Tremor: causes, symptoms, diagnosis, treatment

Tremor - involuntary vibrations of any part of the body caused by alternating or synchronous contractions of reciprocally innervated muscles.

Diagnosis of the disease underlying the tremor is often a very difficult task, the solution of which requires, first of all, the correct syndrome description of the tremor. In connection with the above, great importance is attached to the principles of clinical description of tremor.

• The most important principle is a clear delineation of 3 types of tremors: rest tremor, postural tremor and intentional trembling. If the same patient is diagnosed not only with the tremor of rest, but also postural or intentional tremor, then all types of jitter are described and recorded as separate independent species, necessarily emphasizing the relative severity of each of them. For example, a patient may have a rough resting tremor, a less pronounced postural tremor and an even less pronounced intentional tremor. Such a picture is typical for severe trembling forms of parkinsonism. These components of the trembling outside the framework of parkinsonism usually have different relationships: either postural tremor (which is typical for severe essential tremor) or intentional (with lesions of the cerebellum) predominates.
• Other important principles of the tremor description are as follows:
  • Localization (hands, head, facial muscles, lower jaw, tongue, lips, cheeks, vocal cords, legs, trunk), features of distribution (by hemitip, generalized, etc.), as well as other topographic features (for example, thumb trembling or muscles of the abdominal wall, trembling of the eyeballs or orthostatic tremor, distal or proximal accentuation of jitter, symmetry / asymmetry).
  • Motion picture of jitter (flexion-extension, pronation-supination, like "rolling down pills", "yes-yes", "no-no", flapping).
  • Amplitude-frequency characteristics, severity of jitter, features of its flow (variants of debut and subsequent dynamics).
  • The syndromal environment of tremor, that is, a description of those neurological symptoms, against which jitters appear.

Observance of the above principles of the description of the syndrome of jitter is a necessary prerequisite for successful differential and nosological diagnosis of tremor.

What causes a tremor?

• The tremor of rest (3,5-6 Hz).
  • Parkinson's disease.
  • Secondary (symptomatic) parkinsonism.
  • Syndromes of "parkinsonism plus" and other hereditary degenerative diseases, accompanied by Parkinson's syndrome (Wilson-Konovalov's disease, Gallervorden-Spatz and many others).
• Postural tremor (6-12 Hz).
  • Physiological tremor.
  • Reinforced (accentuated) physiological tremor (with stress, endocrine diseases, intoxication).
  • Benign essential tremor (4-12 Hz): autosomal dominant, sporadic, in combination with certain diseases of the central nervous system (Parkinson's disease, dystonia) and the peripheral nervous system (polyneuropathy, reflex sympathetic dystrophy).
  • With organic pathology of the brain (toxic, tumor and other cerebellar lesions, Wilson-Konovalov's disease, neurosyphilis).
• Intensive tremor (3-6 Hz) is caused by damage to the brainstem, the cerebellum and their connections (multiple sclerosis, degeneration and atrophy in the trunk and cerebellar region, Wilson-Konovalov's disease, vascular diseases, tumors, intoxications, CCT, etc.).
• Rubral tremor.
• Psychogenic tremor.

Neurochemical changes in tremor

A study of the brain of deceased patients with essential tremor did not reveal any specific pathomorphological changes or a certain neurochemical defect. Although the lesions of the cerebellar efferents or afferents can cause a tremor, whether it is based on any specific neurochemical defect, remains unclear. Neuroimaging studies help identify neuronal circles involved in the pathogenesis of tremors.

Types of tremors

The tremor of rest

The restless tremor usually has a frequency of 3.5-6 Hz. Low-frequency (usually 4-5 Hz) resting tremor refers to typical manifestations of Parkinson's disease, as well as many other diseases of the nervous system accompanied by Parkinson's syndrome, which is why it is often called parkinsonian tremor. Secondary (symptomatic) parkinsonism (vascular, post-encephalitic, drug, toxic, post-traumatic, etc.) also usually manifests as a tremor (although it is less characteristic of vascular forms of parkinsonism), which has the same characteristics as Parkinson's disease (low-frequency rest tremor with a characteristic distribution, current and tendency to generalization).

