Electrolyte Homeostasis and Imbalances

  1. What chemicals/situations shift K+ into cells from the plasma?
    • Insulin
    • Epinephrine
    • Alkalosis (H+ ions leave cells which drives K+ ions in)
    • TPN (large amounts of carbohydrate and amino acid put into the blood, which causes release of insulin, which puts the K+ into the cells)
    • Hypothermia (cold triggers the sympathetic nervous system to release epinephrine, which puts K+into cells.)
  2. Factors which cause K+ excretion
    • Diarrhea
    • Aldosterone (retains Na+ and H20, excretes K+)
    • NG tube
    • Glucocorticoid excess
    • Diuretics
    • Hypomagnesia
    • Aldosterone excess (or black licorice)
  3. Plasma Potassium Imbalances
    • Hypokalemia: low K+ in the blood/plasma
    • Hyperkalemia: high K+ in the blood/plasma

    Measurements don't reflect how much is in the whole body because some is in the cells (might have enough, too much, or not enough in the cells.)
  4. Causes of Hypokalemia
    • Increased excretion
    • Loss through abnormal routes
    • Shift from plasma to cells
    • Decreased intake
  5. Signs and Symptoms of Hypokalemia
    • Abdominal distention
    • Decreased bowel sounds
    • Constipation
    • Paralytic ileus
    • Polyuria
    • Orthostatic hypotension
    • Flaccid skeletal muscle weakness (bilateral)
    • Flaccid paralysis
    • Cardiac dysrhythmias
  6. Teaching for Hypokalemia
    • Safe weight-loss diets
    • Bowel management to prevent diarrhea with laxative use
    • Increased Potassium intake to match abnormal loss
    • Potassium-rich foods list.
  7. What chemicals/situations shift K+ from cells into the plasma?
    • Acidosis due to mineral acids (e.g., caused by bicarbonate loss from diarrhea)
    • Tissue injury or massive cell death (includes cytotoxic drugs)
    • Insulin deficiency (untreated diabetes, diabetic ketoacidosis)
    • Massive overdose of digitalis glycosides such as digoxin (Lanoxin) (beyond the scope of this course)
    • Beta-adrenergic blockade and excessive strenuous exercise
  8. Signs and Symptoms of Hyperkalemia
    • Intestinal cramping and diarrhea
    • Flaccid skeletal muscle weakness
    • Flaccid paralysis
    • Cardiac dysrythmias
    • Cardiac arrest
  9. Teaching for Hyperkalemia
    • Stop K+ containing preparation if urine output decreases
    • Keep KCl away from children/grandchildren
    • Reduce intake of potassium-rich foods
  10. Forms of Ca2+ in the Blood
    • Bound to plasma proteins
    • Bound to small organic anions
    • Free ionized (the only physiologically active form)
  11. What is the normal function of parathyroid hormone with regard to calcium?
    • It removes it from the bone and puts it in the blood.
    • It regulates blood calcium levels.
  12. Risk Factors for hypocalcemia
    • Burns: fluid loss in fluid seeping from burn wounds
    • Rapid infusion of protinaceaous plamsa expanders: osmotically pulls fluid
    • Steatorrhea: fat in stools binds calcium (from the diet and from the digestive secretions), which is excreted with the stool
  13. What is the Chvostek sign? What does positive mean?
    Positive Chvostek sign means there is increased neurvous hyperexcitability, possibly from hypocalcemia or hypomagnesemia.

    It is an abnormal reaction of the facial nerve to stimulation.
  14. Signs and Symptoms of Hypocalcemia
    • Positive Chvostek sign, positive Trousseau sign
    • Muscle twitching, cramping
    • Grimacing
    • Perioral and digital paresthesias
    • Carpopedal spasm
    • Tetany
    • Laryngospasm
    • Seizures
    • Cardiac dysrrhythmias
  15. Signs and Symptoms of Hypercalcemia
    • Anorexia
    • Constipation
    • Nausea and emesis
    • Muscle weakness, fatigue
    • Confusion, lethargy
    • Personality and mood changes
    • Polyuria
  16. Which disorders are "twitchy"
    • Hypocalcemia
    • Hypomagnesia
  17. Which disorders are "floppy"
    • Hypercalcemia
    • Hypermagnesia
  18. Forms of Mg2+ in the blood
    • Bound to plasma proteins
    • Bound to small organic anions
    • Free ionized (the only physiologically active form)
  19. Signs and Symptoms of Hypomagnesemia
    • Insomnia
    • Hyperflexia
    • Positive Trousseaus and Chvostek sign
    • Skeletal muscle cramps, twitching, tremors, tetany
    • Dysphagia
    • Nystagmus
    • Seizures
    • Extreme confusion
    • Cardiac dysrythmias
  20. Signs and Symptoms of Hypermagnesemia
    • Hypotension
    • Feeling of warmth
    • Bradycardia
    • Drowsiness, lethargy
    • Weak or absent deep tendon reflexes
    • Flaccid muscle paralysis
    • Respiratory depression
    • Cardiac dysrhythmias
    • Cardiac arrest
Card Set
Electrolyte Homeostasis and Imbalances
flashcards on electrolyte homeostasis and imabalance