12-14 GU - electrolytes and acid base - kruger
fractional excretion of Na =
(urine Na/plasma Na) / (urine creatine/plasma creatine) x 100
serum osmolality =
2 Na + glucose/18 + BUN/2.8
what are the values of normal plasma osmolality
275-290
what part of total body water is lost in hypovolemic hyponatremia
ECF
what are the two components of total body water?
ECF and ICF
what are the causes of hypovolemic hyponatremia
GI loss, burns, sweating, aldosterone deficiency, diuretic, RTA, metabolic alkalosis
how do you treat hypovolemic hypernatremia
IV normal saline
for every decrease in pH of 0.1 what happens to K
K increases by 0.7
why does replacement of K usually need to be higher than reported values in hypokalemia
K is an ICF ion and may be much lower than the serum K value that is reported
what are the major ICF particles
K, organic phosphates, Mg
for every 100 mg increase of glucose what happens to Na
Na decreases by 1.6
what are the causes of euvolemic hyponaturemia
SIADH**, hypothyroidism, addisons, drugs, stress, functional
what is the treatment for severe hyperkalemia
albuterol and insulin and IV sodium bicarb pushes K back into cell
how does isovolemic hypernatreia appear?
appears euvolemic cecause most of free water loss is from intracellular and interstitial spaces
what causes hypocalcemia
chronic renal failure, hypoparathyroidism, vitamin D deficiency, magnesium deficiency
what are symptoms of hypocalcemia
chvosteks sign, trousseaus sign, parethesias, hyperreflexia, muscle spasm
what is central pontine myelinolysis
complication of treatment of patients with profound, life-threatening hyponatremia; happens when you add Na too fast to cells who have adapted to dealing with hyponatremia
what is the treatment of isovolemic hypernatremia
correct water deficit with D5W or hypotonic saline
what are primary causes of drug induced hyponatremia
cyclophosphamide; caramazepine; vincristine; vinblastine, oxytocin, bromocriptine, barbituates, opiates, NSAIDs
what are the causes of hyperkalemia
decreased potassium excretion; intracellular to extracelluar potassium shifts, excess exogenous potassium load, pseudohyperkalemia
what is pseudohyponatremia
dilution of aqueous phase by excessive proteins or lipids; low measued serum sodium but normal measured serum osmolality
what are the causes of hypovolemic hypernatremia
diuretics, sweating, respiratory loss, fever, NVD, DM, renal failure
what is drug induced hyponatremia
drugs may stimulate ADH and cause hyponatremia or stimulate thirst
why are BUN:Cr levels increased in hypovolemia?
due to decrease in GFR
transtubular potassium gradient (TTKG) greater than 8 suggests:
extrarenal cause
what are symptoms of hypercalcemia
fatigue, weakness, depression, confusion, anorexia, abd pain, polyuria, short QT
what are the causes of isovoelmic hypernatremia
fever, diabetes insipidus, electrolyte disorders
what is hypervolemic hypernatremia
gain of water and sodium
what are the values for hyperkalemia
greater than 5 serum potassium
what are the causes of redistributive hyponaturemia
hyperglycemia
what is the most common cause of hypercalcemia
hypoalbuminemia
what is the MC electrolyte disorder in hospital population?
hyponatremia
what are the 3 categories of hypernatremia
hypovolemic hypernatreima, isovolemic hypernatremia, hypervolemic hypernatremia
what are the etiologies of hyponatremia?
hypovolemic hyponatremia, euvolemic hyponatremia, hypervolemic hyponatremia, redistributive hyponatremia, pseudohyponatremia, drug induced
what is the MCC of hypervolemic hypernatremia
iatrogenic
a loss in ECF in hypovolemic hyponatremia leads to what compensation
increase in ADH leads to replenished intravascular volume iwth free water accumulation
what is hypervolemic hyponatremia
increase in total body sodium with greater increase in total body water
what is euvolemic hyponaturemia
increase in total body water without marked edema with dilutional decrease of normal total body sodium
what are the BUN: Cr levels in hypovolemia?
