What is Paget's disease commonly develops in which age group ? and explain in detail?
Ans. is 'c' i.e., 5th decade Paget's disease (Osteitis deformans) Paget's disease is characterized by increased bone turnover and enlargement and thickening of the bone, but the internal architecture is abnormal and the bone is usually brittle. Primary defect is in osteoclasts with increased osteoclastic activity. This results secondarily increase in osteoblastic activity (normal osteoclasts and osteoblasts act in a co-ordinated manner). So, characteristic cellular change is a marked increase in osteoclastic and osteoblastic activity. Bone turnover is acclerated, plasma alkaline phosphatase is raised (a sign of osteoblastic activity) and there is increased excretion of hydroxyproline in urine (due to osteoclastic activity). The pelvis and tibia being the commonest sites, and femur, skull, spine (veebrae) and clavicle the next commonest. Paget's disease occurs after 40 years of age and is more common in males.