Weakness of hands

Introduction The weakness of both hands is one of the symptoms of spinal muscular atrophy. The disease is insidious and occurs in middle-aged men. The performance of the hands is weak and weak, the internal muscles of the hand are atrophy, and there are "claw-shaped hands" and "hands-on" deformities.

Cause

(1) Causes of the disease

Types I to III are autosomal recessive diseases and are the most common lethal genetic diseases in infancy. Type IV is a different genetic pattern such as autosomal recessive, dominant and X-linked recessive.

(two) pathogenesis

The etiology and pathogenesis of SMA has been a problem in neurological research. In recent years, great progress has been made in the research of SMA gene mapping. In 1995, three research groups reported three SMA candidate genes. French Lefebvre et al. found a survival motor neuron (SMN) gene in the 5q13.1 region, which is about 20 kb in length and contains 8 exons. Its transcription product is about 1.7 kb, encoding 294 amino acids, and its function is unknown. The gene has two copies on one chromosome, with a difference of 5 bases between them, called SMNt on the telomere side and SMNc on the centromere side. Studies have shown that SMNt exons 7 and 8 are homozygous deletion or truncation in 98.6% of SMA patients, and 1.4% of patients have small deletions or point mutations, which strongly supports SMN as an important determinant of SMA. Subsequently, Roy et al. cloned the neuronal apoptosis inhibitory protein (NAIP) gene in the 5q13 region, with 16 exons, 70kb in length and encoding 1232 amino acids. 45% SMA-I and 18% SMAII, type III patients have NAIP gene exon 5 and exon 6 deletion, while 2% of normal controls also lack exons 5 and 6, suggesting that NAIP gene is also associated with SMA. . As for adult SMA, only a partial deletion of the SMN gene was found, suggesting similar genetic alterations with childhood SMA, but the genetic location of most patients has not been determined, and the pathogenesis is unknown.

The pathological changes were mainly located in the anterior horn of the spinal cord. The motor cells were significantly reduced and degenerative. The residual nerve cells were pyknosis and nuclear lysis. The anterior root axis mutation was fine and the peripheral cells of the axons were swollen. The brainstem motor neuron degeneration is more common in the facial nerve, vagus nerve and hypoglossal nerve. The muscle pathology examination is shown in the auxiliary examination section below.

an examination

Related inspection

CT examination of cerebrospinal fluid immunoglobulin

1. SMA-I type is also known as Werdnig-Hoffmann disease. About 1/3 of the cases occur in the uterus, and the mother can notice that the fetal movement is weak. Half of the patients started on the first month of life, and almost all cases occurred within 5 months. The incidence rate is about 1 in 10,000 births, and the incidence is equal for men and women. More than shortly after birth, the muscle tone is low, the muscle weakness is mainly affected by the proximal muscles of the extremities, and the trunk muscles are weak. The child has weak sucking and swallowing ability, low crying, shallow breathing, and abnormal thoracic activity. It is difficult to turn over and raise your head. The reflection disappears. Palpation can be found in limb muscle atrophy, but is often masked by subcutaneous fat. Eye movements are normal. The sphincter function is normal. Visible tongue muscle atrophy and tremor. 10% of cases may have joint deformities or contractures. This type of prognosis is poor. About 95% died 18 months after birth.

2. The onset of SMA-II type is slightly later than that of SMA-I type, usually starting within 1 year old, and very rarely starting from 1 to 2 years old. The incidence rate is similar to that of SMA-I. The baby grows normally in the early stage, but after 6 months, the exercise is slow, although it can sit, but the standing and walking have not reached the normal level. More than one third of children can't walk. 20% to 40% of children still have walking ability before the age of 10. In most cases, the proximal limb muscle weakness is severe, the lower limb is heavier than the upper limb, and the respiratory muscles and swallowing muscles are generally not affected. One third of the cases were affected by facial muscles. Tongue muscle and other muscle fibrillation can be seen in more than 50% of cases. The sputum reflection weakens or disappears. This type has a relatively benign course of disease, most of which can live in childhood and live to adulthood individually.

3. SMA-III type is also known as Kugelberg-Welander disease. It usually starts in early childhood and puberty, and most of them start before 5 years of age. Insidious onset, manifested as progressive limb proximal muscle weakness and atrophy. The early thigh and hip muscle weakness is more significant, so that the sick child walks in a duck step, difficult to climb the ladder, gradually involving the scapula and upper limb muscles. The muscles innervated by the brain are usually not affected, but the facial muscles and soft diaphragm muscles may be weak. The extraocular muscles are normal. About 1/4 of cases are associated with pseudohypertrophy of the gastrocnemius, which is almost common in male patients. Half of patients can see fasciculation in the early stage. The arched foot can also be seen. The sputum reflection weakens or disappears. It feels normal. This type of prognosis is good, especially in female patients. Survival usually reaches adulthood, and many patients have a normal life span. More severe cases are often male patients. This type of serum CPK can be increased to varying degrees. In addition to neurogenic changes, EMG can be mixed with myogenic damage, so attention must be paid to the identification of muscular dystrophy.

