Week 11: Calcium

Question 1

What is important for regulating Calcium, Mg and Phosphate?

Answer 1

Parathyroid hormone
vitamin D
calcitonin

Question 2

Normal Ca serum values:

Answer 2

8.8-10.5 mg/dL

Question 3

What acts together to control Calcium absorption and excretion?

Answer 3

parathyroid hormone, vitamin D3, and calcitonin act together to control calcium absorption and excretion

Question 4

What is the function of calcium?

Answer 4

• maintain structure of bones and teeth
• enzymatic cofactor for blood clotting
• needed for hormone secretion and function of cell receptors
• related to plasma membrane stability and permeability
• transmission of nerve impulses, and contraction of muscles

Question 5

Hypercalcemia

Answer 5

serum concentrations greater than 10-12

Question 6

Causes of hypercalcemia:

Answer 6

Hyperparathyroidism;
bone metastases with calcium resorption from breast, prostate, renal, and cervical cancer;
sarcoidosis;
excess vitamin D;
many tumors that produce PTH

Question 7

Effects of hypercalcemia

Answer 7

fatigue,
weakness,
lethargy,
anorexia,
nausea,
constipation;
impaired renal function,
kidney stones;
dysrhythmias,
bradycardia,
cardiac arrest;
bone pain,
osteoporosis

Question 8

Hypocalcemia

Answer 8

(serum calcium concentration <8.5 mg/dL)

Question 9

Causes of Hypocalcemia

Answer 9

Related to inadequate intestinal absorption,

deposition of ionized calcium into bone or soft tissue,
blood administration, or
decreases in PTH and vitamin D; nutritional deficiencies occur with inadequate sources of dairy products or green leafy vegetables

Question 10

Effects of hypocalcemia:

Answer 10

neuromuscular excitability;
tingling,
muscle spasm (particularly in hands, feet, and facial muscles),
intestinal cramping,
hyperactive bowel sounds;
severe cases show convulsions and tetany;
prolonged QT interval,
cardiac arrest

Question 11

Mg normal serum values

Answer 11

Serum: 1.8-3.0

Question 12

What does Mg do with enzymatic reactions?

Answer 12

Cofactor in intracellular enzymatic reactions

Question 13

Mg function

Answer 13

Cofactor in intracellular enzymatic reactions and

causes neuromuscular excitability; often interacts with calcium and potassium in reactions at cellular level and has important role in smooth muscle contraction and relaxation;

Question 14

What does Mg interact with at cellular level?

Answer 14

often interacts with calcium and potassium in reactions at cellular level

Question 15

Functions of Mg:

Answer 15

causes neuromuscular excitability;

important role in smooth muscle contraction and relaxation;

Question 16

Where is Mg absorbed and eliminated

Answer 16

magnesium is absorbed in the intestine and eliminated by the kidney

Question 17

Hypermagnesemia

Answer 17

(serum concentrations >3.0 mEq/L)

Question 18

Causes of hypermagnesemia

Answer 18

renal insufficiency or failure;

excessive intake of magnesium-containing antacids, adrenal insufficiency

Question 19

Effects of hypermagnesemia

Answer 19

Skeletal smooth muscle contraction;

excess nerve function;

loss of deep tendon reflexes;

nausea and vomiting;

muscle weakness;

hypotension;
bradycardia;
respiratory distress

Question 20

Hypomagnesemia

Answer 20

(serum magnesium concentration <1.5 mEq/L)

Question 21

Causes of hypomagnesemia

Answer 21

Malnutrition,

malabsorption syndromes,

alcoholism,

urinary losses (renal tubular dysfunction, loop diuretics)

Question 22

Effects of Hypomagnesemia

Answer 22

Behavioral changes,

irritability,

increased reflexes,

muscle cramps,

ataxia,

nystagmus,

tetany,

convulsions,

tachycardia,

hypotension

Question 23

Treatment for hypomagnesemia

Answer 23

IV administration of Mag. sulfate

Question 24

Treatment for hypermagnesemia

Answer 24

Calcium gluconate