pct sodium disorders

hyponatremia

too much free water

hypernatremia

too little water

more ADH = ______ water retained

more

low sodium can cause

seizures

serum osmolality calculation

2Na + glucose/18 + BUN/2.8

hypertonic

Over 290 mOsm/kg

hypertonicity is caused by

hyperglycemia

hypotonic

Below 275 mOsm/kg

hypotonicity is caused by

SIADH

isotonicity

275-290 mOsm/kg

isotonicity is caused by

hyperlipidemia or hyperpteinemia

Correct sodium for high glucose

Measured Na + 1.6 x ([glucose - 100]/100)

hypovolemia is

solute and water loss

signs of hypovolemia

tachycardia, weight loss, hypotension, v/d

hypervolemia is

Too much sodium and water (water gain is GREATER)

signs of hypervolemia

edema, ascites, weight gain, cirrhosis, heart and kidney failure

Hypovolemic hyponatremia

dehydrated AND low in sodium

in Hypovolemic hyponatremia, the body releases

ADH (tells kidneys to save water)

how to treat asymptomatic Hypovolemic hyponatremia

Maintenance fluids

Replace ongoing loses with replacement fluids

Give additional isotonic fluids for rehydration

how to treat symptomatic Hypovolemic hyponatremia

Isotonic fluid bolus of LR or NS

Why would hypertonic saline (3%) be LESS recommend in Hypovolemic hyponatremic pts?

Pt is volume depleted, need to focus on rehydration first, then sodium replenishment

arginine vasopressor receptor antagonists are used to

BLOCK ADH which pushes the kidneys to start excreting free water, causing increased urine output

Euvolemic hyponatremia

too much ADH; dehydrated and swollen, normal volume

Euvolemic hyponatremia is caused by

SIADH

Medications that CAUSE SIADH which cause euvolemic hypo

Amitriptyline, nortriptyline, haloperidol

Carbamazepine, desmopressin (synthetic form of ADH), oxcarbazepine

Cyclophosphamide, citalopram, sertraline

Treating SIADH

Stop offending agent (med that is causing it, like one above)

Fluid restriction (stop 50-75% of maintenance fluids that are being pushed)

Hypervolemic hyponatremic

swollen, fluid overload and edema

treatment of Hypervolemic hyponatremic

Fluid restriction treats the hyponatremia

Loop diuretics AND sodium restriction treats the water problem

why would you not use thiazide diuretics for Hypervolemic hyponatremic pts?

it worsens the hyponatremia due to the increased Na loss over the water loss

What do diuretics cause?

Hypovolemic hyponatremia

loop diuretics are more potent at

getting rid of WATER

Thiazide diuretic are more for

More SODIUM LOSS than water

Calculate sodium deficit

Desired serum Na [mEq/L] - actual serum sodium x TBW

Sodium replacement goal

>120-130 mEq/L

Rapid increases of sodium can cause

central pontine myelinolysis

How to calculate the rate to administer the sodium deficit (moderate to asymptomatic)

Give 1/3 deficit in first 6 hours

Replace remaining 2/3 over next 24-48 hours

For Hypertonic saline each

4 mL/kg given will INCREASE sodium by 1 mEq/L in children

the serum osmolality of hypertonic saline (3%) is

1027 mOsm/L

hypertonic saline needs to be given as

central line

Vasopressin antagonists

-vaptan

Demeclocycline is indicated for

chronic treatment of SIADH when fluid restriction alone DOES NOT WORK

a patient with Na 112 who is actively seizing has severe symptomatic hyponatremia and needs

hypertonic (3%) saline to rapidly improve neurologic symptoms

Hypernatremia is always _____tonic

hyper

Signs and symptoms of hypernatremia

Hyperosmolar ECF

Brain cell shrinkage, hemorrhages, cerebral contraction

Thirst and dry mucus membranes

Hypovolemic HYPERnatremia is

Pt lost water and sodium, BUT lost more water than sodium

Hypovolemic Hypernatremia presents as

Tachycardic, hypotensive, dehydrated

for Hypovolemic Hypernatremic pts, treat _________ first with

Hypovolemia; resuscitation fluids

Free water deficit calculation =

usual TBW x [(serum Na/140) -1]

free water deficit should be replace over

2-3 days

free water deficit should be given ______ over the first 24 hours

1/3 deficit

Euvolemic hypernatremia is caused by

diabetes insipidus

diabetes insipidus is

deficiency of ADH

Central Diabetes Insipidus treatment

give ADH via DDAVP, carbamazepine, or indomethacin

Nephrogenic diabetes insipidus treatment

problem with kidney not ADH, use HCTZ, DDAVP, indomethacin, amiloride

1st line DI treatment

CORRECT FREE WATER DEFICIT

Hypervolemic hypernatremia is caused by

hypertonic saline, sodium bicarb infusion

Hypervolemic hypernatremia

gained sodium AND water, but sodium gain is MORE

Hypervolemic hypernatremia treatment

Eliminate sources of sodium if possible with a THIAZIDE diuretic