Disrupted Homeostasis: Fluid, Electrolyte, and Acid-Base Imbalances

Comprehensive vocabulary flashcards covering the pathophysiology, clinical presentation, and nursing management of fluid, electrolyte, and acid-base imbalances.

Intracellular Fluid (ICF)

The body fluid compartment contained within the cells, comprising approximately $\frac{2}{3}$ of total body fluid.

Extracellular Fluid (ECF)

The fluid outside the cells, comprising approximately $\frac{1}{3}$ of total body fluid, consisting of approximately $80\%$ interstitial fluid and $20\%$ plasma.

Diffusion

The passive transport mechanism involving the movement of solutes across a membrane from an area of greater concentration to an area of lesser concentration.

Osmosis

The movement of water across a semipermeable membrane from a dilute solution (low solute concentration) to a more concentrated solution (high solute concentration).

Filtration

The fluid movement mechanism where hydrostatic pressure overcomes opposing osmotic pressure, driving fluid across vascular membranes.

Fluid Volume Deficit (FVD)

A condition of negative fluid balance, dehydration, or volume depletion caused by physiologic fluid losses (such as GI losses, burns, excessive sweating, and third-spacing) or disease states.

Fluid Volume Excess (FVE)

An isotonic volume expansion characterized by abnormal retention of water and sodium, commonly resulting from heart failure, liver cirrhosis, kidney disease or injury, or excessive intravenous therapy.

Fluid Extravasation in Heart Failure

The movement of fluid into the interstitial space caused by venous congestion and high hydrostatic capillary pressure following reduced cardiac output and subsequent activation of the sympathetic nervous system, RAAS, and vasopressin.

Hypernatremia

An elevated serum sodium concentration resulting from hypertonic sodium gain, pure water loss, or hypotonic fluid loss.

Hyponatremia

A low serum sodium concentration that can present across three distinct volume classifications: hypovolemic, euvolemic, or hypervolemic.

Hypokalemia

A subnormal serum potassium concentration resulting from increased renal or GI losses, aldosterone release, intracellular uptake (via insulin or alkalosis), or non-potassium-sparing diuretics.

Hyperkalemia

An elevated serum potassium level caused by extracellular potassium shifts (metabolic acidosis, DKA), cellular destruction (rhabdomyolysis, multiple transfusions), renal insufficiency, or medications such as ACE inhibitors.

Hypomagnesemia

A decreased serum magnesium level resulting from decreased intake, excessive sweating, or GI and renal losses, often accompanied by impaired absorption due to phytic acid, PPIs, calcium, phosphates, or fats.

Hypermagnesemia

An elevated serum magnesium level typically caused by renal disease with a creatinine clearance less than $20\,\text{mL/min}$ or excessive intake of magnesium-containing antacids and laxatives, which can cause confusion at levels greater than $7\,\text{mEq/L}$.

Hypocalcemia

A serum calcium deficit triggered by decreased parathyroid hormone, surgical injury or removal of the parathyroid gland, renal failure, sepsis, low vitamin D, or alkalosis, presenting with prolonged QT interval, paresthesias, and tetany.

Osteoporosis

A chronic bone disease characterized by structural weakening, increased porosity, and reduced bone mass that is associated with prolonged hypocalcemia.

Chvostek's Sign

A clinical manifestation of tetany and hypocalcemia characterized by unilateral twitching of the facial muscles elicited by tapping the facial nerve anterior to the ear.

Trousseau's Sign

A diagnostic sign of latent tetany and hypocalcemia demonstrated by carpopedal spasm of the wrist and hand triggered by ischemia during blood pressure cuff inflation.

Hypercalcemia

An elevated serum calcium level primarily resulting from hyperparathyroidism, malignancies, or hypervitaminosis D, which causes encephalitis at levels greater than $14\,\text{mg/dL}$ and becomes life-threatening at levels greater than $15\,\text{mg/dL}$.

Metabolic Acidosis

An acid-base disturbance characterized by an arterial pH below $7.35$ and a decreased serum bicarbonate level, resulting from bicarbonate loss, acid ingestion, or increased endogenous acid production such as in diabetic ketoacidosis.

Metabolic Alkalosis

An acid-base disorder marked by an arterial pH above $7.45$ and an elevated serum bicarbonate level, caused by GI or renal loss of hydrogen ions, intracellular hydrogen shifting, or bicarbonate retention.

Respiratory Acidosis

An acid-base imbalance characterized by an arterial pH below $7.35$ and an elevated serum carbon dioxide ($\text{CO}_2$) concentration due to alveolar hypoventilation or increased physiologic dead space.

Respiratory Alkalosis

An acid-base disorder characterized by an arterial pH above $7.45$ and a decreased serum carbon dioxide ($\text{CO}_2$) concentration caused by alveolar hyperventilation, resulting in reduced carbonic acid and cerebral vasoconstriction.