Harry C. Blair, Author at Cancer Therapy Advisor

Harry C. Blair

All articles by Harry C. Blair

Osteopenia/Osteoporosis

At a Glance Osteoporosis is diagnosed by fractures in the absence of trauma, frequently vertebral fractures in postmenopausal women. Femoral fractures are frequently fatal osteoporotic events in older people, and preventative diagnosis and treatment to avoid this is now standard of care. Low bone mass, or osteopenia, can lead to osteoporosis and should be diagnosed…

Vitamin D Dependent Deficiency/Rickets

At a Glance Vitamin D deficiency with rickets is caused by insufficient cholecalciferol (prohormone) synthesis in the skin due to sun-dependent synthesis to support cartilage mineralization. This causes wide growth plates and secondary bowing of long bones, as well as a number of secondary metabolic problems, including poor calcium uptake. Vitamin D deficiency with rickets…

Osteopetrosis

At a Glance Osteopetrosis, or marble bone disease, is a rare congenital disease caused by any of several gene defects that affect the differentiation or function of osteoclasts. It should be considered in any newborn relative of a proband. Otherwise, it is so rare (<1/10,000 live births, even in areas reporting the disease most frequently)…

Vitamin D Resistant Deficiency/Rickets

At a Glance Vitamin D resistant rickets, typically due to renal phosphate wasting (X-linked hypophosphatemia), is the most common cause of rickets. In adults, it causes osteomalacia. Vitamin D resistant rickets occurs almost exclusively in boys and resembles classic Vitamin D deficiency, therefore, it is usually recognized clinically. Vitamin D resistant rickets can usually be…

Primary Metabolic Osteomalacia

At a Glance This chapter discusses primary metabolic osteomalacia presenting in adults. Osteomalacia as a complication of renal failure and disorders of Vitamin D metabolism are not discussed. Osteomalacia is the presence of excessive nonmineralized bone (also called osteoid). In adults, it presents as bone pain and incomplete fractures. Osteomalacia, as an acquired metabolic disease,…

Familial Hypocalciuric Hypercalcemia

At a Glance Familial hypocalciuric hypercalcemia is an unusual, usually benign condition that causes chronically elevated serum calcium and reduced calcium excretion. It is typically caused by an abnormal set-point for parathyroid hormone (PTH) secretion in the calcium sensing receptor (CASR). The CASR is expressed primarily in the parathyroid and maintains calcium activity (“ionized calcium”)…

Renal Osteodystrophy

At a Glance Renal osteodystrophy is caused by phosphate retention in renal failure. Phosphate retention results in a secondary decrease in calcium activity (“ionized calcium”) and a significant increase in parathyroid hormone (PTH) secretion. Low 1,25 dihydroxyvitamin D is also seen because of renal failure. All of these abnormalities cause very rapid bone degradation and…

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