- Last edited on September 26, 2021
Approach to Tremors
Primer
Tremors are rhythmical, involuntary oscillatory movements of a body part. The most common tremors are enhanced physiologic tremors, followed by essential tremor, and parkinsonian tremors. Tremors also become more common with age.
Classification
Tremors can be classified as a resting tremor and/or action tremor.
- A resting tremor occurs in a body part that is not voluntarily activated and is completely supported against gravity. Rest tremors become more prominent with mental stress/distraction (e.g. - counting backward) or movement of another body part (e.g. - walking). When the affected body part engages in voluntary movement, the tremor will often diminish. Resting tremors are most commonly caused by parkinsonism or Parkinson's Disease, but may also occur in severe essential tremor.
- An action tremor is any tremor that is produced by voluntary contraction of muscle. There are several types of action tremors, including postural, isometric, and kinetic tremor. The latter includes intention tremor.
Resting Tremor
| Type | Description | Physical Exam | Possible Etiologies |
|---|---|---|---|
| Resting | A tremor that occur only when the body part is at rest and completely supported against gravity | Rest arms on lap or chair while supported. | • Parkinson's Disease • Drug-induced parkinsonism (e.g. - antipsychotics) • Supranuclear palsy |
Action Tremor Types
| Type | Description | Physical Exam | Possible Etiologies |
|---|---|---|---|
| Postural | Occurs when the body part is voluntarily maintained against gravity. | Ask patient to hold out their arms | • Normal (physiologic) tremor • Sleep deprivation • Cerebellar • Dystonic • Drugs (excessive caffeine/nicotine use) • Alcohol withdrawal • Increase metabolic states (hyperthyroidism) • Essential tremor |
| Kinetic | Occurs with any form of voluntary movement. | Ask patient to move the affect limb during finger-to-nose testing | Essential, cerebellar, dystonic, or drug-induced tremors. |
| Intention | A subtype of a kinetic tremor. Occurs with target-directed movement. Usually means a disturbance of the cerebellum or its pathways. | Finger-to-nose testing while examining for dysmetria | Essential tremors and cerebellar tremors are always worse on intention. |
| Isometric | Tremor occurring as a result of muscle contraction against a rigid stationary object. | Making a fist or squeezing the examiner’s fingers | - |
Types
Summary
Tremors
| Tremor | Type | Features | Diagnosis | Treatment | Video |
|---|---|---|---|---|---|
| Essential tremor | Postural/kinetic | • Symmetric, involves hands, wrists, lower extremities, head shaking, or voice • Family history and genetic • Improvement with alcohol • Worse with movement and sustained posture (e.g. - outstretched arms) than at rest (opposite of Parkinsonian tremor) | No specific test; CBC, TSH, electrolytes, may rule out other diseases. Refer to the clinical diagnostic criteria for essential tremors below. | Propranolol, primidone, patients may self-medicate with alcohol (which decreases tremor) | Video |
| Enhanced physiologic tremor | Postural | • Low amplitude • Use of exacerbating medication | Serum glucose level, TSH, LFTs, patient history about anxiety and caffeine use | Treat underlying cause, reassurance | Video |
| Parkinsonian tremor | Resting | • Asymmetric • Involves distal extremities • Decreases with voluntary movement • Parkinsonian features: bradykinesia, postural instability, and rigidity • Worse at rest than with movement (opposite of essential tremor) | Clinical diagnosis in combination with other Parkinsonian features. PET or SPECT for atypical presentations. | Dopamine agonists, anticholinergics | - |
| Cerebellar tremor | Intention or Postural | • Ipsilateral involvement to lesion • Abnormal finger-to-nose test (“slow, zig-zag motion”) • Imbalance • Abnormal heel- to-shin test • Hypotonia | Head CT or MRI | Treat underlying cause, deep brain stimulation | Video |
| Functional (Psychogenic) tremor | Variable | • Abrupt onset • Spontaneous remission • Extinction with distraction (or conversely, entrainment) • Changing tremor characteristics | Detailed history | Psychoeducation, CBT | - |
Essential Tremor
Essential tremor is an action tremor characterized by rhythmic shaking of the arms in almost every case. However, it may also involve tremor of the head, tongue, lower limbs, voice and face. For an essential tremor diagnosis, the core criteria must be fulfilled for the diagnosis and the secondary criteria are present in more than half of patients and support the diagnosis. Additionally:
- Essential tremors are commonly autosomal dominant, so asking the family history is important
- Enhanced physiological tremors are commonly misdiagnosed as essential tremor
- The neurological examination in essential tremor is usually normal, apart from the tremor itself, but there can sometimes be gait or eye movement abnormalities suggesting a mild cerebellar component
- Caffeine and fatigue can often exacerbate essential tremors
Diagnostic Criteria
Bain, Peter, et al. Criteria for the diagnosis of essential tremor. Neurology 54.11 Suppl 4 (2000): S7-S7.| Features | |
|---|---|
| Core Diagnostic Criteria | • Bilateral action tremor of the hands and forearms (but not rest tremor) • Absence of other neurologic signs, with the exception of the cogwheel phenomenon • May have isolated head tremor with no signs of dystonia |
| Secondary Criteria | • Long duration (>3 years) • Positive family history • Beneficial response to alcohol |
| Exclusion Findings | Findings that suggest a diagnosis other than essential tremors include: • Unilateral tremor, leg tremor, rigidity, bradykinesia, rest tremor (think PD) • Gait disturbance (think PD, cerebellar tremor); focal tremor (think dystonic tremor) • Isolated head tremor with abnormal posture (think dystonic tremor) • Sudden or rapid onset (think psychogenic tremor or toxic tremor) |
Drug/medication-induced
A variety of medications (both prescribed and OTC) and drugs can cause or exacerbate tremors. Sympathomemetics and psychotropic medications (e.g. - SSRIs, antipsychotics, and TCAs) in particular may increase the risk. Antipsychotics in particular may cause tremors (parkinsonism) as a result of extrapyramidal symptoms. Also, akathisia should be in the differential for patients with complaints of tremor. Drug-induced tremors are usually bilateral.
