Flashcards on Biogenic Elements and Electrolyte Homeostasis
Biogenic Elements & Electrolyte Homeostasis: A Study Guide
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Sodium disorders
21 cards
Card 1
Question: What is the laboratory definition of hypernatremia?
Answer: Serum sodium (Na+) concentration >145 mmol/L.
Card 2
Question: What does hypernatremia reflect about body water and sodium?
Answer: A water deficit relative to total body sodium, associated with serum hypertonicity; total body sodium may be increased, decreased, or normal.
Card 3
Question: Why must a patient's volume status be assessed in hypernatremia?
Answer: Because hypernatremia can occur with hypovolemia, euvolemia, or hypervolemia and the etiology and management depend on volume status.
Card 4
Question: What common mechanisms typically lead to hypernatremia?
Answer: Failure of the thirst mechanism or limited/controlled access to free water.
Card 5
Question: How do clinical manifestations of hypernatremia relate to serum osmolality?
Answer: Most signs and symptoms are nonspecific and result from increased serum osmolality affecting the CNS (cellular dehydration).
Card 6
Question: List common CNS and systemic symptoms of hypernatremia in adults.
Answer: Lethargy, irritability, restlessness, thirst, muscle irritability/spasticity, hyperreflexia, seizures, coma, and death.
Card 7
Question: Why must severe hypernatremia be corrected slowly?
Answer: Rapid correction causes water to move suddenly into brain cells, risking cerebral swelling and brain damage; therefore correction must be careful and
Card 8
Question: Give an example situation that can produce very high blood sodium concentrations.
Answer: Severely dehydrated persons rescued from ocean or desert survival situations often have very high blood sodium concentrations.
Card 9
Question: What are the two main mechanisms that cause hyponatremia described in the content?
Answer: Dilutional hyponatremia (excess body water) and depleting hyponatremia (greater loss of Na+ than water).
Card 10
Question: List common causes of dilutional (excess body water) hyponatremia.
Answer: Drinking excess water, renal failure, cardiac insufficiency, ascites, chronic cardiac failure, uncompensated diabetes, liver cirrhosis, nephrotic synd