Progressive diaphyseal dysplasia

Introduction to progressive dysplasia Progressive diaphyseal dysplasia (PDD), also known as proliferative periostitis, symmetric sclerosing thick bone disease, Engelmann disease or Camurati-Engelmann disease, the disease was named by Camurati (1922) and Engelmann (1927) , is an autosomal dominant hereditary bone disease, characterized by systemic symmetrical bone dysplasia, which is characterized by abnormal hyperplasia of the inner and outer periosteum of the long tube, resulting in thickening of the cortical bone, thickening of the bone and narrowing of the medullary cavity. On the basis of osteosclerosis, the area of plaque bone density reduction can be seen. Osteophytes are generally normal, but can also be affected, so some people claim that PDD is progressive bone-osteogenesis dysplasia. Long bone involvement can cause dyskinesia and bone pain in patients. Skull sclerosis can lead to hearing loss, loss of olfaction or loss. basic knowledge The proportion of sickness: 0.00001% Susceptible population: most infancy Mode of transmission: mother-to-child transmission Complications: anemia, deafness, optic disc edema

Progressive dysplasia

(1) Causes of the disease

The disease is markedly dominant, and the disease-causing gene is located on chromosome 19q13, which is likely to be located at 19q13.1 to 13.3. The markers are located in this region of DL9S425 (58.7cM, 19q13.1) and DL9S900 (67.1cM, 19q13.2). The disease-causing gene was located in the 32 cM region; it was adjacent to DL9S 868 (55.9 cM, 19q13.1) and DL9S57l (87.7 cM, 19q13.4).

Makita et al reported that the phenotype of PDD was significantly heterogeneous even in the same family. Of the 12 patients in three generations, 7 had typical clinical manifestations, and the other 5 had only segmental lesions or asymptomatic bones. Sexually sclerosing, these patients behave like Ribbing's disease (multiple sclerosis) and believe that PDD and Ribbing's disease are variant phenotypes of the same bone disease.

(two) pathogenesis

Progressive dysplasia progresses slowly, mainly involving the long bones of the extremities. The lesions start from the backbone, and the long axial ends of the long bones develop. The backbone is swollen and has a fusiform shape. The cortical bone is thickened and the surface is uneven. There are bone and intima. New bone formation, after fusion with the cortical bone, the cortical bone can be layered, the outer layer of collagen fibers of the bone is disorderly arranged, immature interlaced bone, the middle layer has trabecular bone, collagen fibers such as mesh to form lamellar bone, The inner layer is thickened dense lamellar bone, the trabecular bone is thick, the arrangement is disordered, the trabecular space is fibrotic adipose tissue, the osteoblasts can be increased, the activity is enhanced, the new bone formation, bone resorption and bone reconstruction are slow, the marrow The cavity becomes smaller with fibrosis.

Progressive dysplasia prevention

Muscle atrophy caused by bone pain, in addition to daily massage, kneading, active joints and muscles, it can also be used for joint flexion and muscle contraction to prevent disuse muscle atrophy and nutrient deficiency The body's resistance is declining.

Progressive dysplasia Complications, anemia, deafness, optic disc edema

Anemia

Supplement protein, vitamin C, appropriate supplement B vitamins, calcium and iron.

2. Deafness caused by cranial nerve compression, cochlear transplantation, reconstruction of hearing, due to increased intracranial pressure, patients with optic disc edema, feasible intracranial decompression, reduce intracranial pressure to improve optic disc edema.

Progressive bone dysplasia Symptoms Common symptoms Gait instability Visual impairment Increased intracranial pressure Muscle atrophy Ataxia "Duck step" Gait bone pain Double vision Paralysis wasting

Symptom

The onset is slow and concealed. Because of the long bones of the extremities, it often manifests as limb pain and muscle weakness. Because most of them develop in infancy, the body develops poorly, walks late, and the gait is unstable. It is "duck step", thin, short. The patient can not jump, run, and the swelling and pain of the lesion disappears, due to local swelling of the bone hyperplasia, often involving the bilateral bones or starting with one side, and then the opposite side.

