Clin Med Electrolytes and Volume Flashcards
HYPONATREMIA
what is most common type of hyponatremia?
hypervolemia hypo-osmolar
due to fluid overload
HYPONATREMIA
what does hyperglycemia do to sodium?
hyperglycemia can cause a
hyperosmolar HYPONATREMIA
HYPONATREMIA
how does hyperglycemia cause hyponatremia?
hyperglycemia causes water to shift from the intracellular compartment to extracellular compartment, causing dilution of sodium
HYPONATREMIA
what does SIADH do to sodium?
SIADH causes
hypo-osmolar, euvolemic hyponatremia
HYPONATREMIA
how does SIADH cause hyponatremia?
SIADH causes increase in circulating ADH (due to hypersecretion from post pit)
increased ADH –> increased water retention –> more dilute fluid
HYPONATREMIA
at what serum sodium levels do s/s begin to develop?
125-130 mEq/L
but pt may be asymptomatic until as low as 110 mEq/L
HYPONATREMIA
mild hyponatremia treatment?
fluid restriction only
HYPONATREMIA
severe hyponatremia treatment?
fluid restriction AND sodium replacement
SLOOOOWLY
HYPONATREMIA
sodium level goal of severe hyponatremia treatment?
135 mEq/L
HYPONATREMIA
injury that occurs if hyponatremia treatment occurs too quickly?
CPM
central pontine myelinolysis
HYPONATREMIA
clinical manifestations of hyponatremia?
CNS dysfunction symptoms:
cerebral edema –> HA, n/v, weakness, lethargy, sz, coma, permanent brain damage
HYPERNATREMIA
what sodium level indicates hypernatremia?
> 145 mEq/L
HYPERNATREMIA
in what volume conditions do we find hypernatremia?
hypervolemia
or
hypovolemia
HYPERNATREMIA
what is the most common cause of hypernatremia?
MC cause = volume depletion
usually seen with insensible losses from fever, sweating, vomiting, diarrhea, primary hypodipsia
HYPERNATREMIA
in what two ways does DI cause hypovolemic hypernatremia?
decreased secretion of ADH from post pit
or
increased renal resistance to ADH (with resultant inability to concentrate urine)
HYPERNATREMIA
what is a common cause for hypervolemia hypernatremia in the hospital setting?
aggressive IV admin of NS
or
infusion of hypertonic fluids
HYPERNATREMIA
what are s/s of increased serum sodium?
AMS, sz, hyperreflexia, spasticity, lethargy
HYPERNATREMIA
what is the goal of treatment of hypernatremia?
normalize serum sodium
restore ECF and ECF compartments
with
hypotonic or isotonic fluids
HYPERNATREMIA
what happens if elevated serum sodium correction occurs too rapidly?
administer hypotonic or isotonic fluids slowly!
don’t go too fast, or you may see
cerebral edema,
szs,
permanent brain damage,
death (from cerebral herniation)
what are the most common causes of dyskalemias?
medication side effects
dietary intake
renal dysfunction
HYPOKALEMIA
define hypokalemia
potassium <3.5 mEq/L
HYPOKALEMIA
what are the most common causes of hypokalemia?
increased renal excretion
from diuretic use,
from hyperaldosteronism
from hypomagnesemia
HYPOKALEMIA
what are some other, less common, causes of hypokalemia?
alkalosis
insulin
beta 2 adrenergic agonists
HYPOKALEMIA
s/s of hypokalemia?
muscle weakness
constipation
fatigue
palpitations
HYPOKALEMIA
EKG s/s of hypokalemia?
flat T waves
U wave formation
ST segment depression
HYPOKALEMIA
what is the treatment of mild hypokalemia?
oral replacement using KCl
HYPOKALEMIA
what is the treatment of severe hypokalemia?
IV replacement of potassium (10mEq/hr) WITH TELEMETRY (to watch for arrthymias)
(don’t rebound into hyperkalemia!)
HYPOKALEMIA
what other electrolyte must be checked before replacing potassium?
Mg
if concomitant hypomagnesemia is present, Mg must be repleted prior to potassium replacement
(because of the role of Mg in regulating the sodium-potassium-ATPase pump)
HYPERKALEMIA
how is hyperkalemia defined?
K+ > 5.0 mEq/L
HYPERKALEMIA
hyperkalemia is a common complication seen with:
renal insufficiency,
acidosis,
medication side effects
(ACE-I’s, ARBs, aldosterone antagonists)
HYPERKALEMIA
common s/s of hyperkalemia?
muscle stuff -
muscle weakness
muscle cramping
parasthesias
HYPERKALEMIA
common EKG changes seen in hyperkalemia?
tall/peaked T waves widened QRS P wave loss prolonged PR interval ST depression
HYPERKALEMIA
symptomatic hyperkalemia first treatment
IV CALCIUM
stabilize cardiac membranes, prevent arrhythmias!!!
