Hyperparathyroidism Flashcards
Where are the parathyroid glands situated?
The four corners of the thyroid gland
Which cells within the parathyroid glands secrete parathyroid hormone (PTH)?
Chief cells
The parathyroid glands release PTH in response to three things - what are these?
- Low serum calcium
- Low serum magnesium
- High serum phosphate
Describe the mechanisms by which PTH acts to increase serum calcium…
- Increases osteoclast activity, thereby increasing bone resorption
- Increases calcium reabsorption in the kidney
- Acts in the kidney to convert Vitamin D to its active form (calcitriol) which acts to increase calcium absorption in the GI tract
What is primary hyperparathyroidism? What effect does this have on serum calcium levels?
What is the most common cause? How is this treated?
Parathyroid gland directly producing too much PTH, causing hypercalcaemia
Most common cause = parathyroid tumour. This is treated by surgical removal of the tumour.
What is secondary hyperparathyroidism? What causes this?
What biochemical findings would you expect?
How is this condition treated?
This is when insufficient vitamin D or CKD leads to low absorption of calcium, leading to hypocalcaemia. The parathyroid glands then react to the low serum calcium by producing more PTH.
PTH will be high. Serum calcium will be low/normal.
This condition is managed by treating the underlying cause (e.g. correcting the vitamin D deficiency, performing a renal transplant).
What is tertiary hyperparathyroidism?
What biochemical findings would you expect?
How is this condition treated?
This happens when secondary hyperparathyroidism continues for a long time. Over time the parathyroid glands enlarge to cope with the increased demand to produce more PTH (hyperplasia).
Both PTH levels and serum calcium levels are high.
This condition is treated by surgically removing some of the parathyroid tissue.
What are the symptoms of hypercalcaemia?
Stones, bones, groans, moans:
- Renal stones
- Painful bones
- Abdominal groans
- Psychiatric moans
