Hyponatremia

Question 1

What is hyponatremia?

Answer 1

Serum sodium level under 135 mEq/L

Question 2

What are sodium imbalances usually associated with?

Answer 2

Fluid volume imbalances.

Question 3

What are three basic causes of hyponatremia?

Answer 3

Increased sodium excretion
Inadequate sodium intake
Dilution of serum sodium

Question 4

What causes increased sodium excretion? (7)

Answer 4

Excessive diaphoresis
Diuretics
Vomiting
Diarrhea
Wound drainage, especially GI
Kidney disease
Decreased secretion of aldosterone

Question 5

What causes inadequate sodium intake? (2)

Answer 5

Fasting, NPO status

Low-salt diet

Question 6

What causes dilution of serum sodium? (6)

Answer 6

Excessive ingestion of hypotonic fluids or irrigation with hypotonic fluids
Kidney disease
Freshwater drowning
Syndrome of inappropriate antidiuretic hormone secretion
Hyperglycemia
Heart Failure

Question 7

What are the cardiovascular signs and symptoms of hyponatremia in a normovolemic patient?

Answer 7

Rapid pulse rate, normal blood pressure

Question 8

What are the cardiovascular signs and symptoms of hyponatremia in a hypovolemic patient? (4)

Answer 8

Thready, weak, rapid pulse rate
Hypotension
Flat neck veins
Normal or low central venous pressure

Question 9

What are the cardiac signs and symptoms of hyponatremia in a hypervolemic patient? (3)

Answer 9

Rapid, bounding pulse
Blood pressure normal or elevated
Normal or elevated central venous pressure

Question 10

What are the respiratory signs and symptoms of hyponatremia?

Answer 10

Shallow, ineffective respiratory movement is a late manifestation related to skeletal muscle weakness

Question 11

What are the neuromuscular signs and symptoms of hyponatremia? (2)

Answer 11

Generalized skeletal muscle weakness that is worse in the extremities
Diminished deep tendon reflexes.

Question 12

What are the central nervous system signs and symptoms of hyponatremia? (5)

Answer 12

Headache
Personality changes
Confusion
Seizures
Coma

Question 13

What are the gastrointestinal signs and symptoms of hyponatremia? (3)

Answer 13

Increased motility and hyperactive bowel sounds
Nausea
Abdominal cramping and diarrhea

Question 14

What are the renal signs and symptoms of hyponatremia?

Answer 14

Increased urinary output

Question 15

What are the integumentary signs and symptoms of hyponatremia?

Answer 15

Dry mucous membranes.

Question 16

What are the laboratory findings that indicate hyponatremia? (2)

Answer 16

Serum sodium level less than 135 mEq/L

Decreased urine specific gravity

Question 17

What intervention should be implemented if the hyponatremia is accompanied by fluid volume deficit?

Answer 17

IV sodium chloride infusions are administered to restore sodium content and fluid volume

Question 18

What intervention should be implemented if the hyponatremia is accompanied by a fluid volume excess?

Answer 18

Osmotic diuretics are administered to promote the excretion of water rather than sodium

Question 19

What intervention should be implemented if hyponatremia is caused by inappropriate or excessive secretion of antidiuretic hormone?

Answer 19

Medications that antagonize antidiuretic hormone may be administered.

Question 20

What is the interaction between hyponatremia and lithium?

Answer 20

Hyponatremia can cause diminished lithium excretion, resulting in toxicity