Fluid & Electrolytes
Fluid and electrolyte balance is the body's ability to regulate fluid distribution between intracellular and extracellular
compartments, maintain optimal osmolality, and ensure proper electrolyte concentrations in the plasma. (Giddens)
Exemplars:
Electrolyte Imbalances
Dehydration
Fluid Volume Overload
Basic Principles of Fluid and Electrolytes
Osmosis
The movement of water molecules across a selectively permeable membrane from an area of low solute
concentration to an area of high solute concentration. The goal is to equalize solute concentrations on both sides of
the membrane.
Diffusion
A passive process where molecules (such as gases, ions, or small molecules) move from an area of higher
concentration to an area of lower concentration. This continues until an equal distribution is achieved.
Filtration
The movement of water and solutes across a membrane driven by hydrostatic pressure (typically exerted by blood
pressure). This process is essential in kidney function, allowing fluids to pass through capillaries while retaining larger
molecules like proteins.
Active Transport
The movement of molecules across a cell membrane against their concentration gradient (from low to high
concentration). This process requires energy (ATP) and relies on carrier proteins.
Fluid Compartments
Intracellular Fluid (ICF): The fluid inside cells, including cytoplasm and organelles.
Extracellular Fluid (ECF): The fluid outside cells, including interstitial fluid (between cells) and plasma (within
blood vessels).
,Tonicity & Cell Behavior
Isotonic Solution: Equal solute concentration inside and outside the cell. Water moves in and out at the same rate,
maintaining cell shape.
Hypotonic Solution: Lower solute concentration outside the cell. Water moves into the cell, causing it to swell
and possibly burst (lysis).
Hypertonic Solution: Higher solute concentration outside the cell. Water moves out of the cell, leading to cell
shrinkage (crenation).
Risk Factors for Fluid and Electrolyte Imbalances
Maintaining proper fluid and electrolyte balance is crucial for overall health. Various conditions, lifestyle factors, and
medical conditions can disrupt this balance, leading to imbalances that affect bodily functions.
🚱 Dehydration (Fluid Deficit)
Inadequate Fluid Intake: Due to nausea, vomiting, dysphagia, or limited access to water.
Excessive Fluid Loss: From sweating, diarrhea, vomiting, fever, or burns.
Increased Urination: Caused by diuretics, diabetes mellitus, or diabetes insipidus.
Elderly Age: Reduced thirst sensation increases the risk.
Hot Climates & Strenuous Exercise: Lead to increased fluid loss through sweating.
🌊 Fluid Overload (Hypervolemia)
Kidney Failure: Reduced ability to excrete fluids.
Congestive Heart Failure (CHF): Impaired circulation leads to fluid retention.
Liver Cirrhosis: Affects fluid regulation and retention.
Excessive IV Fluid Administration: Can overwhelm the body’s regulatory systems.
Hormonal Imbalances: High aldosterone levels promote fluid retention.
⚡ Sodium Imbalances (Na⁺)
🔺 Hypernatremia (High Sodium Levels)
Dehydration: Insufficient water intake or excessive water loss.
Diabetes Insipidus: Causes excessive water loss.
Excessive Sodium Intake: High dietary sodium or excessive saline infusions.
Osmotic Diuretics: Increase water loss, leading to higher sodium concentration.
, 🔻 Hyponatremia (Low Sodium Levels)
Excessive Water Intake: Dilutes sodium levels in the blood.
SIADH (Syndrome of Inappropriate ADH): Leads to water retention.
Diuretic Use: Especially thiazide diuretics, which promote sodium loss.
Severe Vomiting or Diarrhea: Causes sodium depletion.
Heart Failure or Liver Disease: Affects sodium and water balance.
🦴 Calcium Imbalances (Ca²⁺)
🔺 Hypercalcemia (High Calcium Levels)
Hyperparathyroidism: Excess parathyroid hormone increases calcium levels.
Cancer: Bone metastases or certain tumors raise calcium levels.
Excessive Vitamin D Intake: Enhances calcium absorption.
Prolonged Immobilization: Leads to bone breakdown and calcium release.
🔻 Hypocalcemia (Low Calcium Levels)
Vitamin D Deficiency: Impairs calcium absorption.
Hypoparathyroidism: Decreased parathyroid hormone reduces calcium levels.
Chronic Kidney Disease: Reduces calcium reabsorption.
Magnesium Deficiency: Affects parathyroid hormone function.
Pancreatitis: Calcium binds with fats, lowering blood calcium levels.
🍌 Potassium Imbalances (K⁺)
🔺 Hyperkalemia (High Potassium Levels)
Kidney Failure: Impaired potassium excretion.
Potassium-Sparing Diuretics: (e.g., spironolactone) Reduce potassium loss.
Adrenal Insufficiency: Low aldosterone reduces potassium excretion.
Excessive Potassium Intake: From diet or IV infusions.
Tissue Damage: Burns, trauma, or hemolysis release intracellular potassium.
🔻 Hypokalemia (Low Potassium Levels)
Diuretic Use: Loop and thiazide diuretics promote potassium loss.
Severe Vomiting or Diarrhea: Leads to potassium depletion.
