Electrolytes

fluid/volume homeostasis

100

what percent of total body weight is water

60% and varies with age, gender, body fat%

200

compartments of body water

ECF 1/3 TBW (1/4-plasma, 3/4- ISF)

ICF 2/3 TBW

300

which organ most immediately alters the ECF

kidneys

400

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

500

volume homeostasis is mediated by

juxtaglomerular apparatus

*decrease in volume triggers JGA to release renin --> RAAS for Na+/H2O reabsorption

Sodium

100

symptoms of hypernatremia

orthostasis

restlesssness

lethargy

tremor, muscle spasm/twtiching

seziures

coma

death

200

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

300

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

400

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

500

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

Potassium

100

serum K+ reflects 

transmembrane regulation more than total body K+

K+ is the major ICF cation

<1.5% in ECF

200

hypokalemia causes

low PO intake

diuretics, hyperaldosternoism

malabsorption/ N/V/D

alkalosis, Beta-agonists, insulin

DKA
HCTZ

excessive licorice

300

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**

400

causes of hyperK

hypoaldosteronism

Drugs that inhibit RAAS

renal failure

Drugs that inhibit K+ secretion

acidosis

cell death (trauma)

massive blood transfusion

Succinylcholine

500

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

Magnesium

100

hypomagnesemia causes

low dietary intake or absorption or renal wasting

200

symptoms and treatment for HypoMg++

muscle spasms/weakness

seziures

torsades

Mg++ Sulfate for Torsades and seizures

300

hypermagnesemia causes

generally overtreatment

* pre-eclampsia, pheochromocotyoma

400

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

500

treatment for hyperMag

Ca++

dialysis

diuretics

Calcium

100

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

200

causes of hypoCa++

decreased PTH secretion

mag deficiency (required for PTH production)

low vitamin D

renal failure

massive blood transfusion (check after 4 units)

300

causes of HyperCa++

hyperparathroid > 11

cancer > 13

less common:

vitamin D intoxication

granulatomous 

milk-alkali syndrome 

400

hypoCa++ symptoms

irritability

paraesthesia

depressed myocardium

hypotension

seizures

prolonged QTi

post-parathyroidectomy - hypocalcemia --> laryngospasm

500

hyperCa++ symptoms

short QTi

lethargy

hypotonia, decreased DTR

abdominal pain

N/V

chronic: hypercalciuria and nephrolithiasis