Bone profile, Calcium and Phosphate

Question 1

What is the role of the osteoclast

Answer 1

To break down old bone

Question 2

What is the role of the osteoblast

Answer 2

to build new bone

Question 3

What is the main substance that makes up bone

Answer 3

Hydroxyapatite

made up of calcium, magnesium, sodium and bicarbonate as well as phosphorous

Question 4

How is phosphate metabolism maintained

Answer 4

Phosphate homeostasis is a balance between GI uptake, renal excretion/ absorption and movement in and out of bone.

Question 5

What is the relationship between calcium and phosphate - in health

Answer 5

When Calcium increases, phosphate decreases - and vice versa

Question 6

What symptoms does hyperphosphatemia present with

Answer 6

non - likely to show signs of hypocalcemia

Question 7

What are the symptoms of hypophosphatemia

Answer 7

when levels fall below 0.3 muscle weakness may occur, rhabdomyolysis, confusion seizures and rarely coma. Haemolytic anaemia may also present

Question 8

Which 2 hormones control the concentration of calcium

Answer 8

PTH - parathyroid hormone and calcitonin

Question 9

What role does vit D play in calcium homeostasis

Answer 9

essential for the utilisation of calciu,
usually, UV light is required in order for the precursors to be made into Vit D. many people are deficient,

The main action is to stimulate the gut to absorb calcium from dietary food

Question 10

When is calcium normally evaluated

Answer 10

Testing for bone disease, parathyroid issues and kidney impairment.

Question 11

If a patient has a raised PTH level what will happen to the calcium and phosphate

Answer 11

Calcium will rise and phosphate will fall.

Question 12

In renal disease what changes will be expected

Answer 12

phosphate levels will be high and calcium levels will be low

Question 13

What causes a rise in both phosphate and calcium

Answer 13

Boney Mets and bone disease

Question 14

Which protein transports 40% of all calcium within the blood

Answer 14

Albumin

Question 15

What relationship will having a raised albumin have on calcium

Answer 15

As calcium is transported within the albumin, the serum calcium will be significantly higher than normal as a proportion

Question 16

Abnormally low albumin will have what effect on serum calcium

Answer 16

proportionally the serum calcium will be lower due to having less available albumin

Question 17

What effect does pH have on calcium

Answer 17

having a raised pH will lower the ionised calcium and acidosis will increase the ionised calcium

Question 18

What is the mechanism of hypercalcemia

Answer 18

When calcium is transported into the ECF from the ICF.

Question 19

What are the primary causes of hypercalcemia

Answer 19

Cancer and primary hyperparathyroidism

Question 20

What are the signs and symptoms of hypercalcemia

Answer 20

weakness, depression, lethargy, nausea and vomiting, anorexia and renal stones.

Question 21

What is the treatment options available for hypercalcemia

Answer 21

fluid resuscitation, diuretics, calcitonin, denosumab, bisphosphonates

Question 22

What is a paraneoplastic syndrome

Answer 22

A paraneoplastic syndrome is a symptom that is the consequence of the presence of cancer in the body but is not due to the local presence of cancer cells.
It is mediated by hormones or cytokines excreted by cancer cells or by an immune response against cancer.

Question 23

What is hypocalcemia and when does it occur

Answer 23

Occurs when there is a net efflux of calcium from the ECF and may be seen in malignant disease, rhabdomyolysis, acute pancreatitis, sepsis, shock and in chronic renal disease.

Question 24

Signs and symptoms of hypocalcemia

Answer 24

paraesthesia, muscle cramps, laryngospasm, tetany and seizures. Cardiac manifestations may include a prolonged QT interval which may progress to VT or heart block

Question 25

What are the treatment options available for hypocalcemia

Answer 25

Treatment is cause specific. Fluid, acid-base and other electrolytes are managed - supplements either oral or parenteral can be employed.