Amyotrophic lateral sclerosis
The content of the article:
- Causes and risk factors
- Forms of the disease
- Symptoms
- Diagnostics
- Treatment
- Possible complications and consequences
- Forecast
Amyotrophic lateral sclerosis (ALS) is an irreversible neurodegenerative disease characterized by primary damage to the upper and lower motor neurons (nerve cells that carry out motor coordination and maintain muscle tone).
Damage to the lower motor neuron leads to a progressive decrease in tone and, as a consequence, muscle atrophy, while damage to the upper motor neuron leads to the development of spastic paralysis and the appearance of pathological reflexes.
For the first time amyotrophic lateral sclerosis was described in 1869 by Jean-Martin Charcot. ALS is often referred to as Lou Gehrig's disease, after the famous baseball player who was diagnosed in 1939.
The disease is rare, however, the reliable incidence of ALS is unknown: in European countries, the incidence, according to various sources, ranges from 2 to 16 cases per year per 100,000 population, while international studies speak of 1–2.5 cases. Men get sick more often, the manifestation usually occurs at the age of 58–63 years with a sporadic form, the hereditary variant of ALS often debuts at the age of 47–52 years.
Stephen Hawking - famous scientist diagnosed with amyotrophic lateral sclerosis
Every year, amyotrophic lateral sclerosis affects about 350,000 people worldwide, about half of whom die within 3-5 years of diagnosis.
Synonyms: amyotrophic lateral sclerosis, motor neuron disease, motor neuronal disease, Charcot's disease, Lou Gehrig's disease.
Causes and risk factors
The vast majority of ALS cases have an unclear etiology; genetic predisposition is traced in no more than 5-10% of cases.
To date, 16 genes have been reliably identified, the mutation of which is associated with the onset of the disease:
- SOD1 on chromosome 21q22 (encoding Cu-Zn-ion-binding superoxide dismutase), currently there are about 140 known mutations of this gene that can lead to the development of ALS;
- TARDBP, or TDP-43 (TAR-DNA-binding protein);
- SETX at chromosomal locus 9q34, encoding DNA helicase;
- VAPB (responsible for vesicle-associated protein B);
- FIG4 (encodes phosphoinositide 5-phosphatase); and etc.
Most inherited cases of the disease are characterized by an autosomal dominant mode of inheritance. The mutation in this case is inherited from one of the parents; the likelihood of developing ALS is about 50%.
Autosomal recessive or dominant X-linked inheritance is much less common.
The main cause of amyotrophic lateral sclerosis is gene mutation
The remaining 90-95% of cases of amyotrophic lateral sclerosis are sporadic: there are no cases of such a disease in the families of patients. The role of external factors is unlikely here, although research on this topic is ongoing.
Forms of the disease
There are several clinical forms of the disease:
- classic spinal form with signs of damage to the central and peripheral motor neurons of the upper or lower extremities (cervicothoracic or lumbosacral localization);
- bulbar form, starting with disorders of swallowing and speech, motor disorders join later;
- primary lateral form, manifested by a predominant lesion of the central motoneurons;
- progressive muscular atrophy, when the leading symptoms are damage to peripheral motor neurons.
Rarely, the disease begins with weight loss, respiratory disturbances, weakness in the upper and lower extremities on the one hand - this is the so-called diffuse debut of ALS.
The disease can have different rates of progression: fast (death within a year, is rare), medium (duration of the disease from 3 to 5 years), slow (longer than 5 years, is rare, in about 7% of patients).
Symptoms
There is a widespread opinion about a rather long preclinical stage of the disease, which cannot be diagnosed at the present level of development of medicine.
A typical clinical picture of amyotrophic lateral sclerosis
It is suggested that during this period, from 50 to 80% of all motor neurons undergo death, and under the created conditions, their function is assumed by the remaining motor neurons. As a result of functional overload (with depletion of the adaptive capabilities of nerve cells), the corresponding symptoms develop:
- muscle atrophy and decreased motor activity;
- fasciculations (muscle twitching);
- violation of fine motor skills;
- change in gait, imbalance;
- difficulty in chewing, swallowing;
- shortness of breath with light exertion, difficulty breathing while lying down;
- inability to maintain a static posture for a long time;
- convulsions;
- pathological reflexes;
- sagging feet;
- psycho-emotional disorders (apathy, depression).
In ALS, 50-80% of all motor neurons die
There are no changes in the intellectual sphere in patients with amyotrophic lateral sclerosis; patients remain critical of the disease. Social activity is limited by decreased exercise tolerance, difficulty in self-care, and impaired fluency.
Diagnostics
There are no specific methods for confirming the reliability of the diagnosis. The diagnosis is based on two facts:
- combined damage to the central and peripheral motoneurons;
- steady progression of the disease.
According to research data, an average of 14 months pass from the moment the first clinically significant symptoms appear to the diagnosis.
Some ALS patients experience changes on MRI
The plan for examining patients with suspected amyotrophic lateral sclerosis includes the following diagnostic methods:
- needle and stimulation electromyography;
- magnetic resonance imaging of the brain and spinal cord;
- transcranial magnetic stimulation.
Treatment
The main direction of treatment of patients with amyotrophic lateral sclerosis is symptomatic therapy aimed at reducing the severity of painful manifestations.
Etiotropic treatment is not carried out, since the causes of the disease have not been established.
At the moment, research is underway on the use of an inhibitor of the release of glutamate, the drug Riluzole (Rilutek); its ability to increase life expectancy by 1-6 months has been proven. Tests are carried out abroad, the drug is not registered in the Russian Federation.
Passive remedial gymnastics and massage are beneficial for all stages of ALS
Arimoklomol was recently approved in the United States and is also currently being tested in patients. In an experiment on transgenic mice with ALS, Arimoklomol increased muscle strength in the limbs and slowed down the progression.
Possible complications and consequences
Complications of amyotrophic lateral sclerosis:
- breathing disorders due to damage to the diaphragm;
- exhaustion due to impaired chewing and swallowing.
Forecast
Amyotrophic lateral sclerosis is an incurable, steadily progressive disease.
During the first 30 months after diagnosis, about 50% of patients die. Only 20% of patients have a life expectancy of 5-10 years from the onset of the disease.
Advanced age, early development of respiratory disorders and debut with bulbar disorders are the least favorable prognostically. The classic form of ALS in young patients, combined with a lengthy diagnostic search, usually indicates a higher survival rate.
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Olesya Smolnyakova Therapy, clinical pharmacology and pharmacotherapy About the author
Education: higher, 2004 (GOU VPO "Kursk State Medical University"), specialty "General Medicine", qualification "Doctor". 2008-2012 - Postgraduate student of the Department of Clinical Pharmacology, KSMU, Candidate of Medical Sciences (2013, specialty "Pharmacology, Clinical Pharmacology"). 2014-2015 - professional retraining, specialty "Management in education", FSBEI HPE "KSU".
The information is generalized and provided for informational purposes only. At the first sign of illness, see your doctor. Self-medication is hazardous to health!