Metabolic
Metabolic causes of tremor are varied. Initial workup of tremor may include blood testing for hepatic encephalopathy, hypocalcemia, hypoglycemia, hyponatremia, hypomagnesemia, hyperthyroidism, hyperparathyroidism, and vitamin B12 deficiency.
Cerebellar
The classic cerebellar tremor is a disabling, low-frequency, intention or postural tremor, and is typically caused by multiple sclerosis with cerebellar plaques, stroke, or brainstem tumors. Other physical exam findings include dysmetria (seen as overshooting on finger-to-nose testing), dyssynergia (abnormal heel-to-shin testing), and/or hypotonia.
Psychogenic
Psychogenic tremors can be difficult to diagnose. They usually have an abrupt onset, spontaneous remission, changing characteristics, and extinction with distraction. Often, there is an associated stressful life events. If patients are on psychotropic medications, akathisia should be in the differential and not missed (especially if they are on an antipsychotic).
Features of psychogenic tremors
| • Abrupt onset • Absence of other neurologic signs • Changing tremor characteristics • Clinical inconsistencies • Employed in allied health professions • Litigation or compensation pending • Multiple somatizations • Multiple undiagnosed conditions • No evidence of disease by laboratory or radiologic investigations | • Presence of psychiatric disorder • Presence of secondary gain • Reported functional disturbances in the past • Responsive to placebo • Spontaneous remission • Static course • Tremor increases with attention, and lessens with distractibility • Unclassified tremor (complex tremors) • Unresponsive to antitremor medications |
Wilson's Disease
Wilson disease is a rare autosomal recessive disorder that can sometimes present with a “wing-beating” tremor.
Approach
History
A good history is key to determining the cause and type of tremor the patient has. The following history should always be obtained:
- Patient’s age at onset of tremor
- Was it sudden or gradual?
- Anatomical site first affected by tremor
- Other sites subsequently affected by tremor
- Sequence of spread of tremor
- Rate of progression to other sites and rate of increase in severity
- Familial history or sporadic tremor
- Family history of other movement disorder or neurological condition
- New medications and/or current medications
- Alcohol use response to the tremor
Physical
- Examine the patient sitting, with their hands in their laps to check for rest tremor
- Have the patient stretch his or her arms and hands out to check for postural tremor
- Do the finger-to-nose test to check for kinetic tremors and dysmetria
- What is the frequency (i.e. - number of tremors per second) of the tremor, is it low (less than 4 Hz), medium (4 to 7 Hz), or high (more than 7 Hz)?
- Checking for asterixis is also important[1]
Investigations
- Thyroid function panel (TSH, parathyroid hormone)
- Liver function tests, BUN (to rule out encephalopathy)
- Calcium, magnesium
- Glucose
- Sodium
- Vitamin B12
- Consider serum copper and ceruloplasmin levels in atypical cases
Pearls
- A resting tremor is virtually synonymous with Parkinsonism
- A high-frequency tremor that involves the head is much more likely to be essential tremor than a Parkinsonian tremor
- A gradual onset of tremor in older patients is more likely to be a Parkinsonian or essential tremor
- An intention tremor often indicates a cerebellar lesion
- Patients with sudden onset of tremor should be evaluated to determine if the tremor is caused by medications, toxins, a brain tumour, or a psychogenic cause
- Sleep disorders (i.e. - sleep deprivation) can amplify physiologic tremors
- A family history of neurologic disease or tremor suggests a genetic component, as is often seen in essential tremor[2]
- A thorough medication history should always be performed be obtained to rule out drug-induced tremor
- Drug use and alcohol overuse/withdrawal can also cause tremor