Electrolytes

Question 1

A patient’s Na level is 90mEq/L and is going to be given fluids to bring their Na level to normal. In the next 24 hours what is the maximum Na level that can be safely achieved for the patient?

Answer 1

102mEq/L (cannot exceed >6-12mEq/L increase in 24 hours or >0.25mEq/L increase per hour)

Question 2

Number one risk if sodium is corrected too quickly

Answer 2

Osmotic demyelination syndrome (central pontine myelinolysis)

Question 3

What are the 3 types of hyponatremia

Answer 3

Euvolemic, hypervolemic, hypovolemic

Question 4

A patient has decreased serum Na but has a serum osmolality of 325mOsm/kg. What is the most likely cause of this patient’s hyponatremia?

Answer 4

The patient has hypertonic hyponatremia from hyperglycemia. Increased blood glucose pulls water to ECF → dilutes Na and increases tonicity

Question 5

Euvolemic hypotonic hyponatremia causes and treatments

Answer 5

Causes: drug induced (SSRi, carbamazepine, opiates) → SIADH, psychogenic polydipsia increase total body water
Treatment: H2O restriction 1st, Vasopressin R antag (Demeclocycline, Conivaptan, Tolvaptan)

Question 6

Hypervolemic hypotonic hyponatremia causes, sx, and treatments

Answer 6

Causes: cirrhosis, HF, nephrotic syndrome all increase total body water and Na levels
Sx: peripheral and pulmonary edema, HF exacerbation, increased JVD, HTN
Treatment: underlying→ Na restriction (2000mg/d) & H2O restriction (1000-1200mL/d), loops

Question 7

Hypovolemic hypotonic hyponatremia causes, sx, and treatments

Answer 7

Causes: nonrenal (diarrhea, vomiting), renal (thiazides)
Sx: urinary Na<20mEq/L (kidneys trying to preserve Na)
Tx: 0.9% NaCl to replace fluid and sodium

Question 8

A patient comes into the hospital and is going to be given a loop diuretic. They currently are on no diuretic medications. What should the patient be started on

Answer 8

40mg IV Furosemide or equivalent

Question 9

Desired UOP within the first 6 hours of loop administration

Answer 9

> 500mL

Question 10

A patient was given 40mg IV Furosemide. 6 hours later the urine output was 400mL. What adjustment should be made to their dose?

Answer 10

Double the dose to 80mg IV furosemide

Question 11

Diuretic dosing for a patient who is on a diuretic at home

Answer 11

Home dose x2 as IV

Question 12

Thiazide diuretics

Answer 12

Hydrochlorothiazide
Chlorthalidone
Metolazone
Adipamide

Question 13

Potassium-sparing diuretics

Answer 13

Spironolactone
Eplerenone
Amiodarone
Triamterene

Question 14

Loop diuretics

Answer 14

Furosemide
Torsemide
Bumetanide

Question 15

Causes in intracellular shift of potassium (decrease serum K)

Answer 15

Alkalosis, Beta agonists, alpha antagonists

Question 16

Causes of extracellular shift of potassium (increase serum K)

Answer 16

Acidosis, alpha agonists, exercise, increase mOsm

Question 17

Hypokalemia correction

Answer 17

Must correct hypomagnesemia FIRST
-Mag oxide 400-
800mg PO BID
-Mag sulfate 2-4g
IV inf over 2-4h
For every desired 0.1 increase in K, dose 10mEq/hour
Maximum oral dose 40mEq to prevent adverse GI effects

Question 18

Patient has hyperkalemia with peaked T waves on an ECG ECG. Which of the following are correct treatment options? (SATA)
K = 6.5mEq/L
ABG: 7.5/39/80/25/98%

A. 1g IV calcium gluconate
B. Regular insulin 10U and 25 mg dextrose
C. Sodium polystyrene sulfonate 5 mg po - wrong dose, normal is 15-30 mg
D. 50-100mEq IV sodium bicarb - patient is not acidotic

Answer 18

A. 1g IV calcium gluconate
B. Regular insulin 10U and 25 mg dextrose

(SPS dose was too low, should be 15-30mg
Patient is not acidotic so sodium bicarb not needed)

Question 19

Sodium polystyrene sulfonate adverse effects

Answer 19

Constipation
Intestinal necrosis
Nausea
Vomiting
Anorexia
Decreased K, Ca, Mg
Increased Na