Hirayama disease is also known as distal upper limb muscular atrophy in young people. It is a benign self-limiting motor neuron disease first reported by Japanese scholar Keizo Hirayama in 1959, which is clinically similar to motor neuron disease amyotrophic lateral sclerosis and spinal progressive myasthenia with a very different prognosis. The disease occurs in adolescence and is more common in males. The ratio of males to females is about 20:1. Muscle atrophy refers to transverse muscle dystrophy, with a smaller than normal muscle size and thinning or even loss of muscle fibers. Neuromuscular disease hypertrophy. In addition to the pathological changes in muscle tissue itself, muscle dystrophy is more closely related to the nervous system. Spinal cord disease often leads to muscle dystrophy and muscle atrophy. A. Clinical manifestations Typical Hirayama disease manifests as muscle weakness in the hand and distal forearm with insidious onset in early adolescence, with progression of the lesion gradually appearing corresponding muscle group atrophy, mostly unilateral damage, some may also show asymmetric bilateral damage. Most patients have “cold palsy”, i.e., the weakness is significantly aggravated by exposure to cold; bundle tremor does not occur in the quiet state, but often occurs during finger extension; the tendon reflexes of the affected limb are normal or occasionally low, and there is usually no pain, numbness or other sensory impairment, nor is there cone fasciculation, sphincter dysfunction, etc. The disease progresses slowly for several years after the onset, and is easily confused with motor neuron disease such as amyotrophic lateral sclerosis or progressive spinal muscular atrophy, but the majority of patients can naturally discontinue the disease within the next 5 years, and the prognosis is obviously different from that of motor neuron disease. The pathogenesis of Hirayama disease is not very clear, but the pathogenesis is generally considered to be: (1) kinetic factors: Hiarayama et al. believe that the pathogenesis is the repeated flexion of the neck or long-term maintenance of the flexion of the neck posture has led to the anterior displacement of the dura mater from the posterior push on the cervical spinal cord, resulting in impaired circulation and chronic ischemic necrosis of motor cells in the anterior horn of the lower cervical medulla. Thus, clinical trials of cervical collar treatment for this disease are effective, supporting the possibility of a mechanism. (2) Growth and developmental factors: Shinibo et al. suggested that Hirayama disease may be related to a developmental imbalance between the spinal cord and the dura mater. The basis is that (1) the disease occurs mostly in young men with rapid growth in arm length or height, suggesting that the age of onset of Hirayama disease is closely related to the period of rapid growth in height; (2) muscle atrophy appears 2-4 years after onset and stops progressing at the end of the period of rapid growth; and (3) the relative shortening of the anterior cervical medullary roots determines the self-limiting course of the disease. Thus, it is believed that the asymmetric atrophy of the anterior horn of the spinal cord in Hirayama disease, the displacement of the anterior dura in the low cervical segment, and the changes such as the dilatation of the epidural plexus are caused by the imbalance in growth and development between the spinal cord and the dura due to rapid growth and the relative shortening of the anterior root of the cervical medulla. (3) Inelastic, restrictive dural compression: Konno et al. suggest that Hirayama disease is the result of abnormal dural traction restriction that not only affects in the upright position, but also aggravates spinal cord injury during cervical flexion. This view is confirmed by the apparent immediate and long term results of the release of the cervical spinal membrane for the plication procedure. (4) Motor neuron disease theory: Some scholars currently consider Hirayama disease as motor neuron disease, a special type of spinal muscular atrophy between amyotrophic lateral sclerosis, a view that is now increasingly questioned. (5) Ethnic inheritance: The incidence of this disease is gradually increasing in Japan, so the influence of ethnic factors cannot be ruled out. Some scholars have examined the genes of two Hirayama brothers with a family history of amyotrophic lateral sclerosis (ALS). Attempts have been made to show that the occurrence of familial Hirayama disease is associated with gene mutations, especially superoxide dismutase (SOD) gene variants that lead to aspartate substitution for alanine (D9OA), but there are no conclusive findings. (6) Immunological mechanism: Some scholars found that patients with Hirayama disease have allergies, and they all have a family history of allergy or abnormal allergic reactions, suggesting that abnormal immune mechanisms may have some influence in the pathogenesis of Hirayama disease, and that the theory of allergic reactions may be reasonable to explain some phenomena of Hirayama disease, because the number of cases is small, there is no definite conclusion. Classification 1. Classification by pathogenesis (1) Muscle atrophy caused by systemic nutritional disorders, disuse, endocrine abnormalities and muscle degeneration, muscle structural abnormalities and other etiologies. (2)Muscle atrophy caused by genetics, poisoning, metabolic abnormalities, infections, metabolic reactions, etc. This classification is of little clinical significance because the cause is difficult to clarify for a while. 