Is there a cure for hereditary hand tremors?

The symptom of hand tremor sometimes occurs in normal people, but people usually don’t pay too much attention to it, thinking that it is caused by overwork or lack of rest. But now research has found that hand tremors may be caused by genetics. Hereditary hand tremor is a type of essential tremor. When the symptoms are mild, no treatment is needed. When the symptoms are severe, you can take some propranolol, which has a good effect on the disease.

Essential tremor is the most common movement disorder, mainly postural and movement tremors in the hands, head and other parts of the body. Essential tremor has a contradictory clinical nature. On the one hand, it is a mild, monosymptomatic disease, but on the other hand, it is a common, progressive disease with significant clinical variability. The tremor of this disease worsens when one is concentrating, mentally stressed, tired, or hungry. In most cases, it disappears temporarily after drinking and worsens the next day. This is also the clinical feature of essential tremor. The cause of essential tremor is unclear and it is easy to be confused with tremors caused by other diseases.

Essential tremor is also called familial tremor, and about 60% of patients have a family history. No cross-generational phenomenon has been found in multiple families with essential tremor, and the gender distribution is balanced. It is generally believed that this is an autosomal dominant inheritance, which is fully penetrant before the age of 65 to 70 years. Incomplete penetrance and sporadic cases have also been reported. The clinical features of sporadic and hereditary cases are exactly the same, and it is usually considered to be the same disease, but the related gene abnormalities have not yet been identified. The bimodal characteristics of the age of onset of essential tremor suggest the possibility of two different abnormal genes. The age of onset of familial tremor is earlier than that of sporadic cases, suggesting that early-onset essential tremor is more strongly affected by genetic susceptibility, which can significantly affect the clinical subtype characteristics.

Essential Tremor Disease Treatment

Most patients with essential tremor have only mild tremors, and only 0.5% to 11.1% of patients require treatment. Among them, less than 50% of patients can control their symptoms well with medication. The remaining patients are insensitive to medication and have poor treatment effects, and require botulinum toxin injections or stereotactic treatment.

Essential tremor drug treatment

l. Ethanol It was discovered early on that drinking alcohol can temporarily and significantly reduce tremors in most patients. Even small doses of ethanol (alcohol) can produce dramatic effects, but the tremors will reappear after 2-4 hours with a greater amplitude. Clinical findings show that over time, more ethanol (alcohol) is needed to suppress tremors. Long-term use of ethanol (alcohol) to treat essential tremor can lead to alcohol abuse, so ethanol (alcohol) should not be used as a long-term treatment, and alcohol withdrawal can also cause tremors. But ethanol (alcohol) can be used occasionally to control symptoms. The mechanism of action of ethanol (alcohol) is still unclear. May act on the cerebellum.

2. The adrenal beta-receptor blocker propranolol has a definite therapeutic effect on essential tremor. To date, no other selective or non-selective adrenal beta-blocker has been found to be more effective than propranolol. Most reports confirm that propranolol can reduce the amplitude of postural tremor in the hands, but not the frequency. Tremors in other parts of the body may have less-than-ideal or even no effect at all. The therapeutic effect is not related to blood drug concentration, and the reason is unclear.

Adrenal beta-blockers block the centrally and peripherally acting endogenous catecholamines. Studies have shown that propranolol has a high lipid solubility and can pass through the blood-brain barrier to act on the central nervous system, so it has the best effect. According to the size of lipid solubility, the adrenal beta-receptor blockers are propranolol, metoprolol, sotalol and atenolol, respectively, but for essential tremor, the effectiveness is propranolol, sotalol, atenolol and metoprolol, respectively. Therefore, adrenal beta receptors not only act through central mechanisms, but also through peripheral mechanisms. Peripheral catecholamine receptor sites are present in both intrafusal and extrafusal muscles. β2-receptors acting on the extrafusal muscles work by shortening the twitch period, thereby enhancing postural tremor. β2-receptor antagonists can block this effect and reduce tremors.

