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ORTHOPAEDICS |
| Case 4: |
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Diagnosis: Biopsy was suggestive of Pagets disease Discussion Introduction Sir James Paget first described this disease in 1876. Its origin is not definitely known, but some believe that a slow virus may be the initiating factor. It is common in the United Kingdom, parts of the United States of America, Australia and New Zealand. Pagets disease is found predominantly in the elderly; monostotic disease is not common (10-20%). It is mainly seen involving the sacrum, lumbar spine, skull, pelvis and femur. Weight bearing and red marrow areas are most commonly involved. Pathology 1. An initial phase of increased osteoclastic activity results in bone resorption. This early phase is osteolytic, and is not commonly seen radiologically, it may persist in the skull as osteoporosis circumscripta. 2. The increased resorption of bone is followed by increased formation of abnormally coarsened trabeculae of increased volume, the margin between cortex and medulla is lost, Haversian systems are destroyed. 3. Sclerotic phase, here the osteoclastic activity declines and osteoblastic activity begins and takes over, so that disorganized new bone of increased density replaces lytic areas. Eventually the disease becomes quiescent. Radiological Features In long bones, Pagets disease starts at a bone end and as it extends to the other bone end, it is demarcated from normal bone by a V shaped zone of transition. Long bones increase in cortical width, and undergo bowing. Prostrusio acetabulae is common with deformity of the pelvic brim and eventually secondary osteoarthritis takes place. In the vertebrae, the neural arch and pedicles are commonly involved, as also the vertebral body. A characteristic, but infrequent finding noted is the picture-frame appearance with condensed thickened end-plates, and vertebral margins enclosing a cystic spongiosa. In the skull, a destructive lytic process is replaced later by a sclerotic process leading to cotton-wool appearance. Complications include transverse fractures, pathological fractures, osteoarthritis at major joints, cranial nerve palsies result when foramina are encroaches upon, deafness due to compression of 8th nerve, CSF obstruction leading to hydrocephalus, increase in cardiac activity due to increased skeletal activity leading to cardiomegaly, cardiac failure, and high output failure, and malignant degeneration in the form of osteogenic sarcoma, and to a lesser extent fibrosarcoma, chondrosarcoma, and malignant fibrous histiocytoma. Contribution Dr. Vinod Naneria, Orthopedic Surgeon, Choithram Hospital & Research Centre |