Fluid and Electrolyte - VOCABULARY Flashcards

Vocabulary flashcards covering key concepts from Water Distribution to Magnesium imbalances in the Fluid and Electrolyte lecture notes.

Total body water (TBW) percentage in males, females, and elderly

Males ~60%; Females ~50% (more fat); Elderly have less due to reduced muscle mass and increased fat.

TBW distribution between ECF and ICF

ECF = 1/3 of TBW; ICF = 2/3 of TBW.

Extracellular fluid (ECF) compartments

Plasma volume = 1/4; Interstitial fluid = 3/4.

Sources of daily fluid intake

Ingested fluids 1300 mL; Water in foods 1000 mL; Oxidation 300 mL.

Sensible fluid loss

Loss that is seen: urine and feces.

Insensible fluid loss

Loss that is not seen: respirations and sweat.

Abnormal fluid losses

Fever/increased room temperature, severe burns, hemorrhage, rapid breathing, emesis, fistulas, secretions (tubes/wounds), paracentesis, thoracentesis.

Fluid loss in severe burns

Skin damage prevents the skin from holding fluid, leading to fluid loss.

Hemorrhage-related fluid loss

Vascular volume decreases at an accelerated rate (e.g., bleeding during surgery, trauma, ruptured aneurysm).

Rapid breathing and fluid loss

Causes increased fluid loss through the lungs.

Goal of isotonic fluids (0.9% saline, LR)

To increase intravascular volume and thereby raise BP.

Goal of hypotonic fluids (e.g., 0.45% saline)

To increase intravascular volume and correct free water deficit; best IV fluid for dehydration.

D5W as a hypotonic fluid

Glucose is rapidly taken up by cells leaving free water; best for replacing free water deficit or hypoglycemia.

Use of hypertonic fluid (3.0% saline)

Used only for severe symptomatic hyponatremia and cerebral edema.

Role of plasma protein (albumin)

Holds fluid in the vascular space; most abundant plasma protein.

Inadequate albumin consequences

Fluid leaks into tissues causing edema and hypovolemia; interstitial fluid accumulation; swelling.

Glucose as an osmotically active substance

Draws water from the ICF into the ECF.

High blood glucose and diuresis

Particle-induced diuresis (PID); kidneys excrete excess glucose leading to polyuria and fluid loss.

Particle-induced diuresis (PID)

Osmotic diuresis from high glucose causing vascular fluid loss as kidneys excrete glucose.

Kidneys in high glucose states

Monitor for imbalances and excrete excess glucose; prolonged action can lead to hypovolemia.

Insulin effect on potassium

Moves potassium from blood into cells, causing serum K+ to drop.

Parathyroid hormone (PTH) action

Increases Ca from bone, decreases Ca excretion, increases phosphate excretion in urine.

Calcitonin action

Lowers serum calcium by inhibiting bone resorption.

RAAS pathway

Low BP/volume → reduced renal perfusion → increased renin → angiotensin I → angiotensin II → aldosterone ↑ → Na+ retention and K+ excretion → water retention → BP ↑.

ADH action

Increased osmolarity or reduced blood volume activates hypothalamus → more ADH → more free water reabsorption in collecting ducts → ↑ circulating volume and ↓ Na.

Normal sodium level

135 to 145 mEq/L.

Most common cause of hyponatremia

Excess free water; can also be due to decreased total body Na.

Signs/symptoms of hyponatremia

Lethargy, confusion (cerebral edema); muscle weakness; decreased DTRs; diarrhea.

Treatment principle for hyponatremia

Depends on cause: excess water → fluid restriction; Na wasting → 0.9% or 3.0% saline; avoid rapid correction to prevent osmotic demyelination.

Causes of hypernatremia

Lack of free water or excess Na intake (e.g., profuse sweating without replacement, diarrhea/vomiting, NPO, diabetes insipidus).

Normal potassium level

3.5 to 5.3 mEq/L.

Causes of hypokalemia

Diuretics, steroids, GI suction, vomiting, diarrhea, NPO/poor intake, Cushing syndrome, alkalosis.

Signs/symptoms of hypokalemia

Paralytic ileus; muscle cramps/weakness; EKG changes (PVCs, V-tach/fib, flattened T, depressed ST, U-wave).

Treatments for hyperkalemia

STAT EKG; hold K+ meds; Kayexalate; calcium gluconate; shift K+ with IV insulin/D50 or sodium bicarbonate; dialysis if severe.

Causes of hyperkalemia

Renal insufficiency; IV KCl overload; burns/crush injuries/rhabdomyolysis; tight tourniquets; hemolysis; salt substitutes; K+-sparing diuretics; blood transfusions; ACE inhibitors; acidosis; Addison’s disease.

Normal calcium level

9.0 to 11.0 mg/dL.

Causes of hypocalcemia

Decreased Ca intake; renal failure; low vitamin D; diarrhea; pancreatitis; hyperphosphatemia; thyroidectomy; low albumin; alkalosis.

Signs/symptoms of hypocalcemia

Muscle cramps; tetany/convulsions; arrhythmias; positive Chvostek’s/Trousseau’s signs; hyperactive DTRs; cardiac changes (increased QT, reduced contractility).

Causes of hypercalcemia

Hyperparathyroidism; immobilization; increased Ca/vitamin D intake; thiazide diuretics; malignancy.

Signs/symptoms of hypercalcemia

Decreased DTRs; muscle weakness; kidney stones; bone pain/fractures; depression/fatigue/confusion; early cardiac changes (decreased QT); constipation/N/V; increased urine output; altered clotting times.

Normal phosphorus level

2.5 to 4.5 mg/dL.

Causes of hypophosphatemia

Malnourished state (ICU); hyperparathyroidism; disorders causing hypercalcemia.

Signs/symptoms of hypophosphatemia

Weakness/numbness/tingling; pathological fractures; nausea/vomiting/anorexia; irritability/seizures/coma; respiratory muscle weakness.

Treatment for hypophosphatemia

Supplemental phosphorus (PO or IV).

Causes of hyperphosphatemia

Acute renal failure; hyperthyroidism; hypoparathyroidism; severe catabolic states; conditions causing hypocalcemia.

Normal magnesium level

1.5 to 2.5 mEq/L.

Causes of hypomagnesemia

Diarrhea; diuretics; decreased intake; chronic alcoholism.

Signs/symptoms of hypomagnesemia

Increased neuromuscular irritability/seizures; hyperactive DTRs; cardiac changes (arrhythmias, peaked T waves, V-tach/fib).

Treatments for hypermagnesemia

Loop diuretics; 0.45% saline with IV calcium gluconate; hemodialysis with magnesium-free dialysate.

Signs/symptoms of hypermagnesemia

Drowsiness to coma; decreased DTRs; generalized weakness; decreased respirations to arrest; cardiac changes (decreased pulse, prolonged PR, wide QRS, arrest).