Fluids & Electrolytes Flashcards
Sodium
135 - 145 mEq/L
most abundant EC cation
major determinant of serum osmolality
HYPOvolemia signs
- postural hypotension
- tachycardia
- decreased skin turgor
- dry mucosal membranes
- flat neck veins
- oliguria (reduced urine output)
- organ failure
- elevated SCr
- dehydration
- absence of jugular venous pulsations at 45 degree angle
HYPERvolemia signs
- hypertension
- tachycardia
- raised jugular venous distension (hands & neck)
- edema (legs & pulmonary)
- pleural effusions
- weight gain
- ascites
- organ failure
- S3 gallop w HF
Isotonic Hyponatremia
low Na with normal osmolality
Isotonic Hyponatremia (causes)
- hyperlipidemia and hyperproteinemia
- plasma cell dyscrasias and malignancy
- chronic infections (HCV), (HIV)
Isotonic Hyponatremia (tx)
correct underlying cause
Hypertonic Hyponatremia
decreased Na with high osmololity
Hypertonic Hyponatremia (causes)
hyperglycemia
+ other osmoles (mannitol, glycine, sorbitol)
Hypertonic Hyponatremia (tx)
correct underlying cause (hyperglycemia)
Hypotonic Hyponatremia
low Na and low osmolality
evaluate volume status
Hypotonic HYPOvolemic Hyponatremia
reduced EC volume
S&S: orthostatic hypotension, hypotension, tachycardia, dry mucous membranes, CNS changes, oliguria
- high urine osmolality > 450 mOsm/kg
Hypotonic HYPOvolemic Hyponatremia (causes)
urine sodium >20 : renal loss, diuretics, ACEi, cerebral salt wasting
urine sodium < 20 : GI (D/V), burns, lung loss
Hypotonic HYPOvolemic Hyponatremia (tx)
- fluid replacement: NS or LR bolus
- if severe consider hypertonic saline
Hypotonic ISOvolemic Hyponatremia (causes)
SIADH:
- malignancy (lung, pancreatic, lymphoma)
- CNS disorder: head trauma, stroke, meningitis, pituitary syndrome
- pulmonary disease: TB, pneumonia, acute respiratory distress syndrome
- medications: ACEi, Carbamazepine, TCAs, SSRIs, NSAIDs
Renal insufficiency
Adrenal insufficiency
Hypotonic ISOvolemic Hyponatremia
present: urine osmolality >100 mOsm/kg; (urine Na >20 mEq/L)
diagnosis: SIADH, renal/adrenal insufficiency
tx: fluid restriction (<1L/d), Na tablets, Tolvaptan, diuretics (IV furosemide)
present: urine osmolality < 100 mOsm/kg (urine Na <20 mEq/L)
diagnosis: psychogenic polydipsia, excessive hypotonic fluid intake
tx: treat underlying cause
Hypotonic HYPERvolemic Hyponatremia
excess ECF volume
presentation: edema, swelling
Hypotonic HYPERvolemic Hyponatremia (causes)
- reduced renal excretion of sodium and water (renal dysfunction)
- cirrhosis, HF
- nephrotic syndrome (too much protein in urine)
Hypotonic HYPERvolemic Hyponatremia (tx)
- Na & H2O restriction
- diuresis with loop diuretic
HYPOvolemic Hypernatremia
loss of H2O and Na
HYPOvolemic Hypernatremia (causes)
- renal: osmotic diuresis, diuretic use, postop diuresis, high-output acute tubular necrosis
- GI: D/V
HYPOvolemic Hypernatremia (tx)
NS or LR (200-300 mL/h)
once intravascular volume is restored use D5W or 1/2 NS
ISOvolemic Hypernatremia
pure water loss
ISOvolemic Hypernatremia (causes)
- Diabetes insipidus
- insensible loss of fluid (sweat, fever, respiratory infection, burns)
ISOvolemic Hypernatremia (tx)
- free water replacement (po or iv)
- treat diabetes insipidus (desmopressin, address cause)
HYPERvolemic Hypernatremia (causes)
sodium overload:
- 3% NaCl, sodium bicarb, salt tabs, concentrated tube feedings, hypertonic dialysate, Na-containing meds
- primary aldosterone
Hypokalemia
S&S:
- muscular: weakness, respiratory distress, cramping, malaise, paralysis
- cardiac: EKG changes, cardiac arrhythmias, heart block, sudden death
Hypokalemia (causes)
- total body K deficit
- renal loss and IC shift
- hypomagnesemia
total body K deficit
- excessive GI loss - D/V, NG suctioning, body drains
- meds: laxatives, sodium polystyrene sulfonate, sorbitol
- poor dietary intake of K
renal loss & IC shift
renal loss:
- meds: diuretics, high-dose penicillin, mineralocorticoids,
IC shift:
- meds: B2 receptor agonists, theophylline, caffeine, insulin
hormones: aldosterone excess
high dose steroids
Potassium Replacement
- PO preferred > IV if asymptomatic
- consider Mg before K
- for every 10 mEq of K given, anticipate 0.1 increase in serum K
- replace over 1-3 days to minimize SEs
- potassium chloride
- potassium phosphate
- potassium bicarb or acetate
- IV infused no > 10 mEq/hr in NS
- re-evaluate 30 mins after infusion of 30-40 mEq
Hyperkalemia
S&S:
- muscular: twitching, cramping, weakness
- cardiac: heart palpitations, EKG changes, cardiac arrhythmias
Hyperkalemia (causes)
- incr. K intake
