Symmetrical muscle weakness

Introduction Progressive muscular dystrophy is a group of primary muscle degeneration diseases characterized by aggravated symmetrical muscle weakness and muscle atrophy, which are hereditary diseases. Duchenne (DMD) and Becker (BMD), two X-linked recessive hereditary muscular dystrophy, have been studied in progressive muscular dystrophy.

Cause

Abnormalities in the DMD gene (including deletions, doublings, and point mutations) cause complete or partial defects in the encoded product dystrophin, which is the cause of both diseases. BMD muscular dystrophy, also known as benign muscular dystrophy, has an incidence of 1/10 of DMD.

1. Certain specific striated muscle groups exhibit symptoms of muscle weakness that are fluctuating and fatigue-prone.

2, usually the extraocular muscle involvement is the most common, morning light and heavy, increased weight after continuous activities, can be relieved after rest.

3, the extraocular muscle weakness caused by asymmetric ptosis and binocular double vision is the most common first symptom of MG (see more than 50% of MG patients), there may be alternating ptosis, bilateral ptosis, bilateral ptosis, Eye movement disorder, etc., the pupil size is normal.

4, facial muscle involvement can cause sputum leaks, eyelid closure, nasolabial folds shallow, bitter smile or mask-like face.

5, masticatory muscle involvement can cause chewing difficulties.

6, the throat muscle involvement of dysarthria, difficulty swallowing, nasal sounds, drinking water cough and hoarseness.

7, the neck muscles are affected by the flexor.

8, the muscles of each group of muscles can appear muscle weakness symptoms, with the proximal end.

9, respiratory muscle weakness can cause difficulty breathing, cyanosis and so on.

an examination

Related inspection

Electromyography muscle tone examination cerebrospinal fluid aspartate aminotransferase

History of disease, attention to onset age, initial site of symptoms, muscle weakness and muscle atrophy in the limb (proximal or distal), symmetry, speed of progression, presence or absence of episode aggravation or relief and remission, with or without pain Whether there is a family history. Physical examination pay attention to the distribution range of muscle atrophy, whether there is muscle hypertrophy, deep reflex change, no steps from supine position to standing (Gower sign), walking posture and gait, presence of winged scapula, face or neck muscles with or without atrophy With or without muscle tenderness or sensory disturbance.

Determination of creatinine and creatinine. Serum enzyme assay (lactate dehydrogenase, aldolase, aspartate aminotransferase, creatine phosphokinase). Electromyography examination. Muscle biopsy (including electron microscopy).

The disease is a hereditary familial disease with congenital genetic defects, mostly manifested as recessive inheritance.

Clinical type:

1, Duchenne type: also known as severe or fake large. It is the most common type of myopathy in children. It is a recessive inheritance of the sex, and the boy is sick. Slow onset, inability to often start from the proximal end of both lower extremities, showing difficulty in running, easy to fall, difficult to stand up after falling. As the disease progresses, proximal limb muscles, scapular muscles, and pelvic muscle atrophy appear. When standing, the lumbar vertebrae are excessively protruding, and when walking, it is a "duck step" gait.

2, Becker type: also known as benign type. Sexual recessive inheritance. The age of onset is mostly 5 to 20 years old. The first symptom is pelvic muscle and femoral muscle weakness, often with pseudohypertrophy of the gastrocnemius. After 5 to 10 years, the scapular muscles and upper arm muscles are weak.

3, limb belt type: also known as Erb type. It is autosomal recessive. The age of onset is often between 10 and 30 years old. Most of the first pelvic muscles or scapular muscles are weak, which is difficult to climb upstairs or lift the arms. The course of the disease is slow. More without pseudo-hypertrophy.

4, face shoulder type: also known as Landouzy-Dejerine type. Autosomal dominant inheritance. Usually onset during puberty. First affect the facial and scapular muscles. Early facial muscle involvement is only manifested as blindness of the eyelids. Typical cases have a special "myopathy surface", the upper jaw is slightly drooping, the frontal and nasolabial folds disappear, the mouth is closed, and the expression muscles are weak or lost. The diaphragm is pseudo-hypertrophy and the lips are thickened slightly. Common shoulders and winged shoulders. Late can involve the trunk and pelvic girdle muscles.

Differential diagnosis

Progressive muscular dystrophy is based on clinical symptoms and signs, electromyography, biochemical tests and muscle biopsy. If there is a genetic family history, the diagnosis is not difficult to establish, but it needs to be identified with the following diseases:

1. Infant spinal muscular atrophy: Mainly different from DMD (dummy hypertrophic muscular dystrophy), mainly due to early onset age, sometimes visible fasciculation, muscle atrophy is also obvious at the distal end of the limb, muscle Electrogram examination and muscle biopsy can be used for identification.

2, benign congenital dystonia: should be differentiated from congenital or infant muscular dystrophy, characterized by no muscle atrophy, normal CPK content, no special findings on muscle biopsy, good prognosis.

3, adult spinal muscular atrophy: mainly different from limb-type muscular dystrophy, according to serum enzyme measurement, electromyography and muscle biopsy and with or without fasciculation. Generally can be identified. If there is difficulty, the method of determining the terminal innervation ratio (TIR) at the time of muscle biopsy proposed by Coers (1979) can be used to estimate the branch of the motor nerve axon in the muscle (ie, a certain number of subterminal axonal The number of muscle fibers that are administered, such as elevated TIR, can be diagnosed as spinal muscular atrophy, and normal should be considered as myopathy.

4, polymyositis: mainly different from the limb band type, the development of myositis is faster, often have muscle pain, and no family genetic history, muscle biopsy can often be clearly identified.

5, amyotrophic lateral sclerosis: should be distinguished from distal muscular dystrophy, clinically in addition to muscle atrophy, there are still high muscle tone, hyperreflexia and pathological reflex, and often fasciculation.

6, myasthenia gravis: must be different from the eye muscle type and the pharyngeal muscle type, muscle weakness has fatigue and fluctuation characteristics, with Neostigmine or Tensilon test significantly improved, EMG can also be identified.

7, myotonic dystrophy: there is muscle rigidity, often accompanied by cataract, hair loss and gonadal atrophy, serum enzymes change little.

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