Chapter 24: Hyponatremia & Hypernatremia

Question 1

Hyponatremia

Answer 1

• a serum sodium concentration below the lower limit of normal
• when present the extracellular fluid contains relatively too much water for the amount of sodium ions present
• extracellular fluid is more dilute than normal
• sodium is the major extracellular cation that is responsible for maintaining the osmolarity of our blood
• Normal sodium level is 135-145 mEq/L

Question 2

Etiology of Hyponatremia

Answer 2

• factors that produce a relative excess of water in proportion to salt in the extracellular fluid
• cells swell
• neurologic symptoms caused when the brain swell or when they shrink because they don’t work properly

Question 3

Other names for Hyponatremia

Answer 3

• hypotonic syndrome
• hypo - osmolality
• water intoxication

Question 4

Primary Causes of Hyponatremia

Answer 4

• a gain of relatively more water than salt (prolonged or excess release of ADH; water intake that exceeds normal limit)
• a loss of relatively more salt than water

Question 5

Clinical Manifestations of Hyponatremia

Answer 5

• Mild central nervous system dysfunction will cause malaise, anorexia, nausea, vomiting, and headache
• Severe central nervous system dysfunction will cause confusion, lethargy, seizures, coma, and fatal cerebral herniation

Question 6

Hypernatremia

Answer 6

• serum sodium concentration above upper limit of normal
• extracellular fluid contains relatively too little water for the amount of sodium ions present; it is too concentrated
• cells shrivel
• upper limit of normal for sodium = 145

Question 7

Other names for Hypernatremia

Answer 7

• Water deficit
• Hypertonic Syndrome
• Hyperosmolality

Question 8

Etiology of Hypernatremia

Answer 8

• gain of more salt than water

- lose of more water than salt

Question 9

Clinical Manifestations of Hypernatremia

Answer 9

• Mild will cause thirst, oliguria, confusion, and lethargy

- severe will cause seizures, coma, and possibly death