Surgical Treatment of Idiopathic Tremor
Introduction
Idiopathic tremor is an autosomal dominant disorder and is the most common extrapyramidal disorder and the most common tremor disorder, with a family history in approximately 60% of patients. Idiopathic tremor is a single-symptom disorder, and postural tremor is the only clinical manifestation of the disease. The so-called postural tremor is a tremor that is triggered when the limb is maintained in a certain posture, and it disappears naturally when the limb is completely relaxed. The tremor is triggered when the limb is in a certain posture and disappears naturally when the limb is completely relaxed.
Clinical manifestations
Essential tremor (ET), also known as familial or benign idiopathic tremor, is a common clinical movement disorder with autosomal dominant inheritance, in which postural or motor tremor is the only manifestation and progresses slowly or does not progress for a long time. Age is currently considered to be an important risk factor for ET and the prevalence increases with age.
The onset of the disease is slow. It can occur at any age, but most often begins in adults, with some literature reporting a slightly higher prevalence in men than in women. Tremor in this disease is common in the hands, followed by tremor in the head, and rarely in the lower extremities. In most cases, the tremor disappears temporarily after drinking alcohol and worsens the next day. It should be treated symptomatically.
Epidemiology
The prevalence of idiopathic tremor in the general population is 0.3% to 1.7%, and increases with age. The prevalence increases to 5.5% in people older than 40 years of age and 10.2% in people older than 65 years of age with no significant difference between men and women. In Finland, the prevalence rate of 5.55% in people over 40 years of age was reported in the literature; the prevalence rate of 12.6% in people aged 70-79 years in Mississippi was 10 times higher than that of people aged 40-69 years.
Symptoms and signs
Tremor is the only clinical symptom of the disease, manifesting as postural or motor tremor, often involving one or both hands or the head, and the symptoms do not become apparent until later. In some cases, the tremor may prevent the hand from completing fine motor movements such as writing, and may affect articulation when the laryngeal muscles are involved, while the lower extremities are not involved. Patients often report that a small amount of alcohol can provide significant relief, but this is short-lived and the mechanism is unclear. There are usually no other neurological signs on examination.
Diagnosis
Idiopathic tremor grading
Idiopathic tremor should be considered based on the patient’s frequent postural and/or motor tremor that is relieved by alcohol consumption, a family history, and the absence of other neurological signs and symptoms.
Clinical grading of tremor The clinical grading of tremor proposed by the National Institutes of Health (NIH) Idiopathic Tremor Study Group in 1996 is 5 grades.
Grade 0: no tremor
Grade I: very mild tremor (not easily detected)
Grade II: easily detectable tremor of less than 2 cm in amplitude without disabling tremor
Grade III: obvious amplitude of 2 to 4 cm partially disabling tremor.
Grade IV: severe disabling tremor with amplitude more than 4 cm.
Diagnostic criteria for idiopathic tremor
Idiopathic tremor diagnostic criteria proposed by the American Movement Disorders Society and the World Tremor Research Organization
(1) Core diagnostic criteria.
①Motor tremor of both hands and forearms.
(2) No other neurological signs except gear phenomenon.
③Or only head tremor without dystonia.
(2) Secondary diagnostic criteria.
①The duration of the disease is more than 3 years
(ii) Family history.
③ Tremor is reduced after drinking alcohol
(3) Exclusion criteria.
①with other neurological signs, or a history of trauma shortly before the onset of tremor
②Physiological hyperactive tremor caused by drugs, anxiety, depression, hyperthyroidism, etc.
③History of psychogenic (psychogenic) tremor
④Sudden onset or segmental progression.
⑤Primary erect tremor.
⑥Position-specific or target-specific tremor only including occupational tremor and primary writing tremor.
(7) Speech only tongue-chin or leg tremor
Treatment options
Most patients with idiopathic tremor have only mild tremor, and only 0.5% to 11.1% of patients require treatment. The following treatment measures are available for those with significant symptoms.
Drinking small amounts of alcohol to reduce tremor
The majority of patients who consume a small amount of alcohol may experience significant temporary relief of tremor, but may need to increase the amount of alcohol consumed over time to achieve the same effect.
Long-term medications
Beta-adrenergic blocking drugs work by blocking peripheral beta2 receptors Propranolol can reduce the amplitude of tremor and has no effect on the frequency of tremor, and should be taken for a long time. In a specific situation tremor obvious people can be pre-temporary application of 30 ~ 90mg in 3 times; or with Aurolol 10mg fire, 3 times / d propranolol (insulin) relative contraindications include: uncontrolled heart failure;
II-III degree AV block; asthma and other bronchospastic diseases; insulin-dependent diabetes mellitus because propranolol (Takeaway) can block the normal adrenergic response to hypoglycemia in diabetic patients. Rare side effects include fatigue nausea diarrhea, rash, impotence and depression, etc. Most patients can tolerate propranolol (Takeaway) well, it is still recommended to monitor the pulse and blood pressure during the use of the drug pulse rate remains above 60 beats / min is usually safe.
