Diffuse idiopathic hyperostosis

Introduction to diffuse idiopathic bone hypertrophy Diffuse idiopathic bone hypertrophy (DISH) mainly involves the spine, especially the cervical vertebrae. It is characterized by a large number of superficial irregular vertebral body anterior and lateral bone hyperplasia that fuse with each other to form a anterior vertebral body with extensive hypertrophic bone. Ankylosing bone hypertrophy or Forestier disease. The disease is common in middle-aged men, the male to female ratio is about 2:1, the incidence rate of men and women increases with age and weight, and there is very little suffering from this disease before the age of 45. basic knowledge The proportion of illness: 0.003% Susceptible people: no special people Mode of infection: non-infectious Complications: spinal stenosis dysphagia

Diffuse idiopathic bone hypertrophy

(1) Causes of the disease

The etiology of this disease is unknown. Although there are reports of family diseases, it is rare. The basic lesions of this disease are at the attachment points of tendons and ligaments. The early lesions before ligament calcification are the proliferation of connective tissue. The number of cells and cells in the lesions is relative. Increased, there are metaplasia of fibrocartilage islands, chondrocytes and proteoglycans increase and collagen is relatively reduced, followed by irregular calcium deposits in the cartilage and adjacent cortical hyperplasia and infiltration, ossification gradually develops in depth, and finally The deep tissue of the ligament also undergoes ossification and fusion with the vertebral body. This point explains the disappearance of the anterior vertebral translucent space on the lateral radiograph of the X-ray. The intervertebral disc can undergo degenerative lesions, the fibrous annulus expands, and the anterior longitudinal ligament is compressed to make the bone. The band is interrupted. In addition, the disc herniation can cause bone hyperplasia and osteophyte formation in the anterior border of the vertebral body, and further transform the anterior longitudinal ligament to make it wavy (Fig. 1, 2).

Although imaging data suggest that this disease may be caused by mechanical factors at some attachment points, more and more data show that the disease is a systemic disease, systemic growth and metabolism abnormalities are easy for this disease. Factors.

In addition to the disease reported by the early Forestier related to obesity, the recent correlation between this disease and impaired glucose tolerance and adult-onset diabetes has been confirmed, 17% to 60% of patients with this disease have abnormal glucose tolerance, significantly higher than the control group; In addition, the prevalence of this disease in adults with diabetes is as high as 13% to 50%. The blood insulin level in adults with diabetes is higher than that in the normal population. Therefore, it is speculated that this disease is associated with hyperinsulinemia, and a large number of clinical studies are This correlation, and this correlation also explains that the disease is not associated with childhood onset diabetes, because the blood insulin levels in childhood-onset diabetes are generally lower than in the normal control population, and insulin has a growth factor-like activity. The formation of new bone may be involved in the pathogenesis of this disease. Some studies have also shown that patients with hyperinsulinemia have significantly higher bone mineral density than patients with hypoinsulinemia. This correlation also partly explains why North American Indians are more than Mabian. Patients with gout have a higher prevalence of this disease. North American Indian horses and gout patients have higher obesity and high blood. The prevalence of diabetes and diabetes in adults, and the above diseases are associated with hyperinsulinemia.

(two) pathogenesis

The pathogenesis of this disease has not been clarified, and may be related to increased secretion of pituitary hormones, acromegaly, hypoparathyroidism, hypervitaminosis A, hypertension, and fluorosis, but they have not been confirmed and recognized.

The formation mechanism of DISH anterior longitudinal ligament extensive ossification is still controversial. The more consistent opinion is that DISH affects the degenerative changes of ligaments and vertebral bodies and is therefore included in the scope of spinal degenerative diseases.

The relationship with HLA-B27 is not clear, and it is more common in patients with type 2 diabetes. It is speculated that osteophyte hyperplasia and ligament calcification may be related to growth hormone stimulation. In addition, in acromegaly, fluorosis, vitamin A In many cases, ankylosing spondylitis, psoriasis, Wright syndrome, hypoparathyroidism and other diseases, bone hypertrophy can be seen, but there is no evidence that they are inextricably linked to DISH.

