Sodium and Potassium Disorders

Question 1

Describe why the use of 5% dextrose with water has a higher risk of causing hypervolemic hyponatremia than other IV fluids

Answer 1

Dextrose metabolizes into water adding even more diluting volume

Question 2

Renal impairment (GFR <15) or CHF are most closely associated with this electrolyte abnormality

Answer 2

Hypervolemic hyponatremia

Question 3

SIADH is mostly associated with this type of electrolyte abnormality

Answer 3

Euvolemic hyponatremia

Question 4

Are EKG changes more reliable in hyperkalemia or hypokalemia?

Answer 4

Hypokalemia

Question 5

Hyperkalemia treatment

Answer 5

IV calcium gluconate to stabilize myocardium, especially in elderly

Give insulin or beta agonists to shift potassium into cells

Consider stopping meds like ACE inhibitors that can raise potassium

Question 6

Are neurons more likely to swell or shrivel in cases of hypernatremia?

Answer 6

Shrivel and dry out, can lead to lethargy and obtundation

Question 7

Two common causes of hypomagnesemia

Answer 7

Diarrhea

Alcohol use disorder

Question 8

Treatment of acute hyponatremia

Answer 8

Hypertonic saline (3%)

Decrease intracranial pressure

Question 9

Drug causes (3) of hypokalemia

Answer 9

Insulin

Beta-adrenergics

Diuretics

Question 10

Which electrolyte abnormality is most closely associated with potomania or a “tea and toast” diet?

Answer 10

Euvolemic hyponatremia

Question 11

Hypokalemia EKG changes

Answer 11

Initially t-wave flattening

Then ST depression

Finally, U-waves

“everything is upside down”

(she said this is “important to know”)

Question 12

Medication to treat hypermagnesemia

Answer 12

Furosemide facilitates excretion of magnesium

Question 13

EKG changes in hyperkalemia

Answer 13

(unreliable)

Peaked T-waves

Wide/flat PR

Wide QRS

Question 14

Which patient is most at risk of developing hypernatremia at home?

Answer 14

Elderly

Reduced physiologic thirst drive, altered mental status (forget to drink), can’t get to their kitchen

Question 15

PACs, PVCs, bradycardia, heart blocks, v-tach/fib can all occur with this electrolyte abnormality

Answer 15

Hypokalemia

Question 16

Main function of magnesium in the body

Answer 16

Regulates nerve transmission and muscle contraction - helps control CNS

Question 17

Under healthy conditions, which organ mostly regulates sodium and potassium balance within a narrow range?

Answer 17

Kidneys

Question 18

Treatment of hypernatremia

Answer 18

Hypotonic fluids (usually 5% dextrose in water)

(give DDAVP which is desmopressin … which is synthetic ADH if central diabetes insipidus)

Question 19

Elderly patient on thiazide and SSRI presents with low blood pressure, with mild concentration deficits and gait disturbances. What electrolyte imbalance does this patient most likely have?

Answer 19

Hypovolemic hyponatremia (chronic)

Question 20

Symptoms of hypermagnesemia

Answer 20

Neuromuscular - diminished reflexes, can lead to paralysis

Question 21

If the extracellular fluid suddenly becomes hypotonic relative to the intracellular fluid there is risk of this serious acute condition

Answer 21

Cerebral edema as brain cells fill with water

Can lead to brain herniation through foramen magnum

Question 22

Renal failure, low insulin, and hypoaldosteronism can lead to this electrolyte abnormality

Answer 22

Hyperkalemia

Question 23

Hypomagnesemia symptoms/signs

Answer 23

Neuromuscular - hyperexcitability (tremor, convulsions, tetany)

May cause a-fib, PVCs/PACs

Typically presents alongside hypocalcemia and hypokalemia