Postural tremor

Postural tremor appears in the limb when it is held in any position. This jitter has a frequency of 6-12 Hz. Postural tremor includes physiological tremor (asymptomatic tremor), strengthened (accentuated) physiological tremor that occurs when emotional stress or other hyperadrenergic states (thyrotoxicosis, pheochromocytoma, caffeine, noradrenaline and other drugs), essential tremor, and tremor in Some organic diseases of the brain (severe cerebellar disease, Wilson-Konovalov's disease, neurosyphilis).

Intensive tremor

Intense jitter has a characteristic motor pattern, its frequency is 3-5 Hz. Intensive tremor is characteristic for the damage to the brain stem, cerebellum and its connections (multiple sclerosis, degeneration and atrophy of the cerebellum and brainstem, Wilson-Konovalov's disease, as well as vascular, tumor and toxic lesions of this area of the brain). Their diagnosis is carried out by the characteristic concomitant neurological symptoms, indicating the involvement of gray and white matter in the trunk and cerebellum, often with a typical picture on CT or MRI.

It should be remembered that the cerebellar variants of tremor include not only intentional tremor, but also phenomena such as titration, which is manifested by rhythmic oscillations of the head and sometimes the trunk (especially noticeable when the patient is standing), postural tremor of the proximal parts of the extremities (hip or plast).

Rubrial tremor

Rubrular tremor (more correct name - mid-cerebral tremor) is characterized by a combination of a tremor of rest (3-5 Hz), an even more pronounced postural tremor and the most pronounced intentional tremor (tremor intestinal → tremor postural → tremor of rest). It appears with damage to the midbrain in stroke, brain injury or, more rarely, with a tumor or demyelinating (multiple sclerosis) process in the legs: the brain. This tremor appears in the extremities opposite to that of the midbrain.

Psychogenic tremor

Psychogenic tremor is one of the variants of psychogenic motor disorders. The clinical criteria of psychogenic tremor include a sudden (usually emotion-like) onset, a static or undulating (but not progressive) course, the presence of spontaneous remissions or remissions associated with psychotherapy, the "complex" nature of the tremor (all major types of tremor can equally be presented) the presence of clinical dissociation (selective preservation of certain limb functions in the presence of gross tremor in it), the effectiveness of placebo, as well as some additional signs (including complaints, anamnesis and results of a neurological examination), confirming the psychogenic nature of the disorder.

Physiological tremor

Physiological tremor is normal, but manifests itself in such small movements that it becomes noticeable only under certain conditions. Usually it is a postural and intentional tremor, low-amplitude and fast (8-13 in 1 second), revealed when stretching the arms. Physiological tremor increases in amplitude with anxiety, stress, fatigue, metabolic disorders (for example, hyperadrenergic states when alcohol, drug or thyrotoxicosis is abolished), in response to the administration of a number of drugs (eg, caffeine, other inhibitors of phosphodiesterase, beta-adrenergic receptor agonists, glucocorticoids ). Alcohol and other sedatives usually suppress tremor.

If no serious treatment complaints are required. Physiological tremor, which increases when alcohol is abolished or thyrotoxicosis, responds to the treatment of these conditions. Benzodiazepines 3-4 times a day (eg, diazepam 2-10 mg, lorazepam 1-2 mg, oxazepam 10-30 mg) help with tremor on the background of chronic anxiety, but their long-term intake should be avoided. Propranolol 20-80 mg orally 4 times / day (as well as other beta-blockers) is often effective in case of tremor in the presence of drugs or acute excitement (eg, fear of the audience). If beta-adrenoblockers are ineffective or not tolerated, you can try the primordone 50-250 mg orally 3 times / day. Sometimes small doses of alcohol are effective.

Other types of tremor

As independent phenomena in the literature mention the so-called dystonic tremor (trembling spasmodic torticollis, trembling writing spasm), the syndrome of "rabbit" (neuroleptic tremor of the lower jaw and lips). Phenomenological reminiscent of trembling such rhythmic phenomena as asterixis (flapping, negative myoclonus), myorhythmia, segmental myoclonus, however, by the mechanism of formation they do not refer to tremor.

Special forms of trembling (orthostatic tremor, "tremor of a smile", tremor of the voice, tremor of the chin - geniospasm) are referred to variants of an essential tremor.

The most frequent type of postural and kinetic tremor is an intensified physiological tremor, which usually has a low amplitude and a high frequency (12 cycles / s). Physiological tremor is strengthened after physical exertion, with thyrotoxicosis, the intake of various medications, such as caffeine, adrenomimetics, lithium, valproic acid.

