Essential tremor: causes, symptoms and treatments

There are a lot of neurological disorders, all with different causes and which can produce a lot of symptoms, depending on the area (s) they affect. Some of them are related to movement control. Of these, Parkinson’s disease is particularly well known, but there are many problems with similar symptoms.

One of them, which is often confused with the previous disease and which is very common, is essential tremor or tremor.

    Essential tremor: characteristics and symptoms

    Essential tremor is a very common neurological disorder in the population, especially in those over 65, characterized by the presence of involuntary and persistent rhythmic tremors or tremors. These shocks occur mostly in the hands and arms, usually in both limbs at the same time and symmetrically. It is also common for tremors to appear on the face and can also affect the voice. Although it is not that common, the same sometimes happens to the legs.

    These tremors occur when the subject performs voluntary movements or maintains certain postures such as stretching the arms, eating, writing, or driving. These shocks can vary in intensity depending on the moment, and without treatment they can get worse with age.

    Typically and unless it overlaps with other disorders (it can appear in conjunction with conditions such as Parkinson’s disease), essential tremor is confined only to the motor domain. In other words, essential tremor by itself does not cause cognitive impairment or other alterations. It is not dementia or a neurodegenerative disease.

    While the main symptoms are the aforementioned tremors (although fatigue and weight loss can sometimes occur) when performing actions or maintaining postures, and do not cause mental deterioration, this disease can become very disabling in different aspects of life.

    For example, actions that require precision like sewing or even drinking from a glass can be very complicated. It is not uncommon for those who suffer from it to also have depressive symptoms. Some people may need to quit their jobs (eg, a surgeon) or seek alternative transportation (driving is extremely dangerous).

    This disease usually appears between the ages of forty and 65. However, cases have been detected at all ages, be able to appear even in childhood.

    Causes of the disorder

    In this mess alterations in the nerve connections of the different nuclei that regulate movement, Such as the cerebellum, thalamus, or black streaky pathway. However, the causes of these alterations are not currently fully understood.

    Data and evidence show that there is a genetic origin in a high percentage of cases. In several families mutations have been localized in the D3 receptor gene, But does not occur in all cases. The genes involved vary depending on the study. But there is also an environmental influence, because there are also sporadic cases in which there is no genetic inheritance.

    Similarities and differences with Parkinson’s disease

    It was previously mentioned that this disease is often confused with Parkinson’s disease for several reasons. The causes of this confusion are based on the similarity of its symptoms and certain neurological features. Additionally, in some cases, people with essential tremors have a predisposition to Parkinson’s disease, which may or may not develop.

    In both cases, we find the presence of involuntary tremors. However, while in Parkinson’s disease, resting tremors stand outIn essential tremors, tremors occur when the subject performs a movement or posture.

    Another common aspect is that in Parkinson’s disease we see a large black striped road assignment, With transmission problems of the neurotransmitter dopamine. In essential tremor, there may also be involvement, degeneration or hypofunction of this pathway, although this is not essential.

    However, in Parkinson’s disease, the presence of so-called Lewy bodies in this pathway can be observed. In many studies carried out so far, they are not present in essential tremors, although in recent literature cases have been found in which they were also present, usually in cases with a predisposition to Parkinson’s disease. . In other cases, they have been found in the cerebellum.

    It also highlights the fact that with regard to pharmacological treatmentSubstances useful in one disorder generally have no effect on the other. For example, L-dopa used in Parkinson’s disease is generally not helpful in essential tremor. There are exceptions such as certain surgeries and drugs such as zonisamide, which in many cases is beneficial for both conditions.

    Usual treatments for essential tremors

    Essential tremor is a disease that he is not currently receiving curative treatmentRather, the treatments aim to reduce the tremors present in him and to improve the patient’s quality of life.

    Essential tremor usually gets worse with the consumption of certain stimulants like coffee, which is why this substance is generally contraindicated. Alcohol in small doses may cause some decrease in tremors, but care should be taken with the doses and over time it can make the condition worse. It has been observed that the shocks may be weaker when performing movements using elements that have a certain weight.

    In terms of pharmacological treatment, different substances such as primidone (1 anticonvulsant) or beta-blockers such as propranolol are generally used. Antidepressants and anxiolytics are also sometimes used. The choice of the drug in question will depend on the characteristics of the patient or its possible side and / or unwanted effects (for example, propanolol lowers blood pressure).

    Another treatment used is botulinum toxin or botox injections, Especially in areas such as the hands or the head, which decrease the intensity of the tremors.

    When the tremors are severe or very debilitating, you may also choose to have surgery. In this sense, deep brain stimulation is generally used, in which a device is installed which has been stimulated by electrical impulses from different points of the brain in a similar way to how a pacemaker would act or to repetitive transcranial magnetic stimulation. . In the most severe cases, it is also possible to opt for excision of part of the thalamus.

    Bibliographical references:

    • Bermejo, PE; Ruiz-Huete, C. and Terrón, C. (2007). Relationship between essential tremors, Parkinson’s disease and Lewy body dementia. Tower. Neurol. 45; 689-694.
    • Labiano-Fontcuberta, A and Benito-León J. (2012) Essential Tremor: an update. Clinical Medicine, 140 (3). 128-133.
    • Lucotte, G .; Lagarde, JP; Funalot, B. and Sokoloff, P (2006). Link with the Ser9Gly DRD3 polymorphism in essential tremor families. Clin Genet; 69: 437-40.
    • Schuurman, PR; Bosch, DA; Bossuyt, PMM et al (2000) .. A comparison of continuous thalamic stimulation and thalamotomy to suppress severe tremors. N Engl J Med .; 342: 461-468.

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