Tremor

Tremor is classified primarily based on when it occurs:

Action tremors include kinetic, intention, and postural tremors.

Complex tremors can have components of more than one type of tremor.

Tremor can also be classified based on whether it is

Tremor is usually described based on frequency of oscillations (rapid or slow) and amplitude of movement (fine [low amplitude] or coarse [high amplitude]).

Physiologic tremor occurs in otherwise healthy people. It is an action or postural tremor that tends to affect both hands about equally; amplitude is usually fine. It is often noticeable only when certain stressors are present. These stressors include

There are many causes (see table Some Causes of Tremor Some Causes of Tremor ), but the most common are

Drugs (see table Some Causes of Tremor by Type Some Drug Causes of Tremor by Type ) can cause or aggravate different types of tremor. Low doses of some sedatives (eg, alcohol) may suppress some tremors (eg, essential and physiologic tremor); higher doses may cause or exacerbate tremor.

History of present illness should cover

If onset is abrupt, patients should be asked about potential triggering events (eg, recent trauma or illness, use of a new drug).

Review of systems should seek symptoms of causative disorders, including

Past medical history should cover conditions associated with tremor (see table Some Causes of Tremor Some Drug Causes of Tremor by Type ). Family history should include questions about tremor in 1st-degree relatives. The drug profile should be reviewed for causative drugs (see table Some Drug Causes of Tremor Some Drug Causes of Tremor by Type ), and patients should be asked specifically about caffeine intake and alcohol and recreational drug use (particularly recent discontinuation).

A complete and extensive neurologic examination Introduction to the Neurologic Examination The neurologic examination begins with careful observation of the patient entering the examination area and continues during history taking. The patient should be assisted as little as possible... read more is mandatory and should include evaluation of mental status, cranial nerves, motor and sensory function, gait, muscle stretch reflexes, and cerebellar function (with observation of finger-to-nose, shin-to-heel, and rapid alternating hand movements). The examiner should test muscles for rigidity by moving the limbs through their range of motion.

Vital signs should be reviewed for tachycardia, hypertension, or fever. General examination should note any cachexia, psychomotor agitation, and absence of facial expressions (which may indicate bradykinesia). The thyroid should be palpated for nodules and enlargement, and any signs of exophthalmus or eyelid lag should be noted.

Focused examination should note distribution and frequency of the tremor while

The examiner should note whether the tremor changes during mental distraction tasks (eg, serial subtraction of 7 from 100). The quality of the voice should be observed while the patient sustains a long note.

The following findings are of particular concern:

Clinical findings help suggest a cause (see table Some Causes of Tremor Some Drug Causes of Tremor by Type ).

Tremor type and onset are useful clues:

Severe essential tremor is often confused with Parkinson disease but can usually be distinguished by specific characteristics (see table Some Characteristics Differentiating Parkinson Disease From Essential Tremor Some Characteristics Differentiating Parkinson Disease From Essential Tremor ). Occasionally, the two syndromes overlap (mixed essential tremor–Parkinson disease).

The following findings may help suggest causes of tremor:

Gait is observed. Gait abnormalities may suggest multiple sclerosis, stroke, Parkinson disease, or a cerebellar disorder. Gait is characteristically narrow-based and shuffling in Parkinson disease and wide-based and ataxic in cerebellar disorders. The gait may have histrionic or inconsistent qualities in patients with psychogenic tremor. In patients with essential tremor, gait is often normal, but tandem gait (placing heel to toe) may be abnormal.

Psychogenic tremor can be identified because psychogenic tremors decrease or disappear when the patient is mentally distracted and when tremor frequency synchronizes (entrains) to a volitional tapping rhythm by an unaffected body part. Maintaining different volitional movement frequencies simultaneously in two different body parts is difficult.

In most patients, history and physical examination are sufficient to identify the likely etiology of tremor. However, MRI or CT of the brain should be done if

When the cause of tremor is unclear (based on history and physical examination findings), the following are done:

In patients with toxic encephalopathy, the underlying condition is usually readily apparent, but measurement of blood urea nitrogen and ammonia levels can help confirm the etiology. Measurement of free metanephrines in plasma is indicated in patients with unexplained refractory hypertension. Serum ceruloplasmin and urinary copper levels should be measured to check for Wilson disease Wilson Disease Wilson disease results in accumulation of copper in the liver and other organs. Hepatic or neurologic symptoms develop. Diagnosis is based on a low serum ceruloplasmin level, high urinary excretion... read more if patients are < 40 and have tremor with an unclear cause, especially if tremor has a wing-beating quality (with or without parkinsonism and dystonic features) and no family history of benign tremor. (Wing-beating is a low-frequency, high-amplitude, posture-induced arm tremor, elicited by sustained abduction of the arms, with flexed elbows and palms.)

