

    Mov Disord

    (1998)
  • E.D. Louis et al.

    Clinical subtypes of essential tremor

    Arch Neurol

    (2000)
  • N.P. Quinn et al.

    Tremor—Some controversial aspects

    Mov Disord

    (2011)
  • C. Singer et al.

    Gait abnormality in essential tremor

    Mov Disord

    (1994)
  • C. Helmchen et al.

    Eye movement abnormalities in essential tremor may indicate cerebellar dysfunction

    Brain

    (2003)
  • R. Fekete et al.

    Revisiting the relationship between essential tremor and Parkinson′s disease

    Mov Disord

    (2011)
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