Hemian dystonia

Introduction Hemidystonia: refers to the muscles involved in the ipsilateral upper and lower limbs, mostly caused by secondary causes. Idiopathic dystonia (idiopathic dystonia) may be autosomal dominant (30% to 40% penetrance), autosomal recessive or X-linked recessive inheritance, and the dominant genetic defect gene DYT1 has been located at number 9 The long arm of the chromosome 9q32-34, which encodes the ATP-binding protein torsin A, may have sporadic cases. Environmental factors such as trauma or overwork can be induced. For example, before the onset of oral-mandibular dystonia, there may be a history of facial or tooth damage, and one side of the limb is overworked, often inducing writing sputum, typist sputum and athlete's limb paralysis.

Cause

(1) Causes of the disease

The cause of idiopathic dystonia is unknown, which may be related to heredity. Secondary dystonia is often a symptom of lesions such as basal ganglia, thalamus and brainstem reticular formation.

(two) pathogenesis

Idiopathic dystonia (idiopathic dystonia) may be autosomal dominant (30% to 40% penetrance), autosomal recessive or X-linked recessive inheritance, and the dominant genetic defect gene DYT1 has been located at number 9 The long arm of the chromosome 9q32-34, which encodes the ATP-binding protein torsin A, may have sporadic cases. Environmental factors such as trauma or overwork can be induced. For example, before the onset of oral-mandibular dystonia, there may be a history of facial or tooth damage, and one side of the limb is overworked, often inducing writing sputum, typist sputum and athlete's limb paralysis.

Secondary dystonia is caused by lesions such as striatum, thalamus, blue spot, and brainstem reticular formation, such as hepatolenticular degeneration, bilirubin encephalopathy, ganglioside deposition, globus pallidus Nuclear pigmentation, progressive supranuclear palsy, idiopathic basal ganglia calcification, hypoparathyroidism, poisoning, stroke, brain trauma, encephalitis, etc.; in addition, drugs (levodopa, phenothiazines, butyl Acylbenzenes, metoclopramide) can also be induced. Dystonia can also be caused by psychological factors that are characterized by cues.

Pathological and neurobiochemical changes: Non-specific pathological changes were observed in idiopathic torsion sputum, including degeneration of small neurons in the putamen, thalamus and caudate nucleus, and increased basal ganglia lipids and lipipidations. The pathological features of secondary torsion spasm vary with the primary disease, and there is no specific pathological change in localized dystonia such as spastic torticollis, Meige syndrome, writing sputum and occupational sputum.

Antagonistic muscle hypertrophic contraction is the main physiological feature of this disease, and each contraction of the limb often extends from the proximal end to the distal end. Electromyography revealed no involuntary motor potential during intermittent muscle contraction. According to the characteristics of EMG, it is divided into 3 types:

1 muscle contraction lasting 30s, resting at short intervals;

2 repeated, rhythmic contraction and resting state, systolic and resting periods are 1 to 2 seconds;

3 rapid, short-term muscle contraction, lasting 100ms, behaves like myoclonus.

an examination

Related inspection

Muscle tone test

Blood electrolytes, drugs, trace elements and biochemical tests help to diagnose and classify the cause.

1. CT or MRI examination: meaningful for differential diagnosis.

2. Positron emission tomography (PET) or single photon emission tomography (SPECT) can show some biochemical metabolism in the brain, which is meaningful for diagnosis.

3. Genetic analysis: It is of great significance for the diagnosis of certain hereditary dystonia.

Differential diagnosis

1 focal dystonia (focal dystonia): only involving the eyelid muscle group, called eyelid (blepharospasm); involving the perioral and mandibular muscle group, called orthodontic dystonia (oromandibular dystonia); disease involving The laryngeal muscles are called spasmodic dysphonia; the disease involves the neck muscles called spasmodic torticollis; the disease involves the forearm and the hand, called writer cramp .

2 segmental dystonia (segmental dystonia): the muscles involved in the cranial and neck muscles, called cranial segmental dystonia (cranial segmental dystonia); the neck and torso are called the longitudinal axis Segmental dystonia; involving one arm and longitudinal axis or upper upper arm, called brachial segmental dystonia; involving one side of the femoral muscle and trunk or both sides The femoral muscle (with or without trunk involvement) is called crural segmental dystonia.

3 dystonia (hemidystonia): refers to the muscles of the ipsilateral upper and lower limbs, mostly caused by secondary causes.

4 generalized dystoina (generalized dystoina): refers to the disease involving 3 or more limbs with the trunk, cranial, cervical or medullary muscles, such as systemic torsion spasm (torsion spasm).

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