Year : 2001 | Volume
: 11 | Issue : 3 | Page : 143--144
Radiological quiz - musculoskeletal
HR Shah, PC Patwa, AV Tank, B Shah, N Sadhu, NR Desai
Dept of Radiology, ESIS general Hosp, Bapunagar, BJ Medical College, Ahmedabad - 380 0204, India
P C Patwa
87/708, Pushpak Appt. Miranbika Road, Narangpura, Ahmedabad - 380 063
|How to cite this article:|
Shah H R, Patwa P C, Tank A V, Shah B, Sadhu N, Desai N R. Radiological quiz - musculoskeletal.Indian J Radiol Imaging 2001;11:143-144
|How to cite this URL:|
Shah H R, Patwa P C, Tank A V, Shah B, Sadhu N, Desai N R. Radiological quiz - musculoskeletal. Indian J Radiol Imaging [serial online] 2001 [cited 2020 Feb 28 ];11:143-144
Available from: http://www.ijri.org/text.asp?2001/11/3/143/30559
A ten-year-old girl presented with a history of trauma to her right leg six months ago [Figure 1],[Figure 2],[Figure 3].
OSTEOGENESIS IMPERFECTA TYPE IB
The radiographic illustrations show bowing of both tibiae, with transverse insufficiency fractures in the shaft with normal epiphyses around the knee [Figure 1],[Figure 2] and bowing of the long bones of the forearm [Figure 3]. On examination, the patient showed blue sclerae, hearing loss and normal teeth. Her mother too showed blue sclerae, short stature and progressive hearing loss. Her siblings were unaffected. These features classically fit into the description of autosomal dominant Type I osteogenesis imperfecta.
Osteogenesis imperfecta is an inherited disorder of the connective tissue characterized by abnormal maturation of collagen in both mineralized and non mineralized tissues. There is relative decrease in amount of Type I collagen due to gene defect . Clinical findings of osteogenesis imperfecta are found in tissues with high collagen Type I content like ligaments, tendons, fasciae, sclerae teeth and bones. The four major clinical criteria are:
Osteoporosis with abnormal fragility of skeleton.Blue sclerae.Dentinogenesis imperfecta. Premature otosclerosis.
The presence of two of the above abnormalities confirms diagnosis .
Osteogenesis imperfecta has been classified by Sillence and co-workers into groups to facilitate genetic counseling ,,. Group-I (autosomal dominant with variable penetrance) is the most frequent and milder form, characterized by fractures of varying severity, blue sclerae, dentinogenesis imperfecta and premature otosclerosis. Subtypes A and B depend on whether dental or otologic features predominate. The inheritance pattern and otologic findings put our patient in Type I B.
Group-2 (autosomal recessive) is lethal in utero or early infancy. Sclerae are blue. Numerous healed or healing fractures are seen at birth despite the protection of amniotic fluid. Group-3 (mostly sporadic cases) are associated with severe progressive skeletal deformities, fractures at birth and most dramatic dwarfism. Group-4 (autosomal dominant) is associated with variable skeletal findings.
Roentgenographic findings include generalised diffuse decrease in osseous density. Fractures occur with minor trauma and are usually transverse in direction and mostly occur in the lower limbs. Micromelia and bowing deformities are the sequelae of multiple telescoping fractures over a course of time. Fracture healing is usually normal but there may be an occurrence of tumoral callus and pseudoarthroses ,. The tumoral callus of osteogenesis imperfecta is an unusual but important finding owing to it's ability to mimic osteosarcoma ,,. An unusual but characteristic feature is ossification of the interosseus membrane between the radius and ulna . In children, epiphyses or metaphyses of the long bones may show popcorn calcification ,. Joints of the extremities show premature degeneration of articular surfaces .
The skull shows enlargement of mastoid and frontal sinuses, Wormian bones and basilar invagination, which may cause hydrocephalus - Tom o'Shanter skull ,,. The spine may show flattening of vertebral bodies, (which may be biconcave or wedge shaped) and severe kyphoscoliosis . The pelvis is narrowed and triradiate in shape. Protrusio acetabuli and Shepherd-Crook deformity of femora may occur .
Antenatal US shows shortening of femora, femoral fractures, disproportion of fetal body to head size, a poorly defined calvarium and a narrow thorax that makes the heart and liver appear enlarged . Features of the extreme or congenital form include the following: grossly demineralized bones of vault indistinct from soft tissue - caput membranacea; only the petrous bone is calcified, micromelia which shows incomplete fracture healing with hyperplastic callus formation and platyspondyly ,. Normal epiphyses around the knee exclude rickets and hypophosphatasia. As fractures are diaphyseal, child abuse may be excluded. Other differential diagnoses include idiopathic juvenile osteoporosis and Cushing's disease, which are differentiated clinically. Fibrous dysplasia is excluded on the basis of types of bones involved and absence of cortical expansion.
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