Although electromyography (EMG) can differentiate true tremor from other movement disorders (eg, myoclonus, clonus, epilepsia partialis continua), it is rarely required. However, EMG may help establish peripheral neuropathy as a potential cause of tremor if a neuropathy is clinically suspected.

No treatment is necessary unless symptoms are bothersome. Avoiding triggers (such as caffeine, fatigue, sleep deprivation, drugs, and, when possible, stress and anxiety) can help prevent or reduce symptoms.

Physiologic tremor is enhanced by alcohol withdrawal, by hyperthyroidism, and by use of drugs and by conditions that can cause tremor. The tremor responds to treatment of the underlying condition.

Oral benzodiazepines (eg, diazepam 2 to 10 mg, lorazepam 1 to 2 mg, oxazepam 10 to 30 mg) given 3 or 4 times a day may be useful for people with tremor and chronic anxiety, but continuous use should be avoided. Propranolol (20 to 80 mg orally 4 times a day) and other beta-blockers are often effective for tremor enhanced by drugs or acute anxiety (eg, stage fright).

Propranolol 20 to 80 mg orally 4 times a day (or other beta-blockers) is often effective, as is primidone 50 to 250 mg orally 3 times a day. For some patients, a small amount of alcohol is effective; however, alcohol is not routinely recommended for treatment because abuse is a risk.

Second-line drugs are topiramate 25 to 100 mg orally 2 times a day and gabapentin 300 mg orally 2 or 3 times a day. Benzodiazepines may be added if other drugs do not control the tremor.

No effective drug is available; physical therapy (eg, weighting the affected limbs, teaching patients to brace the proximal limb during activity) sometimes helps.

Parkinson disease Treatment Parkinson disease is a slowly progressive, degenerative disorder characterized by resting tremor, stiffness (rigidity), slow and decreased movement (bradykinesia), and eventually gait and/or... read more is treated.

Levodopa Levodopa Parkinson disease is a slowly progressive, degenerative disorder characterized by resting tremor, stiffness (rigidity), slow and decreased movement (bradykinesia), and eventually gait and/or... read more is usually the treatment of choice for most parkinsonian tremors.

Anticholinergic drugs Parkinson Disease Parkinson disease is a slowly progressive, degenerative disorder characterized by resting tremor, stiffness (rigidity), slow and decreased movement (bradykinesia), and eventually gait and/or... read more may be considered in certain cases, but their adverse effects (decreased mental concentration, dry mouth, dry eyes, urinary retention and the possibility that they enhance tau pathology) may outweigh their benefits, particularly in older patients.

Other drugs include dopamine agonists Dopamine agonists Parkinson disease is a slowly progressive, degenerative disorder characterized by resting tremor, stiffness (rigidity), slow and decreased movement (bradykinesia), and eventually gait and/or... read more (eg, pramipexole, ropinirole, rotigotine), MAO type B inhibitors Selective MAO-B inhibitors Parkinson disease is a slowly progressive, degenerative disorder characterized by resting tremor, stiffness (rigidity), slow and decreased movement (bradykinesia), and eventually gait and/or... read more (selegiline, rasagiline), catechol O-methyltransferase (COMT) inhibitors Catechol O-methyltransferase (COMT) inhibitors Parkinson disease is a slowly progressive, degenerative disorder characterized by resting tremor, stiffness (rigidity), slow and decreased movement (bradykinesia), and eventually gait and/or... read more (entacapone, tolcapone—used only in combination with levodopa), and amantadine Amantadine Parkinson disease is a slowly progressive, degenerative disorder characterized by resting tremor, stiffness (rigidity), slow and decreased movement (bradykinesia), and eventually gait and/or... read more .

For severe, disabling, drug-refractory essential tremor, surgical management with unilateral stereotactic thalamotomy or chronic unilateral or bilateral thalamic deep brain stimulation may be considered.

Dystonic tremor may respond better to functional neurosurgery targeting the internal portion of the globus pallidus.

In Parkinson disease, tremor substantially lessens after thalamic, internal globus pallidus, or subthalamic nucleus deep brain stimulation.

Although these techniques are widely available, they should be used only after reasonable drug therapy has failed and only in patients who do not have substantial cognitive or psychiatric impairment.

For patients with psychogenic tremor, tremor entrainment may help. This treatment refers to the change or elimination of tremor as the patient performs a voluntary rhythmical movement by the unaffected limb ( 1 Treatment reference Tremors are involuntary, rhythmic, oscillatory movements of reciprocal, antagonistic muscle groups, typically involving the hands, head, face, vocal cords, trunk, or legs. Diagnosis is clinical... read more ).