Osteosclerosis

Introduction to osteopetrosis Osteopetrosis, also known as manblebone, or osteosclerosis fragilis. It is a rare congenital disease of systemic bone structure dysplasia, and the skull is one of the most common sites. The bones are extremely dense and lose their original structure, just like marble. However, the increase in bone fragility is prone to fracture, and it can be accompanied by anemia, eye atrophy and deafness. It is a rare disease, which is often found when X-ray examination is performed due to fracture or other conditions. Men are slightly more than women, and it is generally believed that the vast majority of patients have begun to have lesions before they appear. According to the clinical manifestations, it is divided into malignant (infant type) and benign (adult type). The former is often stillbirth or dying from anemia after birth, and the prognosis is poor. basic knowledge The proportion of illness: 0.001% Susceptible people: no specific population Mode of infection: non-infectious Complications: hydrocephalus facial paralysis sinusitis anemia caries chicken breast

Causes of osteopetrosis

Abnormal bone resorption (20%):

The cause of the osteopetrosis is not clear, and may be related to abnormal bone resorption, resulting in excessive deposition of calcium salts in the bone, the appearance of marble or ivory, increased fragility.

Genetic factors (10%):

The disease has a family history, and is more common among children who are married to close relatives. Some people think that it is a hereditary disease. The disease is divided into two types, the light type is dominant inheritance, and the heavy type is recessive inheritance.

Pathogenesis

Caffey believes that the basic pathological change of osteopetrosis is that during the formation of endochondral bone, the calcified cartilage matrix is poorly absorbed and maintained, resulting in shrinking or even occlusion of the bone marrow cavity, forming hardened and brittle bone, and increasing cortical bone. Thick and dense, cancellous trabecular bone also increased thickening, so that the cortical bone and bone can not be clearly demarcated, under the microscope see osteoclast abnormalities, loss of irregular edges, indicating inactivity, mainly involving the skull base in the skull, Severe cases of the skull can also be widely involved.

Osteosclerosis prevention

Young men and women should understand the family history of both sides before marriage and practice prenatal and postnatal care. Because the current cause of this disease is unknown, it is suspected to be a congenital dysplasia, so there is no effective preventive measure for this disease. The main focus of prevention and treatment of this disease is to prevent the occurrence of complications of this disease. Therefore, early detection, early diagnosis, and early treatment are the key to prevent further damage from this disease.

Complication of osteopetrosis Complications, hydrocephalus, paranasal sinusitis, anemia, caries, chicken breast

Patients with this disease, such as the occurrence of skull sclerosis, can cause hydrocephalus and cranial nerve compression, resulting in eye atrophy, facial paralysis, loss of hearing, etc., paranasal sinus cavity less, occlusion, poor drainage and paranasal sinusitis, anemia About 30%, severe cases can be fatal, often accompanied by spleen, liver and lymph nodes, prone to dental caries, resulting in osteomyelitis of the mandible, some patients can see chicken breasts and beaded ribs, in malignant type, mostly stillbirth Or death in the short term after birth, the cause of death is mostly infection and anemia; in benign type, the disease has a good prognosis, complications are rare, but the recovery of children depends on the degree of anemia and its compensation. In addition, this disease can also be complicated by long bone fractures.

Symptoms of osteopetrosis common symptoms osteosclerosis simple fracture hearing loss demyelin visual impairment intracranial hemorrhage nystagmus intracranial pressure increased strabismus deafness

1. Light type: also known as benign type, more common in adolescents and adults, the prognosis is good, patients may have different degrees of anemia and cranial nerve compression symptoms or no obvious symptoms in the early stage, often found in adulthood due to X-ray examination There may be an increase in blood acid phosphatase.

2. Heavy: also known as malignant type, common in infants and young children, patients with early onset, rapid progress, more blood supply, and the nervous system and blood system are often affected, showing anemia, hemorrhage, liver and spleen increase, this is because Systemic bone marrow cavity shrinkage or occlusion caused by hematopoietic disorders, nervous system manifested as cerebral edema, decreased vision or blindness, nystagmus, giant head disease, strabismus, facial nerve palsy, deafness, hydrocephalus, intracranial hemorrhage, mental retardation, epilepsy and Trigeminal nerve damage, optic atrophy, etc., regarding visual impairment and optic atrophy, often explained as optic canal stenosis caused by optic nerve compression, others are considered to be primary optic nerve demyelination, secondary to retinal vein compression occurs optic disc Edema and optic atrophy or increased intracranial pressure and hydrocephalus.

