Biochemistry

Question 1

What does increased PTH do to bones?

Answer 1

Increase resorption of bone.

Question 2

What does increased PTH do to kidneys?

Answer 2

Increases calcium reabsorption.

Question 3

What does increased PTH do to the intestines?

Answer 3

Increases GI calcium absorption.

Question 4

What three things can cause primary hyperparathyroidism?

Answer 4

Benign adenoma, hyperplasia or rarely a malignant neoplasm.

Question 5

What does overproduction of PTH cause?

Answer 5

Hypercalcaemia.

Question 6

What are the signs and symptoms of hypercalcaemia?

Answer 6

Fatigue, depression, bone pain, myalgia, nausea, thirst, polyuria, renal stones, osteoporosis.

Question 7

What serum results can we expect in hyperparathyroidism?

Answer 7

PTH elevated, high calcium and normal to low phosphate.

Question 8

What is secondary hyperparathyroidism?

Answer 8

Physiological overproduction of PTH secondary to hypocalcaemia caused by vitamin D deficiency or CKD.

Question 9

What is tertiary hyperparathyroidism?

Answer 9

Patients wit chronic secondary hyperparathyroidism who develop an adenoma and continue to make PTH despite chemical correction.

Question 10

What can hyperparathyroidism cause in bones?

Answer 10

Fragility fractures or lytic lesions.

Question 11

What are two other names for lytic lesions in bone?

Answer 11

Browns tumours or osteitis fibrosa cystica.

Question 12

What treatment might lytic bone lesions require?

Answer 12

Skeletal stabilisation.

Question 13

What hormone is made in high levels in hyperparathyroidism?

Answer 13

Parathyroid hormone.

Question 14

What are the treatments for hyperparathyroidism?

Answer 14

Removal of adenomatous gland or treatment of underlying cause e.g. Vitamin D supplement. Hypercalcaemia needs emergency treatment e.g. Bisphosponates, IV fluids and calcitonin.

Question 15

What condition results in renal dystrophy?

Answer 15

Chronic kidney disease.

Question 16

What are the changes we see in renal dystrophy?

Answer 16

Reduced phosphate excretion and inactive activation of vitamin D.

Question 17

What do the changes see in renal dystrophy result in?

Answer 17

Secondary hyperparathyroidism leading to osteomalacia, bone sclerosis and calcification of soft tissues.

Question 18

What does pagets disease cause?

Answer 18

Thickened, brittle and mis-shapen bones.

Question 19

How many bones does Pagets normally effects and what ones are they?

Answer 19

Only one or a few bones typically. Bones commonly include: the pelvis, femur, skull, tibia and sometimes the ear ossicles.

Question 20

What happens if Pagets affects the ear ossicles?

Answer 20

Conductive deafness.

Question 21

What are the possible causes of Pagets?

Answer 21

Genetic or viral (paramyxoviruses)

Question 22

What happens to osteoclasts in Pagets?

Answer 22

Activity increases resulting in increased bone turnover.

Question 23

What happens to osteoblasts in Pagets?

Answer 23

They become more active to try and correct excessive bone resorption. The new bone fails to remodel properly and results in increased bone thickness and brittleness.

Question 24

What can Pagets cause?

Answer 24

It can be asymptomatic, cause arthritis if it near the joint, pathological fractures, deformity, pain and high output cardiac failure (due to increased output through pagetic bone).

Question 25

What serum results would we expect in Pagets?

Answer 25

Raised alkaline phosphatase with calcium and phosphate usually being normal.

Question 26

What radiological features do we see in Pagets?

Answer 26

Enlarged bone with thickened cortices and coarse thickened trabeculae with mixed areas of lysis and sclerosis. Bone scans show marked increased uptake in the affected bone.

Question 27

What is the treatment for Pagets?

Answer 27

Bisphosponates to inhibit osteoclasts.
Calcitonin if there is extensive lysis.
Joint replacement
Stabilisation of pathological femoral fractures with long intramedullary nails or plates.