Salt and Water Disorders Flashcards
a patient with chronic hyponatremia is at greatest risk for?
A. increased cancer mortality
B. Seizures
C. Hip Fractures
C. Hip Fracture
One retrospective cohort study examined ~1400 women with bone mineral density testing. After adjusting for age, CKD stage, osteoporosis risk factors, and osteoporosis treatment, those with hyponatremia had a 2.25-fold increased risk of fracture compared with those with eunatremia. In another cohort study of >5200 subjects, those with hyponatremia had a higher RR of both vertebral (1.61) and non-vertebral fractures (1.34) compared with those with eunatremia after adjustment for age, sex, BMI, disability index, use of diuretics, use of psychiatric medications, prevalent DM, and recent falls. Finally, a cohort study of >31,000 people showed a higher prevalence of hip fracture in those with hyponatremia. After adjustment, those with prolonged hyponatremia (>90 days) had a 4.52-fold increased risk of hip fracture compared with those who were eunatremic.
Name a condition of hyponatremia with low uOsm (< 150 mOSM/kg H2O)
primary polydipsia & low solute intake. e.g. beer potomania, tea and toast diet
to decrease UOP in diabetes insipidus, should solute intake be decreased or increased?
solute intake should be DECREASED by restricting sodium and protein intake
to increase sNa in SIADH, do you increase or decrease solute intake?
INCREASE. increase Na and protein in the diet or use oral urea
if uNa is 70, and uK 70, serum Na is 140. Over time, will the serum Na increase, decrease or stay the same?
SAME. if [uNa + uK] = sNa, then there is zero electrolyte free water clearance
will K administration raise, lower or have no effect on sNa?
it will raise sNa.
sNa = [total body Na + total body K] / TBW
which is riskier over 24 hours, raising sNa from 110 to 120 or lowering sNa from 179 to 150 mEq/L?
riaisng is always riskier. The max goal for increasing sNa should be close to 6 mEq/L/d
A runner collapses and seizes at mile 23 of a marathon. What should the runner be given?
1. Bolus of 3% saline alone
2. Bolus of 3% saline and desmopressin
3. Bolus of 3% saline and tolvaptan
Choice 1. This is SIADH and rate of correction is not impt. The patient needs 3% bolus to decrease brain edema, but should begin diuresis w/o need for additional meds
Absorption of isotonic glycine irrigation during TURP will result in w/c of the ff:
1. low sNa by indirect ion specific electrode (ISE)
2. low sNa by direct ISE
3. both
both. This is true hypoNa, because. the blood is expanded by a fluid that does not contain sodium. pOsm will be nL because it is an isotonic sol’n
which urine composition increase sNa the fastest?
1. uNa 10, uK 50
2. uNa 50, uK 10
3. uNa 20, uK 10
4. uNa 60, uK 60
Choice 3. the lowest combined value of uNa + uK will have the greatest electrolyte-free water clearance
how many milliequivalents (mEq) of Na are in a gram of Na?
1g Na. = 43 meq Na
how many meq of Na are in a gram of NaCl?
1g NaCl = 17 meq
is hypoNa more likely to occur with loop or thiazide diuretics?
with thiazides; thiazides impair dilution only; loop diuretics impair both dilution and concentration
name 2 situations where you can be certain the related hyponatremia is acute and does NOT require slow resolution.
marathon running; use of ectasy or molly
