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Parathyroid gland function
Increase serum calcium concentration by increasing calcium pulled from bone and decreasing excretion at the kidney.
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Primary hyperparathyroidism
Excessive excretion of PTH by one or more PTH gland leading to hypercalcemia. Usually due to an adenoma.
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Secondary hyperparathyroidism
Associated with chronic kidney failure & vitamin D deficiency. PTH glands are stimulated to produce more PTH hormone to make up for decreased serum calcium.
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Tertiary hyperparathyroidism
If PTH glands enlarge due to over-production of PTH associated with secondary hyperparathyroidism, they can start to produce too much PTH on their own.
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Signs and symptoms
- "Bones, stones, abdominal groan & psychic moans with fatigue overtones."
- Bones - pain, arthralgia
- Stones - kidney
- Abdominal groans - stones, duodenal ulcer, pancreatitis
- Psychic moans - depression, apathy (indifference)
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Tests
Serum calcium (corrected) = Ca + (4-albumin) x 0.8
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Treatment (drug)
- Calcimimetic drugs (for primary) - Sensipar
- Good for people with hypercalcemia - binds to Ca sensor in parathyroid & increases affinity for serum Ca, thereby decreasing PTH secretion (it thinks there's more calcium in blood)
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Calcium & vitamin D treatment
- Don't restrict Ca - will stimulate PTH
- Vitamin D with multivitamin
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Monitoring
- Serum calcium level - every 6 mos
- Serume creatinine conc. (check kidneys) - annually
- BMD - annually at all 3 sites.
- All other tests not recommended
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Surgical treatment for hyperparathyroidism
- Calcium level > 1mg/dl over upper limit
- Creatinine clearance reduced to <60 ml/min
- BMD T-scor less than -2.5 at any site, with or without fragility fracture
- Age < 50
- Another thing to consider w/ surgery is whether they have renal stones.
- Order SESTEMIBI scan if considering surgery - will show which glands are abnormal.
- Can lead to hungry bone syndrome
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Surveillance without surgery
- Serum calcium level annually
- BMD every 1-2 years (3 sites)
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Intraoperative PTH
Good way to tell if surgery was successful when only going after 1 gland. PTH is cleared from body within 3 minutes or so, so surgeon can check PTH levels during surgery to decide whether another gland needs to be taken out. iPTH should decrease by more than 50% in successful cases.
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