Calcium Disorders

Question 1

What is the most abundant cation?

Answer 1

Calcium

Question 2

What are the physiologic functions of calcium

Answer 2

Bone mineralization
Muscle contraction
Nerve conduction, coagulations
Cell division
hormone secretion

Question 3

What are the hormones involved in calcium regulations

Answer 3

Vitamin D, PTH, and calcitonin

Question 4

Normal plasma concentration of calcium

Answer 4

8.8-10.4

Question 5

What are the names of ultrafilterable calcium

Answer 5

Citrate, phosphate, lactate, iCa

Question 6

Free ionized calcium normal levels

Answer 6

4.4-5.2

Question 7

What is the relationship between iCa and CaSRs

Answer 7

Rise in plasma iCa causes a activation of CaSRs and inhibits PTH secretion
Fall in iCa causes an inactivation of CaSRs and increases PTH secretion

Question 8

What is the function of PTH

Answer 8

Mobilizes calcium from bone stores
Increase renal reabsorption of ca
Increases conversation of vitamin D to vitamin D3 increasing intestinal absorption of ca

Question 9

What is the function of calcitonin

Answer 9

Produced by the thyroid
Opposes PTH
Inhibits osteoclast activity

Question 10

How does acid base balance and albumin effect calcium levels

Answer 10

Acidemia = increase in iCa
Alkalemia = decrease in iCa

Hypoalbuminemia = reduced calcium
Hyperalbuminemia = increased calcium

Question 11

Risk factors for hypocalcemia

Answer 11

Elderly, sepsis, ARF, blood transfusions, malnutrition, mag deficiency, shock, colloid volume resuscitation

Question 12

Causes of hypocalcemia

Answer 12

Hypoaprathyroidism
Vitamin D deficiency
Parathyroidectomy
Hungry bone syndrome
Citrate
Blood transfusions
Na bicarb
Phosphate mechanism
Rhabdo
Severe acute pancreatitis

Question 13

Neuro, cardiology, psychiatric clinical manifestations of hypocalcemia

Answer 13

Neuro: paresthesias, hyperactive reflexes, tetany, and seizures. Chvostek and Trousseau signs, laryngeal and bronchospasms
Cards: Prolonged QT, Bradycardia, hypotension, heart block, HF, Cardiac arrest
Psych: anxiety, irritability, confusion, and psychosis

Question 14

Diagnositc tests for hypocalcemia

Answer 14

iCa, mag and phos, PTH, vitamin D

Question 15

Treatment for hypocalcemia

Answer 15

IV or PO calcium
HD
Phosphate binder
Replete mag
Await metabolic acidosis correction

Question 16

Side effects from hypocalcemia treatment

Answer 16

Hypertension
Skin flushing
Nausea
Vomiting
Chest pain

Question 17

Causes of hypercalcemia

Answer 17

Hyperparathyroidism or malignancy are the main
Others include: rhabdo, immobilization, milk alkali syndrome

Question 18

Risk factors of hypercalcemia

Answer 18

Bed rest, spinal cord injury, skeletal fractures, Paget’s disease, medications (lithium, thiazide, vitamin A and D)

Question 19

Neuro, cardiology, GI, and renal manifestations of hypercalcemia

Answer 19

Neuro: muscle wasting, fatigue, depression, AMS, coma, myopathy
Cards: shortened QT interval
GI: anorexia, nausea, vomiting, and constipation
Renal: polyuria, polydipsia, renal failure

Question 20

What do suppressed PTH and vitamin D levels suggest in hypercalcemia

Answer 20

Advanced cancer

Question 21

Mild hypercalcemia level and treatment

Answer 21

<12 mg/dl
-withdraw offending agent, volume resuscitation, early mobilization

Question 22

Moderate hypercalcemia level and treatment

Answer 22

12-14 mg/dl
Volume expansion
Isotonic fluid
Loop diuretics

Question 23

Severe hypercalcemia level and treatment

Answer 23

> 14mg/dl
Emergent treatment
Remove offending cause
NSS 200-300ml/hr
Loop diuretics
Biphosphonates or calcitonin reduce bone reabsorption
Corticosteroids decrease Ca absorption
HD if refractory