Paget's Disease and Hyperparathyroidism MCQs

Woven bone is immature bone seen during embryonal development. Woven bone is week and is slowly replaced by stronger lamellar bone during development. Woven bone is almost completely replaced by 2 years of age. However, there are conditions where, woven bone can be seen even after 2 years of age. Eg Around the growth plates in growing children During fracture healing Pathologies of bone Paget's disease Fibrous dysplasia Osteogenic tumors - osteogenic sarcoma, osteoblastoma etc. Reference: Miler's 8th Edition of Review of Orthopaedics, page no. 20. Reference: Kulkarni's 3rd edition of Textbook of Orthopaedics and Trauma page no. 161

Blade of grass lesion is an elongated V shaped lytic area in the diaphysis of long bones, seen in Paget's disease. Paget's disease is a disorder of abnormal bone turnover. It is a chronic disease of bone remodeling characterized by abnormal osteoclastic activity(and later by increased osteoblastic activity) resulting in replacement of normal bone with excessive, weak and hyper-vascular bone. X-ray findings depend on the phase of Paget's disease Lytic phase Flame shaped/Blade of grass appearance Osteoporosis circimscripta Mixed phase Picture frame vertebra Ivory vertebra Cotton wool skull Blastic phase Tam O shanter skull Reference: Manish kumar varshney, 1 st edition, Page no.86.

Drug of choice in Paget's disease are bisphosphonates which reduce bone turnover and increase lamellar bone formation. The only bisphosphonate in the options is Alendronate. Calcitonin is very useful in relieving the pain in Paget's disease and decreasing bone resorption but the effect is only temporary. Calcium and vitamin D should also be supplemented. Pathological fractures usually require surgery and internal fixation. Reference: Fundamentals of Orthopaedics Mohindra and Jain, Page no. 338.

Decreased calcium, increased serum phosphate, increased alkaline phosphatase and increased parathyroid hormone are all characteristic of renal osteodystrophy Renal osteodystrophy is characterized by bone mineralization deficiency due to the electrolyte and endocrine abnormalities associated with chronic kidney disease. The pathogenesis of renal osteodystrophy is multifactorial. Hypocalcemia occurs due to the inability of the damaged kidney to convert vitamin D3 into its active form, calcitriol and because there is loss of calcium through urine. There will also be phosphate retention as the failed kidneys cannot excrete phosphates. The hypocalcemia and lack of phosphate excretion by the damaged kidney causes hyperparathyroidism and secondary hyperphosphatemia. Reference: Manish Kumar Varshney, page no, 33, 1 st edition.

'Von Recklinghausen disease of bone' is another name for the destructive bone changes seen in hyperparathyroidism. 'Von Recklinghausen disease' is neurofibromatosis type I. Reference: J. Maheshwari's 5th Edition of Essential Orthopaedics page no. 317

Deafness in Paget's disease is both conductive and sensorineural. Conductive because of the narrowing of the external auditory meatus and sclerosis of the ear ossicles. Sensorineural because of the narrowing of the cranial nerve foramina, resulting in the compression of the vestibulocochlear nerve. Reference: Miler's 8th Edition of Review of Orthopaedics, page no. 1904