Fluid_and_Electrolytes_Flashcards
(100 cards)
What is the percentage of water in total body weight for women?
50% of body weight.
What are the two major compartments of body fluids?
Intracellular fluid (ICF) and extracellular fluid (ECF).
What determines fluid movement between intravascular and interstitial spaces?
Starling forces: capillary hydraulic pressure and colloid osmotic pressure.
What is the primary extracellular cation?
Sodium (Na+).
What role does vasopressin (AVP) play in water balance?
AVP regulates renal water reabsorption to maintain osmolality.
What is the osmolality threshold for AVP release?
285 mOsm/kg.
Name two major disorders of water balance.
Diabetes insipidus and SIAD (syndrome of inappropriate antidiuresis).
What is the effect of AVP on the renal collecting duct?
Increases water permeability, facilitating water reabsorption.
What is the function of the Na+/K+ ATPase pump?
Maintains intracellular and extracellular ion gradients.
What are the primary causes of hypovolemia?
Renal or nonrenal fluid losses such as diarrhea, vomiting, or burns.
How is hypovolemia diagnosed?
Clinical signs like orthostatic hypotension and lab tests (urine Na+).
What is the treatment for severe hypovolemia?
Intravenous isotonic saline or plasma expanders.
What is the plasma Na+ threshold for hypernatremia?
Plasma Na+ >145 mM.
What are common causes of renal water loss leading to hypernatremia?
Osmotic diuresis (e.g., hyperglycemia, mannitol).
How is hyponatremia defined?
Plasma Na+ <135 mM.
What are the clinical features of severe hyponatremia?
Cerebral edema, seizures, and confusion.
What is the primary treatment for SIAD-related hyponatremia?
Fluid restriction and/or AVP receptor antagonists.
What is the risk of overly rapid correction of chronic hyponatremia?
Osmotic demyelination syndrome (ODS).
What are key causes of euvolemic hyponatremia?
SIAD, hypothyroidism, secondary adrenal insufficiency.
What is the urine osmolality cutoff for polydipsia-related hyponatremia?
Less than 100 mOsm/kg.
What is the percentage of water in total body weight for women?
50% of body weight.
What are the two major compartments of body fluids?
Intracellular fluid (ICF) and extracellular fluid (ECF).
What determines fluid movement between intravascular and interstitial spaces?
Starling forces: capillary hydraulic pressure and colloid osmotic pressure.
What is the primary extracellular cation?
Sodium (Na+).
