progressive myositis ossificans in children
Introduction
Introduction to progressive osteomyelitis in children Myositisossificans can be divided into three categories, namely, traumatic, limited and progressive. Traumatic ossifying myositis refers to the ossification of a certain part of the muscle repeatedly caused by external force damage, and the limited nature usually forms bone in the scar of the muscle. Only progressive myositisositis (myositisossificans progressiva) will be described here. This disease is characterized by intramuscular ectopic calcification and ossification; clinical features are (toe) small deformity and progressive ossification of connective tissue in the fascia, tendon, ligament, sarcolemma and skeletal muscle interstitial tissues. Because the skeletal muscle itself is basically normal, such as the use of the term fibrodysplasiaossificans progressive to describe the lesion, it seems more accurate. basic knowledge The proportion of illness: 0.001% Susceptible people: children Mode of infection: non-infectious Complications: swelling
Cause
Pediatric progressive ossifying myositis
(1) Causes of the disease
The pathogen has not been fully understood. The basic factor is secondary calcification and ossification caused by defects in the genetic components of connective tissue. It is a dominant inheritance and has been reported in twins.
(two) pathogenesis
Early lesions are characterized by interstitial edema and connective tissue infiltration, muscle fibers in secondary atrophy and degeneration, and later, calcification and ossification of the affected mesoderm.
The lesion can be divided into 4 layers:
1. Center: poorly differentiated area, this area is rich in cells, the size and shape of the cells are different, and there is filamentous nuclear division (the cytology in this area is difficult to distinguish with sarcoma).
2. Adjacent to the center: The bone-like tissue adjacent to the center and the loose interstitial cells are well arranged.
3. Peripheral area: Osteoblasts and fibrous tissues form trabeculae and form new bone.
4. The outermost layer: there is a bone structure which is wrapped by fibrous tissue and has a clear boundary. The stratification phenomenon is characterized by benign lesions. The innermost layer of the lesion is poorly differentiated, and the more mature the outer layer, until the outermost normal bone tissue, The more mature the bone tissue, the smaller the extent of the spread.
Prevention
Pediatric progressive ossifying myositis prevention
The disease is a dominant genetic disease, so to prevent dominant genetic diseases, see the following aspects:
1. Pre-marital health check: Men and women who have established a relationship of love should undergo a comprehensive system of health check before applying for marriage registration. In particular, it is important to avoid close relatives getting married. Offspring of close relatives who suffer from mental retardation, congenital malformations, and various genetic diseases are several times more likely to marry than non-close relatives.
2, pre-pregnancy genetic counseling: both men and women or one party, if relatives have genetic disease patients, worried about whether they will give birth to the same genetic disease after marriage, should consult whether they can get married, if the consequences of marriage is very serious; A disease, but I don't know if it is a genetic disease, can I get married, what is the chance of passing it to future generations? The doctor will make a clear diagnosis and tell a reasonable treatment.
3, prenatal screening to avoid the birth of children: prenatal screening is mainly for some diseases that currently have no good treatment, the purpose is to prevent the birth of defective children. Usually in the 16th to 20th week of pregnancy, 2-3 ml of peripheral blood of pregnant women should be examined. If the risk of high risk is found (high risk factor exceeds 1/270), further amniocentesis should be taken to confirm the diagnosis.
Complication
Pediatric progressive ossifying myositis complications Complications swelling
The spine is often stiff and the shoulders are not free to move. The arms, legs and diaphragm are stiff. Local swelling can occur.
Symptom
Pediatric progressive ossifying myositis symptoms common symptoms neck muscle swelling hard nodules low fever
More common in men, most of the disease before the age of 6 years, even the fascia and tendon lesions existed before birth, most of the children with a variety of congenital anomalies, thumb or toe small deformity is particularly common.
Typical lesions first appear in the neck, the dorsal and shoulders of the trunk, and finally the proximal end of the limb. The lesion is swollen, with a small range, sometimes up to the size of the egg. The early acute phase is a soft mud-like swelling, pain. , tenderness and mild fever, may be accompanied by systemic hypothermia, the tumor often close to the deep fascia, local skin can be loose, the skin flushing and swelling may be optional, after a few days or weeks, local swelling subsided The remaining solid nodules, after 2 to 8 months, localized formation of bony tissue, can be touched, can be confirmed by X-ray examination.
Elbows, the limbs of the knee are rarely involved, and the hands, feet, tongue, ankle, throat, sphincter and smooth muscle are not invaded.
Examine
Pediatric progressive ossifying myositis
There are no specific findings in routine laboratory tests.
X-ray photographs showed scattered calcification in the soft tissue of the tumor. After a period of time, the symptoms and signs disappeared in the acute phase, the mass became smaller, the calcification shadow also decreased, but the density increased, and the columnar or irregular shape was visible on the X-ray film. The ossified shadows of different densities can be connected to the bones or completely free, and the bones exhibit a disuse atrophy.
Diagnosis
Diagnosis and differential diagnosis of progressive ossifying myositis in children
diagnosis
Significant case diagnosis is not difficult, early attention should be paid to muscle swelling, the disease gradually progresses, the thumb and toes are small and the intramuscular nodules, the bone mass begins with only the peas, no pain, and then gradually enlarge, merge into irregular groups Piece.
Differential diagnosis
The disease must be differentiated from rheumatism, multiple osteophytes, fibromyositis, dermatomyositis, generalized calcification, rheumatic fever, joints, soft tissue, no calcification, multiple osteophytes, movement-free, It is easy to identify by X-ray examination. There is no bone tissue in fibromyositis. The skin symptoms of dermatomyositis are generally significant. It begins to invade the limb first, and then involves the trunk. The skin and the muscles under it often have inflammation. There are tender indurations, and necrosis of muscle and subcutaneous fat can be calcified. Generalized calcification is not limited to muscles, and there are more lesions in the limbs.
Osteomyositis should be differentiated from hematoma calcification, interstitial calcinosis and osteosarcoma. The calcification site of ossifying myositis is in the diaphysis, parallel to the bone surface, with a clear normal cortical and periosteum. Osteosarcoma always shows signs of cortical and periosteal destruction. The lesion is located at the metaphysis. For suspicious cases, short-term continuous X-rays are helpful for differential diagnosis. Individual histological examination may still be misdiagnosed.
