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* osteitis fibrosa cystica
  amlee - 07/21/10 20:40
  A 60-year-old woman complains of a 1-year history of bone pains, anorexia, weight loss, and constipation. Serum calcium is elevated and she is diagnosed with primary hyperparathyroidism. She is treated surgically, with removal of her parathyroid adenoma. She then has a long period of hypocalcemia and requires continuous treatment with vitamin D and calcium. Subsequently, after 6 months she becomes normocalcemic and does not need therapy. Which of the following conditions best explains these events?

A. Her remaining 3 parathyroid glands were destroyed
B. She has unrecognized pseudohypoparathyroidism
C. She had severe bone disease
D. She has pancreatitis from hyperparathyroidism
E. The wrong parathyroid gland was removed
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* Re:osteitis fibrosa cystica
  gunny - 07/21/10 21:37
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* Re:osteitis fibrosa cystica
  amlee - 07/21/10 21:40
  Could you explain the transient requirement for calcium and vit D replacement???  
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* Re:osteitis fibrosa cystica
  gunny - 07/21/10 21:47
  Hypocalcemia is a common problem after parathyroidectomy or thyroidectomy. The fall in serum calcium is primarily due to functional or relative hypoparathyroidism, leading to reductions in bone reabsorption and intestinal calcium absorption and, in patients without end-stage renal disease, increased calcium excretion. A less frequent contributing factor is acute calcitonin release from the thyroid gland.

The hypocalcemia is generally transient because the degree of bone disease is typically mild and normal parathyroid tissue recovers function quickly (usually within one week), even after long-term suppression.

In some cases, however, the postoperative hypocalcemia is severe and prolonged despite normal or even elevated levels of parathyroid hormone (PTH). This phenomenon, called the hungry bone syndrome, most often occurs in patients who have developed bone disease preoperatively due to a chronic increase in bone resorption induced by high levels of PTH (osteitis fibrosa) [1,2]. The underlying hyperparathyroidism can either be primary or secondary due to end-stage renal disease. In addition to parathyroidectomy, a similar syndrome can occur in patients with end-stage renal disease who are treated with calcimimetics, which reduce PTH secretion by modulating the calcium-sensing receptor in the parathyroid glands .
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* Re:osteitis fibrosa cystica
  gunny - 07/21/10 21:49
  The postoperative hypocalcemia probably results from acute reversal of the PTH-induced contribution of bone to maintenance of the serum calcium concentration (graph 1). In the high turnover state associated with hyperparathyroidism, PTH increases bone formation and resorption with a net efflux of calcium from bone. Sudden withdrawal of PTH in such patients causes an imbalance between osteoblast-mediated bone formation and osteoclast-mediated bone resorption and perhaps other changes affecting calcium fluxes, leading to a marked net increase in bone uptake of calcium, phosphate, and magnesium [2]. Thus, the hungry bone syndrome requires an abrupt decrease in PTH release that upsets the equilibrium between calcium efflux from bone and influx into the skeleton during bone remodeling.

are these q's from usmle cd?
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* Re:osteitis fibrosa cystica
  mie82 - 07/21/10 21:52
  Hungry bone synd. According to that it would be c  
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* Re:osteitis fibrosa cystica
  amlee - 07/21/10 21:53
  the bank says usmle practice test  
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* Re:osteitis fibrosa cystica
  gunny - 07/21/10 21:55
  thanku good q though.  
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