Endocrine 2 Flashcards by Hannah Hutchison

90% of cases of hypercalcemia are due to

primary hyperparathyroidism or malignancy

primary hyperparathyroidism MC cause overall

can also be due to thiazide diuretics

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sx hypercalcemia

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

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dx hypercalcemia

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

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what will EKG show for hypercalcemia

shorted QT
prolonged PR
widened QRS

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tx hypercalcemia

< 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

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common causes of hypocalcemia

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

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sx hypocalcemia

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

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dx hypocalcemia

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

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what will you see on EKG for hypocalcemia

prolonged QT

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tx hypocalcemia

mild, chronic - oral calcium + vitamin D

severe or sx - IV calcium gluconate

K+ or Mg2+ repletion if needed

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what is the MC cause of hypercalcemia

hyperparathyroidism

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causes of hyperparathyroidism

parathyroid adenoma - MC cause
lithium
thiazides
MEN 1 and MEN2A

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sx hyperparathyroidism

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

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dx hyperparathyroidism

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

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tx hyperparathyroidism

parathyroidectomy - definitive

vitamin D and calcium supplementation after parathyroidectomy

bisphosphonates - increase bone mineral density

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hypoparathyroidism causes

what electrolyte abnormality also can cause?

post neck surgery (thyroidectomy, parathyroidectomy)

autoimmune destruction of thyroid gland

hypomagnesemia

sx hypoparathyroidism

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

dx hypoparathyoidism

triad - hypocalcemia + decreased PTH + increased phosphate

EKG - prolonged QT interval

what will you see on EKG for hypoparathyroidism

prolonged QT interval

tx hypoparathyroidism

calcium supplements + activated vitamin D (calcitriol)

acute - IV calcium gluconate plus oral calcitriol

what is hypernatremia

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

causes of hypernatremia

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

sx hypernatremia

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

PE hypernatremia

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

dx hypernatremia

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

tx hypernatremia

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

what is hyponatremia

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

what is clinically significant hyponatremia

hypotonic hyponatremia

hypertonic hyponatermia is due to

hyperglycemia or mannitol infusion

isotonic hyponatremia is due to

lab error due to hyperproteinemia or hypertriglyceridemia

what are the 3 main types of hypotonic hyponatremia

hypovolemic isovolemic hypervolemic

hypotonic hyponatremia - hypovolemic

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

hypotonic hyponatremia - isovolemic

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

hypotonic hyponatremia - hypervolemic

edematous states - CHF, nephrotic syndrome, cirrhosis

sx hyponatremia

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

dx hyponatremia

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

tx hyponatremia

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