Parathyroid Flashcards
What cells release PTH?
Parathyroid chief cells
What is the effect of PTH on serum calcium and how does this happen?
Parathyroid hormone acts to raise blood calcium level by:
Increasing osteoclast activity in bones (reabsorbing calcium from bones)
Increasing calcium absorption from the gut
Increasing calcium absorption from the kidneys
Activates vit D which increases intestinal absorption
What happens to serum calcium levels in hyperparathyroidism?
Hypercalcaemia
What are the symptoms of hypercalcaemia?
Renal stones
Painful bones
Abdominal groans- constipation, nausea and vomiting
Psychiatric moans- fatigue, depression and psychosis
Briefly describe primary hyperparathyroidism
inc cause
Uncontrolled parathyroid hormone is produced directly by a tumour of the parathyroid glands
Briefly describe secondary hyperparathyroidism pathophysiology
This is where insufficient vitamin D or chronic renal failure leads to low absorption of calcium from the intestines, kidneys and bones. This causes hypocalcaemia.
The parathyroid glands reacts to the low serum calcium by excreting more parathyroid hormone. Over time hyperplasia occurs in the parathyroid glands increase as cells respond to the increased need to produce parathyroid hormone. The glands become more bulky.
What is the serum calcium level and PTH level in secondary hyperparathyroidism?
The serum calcium level will be low or normal.
The parathyroid hormone will be high.
How is secondary hyperparathyroidism treated?
Correcting the vitamin D deficiency or performing a renal transplant to treat renal failure.
Briefly describe the cause of tertiary hyperparathyroidism
When the cause of secondary hyperparathyroidism is treated but the baseline PTH remains high due to the hyperplasia that occurred in the parathyroid.
How is tertiary hyperparathyroidism treated?
Surgically removing part of the parathyroid tissue
What happens to calcium in tertiary hyperparathyroidism?
The 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 causes hypercalcaemia.
