Physiological tremor

Introduction Physiological tremor: more common in the distal part of the limb, a posture shock. The amplitude is small and difficult to detect with the naked eye. If the paper is placed on the back of the finger that is stretched forward, the tremor is easier to find. The frequency of tremor varies with age, usually about 6 times/second under 9 years old; about 10 times/second at 16 years old; the frequency of tremors starts to slow down after 40 years old, and returns to 6 seconds after about 70 years old/ second. In addition to the hand, tremor can still be found in the eyelids, the tongue muscles, the trunk and the lower limbs. Physiological tremor is a type of benign tremor. Benign tremor, also known as simple tremor, is a tremor based on the absence of brain organic lesions. Clinically common benign tremors mainly include physiological tremors and functional tremors. Essential tremor (ET) is a common dyskinesia. Also known as idiopathic tremor, benign tremor.

Cause

More than one-third of patients have a family history with autosomal dominant inheritance, and two pathogenic gene loci have been identified, targeting 3q13 (FET1) and 2p22-25 (ETM or ET2).

Benign tremor is hereditary tremor, and about 60% of patients have a family history with autosomal dominant genetic features. Appearance appeared before 65 to 70 years old. Gulcher et al found that the disease-causing gene is located in 3q13, called FET1. Higgins and other genes map the pathogenic gene to 2p22-25, called ETM or ET2. It is found that ETM may be a triplet repeat, and this gene is located in two other families. The family of sexually characteristic tremors was confirmed. It has also been reported that the patient's sex chromosomes are abnormal, and a few male patients have XXY and XYY. The diversity of clinical manifestations of familial ET suggests that there may be genetic heterogeneity, suggesting that new genetic loci may be discovered.

an examination

Related inspection

EEG examination of brain CT

So far, ET has not been very effective in the diagnosis of diagnosis, and is still limited to clinical diagnosis, mainly relying on medical history and clinical features, easy to misdiagnosis or missed diagnosis. Bain and Findley et al. proposed a diagnostic standard in 1994 that included both standard and exclusion criteria.

Including criteria: 1 visible and persistent posture tremors, including the hands or forearms, with or without exercise tremor. The tremor of the upper extremity can be asymmetrical or symmetrical, and tremor can affect other parts of the body; 2 tremors last for at least 5 years, symptoms may fluctuate, but dysfunction cannot occur within 5 years.

Exclusion criteria: 1 other neurological signs appear, but does not include gear-like tonic and Froment's sign. Froment, s sign refers to the occurrence of gear-like rigidity in the side limbs when repeated autonomic movements of the contralateral limbs; 2 physiological tremors caused by known causes, such as hyperthyroidism; 3 simultaneous or recent taking drugs that can produce tremor , or drug withdrawal symptoms; 4 history of trauma 3 months before the start of tremor; 5 clinical evidence of psychogenic tremor; 6 sudden start tremor.

At present, there are many diagnostic criteria, but the differences are very large. Louis et al. analyzed the diagnostic criteria of 10 sets of ETs in 1998 and found that they differed by 30 times because the standards were postural or/and operational tremors and severe tremors. The degree, positive family history, and duration of the disease vary. Clinical diagnosis is only related to postural tremor or / and action tremor and tremor severity.

Genetic diagnosis helps to confirm the diagnosis of ET.

Differential diagnosis

(1) Variability Physiological tremor is caused by the strengthening of physiological tremor. Such as the application of adrenaline, hyperthyroidism, anxiety, fatigue and other tremors.

(2) idiopathic tremor: a dominant genetic disease, manifested as head, jaw, limb involuntary tremor, tremor frequency can be high or low, high frequency is similar to hyperthyroidism; low frequency is similar to Parkinson's tremor. The disease has no reduction in exercise, increased muscle tone, and posture reflex disorder, and disappears after drinking, and the treatment is effective.

(3) The most clinically confusing disease with ET is PD or Parkinson's syndrome. Some scholars have found that there is a high proportion of ET in the family of PD patients; at the same time, there is a high proportion of ET-PD in ET. And often the onset of ET precedes PD; so some scholars believe that ET is a PD type. However, many scholars believe that ET and PD are two different diseases. Clinical identification mainly depends on the form of tremor and signs of the nervous system. PD can have action tremors, but resting tremors are more typical. Static tremor can be found in different parts of the body, often asymmetrical, and the most typical manifestation is the sputum-like action. It is caused by the flexion and extension of the elbow, the pronation of the forearm, and the movement of the thumb. The frequency is 4-6 Hz. The typical resting tremor disappears with the start of the exercise, and can also be converted to posture after the course of the disease. Dopaminergic medication usually improves tremors. In addition to different forms of tremor, PD also has signs of nervous system such as muscle stiffness and decreased movement.

Physiological tremors occur only when maintaining a certain posture, and can be aggravated and become a symptom in certain situations and when using special drugs, such as anxiety, nervousness, fear, exercise, hypoglycemia, thyrotoxicosis, alcohol ring. Broken and some drugs, the frequency of the hand is 6 ~ 12Hz, generally have the corresponding psychological or medical history characteristics, remove the trigger factor symptoms can disappear.

In addition, the disease needs to be differentiated from tremors caused by other diseases such as cerebellar lesions, demyelinating diseases, multiple sclerosis, etc., combined with the characteristics of the corresponding diseases is not difficult to identify. Functional tremor: Common functional tremors include physiologic tremor, rickets, and others. 1 Physiological tremor is strengthened, mostly posture tremor, which is larger than the amplitude of physiological tremor, so it is visible to the naked eye. The cause is believed to be related to an enhanced response to adrenergic receptors. It can be seen that when a normal person is in panic, sputum, anxiety or fatigue, the adrenaline bifurcation also increases. When peripheral neuropathy occurs, the muscle strength at the distal end of the limb is slightly reduced, which can strengthen physiological tremor. Physiological tremor enhancement is also seen in pheochromocytoma, hypoglycemia, hyperthyroidism, cocaine, and alcohol. It is still seen in the side effects of certain drugs. 2 rickets, most of them are action tremors, but also those with static tremors. The tremor is mostly limited to one limb or to the whole body. The magnitude varies, and there is often no regularity. Most of them are relatively large and sometimes shaken. When distracting the patient's attention, the tremor is often slowed down by 3; when the focus is on the tremor, the symptoms are more severe. There are often causes of psychogenicity, or other signs of rickets. 3 Other functional tremors, the tremors presented during fine movements are functional tremors, such as surgeons' surgical operations, intense writing, etc. The tremors that occur at this time are related to emotional stress.

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