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Tremors

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Overview

Tremors may be due to an underlying disease or an existing physiological process. It is defined as a rhythmic oscillatory movement of a body part. It happens due to opposite muscles contracting. Most cases of tremor are due to ‘essential tremor‘.

Epidemiology

  • Essential tremor affects men and women equally
  • 50% of essential tremor cases are familial and autosomal dominant
  • Familial essential tremor presents in childhood, whereas sporadic is >40 years

Types of Tremor

Rest tremors

Action tremors

Action tremors happen during voluntary muscle contraction. They can be subdivided into:

  • Postural tremors:
    • When a body part is held fixed against gravity e.g. holding up a newspaper
  • Kinetic (action) tremors:
    • If the kinetic tremor worsens when goal-directed movement approaches the target, this is known as an intention tremor.

Action tremors can be due to:

  • Exaggerated physiological tremors:
    • Physiological tremors can happen in all healthy people, however, they may be worsened by stimulants (caffeine), drugs, stress, fatigue, and medical conditions such as thyrotoxicosis.
  • Essential tremor
    • Most common movement disorder
  • Cerebellar tremors
  • Orthostatic tremors
    • Happen on standing and resolve with sitting or walking
  • Neuropathic tremors
    • Can happen with any type of neuropathy, commonly Charcot-Marie-Tooth disease.

Tremors that lessen with movement are more likely to be rest tremors, whereas tremors that worsen with movement are more likely to be action tremors. People can also have mixed tremors, in which traits of both rest and action tremors are seen. 

Presentation

Features suggesting essential tremor

  • Distal symmetrical postural tremor of the upper limbs
  • Low amplitude and rapid frequency (8-10Hz)
  • Amplitude changes depending on emotional and physiological state. Frequency is relatively unchanged.
  • Neck muscles may be involved and the resultant head tremor may be seen
  • Voice, face, and jaw muscles may be involved causing issues with speech
  • Tremor is worse with action
  • Tremor does not happen during sleep
  • Tremor improves with alcohol consumption

Features suggesting tremors secondary to neurological disease

  • Other neurological symptoms may accompany the tremor
  • Most people with Parkinson’s disease present primarily with tremors
  • There may be a history of alcohol consumption and withdrawal
  • Intention tremors may suggest cerebellar disease

Differential Diagnoses

Parkinson’s disease

  • Unilateral rest tremor
  • Slowed movements
  • Mask-like facies and flat affect
  • Shuffling gait

Dementia with Lewy bodies

  • Fluctuating cognition
  • Intense visual hallucinations
  • Parkinsonism
  • Cerebellar tremor (stroke, trauma, multiple sclerosis)
  • Loss of coordination and balance
  • Wide-based ataxic gait
  • Speech problems
  • Headache

Hypoglycaemia

  • Sweating
  • Anxiety
  • Nausea/confusion
  • Drowsiness

Thyrotoxicosis

Phaeochromocytoma

  • Headaches
  • Sweating
  • Palpitations
  • High blood pressure

Alcohol withdrawal

  • History of alcohol abuse
  • Delirium tremens
  • Seizures
  • Hallucinations
  • Signs of liver disease

Essential tremor

  • Mainly affects distal upper limb
  • Bilateral symptoms
  • Positive family history
  • Worsens with action and improves with alcohol use
  • Exaggerated physiological tremor
  • Tremor onset is in times of stress, anxiety, excess caffeine use
  • High-frequency tremor

Drug-induced

  • SSRIs
  • Tricyclic antidepressants
  • Lithium
  • Amiodarone
  • Corticosteroids
  • Ciclosporin
  • Tacrolimus
  • Salbutamol
  • Theophylline
  • Amphetamines
  • Neuroleptics
  • Atypical antipsychotics
  • Antiemetics e.g. metoclopramide

Investigations

Investigations are not usually carried out if the patient has a characteristic presentation of essential or physiological tremor.

Investigations may be carried out to identify underlying causes:

  • FBC, U&Es, LFTs, TFTs, CRP, ESR, glucose
  • CT/MRI if a stroke or tumour suspected
  • MRI with contrast if multiple sclerosis suspected

Management

Tremors are managed based on resolving the underlying cause.

In essential tremors, management is conservative with pharmacological options for cases depending on the patient and the impact the essential tremor has on them. Options are:

  • 1st line: propranolol
  • Another option is primidone

Complications

  • Essential tremor is associated with an increased risk of mortality in the elderly
  • Patients’ quality of life may be affected by tremors and affect their occupation and hobbies

Prognosis

  • Essential tremor is considered a neurodegenerative disease
  • There is no cure and nothing to stop its progression, however, the life expectancy is normal
  • Physiological tremors have a very excellent prognosis if underlying causes are managed
  • Tremors secondary to neurological disease have the same prognosis as the disease itself
  • Drug-induced tremors usually resolve once the culprit is withdrawn; however, some tremors can persist, especially if the medication was used for a long time 

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