HYPERKALEMIA
after IV calcium, what treatments are given to restore proper potassium levels?
giving oral or rectal resins to bind to potassium and then be pooped out
hemodialysis
HYPOCALCEMIA
define hypocalcemia
Ca+2 <8.5 mg/dL
HYPOCALCEMIA
common causes of low calcium
thyroid/parathyroid conditions
Vit D deficiency
chronic renal disease
HYPOCALCEMIA
s/s of hypocalcemia
paresthesias muscle cramping tetany Chvostek sign Trousseau sign
HYPERCALCEMIA
define hypercalcemia
Ca+2 > 10.5 mg/dL
HYPERCALCEMIA
common causes of hypercalcemia?
hyperparathyroidism
malignancy
immobilization
HYPERCALCEMIA
s/s of hypercalcemia?
STONES BONES MOANS (lethargy, ab pain/flank pain) PSYCHIC GROANS (depression, confusion) FATIGUE OVERTONES
bone pain nephrolithiasis ab pain m. weakness fatigue
HYPOMAGNESEMIA
define hypomagnesemia
Mg+2 < 1.5 mEq/L
HYPOMAGNESEMIA
what are most common causes of hypomagnesemia?
alcoholism
GI loss
refeeding syndrome (?)
HYPOMAGNESEMIA
s/s of hypomagnesemia
lethargy, confusion
hyperreflexia, paresthesias
HYPERMAGNESEMIA
define hypermagnesemia
Mg+2 >2.5 mEq/L
this is rare
HYPERMAGNESEMIA
most common causes of hypermagnesemia
renal failure
antacid abuse
HYPERMAGNESEMIA
s/s of hypermagnesemia
flaccid paralysis
bradycardia, hypotension
cardiac arrest
magnesium’s claim to fame
Mg+2 is the 2nd most abundant intracellular cation
it’s vital for
ATP processing
macronutrient and energy metabolism
neuromuscular transmission
which form of calcium is most physiologically significant?
ionized calcium
is the most physiologically significant
what is calcium bound to in serum?
albumin
hypERphosphatemia presents similarly to
hyPOcalcemia
they have an inverse relationship
Hypokalemia is associated with (flattened/peaked) _____________T-waves on ECG.
flattened
Insulin lowers serum potassium levels by activating (enzyme) __________
Na/K ATPase
list four findings of hypervolemia
decreased hct
SOB +/- increased RR
pulm edema
low albumin
eight causes of hypervolemia
CHF
nephrotic syndrome
cirrhosis
renal failure
corticosteroids/mineralocorticoids
nephropathy
hyperaldosteronism
Kwashiorkor
what is the best and easiest to identify sign of fluid increase
sudden weight gain
what are four common presentations of hypervolemia?
sudden wt gain
edema/ascites
pulm edema
paroxysmal nocturnal dyspnea/orthopnea
what physical exam findings correspond with hypervolemia?
crackles upon auscultation bounding pulses moist skin JVD S3 gallop
what is used for dx of hypervolemia?
decreased hct
decreased O2 sat
CXR - signs of pulm congestion
increased central venous P
treatment of hypervolemia?
treat underlying cause
- fluid reduction
- fluid/salt restriction
- diuretics
- hemodialysis
if palliative care situation, treat w/ nitroglycerine and morphine (vasodilate and improve pulm congestion)
another name for hypovolemia
intravascular volume contraction
causes for hypovolemia
decreased fluid intake
excess fluid or Na+ loss due to v/d, sweat
burns/hemorrhage/trauma
hypovolemia presentation
sudden wt loss tachy hypotensive pale, dry mucous membranes no skin tenting
hypovolemia dx based on….
increased hct
increased hgb
increased serum protein
increased BUN/creatinine ratio
treatment of hypovolemia
allow permissive hypotension in shock pts
- -> administer fluids to maintain survivable BP (not a normal BP!)
MAP target = 55-60
inpatient - replace fluids
stages of hypovolemic shock
Stage 1: <= 15% blood vol loss (750 mL)
Stage 2: 15-30% blood vol loss (750-1500 mL)
Stage 3: 30-40% blood vol loss (1500-2000mL)
Stage 4: >40% blood vol loss (>2000 mL)
hypervolemia - hematocrit goes up or down?
down
hypervolemia - albumin goes up or down?
down
name four main ways hypervolemia presents
low hematocrit
SOB +/- increased RR
pulm edema
low albumin
s/s of hypERvolemia (name four)
sudden wt gain
edema/ascites
pulm edema
paroxysmal nocturnal dyspnea/orthopnea
three main findings upon PE for hypERvolemia, plus two
crackles in lungs
JVD
increase central venous P
also, lowered Hct
low O2 sat
if hypERvolemia is treated with diuretics, what is given?
loop diuretics (most effective)
thiazides +/- albumin
K+ supplementation
how is hypERvolemia treated palliatively?
improve pulmonary congestion
nitro (vasodilation) and morphine