2, according to the distribution of muscle atrophy classification: (1) generalized diffuse muscle atrophy; (2) head and face muscle atrophy; (3) head and upper limbs or upper and lower limbs proximal muscle atrophy; (4) upper and lower limbs distal muscle atrophy; (5) limited muscle atrophy 3, according to the primary lesion leading to muscle atrophy classification (1) neurogenic muscle atrophy. (2) myogenic muscle atrophy. (3) disuse muscle atrophy. Neurogenic muscle atrophy mainly refers to the lesions of lower motor neurons such as anterior horn cells and peripheral nerves of the spinal cord, which belong to primary neurogenic muscle atrophy. The three are interconnected with each other, while upper motor neuron lesions also appear as muscle atrophy, although some people classify them as secondary, and late as disuse atrophy. Myogenic muscle atrophy is caused by a lesion of the muscle itself. Disuse muscle atrophy can also be postulated in systemic wasting diseases. The course of Hirayama disease is self-limiting and the prognosis is good. The following treatment methods are available: (1) Cervical brace treatment: early diagnosis and early treatment with cervical brace can shorten the course of the disease and relieve clinical manifestations. It is recommended that treatment with a neck brace must be carried out for as long as possible. (2) Surgical treatment: Studies have shown that doing duralplasty plus spinal cord release improves the immediate and long-term results. In modern medicine, polyneuritis, spinal cord cavitation, myasthenia gravis, myasthenia gravis, lateral sclerosis, motor neuron disease, periodic paralysis, myotonic dystrophy, hysterical paralysis and the sequelae of central nervous system infections manifesting as flaccid paralysis are all within the scope of “impotence evidence”, “impotence evidence Impotence” is a condition in which the tendons and veins of the limbs become weak and ineffective. Impotent evidence refers to a type of disorder in which the tendons and bones are impotent and soft, the muscles are thin, the skin is numb, and the hands and feet are not used. Clinically, impotence and weakness of both feet and inability to move freely are more common, hence the name “impotence”. From motor neuron disease, systemic nutritional disorders, disuse, endocrine abnormalities caused by muscle degeneration, muscle structure abnormalities, genetics, poisoning, metabolic abnormalities, infection, metabolic reactions and other causes can cause muscle weakness, muscle atrophy, etc.. V. Health care measures Myasthenia gravis patients are bedridden for a long time due to muscle atrophy and muscle weakness, and are prone to complications such as pneumonia and decubitus ulcers, plus most patients have symptoms of medullary paralysis, posing a great threat to patients’ lives. Myasthenia gravis patients, in addition to the doctor’s treatment, self-treatment is very important. 1, maintain an optimistic and happy mood. Strong long-term or repeated mental tension, anxiety, irritability, pessimism and other emotional changes can make the balance of cortical excitation and inhibition process is out of balance, so that the muscle jump aggravates, so that the development of myasthenia gravis. 2, reasonable deployment of dietary structure. Patients with myasthenia need high protein and high energy dietary supplements to provide substances necessary for the reconstruction of nerve cells and skeletal muscle cells in order to enhance muscle strength and muscle growth. In the early stage, high protein, vitamin-rich, phospholipid-rich and trace element foods are used, and actively cooperate with medicinal meals, such as yam, coix seeds, lotus hearts, Chen Pi, prunus seeds, lily, etc. Spicy foods are prohibited, and smoking and alcohol are abstained. For patients in the middle and late stages, high protein, high nutrition, energy-rich semi-liquid and liquid food is the mainstay, and a small number of meals are used to maintain the patient’s nutrition and water-electrolyte balance. 3. Combine labor and rest. Avoid forced sexual exercise, because forced sexual exercise will be due to skeletal muscle fatigue, and is not conducive to the recovery of skeletal muscle function, muscle cell regeneration and repair. 4, strict prevention of colds, gastroenteritis. Myasthenia gravis patients due to their own immune function is low, or there is some kind of immune deficiency, myasthenia gravis patients once the cold, the disease aggravated, the disease prolonged, myasthenia gravis, muscle jump aggravated, especially ball palsy patients prone to complications of pulmonary infection, if not timely prevention and control, the prognosis is poor, and even endanger the lives of patients. 5, gastroenteritis can lead to intestinal strain dysfunction, especially viral gastroenteritis has different degrees of damage to the anterior horn cells of the spinal cord, thus making myasthenia gravis patients with increased muscle jump, decreased muscle strength, recurrent or aggravated disease. Maintaining normal digestive function in patients with myasthenia gravis is the basis of recovery.