increased
what is hypertonicity
increased solutes in ECF which do not cross cell membranes, shifts water from ICF to ECF
what is hyperosmolality
increased solutes which freely cross membranes; or glucose which does not
what are the causes of hypokalemia
intracellular shift of potassium, decreased net intake, increased net loss
what are the divisions of ECF?
intravascular (plasma water) and interstital compartments
what are the levels of sodium in hyponatremia
less than 135
what is the treatment of hypercalcemia
loop diuretics, bisphosphonates, calcitonin
what is hypovolemic hyponatremia
loss of water and sodium with sodium losses being greater than water losses
what is hypovolemic hypernatreamia
loss of water and sodium with water loss being greater than sodium loss
H moves into the cell causing K to move into serum causes hyperkalemia when
metabolic acidosis
loss of gastric secretions leads to what acid base disorder?
metabolic acidosis
when is H high and moves from ECF into cell
metabolic acidosis
H moves out of the cell and K moves from serum into cell causing hypokalemia when?
metabolic alkalosis
when is H low and moves from in the cell to out of the cell
metabolic alkalosis
an intracellular shift of potassium means:
metabolic alkalosis, insulin use, nebulizer (andenergic drugs)
what are the causes of psudohyponatureamia
multiple myeloma, increase in triglycerides
what is the presentation of hypokalemia
muscle cramps, dysrhythmias, fatigue, weakness -> paralysis;
what are the causes of hypervolemic hyponatremia
nephrotic syndrome, cirrhosis, CHF, renal failure,
what are the symptoms of hyponaturemia
neurological: headache, lethargy, disordeantation, weakness, muscle cramps
what is the treatment of hypovolemic hyponatremia
normal saline
fluid movement between intravascular and interstitial spaces are controlled by
oncotic and hydrostatic pressures
what is the treatment of hypocalcemia
parenteral calcium administration
what is the difference in ECF and ICF
permeability disparity and active electrolyte pumps
what causes hypercalcemia
primary hyperparathyroidism and malignancy
when is hyponaturemia treated with ypertonic saline 3%
pts who are BOTH severely symptmatic and have sodium concentrations less than 120
rapidly correcting hypertonicity to normal osmolality may cause:
pulmonary and secrebral edema; neurological manifestations
how is hypervolemic hyponatremia diagnosed
reduced GFR, urine sodium is less than 10 or greater than 20
what is the treatment of hypervolemic hypernatremia
remove excess water with diuretics or dialysis
transtubular potassium gradient (TTKG) less than 6 suggests:
renal excretory defect
what is the MCC of hyperkalemia?
renal failure - indicator for dialysis
an increased net loss of potassium means:
renal losses, renal tubular damage, renal disease, hyperaldosteronism, GI loss
a fractional excretion of Na greater than 1% indicates
renal salt wasting
how do you treat the water deficit?
replace 1st 50% of deficit in first 24 hours; remainder over 1-2 days
what are the values that mean hypokalemia
serum K is less than 3.5
what is redistributive hyponaturemia
shift of water from ICF to ECF wit hdilution of sodium
what are the levels of hypernatremia?
sodium greater than 145
a fractional excretion of na less than 1% indicates:
sodium retention by kidneys to compensate for extrarenal fluid losses
what are the major ECF particles?
sodium, chloride, bicarb
what is osmolality?
solute or particle concentration of a fluid
a decreased net intake of potassium means:
starvation, clay intake
what is hypovolemia
state of combined salt and water loss esceeding intake
what are secondary causes of drug induce hyponaturemia
thiothixene, amitriptyline, fluphenazine, ectascy, fluoxetine, sertraline, haloperidol
what levels indicate hypercalcemia
total plasma levels greater than 10.5
what levels indicate hypocalcemia
total plasma levels less than 8.7
what is the treatment of hypervolemic hyponatremia
water and sodium restriction; diuretic
what is hypernatremia?
water content of body fluid is deficient compared to sodium content
what is isovolemic hypernatremia
water deficiency without sodium loss
what is the treatment of euvolemic hyponatremia
water restriction and increase salt intake
what is the presentation of hyperkalemia
weakness -> paralysis; dyspnea; abdominal distention, diarrhea
