Endocrine 2

Question 1

90% of cases of hypercalcemia are due to

Answer 1

primary hyperparathyroidism or malignancy

primary hyperparathyroidism MC cause overall

can also be due to thiazide diuretics

Question 2

sx hypercalcemia

Answer 2

most asx
stones - nephrolithiasis
bones - bone pain and fractures
abdominal groans - ileum, constipation, decreased DTR and weakness
psychic moans - depression, anxiety
increased vascular tone - hypertension

polyuria and polydipsia due to hypercalcemia induced nephrogenic DI

Question 3

dx hypercalcemia

Answer 3

repeat measurement; ionized > total

intact PTH
PTH-related protein if intact PTH normal
vitamind D
24h urinary calcium

EKG - shorted QT interval, prolonged PR interval, QRS widening

Question 4

what will EKG show for hypercalcemia

Answer 4

shorted QT
prolonged PR
widened QRS

Question 5

tx hypercalcemia

Answer 5

< 12 - no immediate tx

12-24
IV fluids (normal saline)
IV calcitonin
Bisphosphonates - if associated w malignancy
Loop diuretics can be added to promote calcium excretion

Question 6

common causes of hypocalcemia

Answer 6

hypoparathyroidism - MC overall; autoimmune destruction or inadvertent removal of the parathyroid gland during neck surgery

secondary hyperparathyroidism - chronic renal disease or liver disease, vitamin D deficiency

hypomagnesemia

diuretics

acute pancreatitis

Question 7

sx hypocalcemia

Answer 7

most asx
increased muscular contractions
perioral numbness
paresthesias of feet/hands
myalgias
muscle cramping
prolonged QT
dry, rough skin
diarrhea, ab pain, cramps
bronchospasm or laryngospasm –> stridor
irritability, fatigue, anxiety, depression
Chvostek sign - facial spasm of ipsilateral facial muscles
trousseau’s sign - inflation of BP above SBP for 3 min –> painful carpal spasms
Increased DTR

Question 8

dx hypocalcemia

Answer 8

order PTH, mag, phosphate, BUN, creatinine, vitamin D

serum calcium - repeat measurement

correct albumin levels

intact PTH - most valuable in determining etiology

EKG - prolonged QT interval classic

Question 9

what will you see on EKG for hypocalcemia

Answer 9

prolonged QT

Question 10

tx hypocalcemia

Answer 10

mild, chronic - oral calcium + vitamin D

severe or sx - IV calcium gluconate

K+ or Mg2+ repletion if needed

Question 11

what is the MC cause of hypercalcemia

Answer 11

hyperparathyroidism

Question 12

causes of hyperparathyroidism

Answer 12

parathyroid adenoma - MC cause
lithium
thiazides
MEN 1 and MEN2A

Question 13

sx hyperparathyroidism

Answer 13

most asx
signs of hypercalcemia - moans, groans, stones, abdominal groans, psychic moans - decreased DTRs

Question 14

dx hyperparathyroidism

Answer 14

triad - hypercalcemia + increased intact PTH + decreased phosphate

increased 24h urine calcium excretion, increased vitamin D

may have osteopenia on bone scan
alkaline phosphatase normal or elevated

Question 15

tx hyperparathyroidism

Answer 15

parathyroidectomy - definitive

vitamin D and calcium supplementation after parathyroidectomy

bisphosphonates - increase bone mineral density

Question 16

hypoparathyroidism causes

what electrolyte abnormality also can cause?

Answer 16

post neck surgery (thyroidectomy, parathyroidectomy)

autoimmune destruction of thyroid gland

hypomagnesemia

Question 17

sx hypoparathyroidism

Answer 17

most asx
signs of hypocalcemia - increased DTRs, perioral numbness, trousseau sign, Chvostek sign

Question 18

dx hypoparathyoidism

Answer 18

triad - hypocalcemia + decreased PTH + increased phosphate

EKG - prolonged QT interval

Question 19

what will you see on EKG for hypoparathyroidism

Answer 19

prolonged QT interval

Question 20

tx hypoparathyroidism

Answer 20

calcium supplements + activated vitamin D (calcitriol)

acute - IV calcium gluconate plus oral calcitriol

Question 21

what is hypernatremia

Answer 21

increased serum sodium > 145 due to increased free water loss, hypotonic fluid loss, or hypertonic sodium gain (iatrogenic)

