Severe pseudotrophic malnutrition

Introduction Duchenne type malnutrition (DMD): also known as severe pseudo-hypertrophic large malnutrition, almost only seen in boys, if the mother is a gene carrier, 50% of male offspring, usually starting from 2-8 years old, initial sense Walking benzoquinone, easy to fall, can not run and board the building, standing scalp, abdomen out, two feet open, walking slowly swinging, showing a special "duck step" gait, when walking from the back is very difficult, must first Turn over and prone, then climb your knees with both hands and gradually support the standing up (Gower sign). Can also be seen in the proximal muscles of the limbs, quadriceps and arm muscles.

Cause

The cause of severe pseudo-fat large malnutrition

The disease is caused by a mutation in the gene encoding dystrophin on chromosome Hp21, which belongs to X-linked recessive genetic disease, which is generally caused by men and females carrying mutant genes. However, in fact, only 2/3 of the patients' disease genes are from the mother, and another 1/3 of the patients are mutations in the self-dystrophin gene. The mother of such children does not carry the mutation, and has nothing to do with the onset of the child.

Anti-dystrophin is located in the membrane lipid of muscle cells and plays an important role in stabilizing the cell membrane and preventing cell necrosis and autolysis. Quantitative analysis indicates that the dystrophin in the myocytes of DMD patients is almost completely recovered, so the clinical symptoms are aggravated, while BMD is only partially Reduced, the prognosis is relatively good. Since the protein is also partially present in the nerve structure surrounding the myocardium and brain nuclei, some patients may have myocardial lesions, mental retardation or peripheral nerve conduction function detection disorder.

Under the microscope, there are extensive degeneration and necrosis of muscle fibers ranging from light to heavy, with deep dyed muscle fibers. Intravascular fibrous tissue hyperplasia or fat filling, and seeing reactive focal mononuclear cell infiltration for necrotic muscle fibers.

an examination

Related inspection

Serum myoglobin electromyography myoglobin vitamin B6 vitamin B6 (VitB6)

Severe false fat hypertrophy

Boys are sick, but in addition to carrying mutant genes, individual girls can also develop symptoms due to inactivation of another X chromosome. The main manifestations of this disease include:

1, progressive muscle weakness and motor function regression: the child's birth or early infant movement is basically normal, a few have mild exercise development delay, or independent walking after gait instability, easy to fall. Generally, after 5 years old, the symptoms begin to be obvious, the hip muscle weakness becomes more and more serious, walking swings like duck gait, falls more frequently, can't go upstairs and jump, shoulder strap and whole body spine will decline progressively, most lose after 10 years old. Independent walking ability Most of the throat muscles and respiratory muscles are weak before the age of 20, the sound is low, swallowing and breathing difficulties, it is easy to occur secondary infection such as aspiration pneumonia, BMD symptoms are mild, may survive to about 40 years old.

2, Gower sign: Because the hip muscles are weak early, usually after 3 years old, the child can not stand up from the supine position, must first turn into a prone position, then the two feet are separated, the hands are first supported on the ground, and then one hand supports Go to the ipsilateral calf and alternately shift it to the knees and thighs with the other hand, so that the drive is gradually vertical from the deep position, and finally stands in a lumbar convex position.

3, pseudo-muscle hypertrophy and extensive muscle atrophy: early pelvic and thigh progressive muscle atrophy, but the calf due to fat and collagen football proliferation and pseudo-hypertrophy, contrast with other parts of the muscle crisis, when the shoulder muscles atrophy When lifting the arm, the inside of the shoulder blade is far from the chest wall to form a "winged shoulder." When the child's body is lifted from the armpit, the sick child's arms are upwards and there is a tendency to slip off the hand. Spinal muscle atrophy can lead to spinal deformity, muscle atrophy later in the disease, causing knee, hip or upper arm flexion deformity.

4, other: Most children have cardiomyopathy, and even heart failure, but its severity is not consistent with skeletal muscle weakness. Almost all children with different degrees of intellectual damage, and the severity of muscle weakness is not parallel, of which 2% - 30% is more obvious, IQ <70.

[Clinical manifestations] are divided into the following types:

(1) The fake fertilizer is large. 1. Duchenne type malnutrition (DMD): almost only seen in boys, the initial sense of walking benzene, easy to fall, can not run and boarding, standing scalp when standing, the abdomen is out, the two feet open, showing a special "duck step "Gait, when walking from the back is very difficult, you must first turn over and prone, then climb your hands with both knees, and gradually support standing up." Can also be seen in the proximal muscles of the limbs, quadriceps and arm muscles. 2, Becker type (BMD): The first symptom is weak pelvic and femoral muscles, slow progress and long course.

(B) face shoulder - sacral muscular dystrophy.

(3) Limb-type muscular dystrophy.

(D) other types: quadriceps type, distal type, progressive extraocular muscle paralysis type, eye muscle-pharyngeal muscle type, etc., very rare.

an examination:

(a) Determination of serum enzymes:

1. Serum creatine phosphokinase (CPK).

2. Serum myoglobin (MB).

3. Serum pyruvate (PK).

4, other enzymes: such as aldolase (ADL), lactate dehydrogenase (LDH), aspartate aminotransferase (GOT), alanine aminotransferase (GPT), etc., can also be increased.

(B) urine test.

(3) EMG.

(4) Muscle biopsy.

Differential diagnosis

Severe false fat hypertrophy confusing symptoms

Muscular dystrophy can be divided into several categories, the most obvious is the large scale of fake fat, according to clinical manifestations, can be divided into Duchenne type and Becker.

1, Duchenne type malnutrition (DMD): also known as severe pseudo-fat large-scale malnutrition, more than 4 to 5 years old, usually no later than 7 years old, usually died before the age of twenty.

2, Becker type (BMD): also known as benign pseudo-hypertrophic muscular dystrophy, often onset after 10 years of age, the first symptom is pelvic and femoral muscle weakness, slow progress, long course, 25 years after symptoms appear It can't be walked for more than 25 years, and most of them don't happen when they are 30-40 years old.

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