Motor neuron disease

Introduction to motor neuron disease Motor neuron disease (MND) is a group of chronic progressive neurodegenerative diseases with unknown etiology that selectively invade the spinal cord anterior horn cells, brainstem motor neurons, cortical pyramidal cells, and pyramidal tracts. The incidence rate is about 1 to 3/100,000 per year, and the prevalence rate is 4 to 8/100,000 per year. Since most patients die within 3 to 5 years after the onset of symptoms, the prevalence of the disease is close to the incidence. The etiology of MND is still unclear. It is generally thought to be caused by the exposure of genetically susceptible individuals to the unfavorable environment with age, that is, genetic factors and environmental factors together cause motor neuron disease. basic knowledge The proportion of illness: 0.02% Susceptible people: no special people Mode of infection: non-infectious Complications: amyotrophic lateral sclerosis

Motor neuron disease etiology

Etiology and pathogenesis:

Motor neuron disease prevention As the cause of this disease is unknown, there are no special precautions. Anyone who is involved in the cause of the disease, such as heavy metal contacts, should have regular health checks, paying particular attention to changes in muscle strength for early detection and early treatment. Usually, you should pay attention to physical exercise and emotional adjustment, keep your mood happy, avoid irritating and other mental stimuli. After middle age, it is better to live alone, reduce sexual intercourse, diet should be light, creamy and spicy. It is appropriate to prevent adverse factors such as spleen and kidney yang deficiency, liver and kidney yin deficiency.

Motor neuron disease complications Complications amyotrophic lateral sclerosis

The disease is a progressive disease, but the course of different types of patients is different, even if the same type of patients progressed slowly, the average course of amyotrophic lateral sclerosis is about 3 years, and the progress is fast or even after the onset 1 It can die within the year, and the course of slow progress can sometimes be more than 10 years.

Adult type of spinal muscular atrophy generally develops slowly, and the course of disease often lasts for more than 10 years. Primary side sclerosis is rare in clinical practice, generally slower in development, mostly due to ball paralysis, respiratory muscle paralysis, combined with pulmonary infection or systemic failure. Caused.

Motor neuron disease symptoms Common symptoms Cough, swallowing difficulty, reflexes, muscle atrophy

According to the most severely damaged nervous system, the clinical symptoms vary according to the location of the lesion. The specific classification is as follows:

1. Amyotrophic lateral sclerosis (ALS ): the most common, the age of onset is 40-50 years old, more men than women, the onset of disease is hidden, slowly progressing, clinical symptoms often begin at the distal end of the upper extremity, showing the hand Muscle atrophy, weakness, gradually forward arm, upper arm and scapula belt development; atrophic muscle has obvious fasciculation; at this time, the lower limbs are upper motor sputum, showing increased muscle tone, hyperreflexia, pathological signs positive, symptoms Usually from one side to the other side, the basic symmetry damage, with the development of the disease, can gradually appear medulla, cerebral palsy nerve movement nuclear damage symptoms, tongue muscle atrophy, dysphagia and speech vague; late influence on head muscle strength And respiratory muscles, the main clinical features of ALS: simultaneous damage of upper and lower motor neurons.

2, progressive medullary paralysis : the lesion is limited to the anterior horn cells of the spinal cord, does not affect the upper motor neurons, this type can be divided according to the age of onset and lesions:

(1) Adult type (distal type): occurs mostly in middle-aged males. It starts from the distal end of the upper extremity and develops from the hand to the proximal end. There is obvious muscle atrophy and muscle weakness, sputum reflexes, and muscle fasciculation. Development to the lower limbs or neck muscles, causing respiratory paralysis, very few can develop from the distal to the proximal.

(2) juvenile type (near-end type): most of them start from adolescence or childhood, have a family history, are autosomal recessive or dominant inheritance, clinically with pelvic and proximal limb muscle weakness and muscle atrophy, walking When the gait is unstable, the abdomen is convex when standing, and the scapula and the proximal muscles of the upper limbs are weak and muscle atrophy, and there is a anterior horn stimulation (muscle beam tremor), and the supine position is not easy to get up.

(3) Infant type: It is an autosomal recessive genetic disease, which occurs in the mother or within one year after birth. The clinical manifestations are muscle weakness and atrophy of the limbs and trunk. Therefore, the fetus in the mother is significantly reduced in fetal movement. Or disappear, the child with morbidity after birth is weak, obvious purpura, systemic flaccid muscle weakness and muscle atrophy, atrophy begins with the pelvic and proximal limbs, develops to the scapula, the neck and the distal extremities, cranial nerve innervation The muscles are also extremely vulnerable, but the muscle tremors are rare in the clinic, and the intelligence, sensory and autonomic functions are relatively intact.

3, progressive muscular atrophy : after the onset of 40 years old, early symptoms of medullary lesions, patients may have atrophy of the tongue muscle fibrillation, difficulty swallowing, drinking water cough and language vague, etc., late damage to the pons and brain The brain stem bundle can be combined with the performance of pseudobulbar paralysis, such as hyperactivity of the limbs and the pathological reflex.

4, primary lateral sclerosis : middle-aged males have more morbidity, clinically slow-developing limbs of motor neurons, muscle weakness, increased muscle tone, hyperreflexia and pathological signs, generally less muscle atrophy, Does not affect the sensory and autonomic function, can invade the cortical medullary bundle of the brain stem, showing pseudobulbar paralysis.

The clinical manifestations are the slow progression of tonic muscle weakness. In primary lateral sclerosis, the muscle weakness of the distal part of the limb is the main weakness. In the progressive pseudobulbar medulla, the muscle weakness of the posterior cranial nerve is dominant. Muscle twitching and muscle atrophy can occur many years later. These diseases usually cause a total loss of patient mobility after several years of progression.

Examination of motor neuron diseases

1. The cerebrospinal fluid examination is basically normal.

2, EMG examination can be seen from the self-generated position, nerve conduction rate is normal.

3, muscle biopsy can be seen neurogenic muscle atrophy.

4, head, neck MRI can be normal.

Diagnosis and diagnosis of motor neuron diseases

1, cervical spondylosis: upper limb or shoulder pain, and staged segmental sensory disturbance, no medullary paralysis, imaging examination and sternocleidomastoid EMG are not involved to identify.

2, syringomyelia: the disease is characterized by segmental, separation pain and temperature sensation; according to segmental separation of sensory dysfunction, cervical spinal cord magnetic resonance (MRI) visible cavity.

3, spinal cord tumors and brainstem tumors: different degrees of conduction beam-type sensory disturbances, lumbar puncture, spinal canal obstruction, spinal angiography, CT or magnetic resonance imaging (MRI) showed intra-osseous space-occupying lesions.

4, myasthenia gravis: the same myasthenia gravis easily affects the medulla and limb muscles, but the myasthenia gravis has volatility and other fatigue, it is generally not difficult to identify.

5, multifocal motor neuropathy: clinically similar to motor neuron disease, the main identification is the EMG shows the effect of nerve conduction velocity, especially the discovery of multifocal punctate myelin sheath disease, in addition to this group of patients in the cerebrospinal fluid anti-GMI The positive rate of antibody increase is higher, and sometimes it takes a long time to follow up before identification can be made.

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