Brat et al reported that one case of young sporadic PDD lesions involving the metaphysis, but asymptomatic, due to skull base sclerosis often caused by cranial nerve hole stenosis, cranial nerve compression symptoms, plus chronic intracranial hypertension and other reasons, can produce hearing Decreased (80%), visual impairment, optic disc edema, exophthalmos, diplopia, facial nerve paralysis, etc., can even cause cerebellar ataxia, mild disease can be asymptomatic.

The disease generally develops progressively and worsens, but the progress of the disease varies, and there is no possibility of self-healing. De Vits et al reported a case of PDD women, bone pain after pregnancy, headache disappeared, and glucocorticosteroids could be stopped. The reason is unclear. According to analysis, this may be related to the changes of certain hormone secretion or immune regulation function in pregnancy, and the disease recurs 6 months after childbirth.

2. Signs

Physical examination showed muscle atrophy of lower limbs, thin subcutaneous fat, deformed lower limbs, a few knee valgus, large head, prominent forehead, sexual development retardation, excessive lumbar protrusion, clubbing (toe), anemia and mental retardation, etc. The patient's fundus can be seen with optic disc edema, increased intracranial pressure, and some patients have no abnormal physical condition. The disease was found by X-ray examination.

Progressive dysplasia

Biochemical tests:

1. Hemoglobin decreased, erythrocyte sedimentation rate increased, blood calcium, phosphorus normal or low blood calcium, high blood phosphorus, blood PTH, CT normal, blood ALP increased, serum osteocalcin (BGP), type I procollagen C-terminal propeptide ( PICP) increased.

2. When high blood phosphorus, urine phosphorus is low, and urinary hydroxyproline is normal.

3. A small number of patients with elevated immunoglobulin A, G, M, T lymphocyte subsets CD4 + decreased.

The biochemical indicators of this disease are closely related to bone lesions. The bone metabolism index can reflect the condition of bone lesions, including type I collagen N-terminal propeptide (NTX), type I procollagen C-terminal peptide (PINP), osteocalcin (BGP). ) or bone-derived ALP is of greater significance.

X-ray inspection:

Long tube

In the bone, the outer periosteum is ossified and attached to the surface layer of the original cortex, resulting in thickening and hardening of the cortical bone. The middle part of the bone is prominent, the medullary cavity is narrow or completely disappeared, but there may be a patchy density reduction area, and the soft tissue around the bone is atrophied. The frequency of affected bones is tibia, femur, humerus, ulna, humerus and humerus, which are typically symmetrically distributed. Usually dryness is less involved and occasionally involves osteophytes.

2. Short tube bone

The humerus is often involved, the lesion is lighter, the lesion morphology is similar to that of the long bone, the cortex is thickened, the backbone is thickened, and the bilateral lesions are basically symmetrical.

3. Skull

The calvarial bone hypertrophy is mainly caused by thickening of the inner and outer plates, stenosis of the stenosis, disappearance of the skull base, and narrowing of the stenosis of the skull base and blood vessels.

4. Other bones

Individually visible spine lamina is denser, but also involving the ribs, clavicle and pelvis. The main manifestation of the lesion is thickening and hardening of the cortical bone.

Diagnostic differential diagnosis of progressive dysplasia

Diagnostic criteria

1. Typical cases have muscle weakness, bone pain symptoms, short stature, and thin body.

2. X-ray shows long bone, thickening of the outer membrane, narrowing of the marrow cavity, osteophytes and metaphyseal ends, and joint surface involvement.

3. ESR increases, anemia, ALP, osteocalcin, PICP increase, PTHH, CT and normal urinary hydroxyproline can make a diagnosis.

Differential diagnosis

1. Skull bone marrow dysplasia

Shortly after birth, the head and face deformities gradually appeared. At the same time, there were short stature and mental retardation. The X-ray showed extensive and progressive cranium, hypertrophy of the facial bone, and hardening. In addition to cortical thickening and hardening, the tubular bone was accompanied by Bone swelling and plastic barrier, the disease is autosomal recessive.

2. Stone osteopathy

In order to sclerosive proliferative bone disease, the cartilage arrangement of the long bones is mainly disordered, the collagen content of the bone matrix is reduced, the bone marrow cavity is ossified, and there is no biochemical abnormality. The lesion often involves the spine, while the PDD is mainly a long bone disease, but rare bones. End involvement, narrowing of the marrow cavity is due to bone marrow fibrosis, ALP increased, ESR increased, etc. can be identified.

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