Dystonia

Introduction The tension in the state of static relaxation of the muscle is called muscle tension. Muscle tone is the basis for maintaining various postures and normal movements of the body and is manifested in various forms. When a person is resting in a resting place, the tension of the muscles of the body is called the resting muscle tone. When the body is standing, although there is no significant contraction of the muscles, the muscles of the body and the body maintain a certain tension to maintain the standing posture and the stability of the body, which is called posture muscle tension. The tension of the muscle during exercise, called exercise muscle tension, is an important factor in ensuring continuous and smooth muscle movement (no tremor, convulsions, convulsions). The generation and maintenance of muscle tone is a complex reflex activity, and its reflex arc is called r-, including the afferent part of r- (the receptors of muscle tone reflex is neuromuscular and neurosity) and r- The efferent part of the sputum (the anterior horn cells of the spinal cord and the a motor neurons in the motor nucleus of the brainstem, which innervate the extrafusal muscle, and the r motor neurons emit Ar fibers to reach and innervate the intrafusal muscle). Lesions in any part of the reflex arc can cause changes in muscle tone.

Cause

Muscle tone is reduced in various myopathy, myasthenia gravis, peripheral neuropathy, radiculitis or cerebellar damage, and the muscle tone is also decreased when the spinal cord conducts the proprioceptive nerve fibers. In children with acute hemiplegia, muscle tension may be low in the early stage of sputum, and muscle tension is increased after several days or weeks, and tendon reflexes are enhanced. Familial periodic paralysis, stenosis, epileptic seizures, paroxysmal or interstitial muscle depression. Cone system disease has increased muscle tone. The extra-pyramidal and basal ganglia lesions may be reduced or increased, sometimes manifested as increased gear-like muscle tone. When the brain is strong, the muscle tension is obviously increased, the limbs are stiff, the lower limbs are straight, and the upper limbs are flexed to the back.

an examination

Related inspection

Electromyography muscle tension test

1. Reduced muscle tone: When the muscles are relaxed, the resistance encountered by the active body is reduced, the muscle lacks the expanded muscle belly and the normal toughness and relaxation. The clinical manifestations may vary depending on the location of the lesion. The anterior horn of the spinal cord is accompanied by segmental distribution of muscle weakness, atrophy, no sensory disturbance, and muscle fiber tremor. Peripheral nerve damage with muscle weakness, atrophy, sensory disturbances, tendon reflexes often decline or disappear. Some muscle and nerve joint lesions have reduced muscle tone, muscle weakness, with or without muscle atrophy, no muscle fiber tremors and sensory disturbances. The proprioceptive fibrous damage of the posterior cord or peripheral nerve of the spinal cord is often accompanied by the loss of sensory and deep reflexes, and the walking is a sensory ataxia gait. The cerebellar system is accompanied by motor ataxia and walking is gait. New striatum lesions with dance-like movements.

2. Increased muscle tone: the tillering is two kinds of tonicity. Increased spasm of the sacral muscles is associated with damage to the cone, and spinal cord reflexes are facilitated. When passively moving a patient's joint, a sense of impedance occurs in the case of increased muscle tone, which is related to the speed of being exercised. When the muscles in the shortened state are quickly drawn, they immediately cause contraction and feel paralyzed state. When the force is stretched to a certain extent, the resistance suddenly disappears, that is, the so-called knives-like muscle tension is increased. Increased spastic muscle tension is not related to "sputum", which refers to an involuntary muscle contraction. Increased tonic muscle tone is seen in some extrapyramidal lesions with special tension changes, which are selective for increased muscle tone. The upper limbs are mainly adductor, flexor and pronator, and the lower extremities are superior to extensor muscle tension. The resistance encountered when passively moving a patient's limb is generally smaller than that of a sputum, but it has nothing to do with the length of the muscle at that time, ie, the contraction morphology. There is no difference between the extensor and the flexor. Regardless of the speed, amplitude, and direction of the action, the same resistance is encountered. This increase in muscle tone is called lead-like tonic, such as alternating loose and tight changes due to tremor, called gear-like rigidity.

