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.
Tremors can be classified as a resting tremor and/or action 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 |
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 | - |
Tremor | Type | Features | Diagnosis | Treatment | Video |
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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 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:
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) |
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 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.
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 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).
• 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 disease is a rare autosomal recessive disorder that can sometimes present with a “wing-beating” tremor.
A good history is key to determining the cause and type of tremor the patient has. The following history should always be obtained: