Question | Answer |
Parathyroid hormone (PTH) functions | maintain blood Ca concentration |
PTH actions | increase Ca resorption from bone; increase Ca reabsorption from kidney; increase Ca absorption in intestines |
PTH directly stimulates: | bone (Ca and phosphorous resorption), kidney (production of calcitriol; Ca reabsorption; phosphorous excretion) |
PTH indirectly (through the kidney) stimulates: | bone resorption of Ca and phosphorous, intestinal absorption of Ca and phosphorous |
Increased phosphorous causes _____ (increased or decreased) PTH: | increased PTH |
Increased Ca causes _____ (increased or decreased) PTH: | decreased PTH |
Decreased Ca causes _____ (increased or decreased) PTH: | increased PTH |
Decreased phosphorous causes _____ (increased or decreased) PTH: | decreased PTH |
Phosphorous and PTH have what kind of relationship? | Direct relationship |
Ca and PTH have what kind of relationship? | Inverse relationship |
Increased calcitriol causes _____ (increased or decreased) PTH: | decreased PTH |
Decreased calcitriol causes _____ (increased or decreased) PTH: | increased PTH |
Calcitriol = ? | active vitamin D; 1,25-dihydroxy vitamin D |
Calcitriol and PTH have what kind of relationship? | inverse relationship |
Parathyroid studies | PTH, serum Ca, serum phosphorous |
Primary hyperparathyroidism levels | Inreased Ca; decreased-to-normal phosphorous; increased PTH |
Secondary hyperparathyroidism | normal Ca; increased phosphorous; increased PTH |
Hypoparathyroidism | decreased Ca; increased phosphorous; decreased PTH |
Pseudohypoparathyroidism | decreased Ca; increased phosphorous; increased PTH |
Pseudohypoparathyroidism is a problem with: | decreased tissue sensitivity to PTH (increased resistance to PTH) |
Hypoparathyroidism is a problem with: | deficiency of PTH |
Hyperparathyroidism is a problem with: | abnormally increased PTH |
Secondary hyperparathyroidism is a problem with: | renal insufficiency |
Most common cause of hypercalcemia in ambulatory patients | hyperparathyroidism |
Most frequent patient population of hyperparathyroidism | postmenopausal women |
80% of hyperparathyroidism cases are due to: | solitary parathyroid adenoma |
18% of hyperparathyroidism cases are due to: | hyperplasia of all 4 parathyroid glands |
Primary hyperparathyroidism | caused by one or more hyperfunctioning parathyroid glands that secrete excess PTH |
Primary hyperparathyroidism causes increased Ca due to: | increased bone resorption, increased kidney reabsorption, increased intestinal absorption |
Primary hyperparathyroidism is caused by: | adenoma, hyperplasia, carcinoma |
Secondary hyperparathyroidism is caused by: | pathological condition outside of the parathyroid glands, usually due to long-standing renal insufficiency |
Secondary hyperparathyroidism leads to: | chronic hypocalcemia (due to decreased renal reabsorption of Ca); increased PTH levels (trying to increase Ca levels); parathyroid gland hyperplasia (due to elevated PTH) |
Hyperparathyroidism s/s | stones, bones, abdominal groans, psychic moans, fatigue overtones |
Most common presentation of hyperparathyroidism | asymptomatic! |
hyperparathyroidism diagnostic studies | Ca (high in primary, normal in secondary); phosphorous (low-normal in primary, high in secondary); PTH (high in primary and secondary) |
Hyperparathyroidism treatment | primary (none, surgical excision); secondary (restrict dietary phosporous, phosphate-binding resins, vitamin D, calcitriol) - goal is raise serum Ca level |
Hypoparathyroidism is caused by: | 80% is caused by neck surgery (thyroid or parathyroid surgery); severe magnesium deficiency |
Pseudohypoparathyroidism is caused by: | increased target organ/tissue resistance to PTH |
Hypoparathyroidism s/s | s/s of hypocalcemia |
Chvostek's sign | involuntary twitching of the facial muscles initiated by light tapping of the facial nerve anterior to the auditory meatus |
Trousseau's sign | carpopedal spasm due to reduction in blood supply (BP cuff inflated for a few minutes above elbow) |
Hypoparathyroidism diagnostic studies | Ca (low in both); phosphorous (elevated in both); PTH (decreased in hypoparathyroidism, elevated in pseudohypoparathyroidism) |
Hypoparathyroidism treatment | acute (IV Ca, calcitriol); chronic (vitamin D, dietary Ca supplements) |
Pseudohypoparathyroidism treatment | vitamin D, dietary Ca supplements |