Question 22

causes of hypernatremia

Answer 22

GI water loss - diarrhea, vomiting
renal water loss - DI, diuretics, glycosuria
unreplaced water loss - fever, burns, sweating
hypertonic sodium grain - massive salt ingestion

Question 23

sx hypernatremia

Answer 23

neuro sx - thirst MC initial sx
confusion
lethargy
disorientation
N/V
muscle weakness
seizure, coma, brain damage, respiratory arrest if severe

Question 24

PE hypernatremia

Answer 24

dehydration - dry mouth or mucous membranes, decreased skin turgor, tachycardia, hypotension

Question 25

dx hypernatremia

Answer 25

serum studies - serum sodium, urine osmolality, serum osmolarity, assess volume status
hypernatremia nearly always associated w hyperosmolality

urine studies - urine sodium elevated if renal loss; decreased if extrerenal loss

urine osmolality is increased (concentrated) if extra renal source of water loss is primarily responsible

hypernatremia in the setting of dilute urine (decreased urine osmolality < 250 most/kg) is characteristic of DI

Question 26

tx hypernatremia

Answer 26

hypotonic fluids - preferred route is oral; D5W is preferred IV to replace water deficit

isotonic fluids (normal saline or lactated ringers) then switch to hypotonic fluids to correct hyponatremia

rapid correction > 0.5 mEq/L/h can result in cerebral edema

Question 27

what is hyponatremia

Answer 27

serum sodium < 135 mEq/L due to increased free water (excess total body water when compared to total body sodium content) due to inability of kidneys to excrete excess water

Question 28

what is clinically significant hyponatremia

Answer 28

hypotonic hyponatremia

Question 29

hypertonic hyponatermia is due to

Answer 29

hyperglycemia or mannitol infusion

Question 30

isotonic hyponatremia is due to

Answer 30

lab error due to hyperproteinemia or hypertriglyceridemia

Question 31

what are the 3 main types of hypotonic hyponatremia

Answer 31

hypovolemic
isovolemic
hypervolemic

Question 32

hypotonic hyponatremia - hypovolemic

Answer 32

renal volume loss - diuretics, ACE, extra renal volume loss - GI loss (diarrhea, vomiting, laxatives, burns, fever, pancreatitis)

Question 33

hypotonic hyponatremia - isovolemic

Answer 33

SIADH
hypothyroidism
adrenal insufficiency
reset hypothalamic osmostat
water intoxication
MDMA (ecstasy)

Question 34

hypotonic hyponatremia - hypervolemic

Answer 34

edematous states - CHF, nephrotic syndrome, cirrhosis

Question 35

sx hyponatremia

Answer 35

neuro sx primarily due to cerebral edema - confusion, lethargy, disorientation, N/V, muscle cramps, seizures, coma, respiratory arrest if severe

Question 36

dx hyponatremia

Answer 36

step 1 - measure serum (plasma) osmolality – if true (hypotonic, low osmolality) go to step 2
step 2 - assess volume status - if hypotonic/decreased –> step 3
step 3 - urine sodium concentration. urine sodium < 10 mmol/L indicates extra renal loss of volume with preserved renal ability to hold onto sodium. urine sodium > 20 mol/L suggests renal loss of volume

urine osmolality: distinguishes btwn SIADH and primary polydipsia. primary polydipsia - low urine < 20 mEq/L and low urine osmolality, reflecting suppressed ADH. SIADH: high urine sodium and osmolality - urine sodium is > 40 mEq/L and urice osmolality > 100 mOsm/L

Question 37

tx hyponatremia

Answer 37

correction of serum sodium > 0.5 mEq/L/h can lead to central pontine demyelinolysis

isovolemic - water restriction + treat underlying cause

hypovolemic - volume replacement - normal 0.9% saline; treat underlying cause

hypervolemic - volume removal - diuretics, sodium + water restriction; treat underlying cause

severe hyponatremia - IV hypertonic saline 3% regardless of etiology of volume status

serum sodium < 120 - IV 3% saline at a rate of 0.25 mL/kg/hour

acute hyponatremia - 50 mL bolus of 3% saline