Parathyroid disease Flashcards
(21 cards)
Which cells in the parathyroid produce PTH?
Chief cells
3 main ways PTH raises calcium levels
↑ absorption of calcium from intestines
↑ reabsorption of calcium from kidneys
↑ Osteoclast activity (resorption of calcium)
Role of Vitamin D in calcium homeostasis
Increases absorption of calcium from intestines, kidneys and bone
Most common cause of primary hyperparathyroidism
Adenoma of parathyroid -> uncontrolled PTH release
↑PTH ↑Calcium ↓Phosphate (PTH induces renal re-absorption of calcium but excretion of phosphate)
NOTE: PTH can be normal with a raised calcium
Symptoms of primary hyperparathyroidism
‘bones, stones, abdominal groans and psychic moans’
Bone pain/fracture
Renal stones
Ulceration/constipation/pancreatitis
depression
Polydipsia, polyuria
hypertension
Treatment of primary hyperparathyroidism
Surgical removal of parathyroid adenoma
2 most common causes of secondary hyperparathyroidism
Vit D deficiency
CKD/Chronic renal failure
Reduced calcium reabsorption -> ↑PTH
↑PTH ↓Calcium
↓Phosphate in Vit D deficiency ↑phosphate in renal failure (reduced renal clearance)
What happens overtime to PT gland in secondary hyperparathyroidism
Parathyroid hyperplasia (no of cells increase in response to PTH demand)
Treatment of secondary hyperparathyroidism
Correct underlying cause
Treat vitamin D deficiency
Renal transplant
Main cause of tertiary hyperparathyroidism
PT hyperplasia from secondary hyperthyroidism
Even when secondary hyperparathyroidism, PTH continues to be raised as continuously excreted
↑PTH ↑Calcium
Treatment of tertiary hyperparathyroidism
Surgical removal of ENLARGED glands only
Hyperparathyroidism defined as release of excess..
PTH (not calcium)
Which gene causes MEN type I
MEN1 gene
Which gene causes MEN type IIa and IIb
RET oncogene
MEN type I features
Think 3Ps
Pituitary tumour
Pancreas tumour (gastrinoma or insulinoma)
Parathyroid hyperplasia
MEN type IIa features
Think 2Ms 1P
Medullary thyroid carcinoma
Medulla of adrenal (Phaeocromocytoma)
Parathyroid hyperplasia (adenoma)
MEN type IIb features
Think 3Ms
Medullary thyroid carcinoma
Medulla of adrenal (Phaeocromocytoma)
Mucosal neuroma
Main feature of MEN type I
Hypercalcaemia
Think 3Ps - one of them is parathyroid hyperplasia -> leads to hyperparathyroidism -> increased serum calcium
If a patient is still hypocalcaemic after calcium replacement, what might they be deficient in?
Magnesium
Needed for PTH secretion and absorption of calcium at cell level
Common deficiency seen with malabsorption
With primary hyperparathyroidism, what is seen on a XR of head
Pepper pot skull
areas of osteopaenia, bone resorption of skull
2 most common causes of hypercalcaemia
Malignancy (bone mets)
Primary hyperparathyroidism
