Final Exam: Electrolytes and Acid Base Imbalances

Question 1

Normal serum electrolyte levels

Answer 1

Sodium: 135 – 145 mEq/L
Potassium: 3.5 – 5.0 mEq/L
Calcium: 4.5 – 5.5 mEq/L
Magnesium: 1.5 – 2.5 mEq/L
Phosphate: 2.5 – 4.5 mg/dL

Question 2

What is hypokalemia?

Answer 2

Denotes a decreased ion concentration in the EXTRAcellular fluid

Question 3

What are some factors that may cause hypokalemia?

Answer 3

• Alodsterone increases potassium excretion in the DCT (followed by compensated heart failure and cirrhosis by increased aldosterone levels)
• Black licorice
• Potassium sparing diuretics (prednisone and furosemide)

Question 4

What are factors that shift K+ from ECF to ICF?

Answer 4

Insulin
B adrenergic stimulation
Alkalosis (hypokalemia)

Question 5

What are factors that shift K+ from ICF to ECF?

Answer 5

Insulin deficiency
B blockers
Acidosis (hyperkalemia)
Cell lysis
Strenuous exercisie

Question 6

What are clinical manifestations of hypokalemia?

Answer 6

N&V, weakness, muscle cramps, constipation

Severe: arrhythmias, muscle necrosis, rarely paralysis with respiratory failure

Question 7

Describe the etiology of Calcium ions/ hypocalcemia

Answer 7

• Calcium ions play a role in speed of ion fluxes through nerve and muscle cell membranes
• Therefore, calcium imbalances alter normal neuromuscular excitability
  Increased NM excitability is caused by a decrease in threshold potential of excitable cells so AP are generated more easily

Question 8

What are some causes of hypocalcemia?

Answer 8

Hypoparathyroidism
Renal Failure
Vitamin D deficiency
Pancreatitis
Chronic diarrhea

Question 9

Clinical manifestations of Hypocalcemia

Answer 9

Positive Trousseau’s sign: BP cuff and thumb to wrist
Positive Chvostek’s sign: Nerve excitability, touch face and face should twitch
Paresthesia
Hyperactive reflexes
Tetany
Laryngospasm
Cardiac dysrhythmias
Seizures

Question 10

How would you improve Hypocalcemia?

Answer 10

Treat underlying cause
Increase dietary Ca2+
Severe: IV calcium gluconate

Question 11

Etiology of Hypercalcemia

Answer 11

Primary hyperparathyroidism
- common in later stages of lung, renal, breast, lymphoma and multiple myeloma

Hypercalcemia causes DECREASED NM excitability, where threshold is now elevated

Question 12

Clinical manifestations of Hypercalcemia

Answer 12

“Bones, stones, groans and psychiatric overtones”
Weakness
Nausea and Vomiting
Constipation
Psychosis
Bone pain

Question 13

Treatment of hypercalcemia?

Answer 13

Increase urinary excretion (furosemide)
Diminish bone resorption (biphosphonate drugs)
Decrease GI absorption (corticosteroids)
Last resort (dyalisis)

Question 14

What are factors that cause hypophophatemia?

Answer 14

Starvation
Malabsorption
Antacid use
Renal loss: Hyperparathyroidisim and diuretics

Question 15

Etiology and pathogenesis of Hypophosphatemia

Answer 15

Phosphate plays important component in ATP, the major source of energy. Signs and symptoms relate to decreased amounts of ATP

Question 16

Clinical manifestations of Hypophosphatemia

Answer 16

Anorexia
Malaise
Paresthesias
Diminshed refleces
Muscle aches
Confusion
Respiratory failure
Impaired cardiac function

Question 17

Treatment of Hypophosphatemia

Answer 17

Oral or IV phosphate

Question 18

What may cause hyperphosphatemia? This condition is common in what individuals?

Answer 18

Increased intake of phosphate
Common in individuals with Renal Disease

Question 19

What are the signs and symptoms of Hyperphosphatemia?

Answer 19

Increased neuromuscular excitability because oftentimes it causes hypocalcemia

• Some patients it will cause deposition of calcium leading to things like aching and stiffness of the joints

Question 20

What are causes of Hypomagnesemia?

Answer 20

Chronic alcoholism (decreased MG intake)
Starvation/ malabsorption
Excess renal loss: Hypokalemia, hypercalcemia

Question 21

Clinical manifestations of Hypomagnesemia?

Answer 21

Mg ions in ECF depress relase of ACH at NM junctions, if not enough Mg ions present excessive amounts of ACH are released.
- CM are those of increased NM excitability
- Hyperactive refexes, muscle cramps, twitching, Chovstek andd Trousseau sign

Question 22

Clinical manifestations of Hypermagnesemia?

Answer 22

Too many Mg ions in ECF depress NM function by decreasing release of ACH at NM junction
- deep tendon reflexes, lethargy, hypotension, flushing drowsiness, respiratory depressio, etc