Propranolol has a good effect on essential tremor, but a considerable number of patients still do not respond well to it. Symptoms can be relieved by 50% to 70% and can be reduced by 50%-60%. The therapeutic effect of propranolol is correlated with the dosage. Although 80 mg/d is effective for some patients, for most patients abroad, a dose of 120 mg/d is still insufficient. Generally, 240 to 320 mg is required per day. However, a larger dose does not increase the side effects accordingly. It is recommended to start with a small dose of propranolol and take it three times a day. It will take a few days to take effect, and then increase by 10-20 mg every 2 days, but long-term use will lead to tolerance. After long-term use, withdrawal should be slow (more than 1 week) to prevent withdrawal reactions such as tachycardia, sweating, tremor, and general malaise.

Relative contraindications to propranolol treatment are heart failure, second-degree or third-degree atrioventricular block, asthma or other bronchospastic diseases, and insulin-dependent diabetes mellitus. Most side effects are related to adrenal beta-receptor blocking effects and decreased pulse rate, but heart rates above 60 beats are tolerated. Other less common side effects include fatigue, weight gain, nausea, diarrhea, rash, impotence, and changes in mental status (such as depression). Propranolol side effects are mostly tolerable after a period of treatment. If the patient is asthmatic, β2-receptor blockers and propranolol are not suitable for use. Selective β1-receptor blockers such as atenolol and metoprolol can be used, and the former is more effective.

In some patients with essential tremor, tremor only occurs in foreseeable special occasions. Symptoms are well controlled with intermittent use of propranolol. Taking the medicine 1 hour before the onset of tremor can effectively prevent the occurrence of tremor.

3. Primidone: If idiopathic patients also have chronic obstructive airway disease, heart failure or peripheral vascular disease, and propranolol is contraindicated, primidone may be the first choice for treatment. For large-amplitude tremors, primidone is more effective than propranolol and can even reduce tremors to asymptomatic amplitudes.

Primidone is a commonly used anti-epileptic drug that is completely absorbed in the upper gastrointestinal tract and reaches peak serum concentration within 3 to 5 hours. Primidone is converted into two active metabolites in the body, one of which is the unconjugated phenylethylmalonamide. It accounts for about 50%, with a half-life of 24 to 48 hours. About half of the product phenobarbital is conjugated, with a half-life of 120 hours. During chronic administration of phenobarbital, steady-state serum concentrations are reached after 3 weeks. The antitremor effect of primidone is unclear. Phenobarbital has GABA-like effects, while primidone has a pharmacological mechanism similar to that of carbamazepine and phenytoin, all of which act on the nerve cell membrane to change the influx of ions.

Primidone can be used to treat essential tremor at a dose of 125 mg twice a week, with a maximum dose of 250 mg three times a week. This dose significantly reduced tremor amplitude in both treatment-naive and propranolol-experienced patients. During primidone treatment, 1/5 of patients may experience acute toxic reactions such as dizziness, nausea, vomiting, etc. even when taking very small doses. Therefore, the starting dose is 62.5 mg once daily. The dosage should be increased slowly, by 62.5 mg every 2 days, until a good therapeutic effect is achieved without side effects. The side effects of primidone in treating tremor are greater than those in treating epilepsy. The acute reaction to the first dose and the side effects of large doses often lead to treatment interruption. Nausea, vomiting and ataxia are caused by delayed metabolism induced by liver enzymes, but its metabolite phenethylmalonamide has no side effects, and phenobarbital also has few side effects. If intolerable side effects occur, phenobarbital can be used instead, but it is only moderately effective.

If the effect of single medication is not satisfactory, you can try propranolol and primidone combination therapy.

4. Other drugs: In a small sample open-label study, 0.15-0.45 mg/d of clonidine was effective. In addition, low-dose clozapine (18-75 mg/d) is effective for most patients. Clonazepam is usually ineffective for essential tremor but can reduce essential tremor that has a predominant motor component. Carbonic anhydrase inhibitors (methozolamide) are highly effective for head and vocal tremors, but some have been reported to be completely ineffective.