Essential tremor

The next frequent variant of tremor is the so-called essential, or family tremor, which is usually slower than an intensified physiological tremor. Essential tremor can involve limbs, as well as the head, tongue, lips, vocal cords. Tremor increases with stress and in severe cases can lead to disability of the patient. Patients with this variant of tremor often have close relatives suffering from the same disease. However, the localization and severity of tremors within a single family vary considerably. Limbs can be involved asymmetrically, but a strictly one-sided tremor usually indicates a different disease. Tremor often decreases after taking alcohol, but is enhanced by caffeine, stress, or concomitant hyperthyroidism (like an intensified physiological tremor). In different extremities, the tremor is asynchronous - in contrast to the synchronous resting tremor in Parkinson's disease. In this regard, a patient who is unable to keep a cup of liquid by means of a tremor with one hand, not shedding it, copes much better with this task, holding the cup with both hands - asynchronous hand movements partially extinguish each other's vibrations.

To a benign essential tremor, at present not only autosomal dominant and sporadic variants of essential tremor are considered, but also its combination with other diseases of the central and peripheral nervous system, including dystonia, Parkinson's disease, peripheral neuropathies (CVD, hereditary sensorimotor neuropathy I and II types, GBS, uremic, alcoholic and other polyneuropathies).

There are several variants of diagnostic criteria for essential tremor, one of the most frequently used is given below.

Diagnostic criteria for essential tremor (Rautakoppi et al., 1984).

1. Often appearing (at least several times a week) or a constant tremor of limbs and / or head.
2. The postural or kinetic nature of the tremor {the presence of an intential component is also possible).
3. Absence of other neurological diseases that can cause a tremor.
4. Absence of anamnestic indications for the treatment of any drugs that can cause a tremor.
5. Instructions in a family history for a similar tremor in other family members (confirm the diagnosis).

Tremor can occur with other extrapyramidal diseases, for example, in myoclonic dystonia, characterized by rapid muscle twitching. As individual variants, orthostatic tremor and isolated postural tremor are isolated. Currently, there is an active search for a genetic defect in an essential tremor. To date, it was possible to map the gene only in certain family cases, but it has not yet been possible to identify its product. It is possible that the disease has a connection with multiple genes. Different families often differ in their response to alcohol, the presence of concomitant extrapyramidal syndromes (myoclonia, dystonia, parkinsonism). After identifying a genetic defect in different families, it becomes possible to determine which clinical nuances are genetically determined and which simply reflect the phenotypic variability of the disease.

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Cerebrospinal tremor

With lesions of the cerebellum, the tremor usually also has a kinetic and postural character. Low-frequency limb oscillations arise as a result of instability of its proximal part. At the same time, the tremor passes if the limb is stabilized. Differentiation of cerebellar and essential types of tremor usually does not cause difficulties. Cerebrospinal tremor is enhanced when the limb approaches the target, whereas in the case of essential tremor, the amplitude of hyperkinesis remains approximately the same throughout the course of the entire targeted movement. In cerebellar lesions, in addition to tremors, there is also a marked disruption in the coordination of subtle movements, while in an essential tremor, coordination of movements usually does not suffer.

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Treatment of tremors

In the treatment of essential tremor, several drugs are used - beta-adrenoreceptor antagonists, benzodiazepines and primidone. The most effective beta-blockers, which reduce the amplitude of tremor and often cause significant clinical improvement. Low doses of benzodiazepines (especially clonazepam) are also able to reduce the severity of essential tremor. They are used as monotherapy or in combination with beta-blockers. But since tolerance can develop over time, they are recommended not to be used regularly, but, if necessary, for example, before a public event or during a period of special stress. To reduce tremor, alcohol can be used, but the risk of alcoholism limits its use. Nevertheless, drinking alcohol before eating can allow you to more easily take food and liquid. Finally, to reduce the essential tremor, small doses of primidone (25-250 mg / day) are used as monotherapy or in combination with beta-blockers.

Pharmacotherapy of cerebellar tremor is usually ineffective. However, there are reports of its successful treatment with clonazepam and primidone. An effective approach to the treatment of severe cerebellar tremor may be stereotaxic thalamotomy or microstimulation of the thalamus.