How to diagnose severe pseudohypertrophic malnutrition

Since the pathogenic gene of this disease is located at Xp21.1, which causes the deficiency of dystrophin, there is no specific treatment that can reverse the course of this disease. Therefore, it is necessary to emphasize taking effective measures to reduce the genetic load of this disease in the population and reduce the occurrence of this disease. Boys are sick, but some girls can also get sick due to the inactivation of the other X chromosome function in addition to carrying the mutant gene. The main manifestations of this disease include:

1. Progressive muscle weakness and motor function regression. The motor development of the affected children is basically normal at birth or in early infancy. A few have mild motor development delay, or unstable gait after walking independently, and are prone to falling. Generally, symptoms begin to become obvious after the age of 5, with increasingly severe weakness of the hip girdle muscles, swaying duck-like gait when walking, more frequent falls, inability to go upstairs and jump, and progressive reduction of shoulder girdle and whole body spinal strength. Most lose the ability to walk independently after the age of 10. Most develop weakness of throat muscles and respiratory muscles before the age of 20, with low voice, difficulty swallowing and breathing, and are prone to secondary infection and death such as aspiration pneumonia. BMD symptoms are milder and may survive to around 40 years old.

2. Gower's sign. Due to early weakness of the hip girdle muscles, children cannot stand up directly from a supine position after the age of 3. They must first turn over to a prone position, then spread their feet apart, support their legs on the ground with both hands, then support one hand on the same side calf, and alternately move with the other hand to support the knee and thigh, so that the legs can gradually stand up from a deep bow position, and finally stand in a convex waist position.

3. Pseudo-hypertrophy and widespread muscle atrophy. There is progressive muscle atrophy of the pelvis and thighs in the early stage, but the calf is pseudo-hypertrophic due to the proliferation of fat and collagen, which is in sharp contrast with the muscles in other parts. When the shoulder girdle muscles atrophy, the inner side of the scapula moves away from the chest wall when the arm is raised, forming a "winged scapula". When the child's body is lifted from the armpit, the child's arms are raised and tend to slip out of the examiner's hand. Spinal muscle atrophy can lead to spinal curvature deformity. Muscle atrophy occurs in the late stage of the disease, causing knee, hip or upper arm flexion deformity.

4. Most children have cardiomyopathy and even heart failure, but the severity is not consistent with skeletal muscle weakness. Almost all children have varying degrees of intellectual impairment, which is not parallel to the severity of muscle weakness, and 2%-30% of them are more obvious, with IQ <70.

Clinical manifestations are divided into the following types:

1. Pseudohypertrophic type. It is divided into Duchenne type malnutrition (DMD): It is almost only seen in boys. In the early stage, they feel clumsy in walking, easy to fall, unable to run and climb stairs. When standing, the spinal cord is lordotic, the abdomen is protruding, and the two feet are apart, showing a special "duck step" gait. It is very difficult to stand up from lying on the back. You must first turn over and lie on your stomach, then climb your hands on your knees and gradually support yourself to stand up. It can also be seen in the proximal muscles of the limbs, quadriceps and arm muscles. Becker type (BMD): The first symptom is weak pelvic girdle and thigh muscles, which progresses slowly and has a long course.

2. Facioscapulohumeral muscular dystrophy.

3. Limb-girdle muscular dystrophy.

4. Other types include quadriceps type, distal type, progressive extraophthalmoplegia type, oculo-pharyngeal muscle type, etc., which are extremely rare.