Weakness in the arms is a symptom in which there is a decrease in strength or increased fatigue of the muscles of the upper limbs. The cause of this condition may be neuromuscular defects, muscle damage, pathology of peripheral nerves or blood vessels, and other diseases. Diagnostic measures include clinical examination, laboratory tests, instrumental procedures. In the treatment regimens, medications, physical therapy methods, and surgical interventions are used.
Weakness and pathological fatigue of skeletal muscles is the main symptom of myasthenia gravis, which is an autoimmune neuromuscular disease. The upper limbs are involved in the generalized form of the disease. An important sign is that with an intense load on some muscles of the arm, a strong weakness appears in others. For example, after several clenching of the fist, the patient cannot straighten his fingers.
Weakness in the hands is observed in some myasthenic syndromes, in particular, associated with the slow closing of ion channels. It has a different origin from the primary pathology, is inherited in an autosomal dominant manner. The disease is characterized by weakness, excessive fatigue of the muscles of the shoulder girdle (most often scapular) and neck. The musculature of the limb is gradually involved.
Weakness in the arms is a typical symptom of muscular dystrophies. These are hereditary diseases, the development of which is associated with mutations in genes encoding proteins of muscle tissue (dystrophin, emerin, sarcoglycans). Usually, myodystrophy debuts in childhood and adolescence. The upper limbs are involved in the following types of pathology:
The muscles of the shoulder girdle are affected in Davidenkov's scapuloperoneal myopathy, a limb-girdle variant of myodystrophy (Erba-Rota). During the examination, "pterygoid" shoulder blades, difficulty raising the arms are noted. Involvement of the distal extremities is manifested by difficulties in performing small work.
The initial manifestation of progressive muscle atrophy, which belongs to the group of motor neuron diseases, is weakness in one arm. As structural changes increase in the anterior horns of the spinal cord, symptoms cover other parts of the body. In the early stages, weakness is often accompanied by twitches, convulsive contractions of individual muscles. Gradually, the muscles of the hand atrophy.
Isolated weakness in the left arm or right upper limb in a child can be observed against the background of difficult and protracted labor, a clinically narrow pelvis of a woman, and the use of obstetric aids. The development of obstetric paralysis is due to trauma to the brachial plexus. Taking into account the localization of damage and symptoms, several types of pathology are distinguished:
Violation of the passage of the impulse along the peripheral nerves is due to the picture of tunnel syndromes. Weakness, pain, and numbness in the arms are symptoms of many compression-ischemic neuropathies. Carpal tunnel syndrome (carpal) is characterized by weakness of the flexors of the hand, thumb and forefinger, and a decrease in the sensitivity of their palmar surface. The disease occurs in mechanics, programmers, pianists.
With compression of the ulnar nerve in the carpal canal, sensory disturbances are combined with weakness in the arm. Changes affect the ulnar surface of the hand, ring finger and little finger. As a result of compression of the nerves and vessels passing between the scalene muscles, scalenus syndrome is formed. Patients note a weakening of the shoulder muscles, complain of pain in the arm and neck (cervicobrachialgia), sensory disorders.
Sudden weakness in the arms is often due to damage to the cortex of the lower parts of the precentral gyrus (tumor, hematoma, bone fragments). Strength is reduced in the distal muscle groups, which leads to a violation of the most delicate movements. Muscle tone and deep reflexes are usually not affected. If the focus is located in the region of the radiant crown, a faciobrachial type of lesion is often detected, when weakness in the arm is combined with paresis of the lower half of the face.
Weakness, pain and numbness in the hands are accompanied by diseases of the vessels of the upper extremities. With damage to the aortic branches due to Takayasu's disease, symptoms of vertebral steal are observed. Characterized by dizziness, signs of neurological deficit (impaired vision, tinnitus, dysarthria). On the side of the lesion, the pulse weakens, a difference in blood pressure is visible.
If weakness in the right hand appeared after heavy physical exertion (within 24 hours), Paget-Schretter syndrome or subclavian vein thrombosis can be assumed. The dominant limb is usually affected. The affected arm swells, turns blue, patients are worried about aching pain. In the axillary-shoulder region, a dense cord can be palpated.
The cause of weakness in the hands can be endocrine disorders. With thyrotoxic myopathy, the palmar muscles, biceps suffer, atrophic changes are found in the trapezius and triceps muscles. Hypothyroidism is accompanied by weakness and stiffness in the proximal arms, muscle hypertrophy, and convulsions. Moderate atrophy of the shoulder muscles occurs with hypercortisolism. Proximal myopathy is characteristic of hyperparathyroidism.
Compression of the spinal roots in osteochondrosis, intervertebral hernia is a common cause of weakness in the arm. An objective decrease in muscle strength is accompanied by damage to muscles and nerve fibers after injuries or surgical interventions. Weakness in the joints of the hands, felt as stiffness of movements, can be disturbing in rheumatoid arthritis, deforming osteoarthritis.
Numbness, pain, feeling of weakness in the left hand are found in patients suffering from coronary heart disease (angina pectoris, myocardial infarction), which is due to a deficit in coronary blood flow, reflex disorders. Functional and organic lesions involving the upper limbs are also observed in a number of other cases:
Why there was weakness in the hands, it is possible to find out only according to the data of a comprehensive comprehensive examination. After analyzing the anamnestic information and neurological examination, the neurologist makes a preliminary conclusion about the nature and origin of the pathology. Accurate verification of the lesion is provided by additional diagnostic methods:
Patients with myasthenia gravis undergo a proserine test, with tunnel syndromes a series of motor tests are performed. To detect atrophy, differential diagnosis of some myopathies and myodystrophies, a muscle biopsy can be performed. Damage to peripheral nerves and pathology of myoneural synapses should be distinguished from central paresis.
Electromyostimulation
Therapeutic tactics involves not only the elimination of weakness in the hands as a symptom, but also the elimination of all causes and mechanisms that cause its occurrence. Usually, therapy begins with conservative measures, prescribed taking into account the specific clinical situation. Within the framework of the medical direction, various medicines are used:
Anticholinesterase agents help to stop weakness in the hands in myasthenic conditions. Patients are prescribed a complex of physiotherapy, consisting of electro- and phonophoresis (neuromidin, nicotinic acid, hydrocortisone), electrical muscle stimulation, reflexology. Mandatory components of treatment and rehabilitation programs are massage and exercise therapy.
Radical elimination of individual causes of muscle weakness in the hands is the competence of surgeons. Correction of tunnel neuropathies is performed by decompression of the pinched nerves. Treatment of Paget-Schretter syndrome involves selective thrombolysis, intervertebral hernias are eliminated by microdiscectomy, laser vaporization. With myasthenia gravis that is not amenable to conservative therapy, the thymus gland is removed (thymectomy).