What is Your Diagnosis

Osteomalacia: In osteomalacia the bone matrix is preserved but is mineralized to a lesser degree. This occurs particularly in disturbances of the vitamin D, calcium, and phosphate metabolism, such as in secondary hyperparathyroidism due to chronic renal insufficiency (renal osteopathy). Radiologically, the cancellous texture appears washed out (Fig. 8.28a). Frequent microfractures are stabilized by ongoing periosteal new bone formation (so called "Looser zones," Fig. 8.28b). The earliest and specific radiological signs of hyperparathyroidism are the coarse lamel-lation of the phalangeal cortex (Fig. 8.29a) and subperiosteal bone resorption. Acro-osteolyses of the finger tips may develop. In later phases a "rugger-jersey" spine may result (Fig. 8.29b) with sclerosed bone seen along the superior and inferior end plates of the affected vertebral bodies.

Congenital diseases of the bone often present with typical radiological signs. In osteogenesis imperfecta—a genetic disease that is due to a defect in collagen production— the bones are extremely fragile and poorly mineralized (Fig. 8.30a, b). Deformations and fractures are frequent. Osteosclerosis is a very rare entity in which the mineral content of the bone is greatly increased. It can be due to increased osteoblastic activity, subnormal osteoclastic

I Osteomalacia

OsteomalaciaOsteomalacia

Fig. 8.28 a In osteomalacia the osseous structures appear poorly defined or washed out. b In this severe case of osteomalacia, multiple fractures have occurred (large arrow). The periosteum has in turn reacted with exaggerated new bone formation (small arrows). In spite of this the bones have lost their normal configuration and are bent.

Fig. 8.28 a In osteomalacia the osseous structures appear poorly defined or washed out. b In this severe case of osteomalacia, multiple fractures have occurred (large arrow). The periosteum has in turn reacted with exaggerated new bone formation (small arrows). In spite of this the bones have lost their normal configuration and are bent.

activity, or enhanced mineralization of the bone matrix. In osteopetrosis or "marble bone disease" (Fig. 8.30c), a congenital form of osteosclerosis, the complete marrow space of the skeleton may obliterate (with corresponding devastating consequences for erythropoiesis). Camurati-Engelmann disease is also a congenital form of osteo-sclerosis that is detected early owing to the waddling gait of the children. The sclerotic but weakened bone bends and the central nerve foramina at the skull base taper with time (Fig. 8.30d), with subsequent blindness and deafness.

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