3rd space, SIADH

Question 1

SIADH

Answer 1

syndrome of inappropriate antidiuretic hormone
excessive ADH produced causing water retention
electrolyte dilution 2/2 fluid excess

Question 2

SIADH manifestations

Answer 2

n/v
lethargy
hostility
seizures
coma

Question 3

SIADH diagnostics

Answer 3

r/o other causes of hyponatremia
serum osmolality <275 mOsm/L
urine osmolality >100 mOsm/L
urine sodium >40 mEq/L

Question 4

SIADH tx

Answer 4

monitor for hyponatremia, low serum osmolality
furosemide
IV fluids based on serum sodium levels
(0.9% nacl iv and/or hypertonic sodium chloride solution for severe hyponatremia)

Question 5

third space syndrome

Answer 5

fluid accumulates in extracellular and intracellular spaces of the body
may also accumulate in a third body (i.e. intestine) that does not support circulation

Question 6

causes of third spacing

Answer 6

increased fluid volume (rapid fluid replacement, renal dysfunction)
increased capillary hydrostatic pressure (right sided HF)
hyponatremia
albumin loss
lymphatic obstruction

Question 7

manifestations of third spacing

Answer 7

decreased venous return
-->decreased cardiac output
---->inadequate oxygen delivery
s/s hypovolemic shock, but with edema
hypoxia 2/2 decreased cardiac output

Question 8

third spacing tx

Answer 8

**goal is to replace intravascular volume*
crystalloids to replace electrolytes and restore serum osmolality
isotonic solutions (LR, 0.9% nacl esp if hyponatremic)
colloids (albumin; this is expensive and not necessarily more effective)

Question 9

hypercalcemia

Answer 9

occurs in cancer pts
poor prognosis (50% mortality within one month)
most often bronchial, breast, prostate cancers and melanoma)

Question 10

hypercalcemia causes

Answer 10

reduced renal excretion
increased GI absorption
1. local bone met. induced osteoclastic activity (80% of hypercalc with malignancy 2/2 bone resorption
2. humoral hypercalc of malignancy 2/2 parathyroid-related hormone that increases bone resorption and renal tubular calcium resorption

Question 11

hypercalcemia s/s

Answer 11

mild: n/v, anorexia, abd pain, constipation, fatigue
severe: increased thirst, dehydration, decreased urination, muscle cramping, weakness, irregular heart rate

Question 12

hypercalcemia diagnostics

Answer 12

calcium levels
parathyroid hormone
bone scan (dexa)
chest xray

Question 13

hypercalcemia tx

Answer 13

fluids
bisphosphonates to decrease bone breakdown
calcitonin to lower serum calcium levels
gallium nitrate for cancer related
cinacalcet to reduce serum calcium
steroids
dialysis if severe