calcium & parathyroid d/o Flashcards
familial hypocalciuric hypercalcemia
loss of function mutation in CaSR making it less sensitive to calcium
benign most times
labs with familial hypocalciuric hypercalcemia
mildly high Ca
high-nl/mildly high PTH
low urinary Ca levels
will also have fam hx
why is it important to recognize familial hypocalciuric hypercalcemia?
so you don’t subject them to surgery from thinking that it is primary hyperparathyroidism
labs when there is hypercalcemia with normal parathyroid gland
high Ca with low PTH
parathyroid gland is fine bc its responding to Ca levels
3 ways that hypercalcemia of malignancy works
tumor destroys bone
tumor makes PTHrP
tumor makes 1,25-D
other causes of hypercalcemia w/ normal parathyroid
vit D intoxication
sarcoidosis/granulomatous dz– unregulated 1 alpha-hydroxy
hyperthyroidism
milk-alkali syndrome– renal failure, metabolic alkalosis
prolonged immobilization
thiazide diuretics
symptoms of hypocalcemia
perioral or digital paresthesias
muscle cramping to point of tetany
seizures
primary hyperparathyroidism pathophys
abnormal regulation of PTH by calcium leading to excess PTH secretion causing increased Ca retention in kidneys, absorption in GI and reabsorption from bone
expected Ca and PTH levels with primary hyperparathyroidism
elevated Ca and high/inappropriately normal PTH levels
most common cause of primary hyperparathyroidism
single parathyroid adenoma (benign)
multiple adenoma, diffuse hyperplasia can occur
parathyroid carcinoma is rare
mnemonic for primary hyperparathyroidism symptoms
Bones, Stones, Tummy Groans and Psychic Moans
primary hyperparathyroidism effect on bones
increased osteo activity
brown tumors
fractures
subperiosteal bone resorption
primary hyperparathyroidism effect on kidney
kidney stones
nephrolithiasis and nephrocalcinosis d/t hypercalciuria
primary hyperparathyroidism effect on GI
increased Ca absorption d/t activating Vit D
nausea, vomiting, constipation
primary hyperparathyroidism effect on psych
concussion
memory issues
difficulty concentrating
how is primary hyperparathyroidism usually diagnosed?
it is usually incidental bc people are usually asymptomatic
if patients are usually asymptomatic, what is the concern with primary hyperparathyroidism?
its effect on bone density and the risk of kidney stones
how is hypercalcemia diagnosed generally? what is the lab work up?
ionized serum Ca (more accurate than total)
PTH to r/o primary hyperparathyroidism
PTHrP if normal or low PTH to r/o malignancy
Vit D (which one?)
List causes of hypocalcemia
primary hypoparathyroidism (parathyroid dysfx)
secondary hypERparathyroidism (external force)
electrolyte abnormalities
diuretics & antiresorptives
what is the most common cause of hypocalcemia?
primary hypoparathyroidism
expected Ca and PTH levels with primary hypoparathyroidism
low or inappropriately normal PTH + low Ca
cause of primary hypoparathyroidism
damaged parathyroid glands via congenital, surgery or autoimmune destruction
impaired PTH secretion from intact glands d/t hypomagnesemia
how is hypocalcemia treated?
calcium and active vit D (calcitriol)
why would you want to give active vit D (calcitriol) specifically when treating primary hypoparathyroidism?
if you give any inactive form, you’d need PTH to activate it
bypass this by giving an already active form!
what is secondary hypERparathyroidism? expected Ca and PTH levels?
hypocalcemia causing increased PTH levels
normal Ca + high PTH
what seems odd about the labs with secondary hypERparathyroidism? explain why it actually makes sense.
the increased PTH is due to low Ca so you would expect to see low Ca levels in lab. instead Ca levels are normal
this makes sense because the parathyroid is actually working fine in this condition so the compensatory rise in PTH is able to correct the low Ca levels
what causes secondary hypERparathyroidism
any trigger for PTH production
vitamin D deficiency (osteomalecia, rickets) & CKD
how does Vit D deficiency cause secondary hypERparathyroidism
no vit D= poor Ca absorption in GI, decreased Ca availability for bone mineralization = low Ca
how does CKD cause secondary hypERparathyroidism
poor renal phosphate clearance–> hyperphosphatemia
impaired renal 1 alpha-hydroxylase–> poor Ca absorption
what is Chvostek sign
ipsilateral facial spasm, twitching and contraction on tapping of facial nerve in-front of the tragus
seen in hypocalcemia
what is Trousseau’s sign
inflation of BP cuff above systolic BP for 3 mins causes painful carpal spasms (wrist & MCP joint flexion w/ adducted fingers)
seen in hypocalcemia
primary hyperparathyroidism vs hypoparathyroidism traids
primary hyper– high Ca + high/inappropriately normal PTH + decreased phosphate
primary hypo– low Ca + low/inappropriately normal PTH + increased phosphate
DTR in hypercalcemia vs hypocalcemia
decreased DTR in hyper
increased DTR in hypo
