How does alcohol disturb the nervous system? Doctor clearly describes the mechanism

01 September, 2020 г.
How does alcohol affect the nervous system?
- Getting into the stomach, ethanol is partially cleaved by the enzyme alcoholdehydrogenase, and the rest is absorbed into the blood and spread throughout the body. If the enzyme becomes insufficient for oxidation, acetaldehyde accumulates in the body, which is dozens times more toxic than alcohol itself.
Alcohol is "built into" the shells of nerve cells and changes the functioning of a number of receptors and ion channels. This selectivity is due to the fact that the nerve cells contain fatty formations, and alcohol easily dissolves them. The result is a decrease in the reactivity of cells and their death.
How does alcohol affect the brain?
- Ethanol (in large quantities) first blocks the work of the cerebral cortex: a person ceases to control thoughts and actions, the limiting factor is turned off.
Then, the deep parts of the brain are poisoned: speech is disturbed, coordination of movements is disturbed, there is doubling, the ability of hearing and visual perception is weakened, and the gait becomes shaky. The coordination of feelings, emotions and related actions is reduced due to the disturbance of frontal lobes - excessive resentfulness, tearfulness and aggressiveness appear.
Then comes the stage of so-called "alcohol dullness": a person ceases to respond to external influences, falls asleep, his breathing becomes uneven, there is no sensitivity, involuntary emptying of the bladder may occur (this condition is fatal).
In persons who abused alcoholic beverages, at the pathological examination of the skull can be traced destructive changes in the brain - reducing its size, smoothing the curves, the formation of voids in place of the dead areas, centers of spot hemorrhage.
Why is it popular belief that in small doses alcohol helps to relax?
- Low doses of alcohol do trigger the activity of inhibitory gamma-amino-oil acids - brain systems (inhibitory neurotransmitters). This leads to a sedative effect, which is accompanied by muscle relaxation and euphoria. However, the concept of "small doses" is quite relative, and in each country depends on the idea of its negative impact (this can be traced back to the laws on the permitted amount of ethanol in the blood during driving, time of alcohol sale, etc.).


Фото: Reuters


Genetically determined racial differences, historical features of alcohol consumption culture, gender and age differences, and ratios of muscle and adipose tissue do not clearly define a "safe" dose. At the same time, alcohol is a toxic substance, a mutagen, and an addictive substance. The brain begins to use the products of alcohol splitting as a source of energy, and, accustomed to an additional stimulant, does not want to give it up: this is how addiction develops.
How can the habit of soothing oneself with alcohol affect the nervous system?
- The consequences of prolonged alcohol consumption may cause damage to the peripheral and central nervous system (brain).
This is how alcohol can affect the peripheral nervous system:
  • Alcoholic polyneuropathy. Depending on the type of nerve fiber affected, there is a distinction between sensitive, motor, and mixed forms. At an early stage, numbness and sensory disturbances occur in the fingers and toes, tightening the pain in the calf muscle, "cottoniness" of the legs, coldness or "marble" pattern of the skin of the hands and feet. This is followed by a burning sensation, spreading pain, chilblains in the hands and feet, cramps in the calf muscle, pain in the legs, trophic disorders down to ulcers. Vagus and diaphragmatic nerves may be involved, which leads to disruption of respiratory and cardiac activity.
  • Alcoholic neuropathy. Of all cranial nerves, the optic nerve is more often affected, especially when using surrogates: color vision is disturbed, fields of vision narrow, the reaction of pupils to light changes. Often, neuropathies of the radial and peroneal nerves develop. Their defeat is facilitated not only by toxic and dystrophic factors, but also by the compression that occurs during injuries under the influence of alcohol or during deep sleep.
  • Alcoholic myopathy. Weakness in the upper and lower extremities, gait changes, muscle dystrophy develops.
The consequences for the central nervous system:
  • Convulsive syndrome. It may occur both in the state of withdrawal (2-3 days after cessation of alcohol intake), and at the peak of alcohol intoxication. After the seizures may develop mental complications: delusional disorders, hallucinations. Seizures provoked by drinking have a tendency to recur, and this will require treatment in the intensive care unit.
  • Change of small arteries and capillaries. The brain is nourished by a wide blood net, neurons with systematic alcohol consumption begin to experience oxygen deprivation, because of minor hemorrhages there is a high risk of brain hemorrhagic infarction.
  • Prolonged exposure of ethanol to cerebellum (cerebellar syndrome) leads to trembling of limbs, development of coordination disorders up to inability to move, stand and sit independently.
  • Encephalopathy. In case of long-term alcohol addiction, its acute stage appears first, and then (if the disease did not end lethally) it turns into chronic. Acute alcoholic encephalopathy begins with heart and abdominal pain, thirst, vomiting, general weakness, lack of appetite, shaky walking, trembling hands. Then develops a characteristic triad: eye disorders, extrapyramidal symptoms (motor disorders and changes in muscle tone), mental disorders. Fatal outcome may occur due to cerebral edema or joining other diseases.
When do I need to see a doctor?
- When alcohol is taken in larger than planned quantities or for a longer time than the person intended. When there is a desire to reduce alcohol consumption, but attempts are unsuccessful. When there is a desire to take a breath, alcohol consumption becomes alarmingly high, and the person at this time neglects his or her social and labor responsibilities, does not pay attention to family quarrels, difficulties at work, the development of related diseases and complications that already exist. The person loses interest in his or her appearance. In all these cases, it is not that difficult, but rather impossible to cope on their own, so it is necessary to seek help from a drug psychiatrist.

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