Examination of osteopetrosis

Biochemical examination: due to hematopoietic disorders, blood biochemical tests may have a significant increase in blood acid phosphatase.

Imaging examination: X-ray skull and other flat films. The X-ray of the skull is hardened, especially in the skull base, especially the sphenoid body and the large and small wings are obviously changed. The size of the saddle is normal or reduced, the bed is swollen, the saddle is hardened, and the humerus and occipital bone can also be hardened. The barrier is closed, the three layers of the division are lost, the parietal bone, the frontal bone and the facial bone can be invaded or only slightly changed, the optic nerve hole is narrowed and the edge is blurred, and the mastoid small and the paranasal sinus become small or underdeveloped.

The osteopetrosis has characteristic X-ray changes in the long tubular bone and the spine. The spine body is characterized by a particularly dense upper and lower margin. The lower density is normal bone, which constitutes a three-layer band shadow. The long tubular bone is characterized by bone. The inner bone is dense, the bone is dense, and the medullary cavity is narrowed or disappeared. In the metaphyseal part, a plurality of parallel lines or wavy dense lines are displayed, and the metaphyseal part can be deformed in a shape, especially the inner side of the upper end of the humerus can be represented as a marginal irregularity. In the case of a coarse sawtooth change, the humeral wing is typically changed to a multi-layered concentric arc-shaped hardened band of parallel turns.

In addition, the ribs and the clavicle can be uniformly hardened, and sometimes fractures can be seen. The palms, tendons, fingers and phalanx often have well-defined bone islands.

Diagnosis and differentiation of osteopetrosis

diagnosis

Severe osteopetrosis is easy to diagnose, and mild patients sometimes have difficulty in diagnosis. The diagnosis depends on radiological examination and family history. For patients with optic atrophy, clear optic canal tomography or coronary plus sagittal CT scan can clearly show the lesion. The location and extent of the diagnosis of stone osteopathy is:

1. often in childhood, developmental delay, due to skull sclerosis and hydrocephalus and chronic stress symptoms, such as facial nerve paralysis, hearing loss, optic atrophy, etc., the skull is hard and brittle, prone to fractures, fractures often transverse, fracture It is difficult to heal afterwards, and cutting the skull with a knife during surgery is like cutting a chalk.

2. Patients may have anemia due to hematopoietic disorders, liver, spleen and lymph nodes increase, serum acid phosphatase increases.

3. The same lesions exist in the metaphysis of the bones in other parts of the body.

4. X-ray skull shows that the skull is abnormally dense and thick, and the inner and outer plates and slabs are integrated. It is difficult to distinguish. The skull is highly calcified, the density is significantly increased, the cranial fossa becomes shallow, the pituitary fossa becomes smaller, the frontal sinus shrinks, and the saddle Back proliferation and so on.

Differential diagnosis

(1) Dense bone development disorder: The child is short, the skull bone is enlarged, the frontal occipital bone is prominent, the intercostal bone is common, the distal phalanx is underdeveloped, the long bone density is increased but the bone marrow cavity is present, and the child has no anemia.

(2) Incomplete development of the skull dryness: the skull is progressively enlarged and thickened, and the bone is not brittle. It is only after 5 years of age.

(3) Skull bone dysplasia: mainly manifested as "lion face" hyperplasia, no bone destruction in other parts, poor bone shape, widening of clavicle and ribs.

(4) Neonatal osteosclerosis: usually disappears within 1 month.

(5) Myelofibrosis complicated by anemia or leukemia: sometimes it is difficult to distinguish it from marble bone disease, only by blood test and bone marrow puncture.

(6) skeletal fluorosis: because skeletal fluorosis involving the skull, it can also be manifested as thickening of the skull, increased density, especially the skull base can appear obvious hardening, but fluorosis is caused by chronic fluorosis, the patient has fluoride Long-term exposure history or long-term drinking water fluoride exceeds the allowable amount and fluoride treatment of myeloma, the history of osteoporosis, skeletal fluorosis is not as uniform and dense as stone osteopathy, while skeletal fluorosis is mainly trunk, and The limbs are weakened, the bone streaks are thickened and the mesh is changed. The ligament calcification and interosseous calcification are seen in the late stage, and the above characteristics of the osteopetrosis are not obtained. The fluoride of the skeletal fluorosis is up to 8 mg/L or more.

In addition, the disease also needs to be distinguished from heavy metal poisoning, vitamin D poisoning, hypothyroidism and congenital melamine.

The material in this site is intended to be of general informational use and is not intended to constitute medical advice, probable diagnosis, or recommended treatments.