Endocrinology - Hyperparathyroidism Flashcards

1
Q

What is the normal function of the parathyroid gland?

A

Releases PTH in response to low serum calcium

PTH raises serum calcium by:

  • Increasing the absorption of calcium from the small intestine
  • Increasing the re-absorption from kidneys (reducing excretion)
  • Increasing osteoclast activity
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2
Q

What is the function of PTH?

A

PTH raises serum calcium by:

  • Increasing the absorption of calcium from the small intestine
  • Increasing the re-absorption from kidneys (reducing excretion)
  • Increasing osteoclast activity

It also acts on vitamin D to convert it to active forms- which helps to increase absorption of calcium into serum

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3
Q

What can deficiency in Vitamin D cause?

A

Hypocalcaemia

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4
Q

What is primary hyperparathyroidism?

A

Uncontrolled PTH being produced by tumour of parathyroid gland

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5
Q

What is the treatment of primary hyperthyroidism?

A

Removal of the tumour causing excess PTH release

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6
Q

What is secondary hyperparathyroidism?

A

Caused by either deficiency in vitamin D or chronic renal failure leads to:

  • Reduced calcium absorption from SI
  • Reduced calcium re-absorption from kidneys
  • Reduced absorption of calcium from bones

Leads to low calcium levels and PT glands excrete more PTH

Over time the PT gland undergoes hyperplasia due to increased need for PTH to stimulate calcium release

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7
Q

Treatment of secondary hyperparathyroidism?

A

Treat underlying cause:

  • Vitamin D supplementation
  • Renal transplant in renal failure
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8
Q

What is tertiary hyperparathyroidism?

A

Caused by long-term secondary hyperparathyroidism causing hyperplasia of the gland

The baseline amount of PTH released increases

Then when the cause of the secondary hyperparathyroidism is treated the parathyroid hormone level remains inappropriately high

Causes hypercalcaemia in the blood

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9
Q

Treatment of tertiary hyperparathyroidism?

A

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

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10
Q

High PTH

Low calcium

A

Primary hyperparathyroidism

Uncontrolled PTH release from PT gland caused by tumour

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11
Q

High PTH

Low or normal calcium

A

Secondary hyperparathyroidism

Caused by low vitamin D and CKD

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12
Q

High PTH

High Calcium

A

Tertiary hyperparathyroidism

Cause is hyperplasia due to long term secondary hyperparathyroidism

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