Chapter 24: Plasma Potassium, Hyperkalemia, and Hypokalemia

Question 1

Plasma Potassium

Answer 1

• normal concentration is 3.5 to 5 mEq/L (higher in neonates)
• most of potassium is found inside the cell

Question 2

Hypokalemia

Answer 2

• decreased potassium ion concentration in extracellular fluid

Question 3

Etiology of Hypokalemia

Answer 3

• decreased intake
• shift into the cell
• increased excretion; usual renal but can be through feces, sweat, GI tract, or diuretics

Question 4

Clinical Manifestations of Hypokalemia

Answer 4

• altered smooth, skeletal, cardiac muscle function due to changes in resting membrane potential (hyperpolarization)
• abdominal symptoms such as distension, diminished bowel sounds, and paralytic ileus
• Skeletal muscle symptoms such as bilateral muscle weakness that begins in the legs, and respiratory paralysis
• cardiac symptoms such as ectopic beats, alterations in conduction, and dysrhythmias that may be severe enough to cause sudden cardiac death
• polyuria (excessive urine)

Question 5

Hyperkalemia

Answer 5

• rise of serum potassium above 5 mEq/L

Question 6

Etiology of Hyperkalemia

Answer 6

• increased potassium intake; rapid or excessive IV infusion
• Shift of potassium from cells to extracellular fluid; acidosis, crushing injuries
• Decreased potassium excretion; oliguria, potassium sparing diuretics, drugs that reduce aldosterone effects or are nephrotoxic (cause kidney damage)
• treated with 5% dextrose in water

Question 7

Clinical Manifestations of Hyperkalemia

Answer 7

• muscle dysfunction due to changes in resting membrane potential (hypopolarization)
• Early on you will see intestinal cramping and diarrhea
• Late you will see muscle weakness, ascending, beginning in the lower extremities
• cardiac dysrhythmias and even cardiac arrest
• D50 is used to replace glucose that was pushed into cell