Differential diagnosis

First, abnormal muscle tension is reduced

(a) myogenic disease

1. Progressive muscular dystrophy: is a group of acute muscle diseases caused by genetic factors, manifested by the weakness and atrophy of progressive and exacerbated skeletal muscle of varying degrees and distribution. The decrease in muscle tone is parallel to muscle atrophy, often accompanied by a decrease in muscle tone at the site of muscle atrophy. Due to muscle atrophy, weakness and decreased muscle tone, the clinical manifestation is a special posture when standing and walking. When standing, the anterior and anterior curvature of the lumbar vertebrae are duck steps when walking. This is due to the reduction of muscle tension and atrophy of the paraspinal muscles. Caused by poor fixation of muscle damaged pelvis. The atrophy, weakness and tension of the anterior saw are reduced. When the shoulder and the seat are seated, the shoulder blade is displaced upwards and the thorax and the spine are separated, and the wing is shoulder-shaped. The examiner can penetrate the finger between the shoulder blade and the sternum, and is the trapezius muscle. Rhomboid muscle muscle tension is reduced.

2. Myopathy is also associated with muscle atrophy in muscle atrophy, and is associated with muscle atrophy. Laboratory tests are helpful for diagnosis. For example, polymyositis can increase serum CPK and immunoglobulin in the acute phase, in urine. Muscle protein appears, creatine increases, and electromyography can show fibrillation and increased insertion activity.

(two) neurogenic diseases

1. Peripheral neuropathy: The muscle atrophy of polyneuritis is mainly distributed in the distal end of the limb, and has an equal relationship with the reduction of muscle tone. As the muscle tension decreases, the wrist joint, the finger and the ankle joint increase in amplitude, and the abnormal posture is overextended and flexed. According to the etiology of polyneuritis, there are also choices of damaged muscles, such as alcohol-toxic polyneuritis, tibialis anterior muscle paralysis is the most obvious, muscle tension is also the most prominent, it is often manifested as foot drop.

Mononeruopathy is mainly caused by trauma, ischemia, infiltration, physical damage, etc. When the ulnar nerve and median nerve damage are obvious in the upper limb, the tension of the flexor muscles of the upper limb is significantly reduced, and the tension of the upper extremity muscle (antagonistic muscle) is occupied. Advantages, thus mastering dorsiflexion. When the tibial nerve is damaged, the elbow joint can not be straightened and the wrist is degenerated due to the triceps tendon and the tension is reduced. The forearm can not flex the elbow joint in the semi-rotation position due to the weak muscle strength and the reduced tension.

2. Posterior root posterior cord lesion: The reduction of muscle tone in the posterior root and posterior cord of the spinal cord is one of the prominent symptoms. The side of the spinal cord (tabes dorsalis) is characterized by a decrease in resting muscle tone, accompanied by posture and exercise. Abnormal muscle tone. When the patient is supine, the tibia can even be attached to the bed. When standing, the knee joint has low tension. The knee joint can not be fixed and the "anti-tensional knee" appears. The lower limb muscle tension is lower than that of the upper limb.

3. Spinal cord disease

1 amgotrophic lateral sclerosis (amgotrophic lateral sclerosis) is more common after 40 years of age, spinal cord anterior horn cells (and brainstem motor nucleus) and pyramidal tract are involved, so there are characteristics of upper and lower motor neuron damage coexist. Upper limbs have muscle atrophy, weakness, fasciculation, and hyperreflexia. When the cervical anterior horn cells are severely damaged, the pyramidal tract symptoms are concealed. At this time, the upper limbs have muscle atrophy, the muscle tone is reduced, the tendon reflexes are reduced or disappeared, and the amplitude of the passive movement of the limbs is increased.

2Charcot-Marie-Tooth's disease: Early muscle atrophy occurs in the lower third of the thigh, and late muscle atrophy can be extended to the lower third of the forearm of the upper limb, and the sides are symmetrical. In the muscle atrophy, muscle tension is reduced. 3 acute spinal anterior keratitis: the muscle tension in the muscle atrophy is reduced, because the range of acute spinal anterior horn keratitis and muscle atrophy is small, so the atrophic antagonistic muscle preservation, and its muscle tension predominates, so often accompanied Abnormal position, such as clubfoot and foot drop. The passive movement of the affected limb increases, showing an excessive flexion and extension posture.