Vitamin A may also be related to the pathogenesis of this disease. It has been observed in animal experiments that chronic vitamin A poisoning can cause pathological changes similar to this disease. Some studies have also found that blood vitamin A and its metabolites are higher in patients with stimuli. Normal controls; in addition, vitamin A-like substances cause acne and skin lesions and cause joint pain and new bone formation at the point of attachment also support this correlation, people generally do not get a poisoned amount of vitamin A in a normal diet, therefore, It is not clear whether vitamin A is directly related to the disease or indirectly related to the disease through insulin.

In short, the occurrence of this disease is related to systemic growth and metabolism abnormalities, especially the correlation with insulin has been widely recognized, it is generally assumed that insulin has the potential role of bone formation in the attachment point region, in common with other factors such as mechanical factors Under the action, the attachment point area, especially the spine, the characteristic points of the attachment point area of the heel and the elbow.

Calcification is first seen in the adjacent tissue in front of the vertebral body. Focal calcification or ossification can be seen in the anterior longitudinal ligament. Occasionally, the internal ossification of the ligament in the ligament forms a new bone. The adjacent ossification adjacent to the intervertebral disc is normal. As the disease progresses, the intervertebral disc Fiber ring fiber degeneration, peripheral tear, accompanied by anterior lateral swelling of fibrous tissue, ossification occurs in the mixed fibers of the annulus fibrosus and anterior longitudinal ligament, showing hypervascular hyperplasia and mild chronic inflammatory cells surrounding adjacent degeneration The annulus fibrosus and anterior longitudinal ligament, new bone formation of periosteum; the final local ossification involves the anterior longitudinal ligament, the connective tissue around the vertebral body and the annulus fibrosus, and the anterior longitudinal ligament has irregular osteophyte formation at the attachment of the vertebral body.

Diffuse idiopathic bone hypertrophy prevention

1. Eliminate and reduce or avoid the disease factors, improve the living environment, develop good living habits, prevent infection, pay attention to food hygiene, and rational diet.

2. Pay attention to exercise, increase the body's ability to resist disease, do not fatigue, excessive consumption, quit smoking and alcohol.

3. Early detection and early diagnosis and early treatment, establish confidence in the fight against disease, adhere to treatment.

4. Avoid obesity has a positive effect on the prevention and treatment of this disease. Avoid using drugs that cause blood sugar elevation and increase cardiovascular and cerebrovascular events, such as thiazides, beta blockers, exogenous insulins, etc. To avoid heavy drinking.

Diffuse idiopathic bone hypertrophy Complications, spinal stenosis, difficulty swallowing

Local spinal canal stenosis can be complicated. When the new bone formed at the cervical vertebra is thick, it can compress and erupt the esophagus to produce dysphagia. The posterior longitudinal ligament ossification and paraspinal joint hypertrophy can compress the spinal cord to cause spinal cord lesions, and severe sputum.

Diffuse idiopathic bone hypertrophy symptoms common symptoms hardened heel pain, dyslipidemia, foot pain, calcified ligament, ossified elbow pain

The onset of the disease is insidious, slow, mild symptoms, generally no special discomfort in the early stage of the disease, fatigue, limited activity after cold or long-distance ride, and even stiffness of the neck, back and peripheral joints and pain in the limbs, when the calcaneus appears When the olecranon or talus bone spurs, there may be heel pain, elbow pain or foot pain; sometimes sputum, ligament and bone adhesion occurs caused by spastic inflammation, a significant feature of this disease is clinical symptoms compared with X The line behaves lightly.

Diffuse idiopathic bone hypertrophy

Some patients have changed blood glucose levels, suggesting that patients have diabetes, and the rest of the laboratory tests are non-specific; occasionally rheumatoid factor-positive, also not directly related to the disease.

1. Thoracic X-ray shows the thoracic vertebra is the typical affected area of DISH. Abnormal calcification and ossification are most common in the chest 7-11. The upper thoracic vertebra is rare, but it is also seen in the chest 11-12 continuous calcification. The ossification is more common in the anterior aspect of the vertebral body. Continuous calcification and ossification, calcification and ossification are flaky, continuous across the intervertebral space, a wide range; when extensively, a dense shield-like change is formed on the anterior side of the spine; late ossification is uneven, especially in Intervertebral disc level.

The upper and lower margins of some vertebral bodies are formed, but the intervertebral discs maintain a relatively high height. The callus is mostly brush-shaped and often merges with the anterior bone deposition of the vertebral body. It often maintains a complete level in the intervertebral disc, and the formation of the epiphysis is the most serious. The ligament is deposited. A linear or semi-annular translucent band appears between the anterior edge of the vertebral body. Although the translucent band does not appear in each vertebral body, it is a characteristic X-ray change of DISH, which often abruptly terminates at the upper edge of the vertebral body. And the lower edge, the late translucent band can disappear with the progress of ossification (Figure 3).

