Sodium Disorders

what element is the major cation in the ECF

Na

what is the major role of Na

fluid balance

sodium disorders stem from what

issues related to water

what is hypernatremia in mEq/L and its osmolarity

>145mEq/L

hyperosmolar

which way does water move in hypernatremia

out of cells into ECF

what are the symptoms related to the brain in a hypernatremic patient

dehydration of brain cells

hypovolemic hypernatremia

decrease in sodium and TBW but TBW decreases faster than Na

what are the common causes of hypovolemic hypernatremia

inadequate water intake

excess loss of water

GI water loss

euvolemic hypernatremia

decrease in TBW while Na content stays close to normal but are more concentrated

what are the common causes of euvolemic hypernatremia

diabetes insipidus

pituitary gland disease

CKD

hypervolemic hypernatremia

increase in Na while TBW remains the same or increases

what are the common causes of hypervolemic hypernatremia

excessive hypertonic fluids

seawater ingestion

steroids

what are the causes of a relative increase in sodium due to water loss

kidney disease

osmotic diuresis

vomiting

diarrhea

burns

DI

Mineralcorticoid excess

increased insensible loss

excessive sweat

what are the s/sx of hypernatremia

thirst

weakness

irritability

if sodium is more than 158, what will this cause

twitching

seizure

coma

death

what can brain cell dehydration cause

cerebral vein rupture leading to brain hemorrhage

if the patient has symptomatic chronic hypernatremia what is the goal

decrease Na by 0.5 mEq/L/hr

Max: 12 mEq/L/day

if the patient has symptomatic acute hypernatremia what is the goal

decrease Na by 1-2 mEq/L/hr

Max: 12 mEq/L/day

what is the maximum correction in 24 hours to be made on a symptomatic hypernatremic pt

8-12 mEq/L

what should not be given when treating hypernatremia

sterile water without additives

what are the 3 ways to replace free water

IV using D5W

free water flushes

oral intake

what is the formula when calculating TBW for men

0.6 x wt (kg)

what is the formula when calculating TBW for women

0.5 x wt(kg)

what is the formula to use when calculating free water deficit

TBW x ( (serum Na/140) - 1)

what is the formula to use when calculating how much to give a hypernatremic patient in 24 hours

free water deficit x ( (goal change in sodium/ (serum Na-140))

when treating a patient with hypovolemic hypernatremia with hypotension, what should be used and why

restore IV volume with isotonic crystalloid to restore perfusion to the organs and then give free water

what may be added in a patient with hypovolemic hypernatremia with hypotension to keep the IV volume

1/2 NS to D5W

what should be used when treating a patient with hypervolemic hypernatremia

free water and loop diuretics

when should sodium be monitored in a patient with hypernatremia

every 2hrs and space out further as approaching the goal Na

what can happen if you overcorrect a patient with hypernatremia too fast

cerebral edema

what is hyponatremia

loss of solute containing fluid ort excess water

<135

euvolemic hyponatremia

increase in TBW while sodium content stays close to normal and Na ions are more diluted

what are the common causes of euvolemic hyponatremia

SIADH

trauma

severe pain

hypervolemic hyponatremia

increase in TBW and Na but TBW increases more than Na

what are the common causes of hypervolemic hyponatremia

HF

cirrhosis

nephrotic syndrome

hypovolemic hyponatremia

decrease sodium and TBW but sodium decreases faster than TBW

what are the common causes of hypovolemic hyponatremia

third spacing

severe diarrhea

meds

cerebral salt wasting

what is the main symptom of hyponatremia

water moves into brain cells causing cerebral overhydration

symptoms severity increases with what in hyponatremia

severe hyponatremia and onset of hyponatremia

describe patients with chronic hyponatremia

allows the body to adapt to having chronically low levels of Na making the symptoms less severe or asymptomatic

what are the symptoms of a patient with a serum sodium of 120-125

nausea, malaise

what are the symptoms of a patient with a serum sodium of 115-120

headache, confusion, unsteady gait, lethargy

what are the symptoms of a patient with a serum sodium of <115

delirium, seizure, coma, respiratory failure, death

what is the serum sodium of a patient with mild symptoms of hyponatremia

130-134

what is the serum sodium of a patient with moderate symptoms of hyponatremia

125-129

what is the serum sodium of a patient with severe symptoms of hyponatremia

<125

what is acute hyponatremia

less than 48hrs with a high risk of brain edema

what is chronic hyponatremia

greater than 48 hrs

pseudohyponatremia

sodium content in body is actually not low

what interferes with accurate reading of sodium levels that can cause pseudohyponatremia

abnormally high protein or lipids in blood

hyperglycemia induced hyponatremia

low sodium by dilution due to glucose-induced hyperosmolarity

what happens to sodium if we treat hyperglycemia

water moves back to the ICF causes the serum Na to increase and restore to normal

what is the equation to correct serum Na for hyperglycemia

measure Na + 1.6 x ((GLUC-100)/100)

in a hyperglycemia patient, when should we correct serum Na

if glucose is >100

what drugs cause hypovolemic hyponatremia

thiazide diuretics

osmotic diuretics

what drugs cause isovolemic hyponatremia

antineoplastic agents

antipsychotics

carbamazepine

desmopressin

NSAIDs

Opiates

Oxytocin

SSRI

TCA

what category of drugs cause hypotonic hyponatremia

diuretic induced

SIADH

which diuretic is responsible for causing hypotonic hyponatremia

within 1-2 weeks of starting a thiazide

what is the most common cause of euvolemic hyponatremia

SIADH

what are examples of SIADH drugs

antidepressents

anticonvulsants

antipsychotics

chemotherapy

vasopressin analogs

what is the formula for Na deficit

TBW x (desired Na - measure Na)

what is the equation to use when estimate a change in Na from fluid

(Na IV - Na S)/ ( TBW +1)

what can we use in an emergent treatment for hyponatremia

hypertonic saline

free water restriction

what is the dosing when using hypertonic saline

150mL of 3% NaCl over 20 min

what is the goal when treating hyponatremia

change in serum Na greater than or equal to 5mEg/L in 24 hrs

when should Na be checked in a patient with hyponatremia using emergent treatment

1-2 hrs

what is the goal correction rate of hyponatremia

increase sodium by max of 8-12 mEq/L in 24 hrs

if the patient has an acute onset of hyponatremia, what may the correction go up to

1-2 mEq/L/hr

if the patient has an chronic onset of hyponatremia, what may the correction go up to

0.5 mEq/L/hr

which electrolyte imbalance causes osmotic demyelination syndrome

hyponatremia

if we rapidly increase sodium levels above 12 within 24 hours what could happen

ODS

what are s/sx of ODS

hyperreflexia

paresis

parkinsonism

pseduobulbar palsy

locked in syndrome

dearh

what are Vaptans CI in

hypovolemic hyponatremia

what is the BBW associated with Tolvaptan

initiate and reinitiate only in hospitals to monitor Na closely

why should we not use Tolvaptan for more than 30days

hepatotoxicity