Fluid and electrolyte balance is the body's ability to regulate fluid distribution between intracellular and extracellular
compartments, maintain optimal osmolality, and ensure proper electrolyte concentrations in the plasma. (Giddens)
Exemplars:
Electrolyte Imbalances
Dehydration
Fluid Volume Overload
Basic Principles of Fluid and Electrolytes
Osmosis
The movement of water molecules across a selectively permeable membrane from an area of low solute
concentration to an area of high solute concentration. The goal is to equalize solute concentrations on both sides of
the membrane.
Diffusion
A passive process where molecules (such as gases, ions, or small molecules) move from an area of higher
concentration to an area of lower concentration. This continues until an equal distribution is achieved.
Filtration
The movement of water and solutes across a membrane driven by hydrostatic pressure (typically exerted by blood
pressure). This process is essential in kidney function, allowing fluids to pass through capillaries while retaining larger
molecules like proteins.
Active Transport
The movement of molecules across a cell membrane against their concentration gradient (from low to high
concentration). This process requires energy (ATP) and relies on carrier proteins.
Fluid Compartments
Intracellular Fluid (ICF): The fluid inside cells, including cytoplasm and organelles.
Extracellular Fluid (ECF): The fluid outside cells, including interstitial fluid (between cells) and plasma (within
blood vessels).
,Tonicity & Cell Behavior
Isotonic Solution: Equal solute concentration inside and outside the cell. Water moves in and out at the same rate,
maintaining cell shape.
Hypotonic Solution: Lower solute concentration outside the cell. Water moves into the cell, causing it to swell
and possibly burst (lysis).
Hypertonic Solution: Higher solute concentration outside the cell. Water moves out of the cell, leading to cell
shrinkage (crenation).
Risk Factors for Fluid and Electrolyte Imbalances
Maintaining proper fluid and electrolyte balance is crucial for overall health. Various conditions, lifestyle factors, and
medical conditions can disrupt this balance, leading to imbalances that affect bodily functions.
🚱 Dehydration (Fluid Deficit)
Inadequate Fluid Intake: Due to nausea, vomiting, dysphagia, or limited access to water.
Excessive Fluid Loss: From sweating, diarrhea, vomiting, fever, or burns.
Increased Urination: Caused by diuretics, diabetes mellitus, or diabetes insipidus.
Elderly Age: Reduced thirst sensation increases the risk.
Hot Climates & Strenuous Exercise: Lead to increased fluid loss through sweating.
🌊 Fluid Overload (Hypervolemia)
Kidney Failure: Reduced ability to excrete fluids.
Congestive Heart Failure (CHF): Impaired circulation leads to fluid retention.
Liver Cirrhosis: Affects fluid regulation and retention.
Excessive IV Fluid Administration: Can overwhelm the body’s regulatory systems.
Hormonal Imbalances: High aldosterone levels promote fluid retention.
⚡ Sodium Imbalances (Na⁺)
🔺 Hypernatremia (High Sodium Levels)
Dehydration: Insufficient water intake or excessive water loss.
Diabetes Insipidus: Causes excessive water loss.
Excessive Sodium Intake: High dietary sodium or excessive saline infusions.
Osmotic Diuretics: Increase water loss, leading to higher sodium concentration.
, 🔻 Hyponatremia (Low Sodium Levels)
Excessive Water Intake: Dilutes sodium levels in the blood.
SIADH (Syndrome of Inappropriate ADH): Leads to water retention.
Diuretic Use: Especially thiazide diuretics, which promote sodium loss.
Severe Vomiting or Diarrhea: Causes sodium depletion.
Heart Failure or Liver Disease: Affects sodium and water balance.
🦴 Calcium Imbalances (Ca²⁺)
🔺 Hypercalcemia (High Calcium Levels)
Hyperparathyroidism: Excess parathyroid hormone increases calcium levels.
Cancer: Bone metastases or certain tumors raise calcium levels.
Excessive Vitamin D Intake: Enhances calcium absorption.
Prolonged Immobilization: Leads to bone breakdown and calcium release.
🔻 Hypocalcemia (Low Calcium Levels)
Vitamin D Deficiency: Impairs calcium absorption.
Hypoparathyroidism: Decreased parathyroid hormone reduces calcium levels.
Chronic Kidney Disease: Reduces calcium reabsorption.
Magnesium Deficiency: Affects parathyroid hormone function.
Pancreatitis: Calcium binds with fats, lowering blood calcium levels.
🍌 Potassium Imbalances (K⁺)
🔺 Hyperkalemia (High Potassium Levels)
Kidney Failure: Impaired potassium excretion.
Potassium-Sparing Diuretics: (e.g., spironolactone) Reduce potassium loss.
Adrenal Insufficiency: Low aldosterone reduces potassium excretion.
Excessive Potassium Intake: From diet or IV infusions.
Tissue Damage: Burns, trauma, or hemolysis release intracellular potassium.
🔻 Hypokalemia (Low Potassium Levels)
Diuretic Use: Loop and thiazide diuretics promote potassium loss.
Severe Vomiting or Diarrhea: Leads to potassium depletion.