The bilateral ossification of the spine is asymmetrical, although bilateral involvement is common, but the right side of the thoracic vertebrae is good, and the left bone deposition and osteophytes are rare.

2. The cervical vertebrae are most common in the front of the neck 5 and the neck 6 vertebral body. The neck 1 and the neck 2 are rare. The cortical hypertrophy first occurs along the anterior surface of the vertebral body. The leading edge, especially the anterior inferior border, has a callus that extends downward and crosses the intervertebral disc. As the disease progresses, it can be seen that several vertebral bodies are involved, but it is rare compared with the thoracic vertebrae. The ossification is smooth, the armor is uneven and irregular, and the thickest can reach 11~12mm. The level of the intervertebral disc is often in the vertebral body. A low-density defect formed by bulging of the intervertebral disc, but a translucent band between the deposited bone and the vertebral body is rare.

3. Lumbar vertebral anterior bone hypertrophy is the initial manifestation, the disease progresses, the cloud-like density increases and the sharp-angled callus appears at the edge of the vertebral body, especially in the anterior and posterior vertebral body. The epiphysis extends over the intervertebral disc, and the bone in the front of the intervertebral disc is visible. Low-density shadows, even visible translucent bands between new bone and vertebral body, but the bone deposition of several consecutive vertebral bodies is rare, and the vertebral lumbosacral ridge of the vertebral body is more common.

4. There is a beard-like bone deposition on the ligament attachment of the pelvis, the ischial tuberosity, the femoral trochanter, etc. The epiphysis is visible around the lower joint of the ankle joint, and the upper pubis and the suprapubic bone bridge are formed.

5. The heel of the posterior surface of the heel, the Achilles tendon and the decidua, the dorsal talus, the humerus, the dorsal medial aspect of the scaphoid, the posterior femur and the fifth metatarsal basal specific bone hyperplasia, the latter It is characterized by decidual calcification or large "talar groove".

6. Other parts of the iliac crest, humeral bone hypertrophy often involves the attachment of the interosseous membrane, the upper and lower tibia bone hyperplasia, especially in the attachment of the quadriceps tendon, the elbow is most common with the olecranon.

Diagnosis and diagnosis of diffuse idiopathic bone hypertrophy

Diagnostic criteria

Because the clinical symptoms and signs of DISH are light and lack specificity, the clinical diagnosis mainly relies on X-ray findings and clinical manifestations, and comprehensive judgment is based on the exclusion of other related diseases.

1. X-ray diagnostic criteria Diagnosing spinal lesions in DISH requires the following three criteria:

(1) At least 4 consecutive vertebral bodies have calcification and ossification on the anterior lateral side, with or without obvious neoplasms.

(2) The existence of intervertebral space, lack of extensive changes in typical degenerative disc disease.

(3) Bone rigidity or erosion of the non-bone joint, hardening, or bone fusion of the ankle joint.

2. The disease mainly relies on imaging diagnosis. The most commonly used examination is the anterior and lateral X-ray examination of the vertebral tract with suspected lesions. CT examination is feasible for patients with suspected spinal stenosis; ligament bone can be found by MRI. The ligaments before the transformation are hypertrophic.

The disease was not associated with human leukocyte antigen, routine blood biochemical examination and erythrocyte sedimentation rate were normal, and all diseases and auxiliary examinations associated with hyperinsulinemia may be abnormal, such as hypertension, obesity, adult-onset diabetes, dyslipidemia, Gout and so on.

Differential diagnosis

1. The disease should be differentiated from degenerative disc disease and ankylosing spondylitis. The former often has intervertebral disc involvement, the spine becomes short, and there is vertebral edge hardening or vacuum phenomenon; the latter has vertebral facet joint blur, rigidity and ankle joint Erosion, hardening or fusion.

2. The first of the three conditions for the diagnostic criteria of X-ray in diagnosis is the identification of the deformity of the deformity of the spine, the latter is the degeneration of the annulus fibrosus, and there may be ossification between only 2 or 3 vertebral bodies; The second condition was used to identify degenerative disc disease; the third condition was used to rule out ankylosing spondylitis.

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