Potassium
Name 11 sources of potassium.
Potatoes, raisins, avocados, spinach, strawberries, oranges, bananas, cantaloupe, meat, fish, tomatoes
Name five sources of calcium.
Milk, cheese, yogurt, dark leafy greens, sardines
Name eight sources of sodium.
Milk, cheese, bacon, soy sauce, mustard, lunch meat, butter, canned food
Name nine sources of magnesium.
Milk, yogurt, cauliflower, dark leafy greens, avocados, meat, peanut butter, potatoes, raisins
List several reasons why drinking a fluid containing water, glucose and electrolytes would be better than drinking tap water after vomiting.
Electrolytes could replace lost sodium, restoring better balance in the body. Water alone would dilute electrolytes in the ECF, decreasing osmotic pressure and leading to further fluid shifts in the body. Glucose provides nutrients for the cells with a higher metabolic rate, thus reducing the risk of acidosis.
Why is any small change in potassium level considered a serious problem?
Potassium is primarily an intracellular ion, and the normal range for potassium is very low (see Ready References). Any change in the content has a significant effect. Both hyperkalemia and hypokalemia cause cardiac dysrhythmias and possible cardiac arrest.
What is the normal value of calcium?
9-10.5 mg/dL
Explain how a high concentration of sodium ions in the interstitial fluid affects intracellular fluid levels.
Fluid could be drawn out of the cells into the ISF by osmosis.
State one cause of hypomagnesemia.
Hypomagnesemia can be caused by malabsorption syndrome or malnutrition.
Compare the manifestations of hyponatremia and hypokalemia.
Hyponatremia causes a movement shift of water into cells, resulting in muscle cramps, weakness and fatigue, abdominal cramps, and nausea. Increased intracellular fluid in the nervous system causes lethargy, confusion, and headache. Hypokalemia causes muscle weakness and paresthesias, nausea, abdominal distention, and decreased bowel sounds. Hypokalemia causes serious cardiac arrhythmias, polyuria, and metabolic alkalosis.
What is the normal value of potassium?
3.5-5 mEq/L
Explain the different effects of low serum calcium on skeletal and cardiac muscle.
Hypocalcemia increases neural excitability, causing skeletal muscle spasms. Calcium is stored in skeletal muscle; therefore, it is readily available for muscle contraction. Contraction of cardiac muscle depends on the movement of calcium from the blood into muscle fibers; therefore, hypocalcemia results in a weak cardiac contraction and arrhythmias. Nerves are not involved in cardiac contraction.
Hypernatremia accompanied by an elevated hematocrit value indicates what about body fluids?
Excessive loss of water from the vascular compartment has resulted in a relatively higher proportion of sodium and RBCs in the blood.
What is the normal value of magnesium?
1.3-2.1 mEq/L
Explain why severe kidney disease may cause generalized edema.
Decreased blood flow through a diseased kidney stimulates renin secretion and increased aldosterone levels, resulting in higher sodium and water levels in the ECF (including the ISF) and general vasoconstriction, which increases vascular hydrostatic pressure. Usually plasma proteins are lost in the urine with kidney disease, causing decreased plasma osmotic pressure. If kidney disease causes a significant drop in the GFR, the resultant fluid retention increases blood volume and hydrostatic pressure.
Which patient is at risk for developing hyperkalemia and why?
a. patient with colitis
b. patient with Cushing's syndrome
c. patient overusing laxatives
d. patient who had sustained traumatic burns
Patient who has sustained a traumatic burn due to massive cell destruction
What are the signs of hypocalcemia?
decreased heart rate, hypotension, diminished peripheral pulses, irritable skeletal muscles, painful muscle spasms, hyperactive deep tendon reflexes, anxiety, hyperactive bowel sounds, increased gastric motility, cramping, diarrhea
Compare the effects of aldosterone with those of ADH on serum sodium levels.
Aldosterone would likely increase serum sodium levels or maintain a normal value if an equivalent amount of water is added. (The total amount of sodium in the body would increase.) ADH would decrease serum sodium levels because increased water reabsorption reduces the concentration of sodium.
What is a risk of taking oral magnesium?
Diarrhea, which can cause further magnesium loss
A high fever is likely to cause deep, rapid respirations, excessive perspiration, and a higher metabolic rate. How would this affect the fluid and electrolyte balance in the body?
Fluid loss would occur with hyperventilation and perspiration. Sodium loss in sweat also affects osmotic pressure of the ECF and fluid balance. A higher metabolic rate requires increased turnover of fluid.
Compare the manifestations of hyponatremia and hypokalemia.
Hyponatremia causes a movement shift of water into cells, resulting in muscle cramps, weakness and fatigue, abdominal cramps, and nausea. Increased intracellular fluid in the nervous system causes lethargy, confusion, and headache. Hypokalemia causes muscle weakness and paresthesias, nausea, abdominal distention, and decreased bowel sounds. Hypokalemia causes serious cardiac arrhythmias, polyuria, and metabolic alkalosis.
Describe the effect of each of the following conditions on serum calcium levels and on bone density: (1) hyperparathyroidism, (2) renal failure, and (3) a large intake of vitamin D.
If more sodium is lost from the extracellular fluid compartment than water, how will fluid move between the cell the interstitial fluid compartment? (think types of pressure)
The ECF or ISF has a deficit of sodium ions (lower osmotic pressure); therefore, water will tend to move into the cell (which has normal osmotic pressure)
What is the antidote for magnesium overdose?
calcium gluconate
The nurse is caring for a patient with hypocalcemia. Which patterns would the nurse watch for on the electrocardiogram?
prolonged QT interval and prolonged ST segment