Parathyroid Flashcards
Chotzeks sign
Trausseau’s sign ypocacemic tetany
Chotzeks sign - tap on facial nerves > corner of mouth twitch
Trausseau’s sign - BP cuff >20mmHg above systolic > clawed spasm
in PTH resistance, serum phosphorus is
high normal
Excess/deficiency of FGF23 can cause…
Excess: hypophosphatemia
imparied bone mineralization (genetic ricketts, tumor-induced osteomalcia)
Decreased - hyperphosphatemia and tumor calcinosis (calcified masses)
FGF423 action
made by osteocytes
increases urinary phosphate excretion
decreases renal production of 1,25(OH)2D
in hypoparathyroidism
Serum Ca
Serum PO4-
Intact PTH
25-OHD3-
Serum Ca - low
Serum PO4 - high/normal
Intact PTH = low normal
25-OHD3 -normal
in pseudohypoparathyroidism
Serum Ca
Serum PO4 -
Intact PTH
25-OHD3 -
Serum Ca low
Serum PO4 -high normal
Intact PTH high
25-OHD3 - normal
most common cause of PTH INdependent hypercalcemia
cancer and granulomatous diseases
primary hypocalcemia caused by
secondary
deficiency in PTH secretion
secondary - renal failure - cannot produced adequate 1,25(OH)D)
malabsorption
vitamin D deficiency
highly regulated step 1-hydroxylating 25(OH)D to 1,25(OH)D is stimualted by
PTH
in PTH independent hypercalcemia, PTH is usually
supressed
pseudohypoparathyroidism =
resistnace to PTH
Treatment of Hypercalcemia
IV fluids - normal saline
Loop diuretics (Furosemide) (augemnt Ca2 exretion)
Calcitonin - rapid reduction in Ca2 (escape occurs in several days)
Bisphosphonates - inhibit osteoclastic boen reabsorption
Familial hypocalciuric hypercalemia findings
asymptomatic lifelong hyercalcemia
hypocalciuria
PTH not surpressed
in secondary hyperparathrydoism
Serum Ca
Serum PO4 -
Intact PTH
25-OHD3 -
Serum Ca - low
Serum PO4 - low normal
Intact PTH - High
25-OHD3 - low
in magnesium depletion
Serum Ca
Serum PO4 -
Intact PTH
25-OHD3 -
Serum Ca - low
Serum PO4 -normal
Intact PTH - low normal
25-OHD3 - N
Familial hypocalciuric hypercalcemia genetics
AD
FHH1 most familes (CaSR on chromosome 3)
not all FHH have CaSR mutations
PTH-indepednet hypercalcemia etiology
Malignancy - bone metastes, PTH-related protein, osteoclast activating factors, unregulated calcitriol production, ectopic PTH
Calcitriol mediated granulomatous, inflammatory
Hyperthyroidism
Milk-alkali syndrome or calcium-alakli syndrome (CaCO3 over dose)
imobilization
deactivates 25D
24-hydroxylase
symtpoms hypocalcemia
Neuromusuclar iratability - parathesias, muscle cramps, tetany,
lowered seizure threshold
mental status changes
prolonged QT, arrhythmias, CHF
basal ganglia calcification
cataracts
Chvosteks and trousseasus sign
treatment of hypocalcemia
IV calcium gluconate (initially)
Vitamin D2, D3, calcitriol
most common cause of PTH dependent hypercalcemia
hyperparathyroidism
2 underlying mechanisms of ECF volume contraction ion hypercacemia
Anorexia, nausea, vomiting
renal salt and water loss
in secondary hyperparathyroidism, serum phosphorus is
low normal (unless from renal failure, then it is low high)
skeletal morphology in primary hyperparathyroidism
BMD decreased preferentially at cortical sites
fractures increased
Calcimimetic (cinacalcet) can be used to treat
severe hyperparathyroidism
Calcitriol (1,25OH2D) mediated hypercalcemial =
found in:
non-renal/unregulated expression of 1-hydroxylase
sarcoid
lymphoma
tubercuolosis
findings in primary hyperparathyroidism
decreased sensitivity of PTH secreting cells to inhibition by Ca
increased/inappropriately not supresssed PTH
Hypercacelmia (bone resorption, calcium reabsorption, increase in 1,25D production in kidneys)
Hypophosphetemia - phosphaturic effects
**some patients Hypercaciuric **(filtered load exceeds Tm for reabsorption)
