Fluid/electrolyte abnormality treatments

Euvolemic hypotonic hyponatremia; asymptomatic

Water restriction (± sodium restriction – e.g. loop diuretics) [first-line]

Hypovolemic hypotonic hyponatremia; asymptomatic

Sodium-containing fluids (so IV fluids) [first-line]

Hypervolemic hypotonic hyponatremia

Water restriction ± sodium restriction ± diuretics (loop diuretics can cover the second two) [first-line]

Treatment for all symptomatic hypotonic hyponatremia, regardless of volume status

First-line: 3% sodium chloride

Euvolemic (hypertonic) hypernatremia; central diabetes insipidus

Desmopressin

Euvolemic (hypertonic) hypernatremia; nephrogenic diabetes insipidus

• Hypotonic IV fluids (D5W)

• Sodium restriction + HCTZ (“weaker” than loop diuretics, can block Na+ reabsorption at distal tubule)

Hypervolemic (hypertonic) hypernatremia

Remove cause of drastic Na+ increase ± loop diuretic to get rid of excess water

Hypovolemic (hypertonic) hypernatremia

Isotonic IV fluids (LRs, NS), then maybe hypotonic IV fluids

True hypokalemia

Most cases:

• Potassium chloride PO preferred

• Alternatives are other potassium supplements PO: potassium gluconate, potassium phosphate (if patient also needs phosphate replenishing), potassium bicarbonate

If severe (<2.5 mEq/L), symptomatic, or NPO

• Potassium chloride IV preferred

• Alternatives are other potassium admixtures IV: potassium acetate (if patient is hypercholermic), potassium phosphate (if patient also needs phosphate replenishing)

What should IV K+ admixtures be given in?

Sodium-containing solutions — not dextrose-based solutions bc dextrose triggers insulin, which triggers intracellular K+ shift

Max IV K+ admixture peripheral access concentration?

10 mEq/100 mL

Max IV K+ admixture peripheral access administration rate?

10 mEq/hour

Max IV K+ admixture central access concentration?

40 mEq/100 mL

Max IV K+ admixture central access administration rate?

40 mEq/hour

For hypokalemia treatment: if patient has kidney dysfunction, dose should…

Be reduced by 50%

For hypokalemia treatment: how much does 10 mEq of K+ (PO or IV) increase serum K+?

0.1 mEq/L

What rates of K+ admixture IV should be monitored?

>10 mEq/hour — should do cardiac monitoring

What is the “first step” of the treatment of true hyperkalemia and what agents are used for it?

Calcium gluconate IV — to stabilize EKG IF EKG is abnormal

• If patient displays no EKG changes, skip this step

What is the “second step” of the treatment of true hyperkalemia and what agents are used for it?

Intracellular K+ shifting — to get K+ out of blood

• First-line: regular insulin IV + 50% dextrose

• Alternatives:

  • Sodium bicarbonate IV — if concomitant acidemia

  • Albuterol nebulized — “if all else fails,” though not preferred bc ADRs and high doses necessary

What is the “third step” of the treatment of true hyperkalemia and what agents are used for it?

K+ elimination

• First-line: sodium zirconium cyclosilicate (Lokelma) PO

  • Must have functioning GI tract

• Alternatives: furosemide (must have adequate kidney function), hemodialysis (if refractory/severe hyperkalemia or already on hemodialysis)

What, in general, is hypomagnesemia treated with?

Magnesium sulfate (IV or PO)

When should hypomagnesemia be treated with IV magnesium?

Patient Mg <1 mg/dL, or patient NPO

1 gram of magnesium sulfate is equivalent to ____ elemental magnesium?

8 mEq

How is urgent/emergent hypomagnesemia treated?

IV magnesium sulfate, administered over 15-20 minutes

How is asymptomatic hypomagnesemia treated?

IV magnesium sulfate, administered over 1g (8 mEq)/hour

What consideration is there for PO magnesium products used to treat hypomagnesemia?

More elemental magnesium ==> greater Mg2+ replenished, but more diarrhea ADRs

How is hypermagnesemia treated

ONLY when symptomatic (which is very rare)

• Most commonly use calcium gluconate to help stabilize

When should hypocalcemia be treated?

If calcium <8.5 mg/dL (make sure to use corrected calcium if albumin is low)

Symptomatic hypocalcemia treatment

Calcium gluconate IV (preferred), OR calcium chloride IV

When should calcium chloride be used for treatment of hypocalcemia (as opposed to preferred calcium gluconate)?

If patient is in cardiac arrest — basically need a lot of calcium really quick

Which hypocalcemia treatment drug is a vesicant and has a risk of necrosis with extravasation?

Calcium chloride IV

Asymptomatic hypocalcemia treatment

Oral calcium

For treatment of hypercalcemia, we “go to the drugs” when…

• Asymptomatic but serum calcium >12 mg/dL

• Symptomatic and non life-threatening

• Symptomatic and life-threatening (EKG changes, tetany/pancreatitis, with functioning kidneys

  • (If no functioning kidneys, do hemodialysis + calcitonin + glucocorticoid)

Which hypercalcemia drugs are first-line?

0.9% saline, loop diuretmics

Which hypercalcemia drugs are used after first-line therapy or if first-line therapy should be avoided?

Calcitonin

Which hypercalcemia drugs are used for cancer-associated hypercalcemia?

Pamidronate, zoledronate (bisphosphonates)

Which hypercalcemia drugs are used for hypercalcemia that is refractory to bisphosphonates?

Denosumab

Which hypercalcemia drugs are preferred for blood cancers?

Glucocorticoids

Which hypercalcemia drugs are used for primary hyperparathyroidism?

Cinacalcet

First-line treatment for hypophosphatemia

Sodium phosphate

Treatment for hypophosphatemia if patient also has hypokalemia

Potassium phosphate

Treatment if hyperphosphatemia and hypocalcemic

IV calcium

Treatment if hyperphosphatemia and normocalcemic

Phosphate binders — first-line is calcium carbonate

Treatment if hyperphosphatemia and hypercalcemic

Phosphate binders — first-line is calcium carbonate

Treatment if hyperphosphatemia is symptomatic and has failed other therapies

Hemodialysis