4. Cerebellar disorders: Reduced muscle tone is a common symptom of cerebellar lesions. Due to the reduction of muscle tone, the posture of the limb is abnormal. For example, if the muscle is overextended and flexed, the muscle tension is low except at rest, and it is also visible during passive exercise. To the obvious reduction of muscle tension, the main movement begins and ends slowly, consciously weak, easy to fatigue, due to the reduction of muscle tension, the tendon reflex is also reduced or disappeared, and the bell-like sputum reflection can be seen. It is also due to the reduction of muscle tone and insufficient antagonism of the muscles.

5. Cone disease: In the acute phase of pyramidal tract damage, due to the generation of pyramidal corpuscle, the muscles are reduced during the period of cone beam shock, the muscles of the tendon are relaxed, and there is no impedance during passive movement.

Second, increased muscle tone

(1) Pyramidal tract lesions of the pyramidal tract lesions after the shock period, or the cone-shaped lesions of the insidious onset, increased muscle tone in the temporal side, such as the Wernicke-Mann position expressed in the hemiplegia. Significant cone-shaped lesions have triple-buckling: hip flexion of the hip, knee, and metacarpal joints of the following limbs. In the pyramidal tract lesion, the site of increased muscle tension is consistent with the sacral site. The muscle tension is also increased at rest, the palpation muscle is hard, and there is a knife-like impedance during passive movement.

(2) Extrapyramidal disorders

1. Parkinson's disease: The increase in muscle tone caused by this disease is called stiff muscle. The tension of the agonist muscle and the antagonist muscle are increased. When the joint is passively moved, the increased muscle tension is always consistent, and the uniform resistance is felt and the "lead tube-like rigidity" is present. If the patient has tremor, the limb is flexed and stretched. When you feel the uniform resistance, there is an intermittent pause, such as the gear is rotating, that is: "the gear is strong." Facial expression muscle muscle stiffness is an expressionless "mask face", swallowing muscle muscle stiffness can not be swallowed and swallowed well, eye muscle muscle rigidity shows eye movement slowed, there is a viscous phenomenon of gaze movement. The neck muscles and the trunk muscles are stiffened to form a flexion state, that is, the head and torso are forward, the upper muscles are slightly externally rotated, the elbow joint is flexed, the metacarpophalangeal joint is flexed, the thumb is adducted, the lower limbs are slightly adducted, and the knee is flexed. The neck and the spine move slowly.

2. Huntington's chorea: Muscle tone is mostly normal, but a few patients have Porkson's disease-like muscle stiffness, and the dance symptoms are mostly or completely absent. This type is finally posture dystonia, upper limb flexion, and both lower limbs straight. This chronic, progressive dance symptom of muscle stiffness is thought to be the result of globus pallidal damage.

3. Torsion spasm: also known as dystrophic dystonia (dystonia musculorum defoumans) is a torso of the trunk, a rare basal ganglia lesion. Clinically, it is characterized by increased muscle tone and severe involuntary torsion of the limbs and even the whole body. Muscle tone increases when the limb is twisted, and normal when the twist stops.

4. Drug-induced muscle tone abnormalities:

(1) acute dystonia (acute dystonia): acute onset, appear shortly after medication, more common in young people, characterized by strange tendons. Mainly the neck and head muscles are involved, the most common is the involuntary paralysis of the tongue and oral muscles, so that the masticatory muscles contract tightly, the mouth does not open, speech, difficulty swallowing, facial eccentricity, or accompanied by spasmodic torticollis This response is related to the sensitivity of the individual and is effective with anti-shock palsy, antihistamines or barbiturates.

(2) tardive dykinesia: slow onset, occurring after several weeks, months or years of taking neuroleptics, even after stopping the drug. It is characterized by a rigid, repetitive lip, involuntary movement of the tongue, sometimes accompanied by a dance-like movement of the limb or trunk, and a body-axis movement. The use of anti-shock palsy drugs is not only ineffective, but sometimes worsens the symptoms. It may also have low muscle tone and paralysis. It may involve the neck muscles, the lumbar muscles, etc., such as the waist can not straight up, the bulge, the neck is soft, can not look up, can not walk when walking, can not lift the legs, heel dragging the ground .

(C) When the cerebellar disease is extensive on both sides of the cerebellar lesions, sometimes the muscle tension is increased, and the passive movement of the limbs has a sense of impedance. When standing, the trunk and limbs are stiff. Olive cerebellar atrophy sometimes presents Parkinson-type muscle stiffness, suggesting structural damage associated with the basal ganglia of the brain.

