Dense bone dysplasia
Introduction
Introduction to Dense Bone Development Disorder Dense bone development disorder (condensingosteodysplasty) is an autosomal dominant hereditary disease. In the past, many scholars only thought it was a dwarf. Later, due to systemic skeletal sclerosis and clavicular hypoplasia, Palmar et al considered it a kind of osteosclerosis. , or called clavicle skull hypoplasia. From the histological point of view, the ultrastructure of cartilage shows abnormal inclusion bodies in the chondrocytes. basic knowledge The proportion of illness: 0.002% Susceptible people: no specific population Mode of infection: non-infectious Complications: fracture
Cause
The cause of dense bone development disorder
Hyperparathyroidism (35%):
In addition to genetic factors, there are still endocrine factors. Dupont believes that the original factor may be hyperparathyroidism. Injecting parathyroid hormone into animals every day will cause bone calcium to appear freely. If continuous injection, osteoblasts are stimulated. There is bone deposition, and Ellis believes that persistent hyperparathyroidism cannot be explained. It may be that the parathyroid function is active and alternates with normal stages, resulting in alternating bone density rings.
Pathological changes (25%):
The pathological changes are membranous bone and cartilage bone are absorbed, the typical change is the increase of bone density and thickness, trabecular bone completely disappeared, all bones will be affected, and symmetry, long bone cortex and bone marrow The boundary disappeared, and the change of the metaphysis was most obvious. The size and shape of the epiphyseal cartilage of the long bone did not change, but the ossification center of the epiphysis could have the same change. In addition to the disappearance of the bone structure, the bone density increased, and it was granular, bone. The thickening indicates that not only the formation of bone from the epiphyseal cartilage is affected, but also the growth of the subperiosteal osteoblast is affected. The fastest growing parts, such as the lower end of the femur, the lower end of the humerus, the upper end of the humerus and the upper end of the tibia are also the largest, the ribs are also the same. Also affected, it becomes an unstructured thickened bone. The upper 1/3 and lower 1/3 of the vertebral body have a dense area, while the middle 1/3 can remain normal, and the skull can also have obvious hyperplasia, carpal and tibia. It is a dense bone that is concentric in shape.
Excessive calcification of bone-like tissue (25%):
Microscopic examination showed a mixed state of calcified cartilage mass, bone, dead bone and sclerosing fibrous tissue, tissue avascular, medullary space filled with hardened tissue, few capillaries, no lamellar ossification, no osteoblast activity, Hardening is mainly due to excessive calcification of bone-like tissue.
Secondary pathological changes are mainly caused by interference between the hematopoietic system and the nervous system. The former affects normal blood formation and the latter affects nerve conduction.
Prevention
Prevention of compact bone development disorder
There is no effective preventive measure for this disease. Early detection and early diagnosis are the key to the prevention and treatment of this disease.
Complication
Complications of dense bone developmental disorders Complications
Easy to have spontaneous fractures.
Symptom
Dense symptoms of bone development disorders Common symptoms Nail fragile bone brittle abnormal short spine scoliosis
The main clinical features of this disease are short stature, small body length of more than 1.5m, small face, hook nose, contracture, caries, cranial ridge, anterior cardia and cranial suture often do not close; distal phalanx, nail dysplasia Easy to break; bone fragile, prone to spontaneous fracture; poor development of the shoulder of the clavicle; prominent eyeballs, other bone changes including narrow chest and spinal deformity.
Examine
Examination of dense bone development disorders
The level of insulin-like growth factor-1 (IGF-1) was reduced, and the growth hormone stimulation test showed growth hormone deficiency.
1. X-ray examination: visible bone density increased, cranial suture width, facial bone dysplasia, lower forehead angle flattened, vertebral compression deformation, scaphoid sinus dysplasia.
2. Magnetic resonance examination: can show pituitary dysplasia.
Diagnosis
Diagnosis and differentiation of dense bone development disorder
Diagnosis: According to clinical manifestations and X-ray examination, and refer to laboratory tests, it is generally not difficult to diagnose.
Identification: Generally not confused with other diseases.