Antispasmodics and tranquilizers
(1) paracetamol (paroxetine): can reduce the amplitude of tremor, does not affect the frequency of tremor, the mechanism is unknown, used to reduce hand tremor, the efficacy of the head tongue tremor ET patients are often very sensitive to this drug, not according to the treatment of epilepsy medication, since the small dose of 50mg / d starting every 2 weeks to increase the dosage of 50mg / d until effective or the emergence of side effects, usually effective dose of 100-150mg, 3 times / d Health search to improve drug compliance to reduce drowsiness side effects recommended to be taken before bedtime 20% to 30% of patients after taking the drug, dizziness, nausea and postural instability and other acute side effects temporary, can be gradually alleviated, does not affect the continued use of drugs.
(2) antiepileptic gabapentin (gabapentin): for the treatment of idiopathic tremor is still controversial. Although several open studies suggest that gabapentin is effective in reducing tremor, a double-blind controlled study did not find it to be more effective than placebo.
(3) Neuroleptics: Phenobarbital, diazepam (Valium), etc. are commonly used. Recent studies have concluded that clonazepam (clonazepam) may have better efficacy, with side effects mainly drowsiness. Anxiety can aggravate tremor therefore it is speculated that the treatment mechanism may be related to the central sedative effect.
Botulinum toxin A
Botulinum toxin A (BTX-A) is effective in reducing tremor in the limbs and soft palate to reduce tremor amplitude, with little effect on tremor frequency. In one observation, BTX-A injections into the extensor and flexor muscles of the hand for 4 weeks relieved mild to moderate tremor in 75% of patients.
BTX-A can also treat primary verbal tremor. Blitzer et al. injected BTX-A subcutaneously into the vocal folds of patients via the cricothyroid membrane, and most patients showed significant improvement in vocal function; some patients required re-injection into the sternocleidomastoid and sternocleidomastoid muscles. The mechanism may act on peripheral nerve endings to block the release of the neurotransmitter acetylcholine. Attention should be paid to the individualization of injection dose and site.
Others
(1) Clozapine: It is effective in relieving idiopathic tremor, but because it can cause granulocytopenia and lead to fatal infection, it is recommended to check blood counts weekly for 6 months and then every 2 weeks after administration.
(2) Carbonic anhydrase inhibitor vincristine (methazolamide): can effectively reduce tremor, especially head and speech tremor average maximum dose 200mg/d common side effects such as drowsiness, nausea anorexia numbness and abnormal sensation
(3) calcium antagonists: flunarizine 100mg/d health search or nimodipine 30mg, 4 times/d can reduce tremor in some patients but the efficacy is still controversial.
(4) Methylxanthine derivatives: In the past, theophylline (theophyl-sr) was thought to induce or even aggravate the condition. One study with theophylline improved tremor after 4 weeks and further confirmation is needed.
(5) Theophyl-sr: 50-100mg, 3 times/d
The recommended treatment plan abroad is to first try paracetamol (paroxetine) 50mg in the evening, which can be increased to 125-250mg according to the condition; if necessary, switch to or combine with long-acting propranolol (insulin) 40mg in the morning, and increase the dose according to the condition.
Surgical treatment
Patients with idiopathic tremor after regular drug treatment, still can not completely eliminate the tremor can try surgical procedures include.
(1) Stereotactic thalamic disruption: the best target is the ventral median nucleus of the thalamus or the ventral lateral nucleus Unilateral thalamic disruption can relieve tremor in more than 90% of patients Safe and effective drug therapy is ineffective in severe lateralized tremor can be applied. 10% of ET patients develop dysarthria balance disorder, contralateral limb weakness cognitive impairment and epilepsy after surgery, mortality rate <0.5%, radiofrequency disruption is safer than cerebral white matter dissection and thalamic chemical The mortality rate is <0.5%.
(2) Deep brain stimulation (DBS): It is a new surgical treatment to control tremor by implanting miniature pulse generators in the ventral nucleus of the thalamus, generally using 135-185 times/s high-frequency stimulation pulses 60-120 μs wave amplitude 1-3V, interfering and blocking the electrophysiological activity of neurons without destroying the thalamic nucleus.
DBS is more effective for resting and postural tremor than for motor tremor, more effective for distal limb tremor than for proximal limb and trunk, and less effective for head and speech tremor. Bilateral stimulation is possible with less damage and fewer long-term side effects. The disadvantage is the high cost.