Hyperparathyroidism

Question 1

Aetiology of hyperparathyroidism:

Answer 1

Primary hyperparathyroidism

Secondary hyperthyroidism

Tertiary hyperparathyroidism

Question 2

primary hyperparathyroidism?

Answer 2

caused by uncontrolled parathyroid hormone produced directly by a tumour of the parathyroid glands. This leadshypercalcaemia: an abnormally high level of calcium in the blood.

Question 3

secondary hyperthyroidism

Answer 3

• This is where insufficientvitD orchronic renal failureleads to low absorption of calcium from the intestines, kidneys and bones. This causeshypocalcaemia: a low level of calcium in the blood.
• The parathyroid glands reacts to the low serum calcium by excreting more parathyroid hormone. Over time the total number of cells in the parathyroid glands increase as they respond to the increased need to produce parathyroid hormone. This is calledhyperplasia. The glands become more bulky. The serum calcium level will be low or normalbut theparathyroid hormone will be high.

Question 4

Tertiary hyperparathyroidism

Answer 4

This happen whensecondary hyperparathyroidism continues for a long period of time. It leads tohyperplasia of the glands. Thebaseline level of parathyroid hormone increases dramatically. Then when the cause of the secondary hyperparathyroidism is treated the parathyroid hormone level remains inappropriately high. This high level of parathyroid hormone in the absence of the previous pathology leads to high absorption of calcium in the intestines, kidneys and bones and causeshypercalcaemia.

Question 5

Pathophysiology of hyperparathyroidism

Answer 5

There arefourparathyroid glandssituated in four corners of the thyroid gland. The parathyroid glands, specifically thechief cellsin the glands, produce parathyroid hormone in response tohypocalcaemia*(low blood calcium).

PTH acts toraise blood calciumlevel by:

• Increasingosteoclast activity in bones (reabsorbing calcium from bones)
• Increasing calcium absorption from the gut
• Increasing calcium absorption from the kidneys
• Increasingvitamin Dactivity

Vitamin D acts to increase calcium absorption from the intestines.Parathyroid hormoneacts onvitamin Dto convert it into active forms. So vitamin D and parathyroid hormone act together to raise blood calcium levels.

Question 6

Clinical presentation of hyperparathyroidism

Answer 6

“renal stones, painful bones, abdominal groans and psychiatric moans” mnemonic for the symptoms of hypercalcaemia:

• Renal stones
• Painful bones
• Abdominal groans refers to symptoms of constipation, nausea and vomiting
• Psychiatric moans refers to symptoms of fatigue, depression and psychosis

Question 7

Investigation/diagnosis of hyperparathyroidism

Answer 7

Primary: cause = tumour, PTH = high, Calcium = high

Secondary: cause = low vitamin D or CKD, PTH = high, Calcium = low/normal

Tertiary: cause= hyperplasia, PTH = high, calcium = high

Question 8

Treatment of hyperparathyroidism:

Answer 8

• primary → This is treated bysurgically removing the tumour
• secondary → This is treated by correcting the vitamin D deficiency or performing a renal transplant to treat renal failure.
• tertiary → This is treated bysurgically removing part of the parathyroid tissue to return the parathyroid hormone to an appropriate level.