(D) brain stem disease caused by brain stem lesions increased muscle tension is most obvious in the midbrain, the midbrain lesions show muscle stiffness, belonging to a kind of brain tonic, the proximal extremities of the limbs, suffering in the extensor group. The upper limbs are straight, the wrists are flexed and adducted. The lower extremities are straight and the internal rotation is adducted, which is called to go to the midbrain. Diffuse white matter of the cerebral cortex, such as encephalitis, severe traumatic brain injury, cerebral hemorrhage can also appear limb stiffness, the difference between the forearm tonic is the forearm flexion, the other performance is completely the same as the midbrain tonic, said For "to cortex rigidity."

(5) Peripheral neurological disorders Peripheral neurological diseases are characterized by lower motor neuron damage, which is manifested by decreased muscle tone. However, in the case of incomplete facial paralysis, there may be an increase in facial muscle tone, which is manifested as hemifacial spasm. In addition, when the peripheral nerves are inflamed, tumors, and the like, and the peripheral nerves are stimulated, the muscle tension is increased. This increase in muscle tension is mostly due to increased defensive muscle tone.

(6) Myogenic lesions Although muscle tension can be increased, but the tendon reflex is normal or reduced, there is no hyperreflexia.

1. Congenital myogenicity (congenital paramyotonia): also known as Eulenberg disease. The disease only shows an increase in muscle tone during exercise and a normal muscle tension at rest. The muscle tension of this disease is increased, and the muscle tonic contraction is seen at the beginning of exercise, and it returns to normal after repeated exercise. At the time of palpation, the muscles have a special toughness, which is hard like a rubbery skin. It is obvious when the muscles are contracted after mechanical stimulation.

2. Stiff mandy syndrome (stiffmansyndrome): an epileptic seizure with unknown etiology. The muscle tension of the neck muscles, trunk, back bones, and abdominal muscles is obvious, and the pain is stimulated by the outside world. Sniper, sound and light, mental stress, etc. can be induced and aggravated. The common proximal extremities begin to develop toward the body, and the muscle strength and tendon reflexes are normal. The symptoms of stiffness disappear during sleep.

(7) Others

1. Tetanus: early local muscle tension is increased, the common is the chewing tendon contraction on both sides, accompanied by cervical muscle rigidity, followed by facial muscle spasm; the mouth angle is outward, the nose is contracted, and the eye is cracked. It is called "smiley appearance". Increased systemic muscle tone with the development of the disease. For example, when the muscle tension of the trunk stretch muscle is dominant, the angle bow is reversed. When the flexor muscle tension is dominant, the anterior arch is reversed. The patient's position is like the intrauterine position of the fetus: the head flexor, the knee and the ankle are tightly attached. Close to the hips. When the muscle tension on one side of the trunk is dominant, the body is bent laterally, that is, the side bow is reversed: the head and shoulders are inclined to one side, the side shoulders are drooping, and the body is bent toward the crescent shape.

2. Tetany: Low blood calcium is the main cause of this disease. Increased muscle tone is mainly seen in the distal extremities, and even spread to the trunk. Some scholars divide the hand, foot and ankle syndrome into three types:

(1) benign type: mainly occurs in the distal extremity of the toe, the thumb is strongly adducted and semi-flexible, and the other fingers are close together, the middle finger of the finger is flexed obviously, and the lateral edge of the hand is close to the lateral edge. Sometimes the end finger is more pronounced than other fingers, and the last finger is often folded under the rest of the finger, or the thumb is folded into the glove, which is called the "midwife hand". The lower limbs are toe flexion, which is a horseshoe inversion, the calf is straight, free to move, and there is a sense of impedance during passive movement.

(2) Moderate type: early upper limbs first appear muscle tension, muscle rigidity, break to the trunk, facial muscles and lower limbs, sometimes rectus abdominis, sternocleangepsis, pectoralis major muscles can be strong and straight. When the facial muscles appear to be myotonic, they have a special face: extraocular oblique or internal oblique, closed jaw, tongue stiff, poorly structured, difficult to swallow, such as dyspnea and asphyxia when the larynx is sore.

(3) Severe type: repeated episodes in a short period of time, showing generalized muscle rigidity, accompanied by laryngeal spasm.

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