Paget's Disease of Bone
= Osteitis Deformans
Definition: Disorganised bone metabolism.
Pathology: ?Slow virus infection of osteoclasts.
EM: viral inclusion bodies
in osteoclasts. PCR
of reverse transcribed DNA suggests a paramyxovirus (?measles ?RSV
?canine distemper virus). 3–4% of Anglo-Saxons, but
very rare outside of England. Incidence is higher in Lancashire towns.
Bone is large, deformed and vascular. Brittle.
Histology: busy osteoclasts and osteoblasts. Defective mineralisation
(matrix changes too quickly). Cement lines, mosaic appearance.
- bone pain
- pathological fractures
- deformed bones ("tam-o'-shanter" vault, sabre tibia, kyphosis)
- nerve compression (multiple crainial nerve palsies, paraplegia, corda equina lesions)
- high output heart failure
- osteogenic sarcoma
- ↑ alk phos
- Ca, PO4 not elevated
- radiology: thickened, sclerotic, deformed bone.
- calcitonin (ineffective after 3/12)
- surgery (to correct deformity)
- Fibrous dysplasia
- Fibrogenesis imperfecta ossium