Thick long bones

Introduction Patients with malformation osteitis showed long bone flexion and gross deformity on X-ray examination. Osteitis deformans is a chronic progressive bone disease characterized by local bone tissue osteoclastic and osteogenesis, bone resorption and reconstruction, osteoporosis and calcification.

Cause

(1) Causes of the disease

The exact cause is unknown. Some data show that patients with HLA-DQW1 frequency are higher; 15% to 30% have a family history, 7 times higher than the general population, and family history positive patients have earlier onset and more severe disease; In association with certain viral infections, viral capsids have been found in the osteoclast nucleus and cytoplasm of the pathological site of the patient. According to the shape of the inclusion body, it appears to be a paramyxovirus family; in vitro studies have found that this virus can be associated with infected cells. Fusion, and formation of multinucleated giant cells; IL-6 can regulate this process, but not complete virions have been isolated. Indirect immunofluorescence and immunoperoxidase staining also demonstrated measles virus antigens and respiratory syncytial virus antigens in the nucleus and cytoplasm. Clinical studies have found abnormal collagen in the skin of patients; some patients with retinal angioid streaks, elastic pseudo-xanthoma and vascular calcification suggest that may be related to collagen metabolism. There are several the following theories.

1. Viral infection: It has been found by electron microscopy that there is an RNA virus nucleocapsid in the cytoplasm and nucleus of osteoclasts in the lesion site, and it is speculated that the paramyxovirus infection may be related to the disease. However, similar structures have recently been found in osteoblasts of bone giant cells and osteoblasts of osteopetrosis. Other studies have found that measles virus and canine distemper virus infection may also be associated with this disease. The relationship between viral infection and malformation osteitis has not been further confirmed and verified by animal models.

2. Genetics: 15% to 30% of patients have a positive family history, suggesting that the disease has a genetic predisposition. It has been reported that the disease is autosomal dominant, and it has been reported that this disease is associated with HLA-DQw1 antigen, but it has not been widely verified.

(two) pathogenesis

The bone structure and function of the lesion are closely related to the process of the lesion. The lesion process is generally divided into three phases: the early stage is mainly osteolytic, the later stage is mainly osteosclerosis, and the middle stage is a mixed type of two changes.

At the beginning of the lesion, giant multinucleated osteoclasts invade normal bone tissue. More than 50% of osteoarthritis osteitis has more than 7 osteoclast nuclei, 10% of osteoclast nuclei exceeds 20, and some can have more than 100; while normal bone tissue contains 50% of osteoclast nuclei over 3 The number of 10% osteoclast nuclei exceeds 5. As osteoclast activity is enhanced, bone resorption is accelerated and accompanied by angiogenesis and medulla fibrosis. Then, at the same time as bone resorption, osteogenesis also increases compensatoryly, mainly in the disordered lamellar bone formation (mixing period). . Finally, there is only osteogenesis without bone resorption, new bone formation is irregular, and the arrangement is disordered, forming a woven bone (normal woven bone is not present in normal adults except for fracture repair and high bone transition), woven bone and lamellar bone inlay, small bone The thickness and direction of the beam are very irregular, like a pile of chaos. A calculus kinetic analysis showed that the bone turnover rate of the lesion was 46 times higher than that of the normal site.

The above pathological changes lead to an increase in bone fragility in the lesion site, which is prone to fracture.

an examination

Related inspection

X-ray examination of bone imaging, bone imaging, bone density, bone and joint plain film

Laboratory biochemical indicators are important for the diagnosis of this disease, other metabolic bone diseases caused by other causes and judgment of efficacy. Since the disease affects bone absorption and formation, biochemical indicators reflecting bone resorption and formation often increase.

1. Indicators reflecting bone resorption: such as urinary pyridinium cross-linking and deoxypyridinoline cross-linking can be elevated.

2. Reflecting bone formation indicators: There are blood alkaline phosphatase or bone alkaline phosphatase and urinary hydroxyproline, these indicators can be increased. When only blood alkaline phosphatase is detected, attention should be paid to the exclusion of liver disease. Alkaline phosphatase detection is the most effective indicator for monitoring disease activity and judging efficacy. When the lesions are wide, especially when the skull is invaded, the alkaline phosphatase rises more than 10 times the upper limit of the normal reference value.

3. Other indicators for determining metabolic bone disease: such as blood calcium, phosphorus, magnesium, etc. often in the normal range of elevated blood calcium should pay attention to the presence or absence of malignant tumors, primary hyperparathyroidism or long-term bedridden. During the active period of the disease, some patients have elevated blood parathyroid hormone and normal blood calcium.

4. X-ray examination: X-ray performance has certain characteristics, such as the early X-ray of skull lesions, which is the most osteoporotic area in the skull area, which is developed from the outer plate to the inner plate, and the lesion is surrounded by the osteosclerosis zone. During the progression of the lesion, the bone layer is thickened between the lamellar bone and the braided bone to form an irregular or cotton-like bone shadow. When the outer panel appears loose, the inner panel can be expressed as a sclerotic image, which is the X-ray characteristic of the disease. One of the performances. Long bone lesions are often caused by the presence of a translucent area in the cortical bone, followed by a cystic area in the bone sponge, which makes the cortex phenotype a double contour. At the junction of the initial zone of the lesion and the normal zone, a V-shaped or "flaming" osteolytic zone is seen, which is caused by bone resorption. After the lesion enters the repairing period, the V-shaped boundary zone is covered by the repaired tissue, and a multi-layered periosteal new bone is formed, which thickens the backbone and is arranged along the line of force in the form of extensive strips or reticular trabeculae, resulting in long bone bending and coarsening. deformity.

5. Bone scan: can be used to understand the extent and extent of the lesion, but generally not used for diagnosis. Bone scans suggest that other bone injuries, such as fractures, infections, and malignant tumors, should be noted. Due to the constant location of the disease, changes in the condition that may or may not be associated with the disease during long-term follow-up may be determined and identified by the patient's initial bone scan data.

Differential diagnosis

Differential diagnosis of long bones:

1. Long bone epiphyseal calcification: cartilage ectodermal dysplasia syndrome, also known as Ellis-van Creveld congenital malformation syndrome, congenital cartilage calcification disorder heart disease syndrome, cartilage ectodermal dysplasia syndrome and other health searches, is autosomal Recessive hereditary disease, characterized by short-legged dwarfs, often with congenital heart disease and mental retardation. The newborn baby is in a dwarf state, such as the short bones of the limbs are short and thick, the distal fingers (toes) are particularly small, and multiple fingers (toes) can appear, hair, teeth development is poor, and the long bones of the whole body are incompletely calcified.

2, long bone swelling and pain: limbs long bone fracture often accompanied by different degrees of swelling, can lead to limb pain, affecting postoperative functional exercise, wound healing. If the swelling is serious, it can directly affect the blood circulation of the limbs, and even serious complications such as compartment syndrome.

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