Arm muscle atrophy

Introduction Muscle atrophy refers to dystrophy of striated muscle, muscle volume is reduced compared to normal, muscle fibers become thinner or even disappear. Clinically similar to motor neuron disease amyotrophic lateral sclerosis, spinal progressive muscle atrophy, but the prognosis is completely different. The age of onset is young, and the affected part is mostly the distal hand muscle of the unilateral upper extremity. The EMG is neurogenic damage, and the course is benign and can be stopped by itself. Atrophy of the arm muscles: the arm muscles are atrophied and the fingers are numb.

Cause

Cause: If the arm muscle atrophy caused by injury is called traumatic muscular atrophy, the disability rate is very high. The cause of the disease is due to traumatic blood edema invading the nerve and causing nerve function paralysis not to dominate the muscles. Muscle atrophy. Spinal cord dysfunction, localized atrophy of the lower neck to upper chest spinal cord. Domestic Li Zuohan et al (1994) reported 22 cases. According to the EMG test, it is considered that the anterior horn cells of the spinal cord, especially the lower neck, are most likely to be damaged.

an examination

Related inspection

Parathyroid hormone (PTH) parathyroid hormone biceps reflex electromyography

Electrophysiological examination of electromyography (EMG) and nerve conduction velocity (NCV) have important reference value for the degree of neurological injury and injury, and are generally examined 3 weeks after injury. Sensory nerve action potential (SNAP) and somatosensory evoked potential (SEP) contribute to the identification of post-ganglionic lesions. SNAP is normal at preganglionic injury (the reason is that the posterior root sensory nerve cell is located outside the spinal cord, and the injury occurs just in the proximal side of the node, the sensory nerve has no Waller degeneration, can induce SNAP), SEP disappears; post-ganglionic injury Both SNAP and SEP disappeared.

Differential diagnosis

Differential diagnosis of arm muscle atrophy:

First, acute or subacute muscle atrophy

It is generally neurogenic atrophy, and its rate of occurrence is related to the speed and extent of nerve damage. The more acute and severe the nerve damage and interruption, the faster and more obvious the muscle atrophy occurs. After acute onset, muscle atrophy occurs after sputum, and the clinical manifestations are sputum, such as poliomyelitis, peripheral neuritis, Guillain-Barré syndrome, and alcoholism. Early neuropathic muscle atrophy is characterized by severe pain near the scapula, followed by a rapid decrease in muscle tone, tendon and muscle atrophy near the scapula, and a single atrophy in some muscle groups, inlaid.

Second, progressive distal extremity muscle atrophy

Often neurogenic muscle atrophy, mainly in the distal extremities, upper limbs in the interosseous muscle of the hand, large and small intermuscular muscles are obvious, while the lower extremity atrophy in the tibialis anterior muscle is more obvious. The sides are basically symmetrical, often occurring before the sputum, as a single symptom. Common diseases include amyotrophic lateral sclerosis and progressive spinal muscular atrophy of motor neuron disease, and weakness and muscle atrophy of the distal extremity caused by cervical spondylosis. Gastrocnemius atrophy is characterized by muscle atrophy of the lower third of the thigh of the lower extremity, accompanied by deep sensory disturbance and sensory ataxia. In addition, syringomyelia, spinal vascular malformations, leprosy, and chronic anterior polio can cause progressive muscular atrophy at the distal extremities. Muscular atrophic myotonia and distal progressive muscular dystrophy also manifest as muscle atrophy at the distal extremities.

Third, progressive extremity muscle atrophy

Often myogenic atrophy, with the proximal and trunk muscles of the extremities, often manifested as atrophy and weakness of the scapular and pelvic girdle muscles. If the neck muscles are weak, some patients need to support them by hand to lift the head. The muscle atrophy of the shoulder blades constitutes a winged shoulder blade. The atrophy of the pelvic girdle muscles is unable to form a specific 'duck step' gait. Common diseases are progressive muscular dystrophy, polymyositis, diabetic muscular atrophy, and hormonal myopathy.

Wohfart-Rugelberg-Welancter disease is a genetic disease found in young people with muscle atrophy in the proximal extremities and limbs, and pseudo-hypertrophy in the gastrocnemius. Muscle fibrillation is sometimes seen in this disease and can be induced with neostigmine. No duck steps and winged shoulders.

Fourth, localized muscle atrophy

Atrophy, which is mainly caused by local muscles or muscle groups, is often caused by various types of single neuritis or injury. It is usually accompanied by the corresponding sensory area disorder. The lesion can be located according to its anatomy. The common cause is single nerve. Inflammation (such as phrenic nerve, phrenic nerve, sciatic nerve injury, etc.), carpal tunnel syndrome, brachial plexus injury, neurofibromatosis, etc. Others are:

1. The softening of the gray matter of the spinal cord can be manifested as distal progressive amyotrophic, or confined to the hand, does not invade the forearm and upper arm, and stops when the atrophy reaches a certain level. It is accompanied by sensory disturbances, which occur in the elderly and are often caused by syphilitic vascular lesions.

2. On the side of the young man with upper limb muscle atrophy, the onset of 14 to 24 years old, more common in men, insidious onset, manifested as thinning below the midpoint of the forearm, large and small inter-crop and bone atrophy, often single On the side, the atrophy boundary is clear and there is no sensory disturbance, but the autonomic nerve disorder is more obvious. The disease will stop on its own within 1 to 3 years.

3. Reflex muscle atrophy refers to a kind of disuse atrophy caused by local lesions such as joint lesions. Found in traumatic, infectious, rheumatoid arthritis. Rheumatoid arthritis can cause systemic muscle atrophy.

Diagnosis: The arm muscles are atrophied and the fingers are numb.

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