Electrolytes

Question 1

Sodium (normal range)

Answer 1

136-154 mEq/L

Question 2

Euvolemic hypotonic hyponatremia
(normal: 136-154)

Answer 2

(SIADH - increase urine Na secretion)
1. Demeclocycline
2. Vasopressin receptor antagonists (tolvaptan, conivaptan)

Question 3

Euvolemic hypernatremia
(normal: 136-154)

Answer 3

(diabetes insipidus - inability to concentrate urine with Na)
1. desmopressin
(nephrogenic diabetes insipidus - no response to ADH by kidneys)
1. HCTZ
2. Indomethacin
3. amiloride

Question 4

Hypervolemic hypernatremia
(normal: 136-154)

Answer 4

Diuretics
+/- hypotonic saline or D5W

Question 5

Calcium (normal range)

Answer 5

8.5-10.8 mg/dL

Question 6

Hypocalcemia
(normal: 8.5-10.8)

Answer 6

Calcium supplements

Calcium carbonate > chloride > acetate > citrate > gluconate

Question 7

Hypocalcemia (etiology)

Reg by PTH, vitamin D

Answer 7

1. hypoalbuminemia
2. hypomagnesemia
3. hyperphosphatemia
4. renal insuff
5. hypoPTH
6. vitamin D def

Question 8

Hypercalcemia (etiology)

Reg by PTH, vitamin D

Answer 8

1. malignancy (e.g. cancer)
2. hyperthyroidism
3. bone disease
4. medications: thiazides, excessive vitamin D, hormones, lithium

Question 9

Hypercalcemia

Answer 9

1. NS infusion
2. furosemide IV
3. pamidronate
4. zoledronic acid
5. calcitonin

Question 10

Phosphate (normal range)

Answer 10

2.7-4.5 mg/dL

Question 11

Hypophosphatemia
(normal: 2.7-4.5)

Answer 11

1. K-phos neutral
2. IV phosphorus

Question 12

Hypophosphatemia (etiology)

Lipid & carb metabolism, ATP formation, DNA; reg by kidney & PTH

Answer 12

1. malnutrition
2. alcoholism
3. vomitting
4. CRRT
5. diuretics
6. antacids, sucralfate

Question 13

Hyperphosphatemia (etiology)

Lipid & carb metabolism, ATP formation, DNA; reg by kidney & PTH

Answer 13

1. tumor lysis syndrome
2. rhabdomyolysis
3. hypoPTH
4. vitamin D toxicity
5. renal impairment

Question 14

Hyperphosphatemia
(normal: 2.7-4.5)

Answer 14

1. calcium acetate > carbonate - preferred in CKD (but NOT citrate)
2. aluminum hydroxide - reserved for Phos >7, no good for CKD
3. magnesium hydroxide
4. sevelamer
5. lanthanum carbonate

Question 15

Normal range

Potassium

Intracellular

Answer 15

3.5-5.0 mEq/L

Question 16

Etiology

Hypokalemia

Reg by kidney

Answer 16

1. Inadq intake (starvation, anorexia, alcoholism)
2. transcellular shift (alkalosis, refeeding syndrome, dextrose, DKA tx)
3. Excessive loss (V/D, hypomag)
4. Med induced (insulin, B-agonists, PDE-i, levothyroxine, thiazides, loops, AG, cisplatin, amphotericin)

Question 17

Treatment

Hypokalemia

Normal: 3.5-5.0

Answer 17

1. Potassium supplements (most common: chloride)

Question 18

Etiology

Hyperkalemia

Reg by kidney

Answer 18

1. acidosis
2. HF, renal insuff
3. ACEi/ARBs
4. K-sparing diuretics
5. NSAIDs
6. heparin
7. non-selective BB

Question 19

Treatment

Hyperkalemia

Normal: 3.5-5.0

Answer 19

1. calcium gluconate
2. insulin + dextrose
3. sodium bicarb
4. albuterol
5. sodium polystyrene sulfonate (SPS, Kayexalate)
6. patiromer (Veltessa)
7. sodium zirconium (Lokelma)
8. hemodialysis

Question 20

Normal range

Magnesium

Answer 20

1.8-2.5 mg/dL

Question 21

Etiology

Hypomagnesemia

Carb & protein metab; reg by kidney and GI

Answer 21

1. “Refeeding syndrome”
2. V/D
3. alcoholism
4. Renal insuff + meds
5. CRRT

Question 22

Treatment

Hypomagnesemia

Normal: 1.8-2.5

Answer 22

1. Mag supplements (IV - sulfate, PO - slow onset)

Question 23

Etiology

Hypermagnesemia

Carb & protein metab; reg by kidney and GI

Answer 23

1. renal insuff
2. dec GI motility (inc GI absorption) - constipation, bowel obstruction, GI perforation
3. Mg supplements, antacids

Question 24

Treatment

Hypermagnesemia

Normal: 1.8-2.5

Answer 24

1. NS
2. Loops
3. Calcium IV (chloride, gluconate)
4. Hemodialysis