neurologic disorders
Tremor
Evaluation of Tremor
Because the diagnosis of tremor is largely clinical, a meticulous history and physical examination are essential. History of present illnessshould cover Acuity of onset (eg, gradual, abrupt) Age at onset Body parts affected Provoking factors (eg, movement, rest, standing) Alleviating or exacerbating factors (eg, alcohol,caffeine, stress, anxiety) If onset is abrupt, patients should be asked about potential triggering events (eg, recent trauma or illness, use of a new drug). Review of systemsshould seek symptoms of causative disorders, including Multiple episodic neurologic problems: Multiple Sclerosis (MS) None Recent sudden onset of motor weakness, language difficulties, or dysarthria: Overview of Stroke None Confusion and fever: Overview of Meningitis , Muscle rigidity, gait and postural problems, and slowness of movement: Parkinson Disease or other forms of Weight loss, increased appetite, palpitations, diarrhea, and heat intolerance: Hyperthyroidism None Sensory deficits: Overview of Peripheral Nervous System Disorders None Agitation and hallucinations: Alcohol Toxicity and Withdrawal or drug toxicity should cover conditions associated with tremor (see table 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 A complete and extensive Introduction to the Neurologic Examination 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 affected body parts are at rest and fully supported (eg, in the patient’s lap). The patient assumes certain postures (eg, holding the arms outstretched). The patient is walking or doing tasks with the affected body part. 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: Abrupt onset Onset in people<50 and with no family history of benign tremor Other neurologic deficits (eg, change in mental status, motor weakness, cranial nerve palsy, ataxic gait, dysarthria) Tachycardia and agitation Clinical findings help suggest a cause (see table Some Drug Causes of Tremor by Type ). Tremor type and onsetare useful clues: Resting tremorsusually indicate Parkinson disease, particularly when they are unilateral or when tremor is isolated to the chin or leg. suggest a cerebellar disorder but may result from Multiple Sclerosis (MS) or Postural tremorssuggest physiologic or essential tremor if onset is gradual; it suggests a toxic or metabolic disorder if onset is sudden. 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 ). Occasionally, the two syndromes overlap (mixed essential tremor–Parkinson disease). The following findings may help suggest causes of tremor: Sudden onset is most typical of psychogenic tremor after physical pathologic processes have been ruled out. Stepwise progression suggests an ischemic vascular disorder or multiple sclerosis Development of tremor after use of a new drug suggests that the drug is the cause. Onset of tremor with agitation, tachycardia, and hypertension within 24 to 72 hours of hospitalization may suggest withdrawal from alcohol or another sedative or use of an illicit substance. Gaitis 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 Tremor onset is acute. Progression is rapid. Focal neurologic signs suggest a structural lesion (eg, stroke, brain tumor, a demyelinating disorder). When the cause of tremor is unclear (based on history and physical examination findings), the following are done: Thyroid-stimulating hormone (TSH) and thyroxine (T4) are measured to check for hyperthyroidism. Calcium andparathyroid hormoneare measured to check for hyperparathyroidism or hypoparathyroidism. Glucose testing is done to rule out hypoglycemia. levels should be measured to check for Wilson Disease if patients are 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. 