4. SMA-IV type is collectively referred to as adult SMA. The age of onset is 15 to 60 years old, and is more common in the age of 35 years. Both onset and progression are more insidious, but there are also cases of progressive or relatively static cases. This type of prognosis is relatively good, and walking ability can often last a lifetime. The incidence rate is less than 0.5/100,000. About 1/3 of the cases are autosomal dominant, showing proximal muscle weakness, a slightly faster progression, and loss of running ability after about 5 years. There are still autosomal recessive inheritance types, which generally show a more benign course. The other type is X-linked recessive inheritance, also known as spinal brainstem-type SMA (Kennedy's disease), which varies in age from onset, but often occurs before the age of 40. Early manifestations of painful tendons can occur several years before muscle weakness. The proximal muscle weakness often begins in the lower extremities, gradually affecting the scapula, the facial muscles, and the medulla oblongata. The muscles of the lower and the muscles of the tongue can be seen. Difficulty swallowing and eating after a few years. About 50% of cases combined with some endocrine dysfunction, showing feminine breast and primary testicular lesions.

5. Other types of SMA

(1) Distal type SMA: This type accounts for about 10% of SMA and is an autosomal dominant or recessive inheritance form. The former develops before the age of 20, the latter is slightly later, and the symptoms are mild. Most patients show a slow progression of distal muscle weakness and atrophy of the lower extremities, and the tibialis anterior and tibial muscles are particularly susceptible. Bow feet and scoliosis are also common. In about half of the cases, the distal extremity will be affected sooner or later, but to a lesser extent. No sensory disturbances. Peripheral nerve conduction velocity is normal.

(2) Chronic asymmetric SMA: This type is onset at 16 to 45 years old, and male patients are twice as likely as female patients. Demonstrate one or more limb asymmetry muscle atrophy without pyramidal or medullary involvement. Myasthenia gravis can be predominantly proximal or distal, and is relatively limited to a single limb at the time of onset. This type of natural course is longer, even more than 30 years.

(3) scapular type SMA: the age of onset is 30 to 40 years old. It shows that the scapular muscles and the distal muscles of the lower limbs (especially the gastrocnemius) are obviously weak and atrophic. Bow feet are also more common.

(4) Single-arm type SMA: Some cases have been reported in Japan and India, and their age of onset varies, and men are more common. The onset is relatively fast, and then enters the non-progressive period. Due to impaired localized anterior horn cells, a single arm with obvious muscle atrophy. EMG shows an abnormality that is strictly limited to a single limb. The bulbar muscles and other muscles are not invaded. The Japanese literature says that the young-type single-limb SMA is Hirayama disease.

(5) In addition, there are rare cases of medullary SMA complicated with deafness (Viatetto-Vanlaere syndrome), medullary SMA (Fazio-Londe syndrome), ocular pharyngeal SMA, facial scapular SMA, and aminoglycosidase A deficiency. Types of.

According to this disease, only the lower motor neurons are involved, the limbs are progressive flaccid paralysis, the proximal end is heavier than the distal end, the lower limb is heavier than the upper limbs, and the clinical manifestations of the cervical or lumbar spine are not consistent with the clinical manifestations, and the muscles. Electrograms, muscle pathology and other characteristics, it is generally not difficult to make a diagnosis.

If there is a positive family history, it is more supportive of the diagnosis. Genetic testing can provide reliable evidence for establishing a diagnosis. According to the clinical characteristics, age of onset, prognosis and genetic mode, the classification diagnosis was made.

Differential diagnosis

The diagnosis should be differentiated from the following symptoms:

1. Both hands tremor can not be diagnosed as Parkinson's disease by shaking hands with both hands. There are many reasons for causing tremors in both hands. We should first understand that there are many types of tremors. According to the relationship between tremor and voluntary movement, tremor can be divided into the following categories: static tremor, posture tremor, intentional tremor, and other tremors.

2. Two-handed rotation for awkward hands and two-handed rotations is awkward because of the symptoms of both hands caused by ADHD, hereditary ataxia polyneuritis, ataxia, and progressive hypertrophic interstitial neuritis. Clumsy clinical symptoms.

The normal movement of the human body is the balance and coordination of the movement in the cerebral cortex motor area, the basal nucleus of the cortex, the vestibular labyrinth system, the deep sense and the vision, and is called the mutual aid movement. The lesions of these structures lead to coordination disorders called ataxia.

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