For lovers of active lifestyles, feelings after exercise are well-known: a pleasant fatigue is poured into the body, with added strength and a rising mood. But sometimes, after insignificant loads, people are literally crushed by excessive fatigue. This is the fault of muscle weakness.
Muscle weakness, or myasthenia, is an autoimmune neuromuscular disease. It is accompanied by fast fatigue of transversal muscle, performing key functions in the locomotor system.
The disease may have an objective character-a decrease in muscle strength is confirmed by a special examination; And subjective - when examining muscle strength is maintained, but weakness is present.
Muscle weakness: neurological causes
In fact, there can be many reasons for developing muscle weakness. The main cause of myasthenia is violation of innervation. Simply put, weakness in the muscles develops due to the defeat of the joints of nerves with muscles (synapses).
A substance that provides innervation of the muscle - acetylcholine. Perceiving acetylcholine as a foreign body substance, the immune cells begin to produce antibodies against it.
The trigger mechanism may be normal stress or infectious diseases. As a result, the nervous impulse in the muscle is disturbed. But with myasthenia, muscle fibers retain motor abilities and do not atrophy. All because the violation of the nerve impulse includes additional backup systems. It is they who maintain the muscular performance.
From neurological causes to muscle weakness can lead to the following diseases:
- Nerve damage
- Multiple sclerosis;
- Cerebral palsy, etc.
Muscle weakness: hormonal causes
Another important factor in the development of myasthenia is hormonal disorders in the body. Again, this is due to a violation of the immune system.
It is known that the thymus gland is responsible for maintaining immunity in the body. It is located in the thoracic department, next to the thyroid gland. Pathological changes in this gland lead to an incorrect reaction of the organism as a whole.
In myasthenia, myasthenia also find antibodies to the thymus gland epithelium cells, as well as to the skeletal (cross-banded) muscles, or more precisely to the protein of the cholinergic receptors. Antibodies destroy cell membranes, thus preventing the normal work of binding acetylcholine to muscle receptors.
As a result, the thymus gland is affected and the transmission of nerve impulses to the muscles is disturbed. This often leads to the growth of the gland and the need for its removal.
Endocrinological diseases in which myasthenia develops:
- Addison's disease;
- Hyperparathyroidism and others.
Other causes of muscle weakness
For some signs of muscle weakness refer to genetic diseases. It is believed that the cause of myasthenia development can be a mutation of the gene responsible for the transmission of neuromuscular synapses. That is, the basis of the cause of the disease is also the termination of the transfer of nerve impulses to the muscles. But this assumption has not yet been sufficiently studied.
Muscular weakness can cause the following diseases:
- Dermatomyositis or polymyositis;
- Muscular dystrophy;
- Mitochondrial myopathy;
- Various poisoning;
- Poliomyelitis and others.