Endo - Parathyroid, Primary, Secondary, Tertiary Hyperparathyroidism

Question 1

Where are the parathyroid glands located?

Answer 1

The 4 parathyroid glands are located in the 4 corners of the thyroid gland

Question 2

What does the parathyroid gland produce?

Answer 2

The chief cells produce PTH in response to low blood calcium (hypocalcaemia)

Question 3

What are the 4 ways PTH work to increase blood Ca2+?

Answer 3

1. Increase intestinal absorption
2. Increase osteoclast activity in bones (resorbing calcium from bones)
3. Increasing calcium absorption from kidneys
4. Increasing vitamin D activity

Question 4

How does vitamin D increase calcium levels?

Answer 4

Vitamin D acts to increase calcium absorption from the intestines

Parathyroid hormone acts on vitamin D to convert it into active forms

So vitamin D and parathyroid hormone act together to raise blood calcium levels.

Question 5

What are the symptoms of Hypercalcaemia?

Answer 5

STONES BONES GROANS THRONES MOANS

Constipation
Polyuria and Polydipsia
Altered mental state - fatigue, psychosis, depression
Renal calculi (kidney stones)
Bone pain
N+V

Question 6

Primary hyperparathyroidism - what is it, and what are the two most common causes?

Answer 6

Uncontrolled parathyroid production by a tumour of the parathyroid glands, which leads to HYPERCALCAEMIA

80%: Solitary adenoma
15%: Hyperplasia

Question 7

Primary hyperparathyroidism - what are the clinical features?

Answer 7

Symptoms of hypercalcaemia

‘bones, stones, abdominal groans and psychic moans’

polydipsia, polyuria
peptic ulceration/constipation/pancreatitis
bone pain/fracture
renal stones
depression
hypertension

Question 8

Primary hyperparathyroidism - what are the investigations and blood results?

Answer 8

PTH Increased

Ca2+ Increased

Phosphate Decreased

Question 9

Primary hyperparathyroidism - what is definitive management?

Answer 9

Definitive management is total parathyroidectomy

Question 10

Secondary Hyperparathyroidism - what is it?

Answer 10

Insufficient vitamin D or chronic renal failure leads to low absorption of calcium from the intestines, kidneys and bones

Causes hypocalcaemia

Parathyroid gland hyperplasia occurs as a result of low calcium, as it keeps trying to secrete more PTH

Almost always occurs in a setting of chronic renal failure

Question 11

Secondary Hyperparathyroidism - calcium, PTH, Vitamin D and phosphate levels?

Answer 11

PTH - high

Phosphate - high

Calcium - low/normal

Vitamin D - low

Question 12

Secondary Hyperparathyroidism - management?

Answer 12

Correct the vitamin D deficiency

or

Perform a renal transplant to treat renal failure

Question 13

Tertiary Hyperparathyroidism - what is it?

Answer 13

When secondary hyperparathyroidism continues for long period of time, leads to hyperplasia of the glands

Baseline level of parathyroid hormone increases

When cause of secondary hyperparathyroidism is treated (CKD or VitD def), parathyroid hormone level remains inappropriately high

High level of parathyroid hormone in absence of previous pathology leads to high absorption of calcium in the intestines, kidneys and bones and causes HYPERCALCAEMIA

Question 14

Tertiary Hyperparathyroidism - what is the levels of PTH, calcium, phosphate and vitamin D?

Answer 14

PTH - high

Calcium - high

Phosphate - normal/low

vitamin D - normal/low

Question 15

Tertiary Hyperparathyroidism - management?

Answer 15

Surgically removing part of the parathyroid tissue to return the parathyroid hormone to an appropriate level

Question 16

Primary hypoparathyroidism - what is it?

Answer 16

Decreased PTH secretion

Question 17

Primary hypoparathyroidism - what is the main cause?

Answer 17

Usually occurs following thyroid surgery

Question 18

Primary hypoparathyroidism - symptoms and signs?

Answer 18

Symptoms:

1. Tetany: muscle twitching, cramping and spasm
2. Perioral paraesthesia

ECG - PROLONGED QT interval
Chvostek’s sign: tapping over parotid causes facial muscles to twitch

Question 19

Primary hypoparathyroidism - what is the blood levels of calcium and phosphate?

Answer 19

Calcium - low

Phosphate - high

Question 20

Primary hypoparathyroidism - management?

Answer 20

Alfacalcidol - analogue of vitamin D

Question 21

Pseudohypoparathyroidism - what is it?

Answer 21

Genetic condition resulting in failure of target organs to respond to normal levels of PTH

In contrast to hypoparathyroidism where there is a PTH deficiency

Normally PTH acts on bone, kidney, gut to elevate calcium levels

Question 22

Pseudohypoparathyroidism - clinical presentation?

Answer 22

Same as hypoparathyroidism

Short stature and fingers

Hypocalcaemia:
Numbness/tingling of fingers and toes
Muscle cramps
Carpopedal spasm
Seizures

Chvostek’s sign
Trousseau’s sign = inflation of a blood pressure cuff results in carpopedal spasm

Question 23

Pseudohypoparathyroidism - what are carpopedal spasms?

Answer 23

Frequent and involuntary muscle contractions in the hands and feet

Question 24

Pseudohypoparathyroidism - investigations and results?

Answer 24

Calcium - low

Phosphate - high

PTH - normal/high

Question 25

Pseudohypoparathyroidism - management?

Answer 25

Same as for hypoparathyroidism
Calcium supplementation
Vitamin D supplementation