Parathyroid Flashcards
What is the affect of the parathyroid hormone?
- normally secreted in response to low Ca2+
- increases osteoclast activity
- increases Ca2+ reabsorption in kidneys
- activates vitamin D3
Overall affect of normal parathyroid hormones?
- increase calcium
- decrease phosphate
Where is vitamin D3 activated?
- kidneys
- by PTH
Where are calcium sensing receptors located?
- parathyroid glands
- G-protein coupled receptor
What are symptoms of hypercalcaemia?
- Stones
- Bones
- groans
- psychiatric overtones
- thirst
- dehydration
Chronic affect of hypercalcaemia?
- myopathy
- fractures
What are some causes of hypercalcaemia?
- primary hyperparathyroidism
- malignancy
High Calcium
High PTH
Low urinary excretion of CAa2+
What could it be?
- Familial hypocalciuria hypercalcaemia
Causes of primary hyperparathyroidism?
- adenoma
- hyperplasia of parathyroid gland
Tests and results for primary hyperparathyroidism?
- high calcium
- high PTH
- increased urine calcium
- low phosphate
Treatment of primary hyperparathyroidism?
- increase fluids
- avoid thiazides
- removal of gland
Explain hypercalcaemia associated with malignancy?
- PTHrP from solid tumours
- drives osteoclast activity
What is PTHrP
- parathyroid related protein
- released from a malignant tumour
- increases calcium levels
Treatment of hypercalcaemia?
- fluids
- bisphosphonates
- surgery
What scan should be performed before surgery of the parathyroid glands?
- Sestamibi scan
Explain secondary hyperparathyroidism?
- low Ca2+
- high PTH
- physiological response to low Ca2+ or vitamin D
Explain tertiary hyperparathyroidism?
- autonomous overproduction of PTH
- high PTH
- high calcium
Explain Familial hypocalciuria hypercalcaemia (FHH)
- genetic
- autosomal dominant
- low excreted calcium
- high serum calcium
- calcium receptor less sensitivity
Symptoms of hypocalcaemia?
- paraesthesia
- muscle cramps and weakness
- fatigue
- Chvostek’s sign
- Trousseaus sign
Explain Chvostek’s sign?
- hypocalcaemia
- twitching of facial muscles upon tapping of facial nerve
Explain Trousseaus sign?
- contraction of hands/feet when inflating BP cuff
Emergency treatment of hypocalcaemia?
- Prolonged QT
- IV calcium gluconate
Test results with hypocalcaemia?
- decreased PTH
- Decreased Ca2+
- increased phosphate
Long term treatment of hypocalcaemia?
- calcium supplements
- vitamin D tablets
Explain pseudohypoparathyroidism?
- low calcium
- high PTH
- bone abnormalities
Explain pseudo-pseudohypoparathyroidism?
- morphological features
- normal biochemistry
Calcium release from cells is dependant on what?
- magnesium
Calcium levels in magnesium deficiency?
- intracellular calcium high
Causes of hypomagnesaemia?
- alcohol
- drugs (PPI and thiazide)
Calcium levels in osteomalacia?
- low calcium
- high PTH
Chronic renal disease can cause what?
- secondary hyperparathyroidism
