fluid/volume homeostasis
what percent of total body weight is water
60% and varies with age, gender, body fat%
symptoms of hypernatremia
orthostasis
restlesssness
lethargy
tremor, muscle spasm/twtiching
seziures
coma
death
serum K+ reflects
transmembrane regulation more than total body K+
K+ is the major ICF cation
<1.5% in ECF
hypomagnesemia causes
low dietary intake or absorption or renal wasting
iCa++ influences
hormones that regulate Ca++
1.2 - 1.38 mmol/L
iCa++ influenced by pH and albumin
(increased pH decreased iCa++)
hormones: PTH, vitamin D
compartments of body water
ECF 1/3 TBW (1/4-plasma, 3/4- ISF)
ICF 2/3 TBW
hyponatremia causes
hypovolemia- loop diuretics/osmotic diuretics, renal tubular acidosis, metabolic alkalosis, GI loss, burns, pancreatitis, 3rd spacing, muscle trauma
euvolemia - salt-restricted diet, hypothyroidism, SIADH, sympathetic overdrive, glucocorticoid deficiency
hypervolemia - ARF/CKD, heart failure, cirrhosis, nephrotic syndrome
hypokalemia causes
low PO intake
diuretics, hyperaldosternoism
malabsorption/ N/V/D
alkalosis, Beta-agonists, insulin
DKA
HCTZ
excessive licorice
symptoms and treatment for HypoMg++
muscle spasms/weakness
seziures
torsades
Mg++ Sulfate for Torsades and seizures
causes of hypoCa++
decreased PTH secretion
mag deficiency (required for PTH production)
low vitamin D
renal failure
massive blood transfusion (check after 4 units)
which organ most immediately alters the ECF
kidneys
treatment for hyponatremia
electrolyte drinks, NS, diuretics, hypertonic saline (3% @ 80 mL/hr for 15 hours)
**correction no more than 1.5 mEq/L/hr and no more than 6 mEq/L/24 hr to prevent osmotic demylineation syndrome
**hyponatremic seizures = 3-5 mL/kg 3% over 20 min
symptoms and treatment of HypoK+
muscle cramps/weakness, ileus, U-wave
PO K+ > IV K+
10-20 mEq/L/hr
10 mEq increases serum K+ 0.1 mmol/L
**avoid excessive insulin, beta-agonists, bicarb, hyperventilation, diuretics**
hypermagnesemia causes
generally overtreatment
* pre-eclampsia, pheochromocotyoma
causes of HyperCa++
cancer > 13
less common:
vitamin D intoxication
granulatomous
milk-alkali syndrome
osmolality sensors mainly mediate osmolar homeostasis.. where are they located and what are the effects
anterior hypothalamus
*stimulate thirst
*cause pituitary release of ADH (vasopressin)
*cardiac atria stop release of ANP which increase Na+/H2O excretion
causes of hypernatremia
excessive evaporation, poor oral intake (really old, really young, AMS), DI, overcorrection of hyponatremia, NaHCO3, GI losses
Hypovolemic - osmotic/loop diuretics, profound glucosuria, intrinsic renal disease, post-renal obstruction
euvolemic - DI, respiratory tract/skin water loss
hypervolemic - hyperaldosteronism, cushing, hypertonic enema/dialysis, NaHCO3, salt water drowning, hyperalimentation, Na+ tablets
causes of hyperK
hypoaldosteronism
Drugs that inhibit RAAS
renal failure
Drugs that inhibit K+ secretion
acidosis
cell death (trauma)
massive blood transfusion
Succinylcholine
symptoms of hyperMg++
4-5 mEq/L - lethargy, N/V, flushing
>6 mEq/L - decreased DTR, hypotension
> 10 mEq/L - paralysis, apnea, heart block, cardiac arrest
hypoCa++ symptoms
irritability
paraesthesia
depressed myocardium
hypotension
seizures
prolonged QTi
post-parathyroidectomy - hypocalcemia --> laryngospasm
volume homeostasis is mediated by
juxtaglomerular apparatus
*decrease in volume triggers JGA to release renin --> RAAS for Na+/H2O reabsorption
treatment for hypernatremia
hypovolemic- NS
euvolemic - D5W/PO intake
hypervolemic- diuretics
want to reduce no more than 0.5 mmol/L/hr and no more than 10 mmol/L/day to prevent cerebral edema and seizures leading to permanent neuro damage
symptoms and treatment for HyperK+
Chronic: GI upset, malaise
Skeletal muscle paralysis, decreased fine motor, peaked t waves -> loss of P wave -> widened QRS -> sine wave -> asystole
Ca++, dialysis, Hyperventilation, Insulin/Dextrose, Bicarb, Loop Diuretics, Kayaxelate
treatment for hyperMag
Ca++
dialysis
diuretics
hyperCa++ symptoms
short QTi
lethargy
hypotonia, decreased DTR
abdominal pain
N/V
chronic: hypercalciuria and nephrolithiasis