- redistribution into EC space (metabolic acidosis, DM, direct tissue damage, digoxin tox, beta blockers, hyperosmolality)
- decr K excretion (kidney disease, adrenal insufficiency, Addison’s disease, low aldosterone levels, meds)
–> ACEi/ARBs, direct renin inhibitors, K-sparing diuretics, prostaglandin inhibitors (NSAIDs), digoxin, cyclosporine, bactrim, heparin, pentamidine
Hyperkalemia (tx)
- remove meds and supp that incr. K
- determine severity
- stabilize the heart with Calcium (IV Calcium Gluconate)
- Shift K intracellularly
- insulin (+ dextrose)
- albuterol
- Sodium bicarbonate - increase K elimination
- exchange resins (Na polystyrene sulfate, Patiromer, Na zirconium cyclosilicate)
- loop diuretics
- renal replacement therapy
Hypomagnesemia
S&S:
- muscular: muscle cramping, twitching, tetany
- cardiac: arrhythmias, ECG changes
- neuro: irritability, seizures, coma, death
- electrolytes: refractory hypokalemia & hypocalcemia
Hypomagnesemia (causes)
- decr. GI absorption (bowl resection, short bowel syndrome, pancreatic insufficiency)
- incr. GI loss (excess laxative use, V/D, NG suctioning)
- renal causes (diuresis c diuretics, alcoholism, increased urinary excretion)
- decr. oral intake (alcoholism, TPN, poor nutrition)
- med: diuretics; amphotericin B, caspofungin, pip/tazo; lactulose; long-term digoxin or PPI use
- trauma, burn, sepsis/critical illness
Hypomagnesemia (tx)
oral: Mg oxide
IV: Mg Sulfate
Hypermagnesemia
S&S:
- GI: N/V, hypotension, bradycardia
- muscular: muscle weakness
- cardiac: bradycardia, heart block, asystole, hypotension
- neuro: drowsiness, paralysis, coma
Hypermagnesemia (causes)
- renal failure
- incr. oral intake
- lithium therapy
- hypothyroidism
- addison’s disease
Hypermagnesemia (tx)
- reduce Mg intake
- enhance elimination (loop diuretics, renal replacement therapy, dialysis)
- stabilize the heart (IV Calcium gluconate)
Hypophosphatemia
S&S:
- CNS: irritability, weakness, numbness, paresthesia, dysarthria, confusion, obtunded, coma
- cardiac: congestive cardiomyopathy, cardiac arrest
- neurologic: delirium, hallucinations, paranoia, seizures
Hypophosphatemia (causes)
- decr. GI absorption
- reduced tubular reabsorption
- internal redistribution
- med (phosphate-binding, sucralfate, aluminum/Mg antacids, Ca supp, diuretics, parenteral nutrition, insulin
- critical illness, hyperparathyroidism, cancer
Hypophosphatemia (tx)
- oral: neutra-phos, neutra-phos-k
- iv: sodium phosphate, potassium phosphate
Hyperphosphatemia
S&S:
- short-term: N/V/D, lethargy, tetany, prolonged QT, seizures
- long-term: hypocalcemia, vascular and organ damage due to calcium-phosphate deposits/calcifications
Hyperphosphatemia (causes)
- renal failure
- hypoparathyroidism
- vitamin D toxicity
- rapid tissue catabolism (rhabdo, trauma, tumor lysis, hemolysis)
- IC shifts
- immobility
- diabetic ketoacidosis
- excessive phosphorous intake (TPN, enemas containing phosphorous)
Hyperphosphatemia (tx)
- severe (hypocalcemia and tetany)
- -> IV Ca Carbonate or Ca Acetate
- mild-mod (no hypocalcemia)
- -> phosphate binders (Ca acetate, Ca carbonate; sevelamer carbonate, sevelamer hydrochloride
Hypocalcemia
S&S:
acute drop (neuromuscular symptoms)
- paresthesia, muscle cramps, tetany, and laryngeal spasm
- prolonged systole, heart block, heart failure symptoms, ventricular arrhythmias
chronic (CNS and dermatologic symptoms)
- depression, anxiety, confusion, hallucination, tonic-clonic seizures
- hair loss, grooved/brittle nails, eczema
Hypocalcemia (causes)
- hypoparathyroidism
- vit D deficiency (liver failure, CKD, GID disease)
- med: furosemide, calcitonin, biphosphates, po phosphorous agents
- Mg deficiency, blood transfusions with citrated blood products, continuous renal replacement
Hypocalcemia (tx)
po: Ca carbonate, Ca citrate
IV: Ca Chloride, Ca gluconate
- Hypoparathyroidism (oral calcium + vit D)
- malabsorption of Vit D (large vit D dosing)
- CKD (vit D)
Hypomagnesemia (replace Mg)
Hypercalcemia
S&S:
- GI: N/V, constipation
- renal: polyuria, polydipsia, reduced renal function
- neuro: confusion, fatigue, muscle weakness, disorientation, depression, insomnia, psychosis, coma
- cardio: cardiac arrhythmias, shortened QT, slower conduction
Hypercalcemia (causes)
- cancer
- primary hyperparathyroidism
- other causes: immobility, Paget’s disease, rhabdo, dehydration
meds: thiazide, lithium, vit D, Ca supp
Hypercalcemia (tx)
chronic:
- remove supp/evaluate meds; remove tumor
acute:
- NS 200-300 mL/hr x 48 hr
- loop diuretic (furosemide)
- calcitonin
- IV bisphosphates (Pamidronate, Zolendronic acid)
