What causes sarcoplasmic atrophy and what causes amyotrophy?

Common causes of neurogenic muscular atrophy are disuse, dystrophy, ischemia, and toxicity. Anterior horn lesions, nerve roots, plexus, peripheral nerve lesions, etc. can cause conduction disorders of nerve excitatory impulses, so that some muscle fibers are disused, resulting in disuse amyotrophy. On the other hand, after any part of the motor neuron is damaged, the release of acetylcholine from its terminal part decreases, and the sympathetic nerve nutrition is weakened, resulting in muscle atrophy.

Myogenic muscular atrophy is caused by a disorder of the muscles themselves, and may also include other factors, such as muscular dystrophy in patients with shoulder girdle or faciculoscapulohumeral type, confirmed by morphological examination. Examination of animals with muscular dystrophy using microelectrode techniques shows that functional denervation of myofibers accounts for about 1 3. There are two major types of diseases that can cause "amyotrophy", one is nerve damage called neurogenic amyotrophy, and the other is muscle itself disease called myogenic amyotrophy.

Hello! The main features are muscle weakness in the distal upper extremities, symmetrical toe extension and flexor weakness in the ankle, decreased or absent ankle reflexes, and symmetrical terminal sensory deficits. Motor nerve conduction velocity slows, and sensory nerve conduction velocity slows less [21].

Alejadro et al. [21] mapped their disease genes to . Based on the relationship between PMP22 and surrounding polyneuropathy, the E*** gene was once considered a candidate gene for CMT2B2, but through sequencing and PCR amplification of the E*** gene, it was ruled out that E*** was a pathogenic gene of CMT2B2. CMT4F has also been mapped to CMT2B2, and analysis of its locus and phenotype has revealed that it is not related to CMT2B2, and there is currently no suitable candidate gene for CMT2B2 [21].

Patients with neurological diseases are prone to muscle atrophy, such as cervical spondylosis.

Patients who have been bedridden for a long time or have been immobilized for a long time due to diseases, such as necrosis of the femoral head, fractures, etc.

Long-term malnutrition leads to a decrease in muscle content and a thinning of muscle fibers, which can easily lead to muscle atrophy.

At present, there is no unified classification of muscle atrophy, and we start from the clinical practice and classify the causes of the disease as follows.

1. Neurogenic amyotrophy is mainly caused by spinal cord and lower motor neuron lesions. It is seen in vertebral hyperostosis, intervertebral disc lesions, spinal nerve tumors, arachnoiditis, neuritis, plexopathy, spinal nerve tumors, arachnoiditis, neuritis, plexopathy panicle, nerve injury, syringomyelia, motor neuron disease, Guillain-Barré syndrome, brain lesions, and disuse muscular atrophy due to spinal myeloid lesions.

2. Myogenic amyotrophy is commonly found in muscular dystrophy, dystrophic myotonic disease, periodic paralysis, polyphobic myositis, trauma such as crush syndrome, ischemic myopathy, metabolic myopathy, endocrine myopathy, drug-induced myopathy, neuromuscular transmission disorder myopathy such as myasthenia gravis, etc.

3. Disuse amyotrophic upper motor neuron lesions are caused by long-term inactivity of muscles, systemic wasting diseases such as hyperthyroidism, malignant tumors, autoimmune diseases, etc.

4. Amyotrophy of other causes, such as cachexia amyotrophia, sympathetic muscular dystrophy, etc.

There are many causes of muscle atrophy, and when a patient's motor neuron is damaged, the nerves are unable to innervate the local muscles, which can cause muscle atrophy. It is also considered that the patient may be bedridden for a long time and the muscles have not been exercised for a long time, causing disuse atrophy.

Genetic factors.

For example, Duchenne muscular dystrophy, also known as pseudohypertrophic muscular dystrophy, is a genetic disorder. Patients with this type of disease develop in adolescence and have difficulty rolling over, sitting up, and standing up. The disease is rare, there is no way to do it, and muscle atrophy will gradually worsen until death.

Neuropathy. It mainly refers to neurogenic amyotrophic atrophy, such as amyotrophic lateral sclerosis, cerebral infarction, poliomyelitis, etc. Nerve lesions can cause nerve signaling disorders, which can lead to the disuse of some muscle fibers, the reduction of motor capacity, and the disuse of muscle atrophy.

In addition, when neurons are damaged, the release of acetylcholine from their terminals decreases, and neurotrophic effects are weakened, resulting in muscle atrophy.

Trauma: When a fracture occurs, it may cause muscle atrophy in the affected area. On the one hand, during the fracture**, due to the long-term fixation of the affected limb and other reasons, the limb activity is reduced, and disuse muscle atrophy occurs. On the other hand, a fracture may damage the surrounding nerves or cause compression of the spinal cord or nerves, and muscle atrophy may occur in the innervated area.

Other diseases. For example, cervical spondylosis, lumbar disc herniation, tumors, etc. can cause compression of the spinal cord and nerves in the corresponding parts, which may cause muscle atrophy;

Anorexia, malnutrition, Cushing's syndrome, hyperthyroidism, etc. can also cause muscle atrophy;

Inflammatory diseases, such as myositis, arthritis, and chronic infection can also cause muscle atrophy.

1.Ptosis eyelids: most common. It is manifested by drooping of one or both eyelids, diplopia, which may be relieved or disappeared after sleep rest, and worsened again after awakening.

2.Weakness of the limbs: Feeling weakness in the limbs, difficulty standing up, going upstairs, holding objects, or raising arms over the head.

3.Whispered voice: When you speak too much or too long, your voice becomes deeper and nasal. Difficulty chewing and swallowing.

4.Cough weakness: cough weakness and dyspnea occur when the intercostal muscles are affected. Failure to maintain ventilation is also referred to as a "crisis".

5.Symptoms of various types of muscle weakness are more likely to worsen in the afternoon or evening and lessen in the morning and after rest.

6.Weakened muscles but no sensory impairment.