Calcium homeostasis Flashcards
(19 cards)
What hormone is secreted by the parathyroid glands and involved in Calcium homeostasis?
PTH, parathyroid hormone
What are the symptoms of Hypercalcaemia?
Stones, groans, bones, psychic moans
- thirst
- dehydration
- confusion
- polyuria
- fractures
- depression
- hypertension
Why do granulomatous diseases cause hypercalcaemia?
TB and sarcoidosis
-produce vitamin D
Name 4 causes of Hyoercalcaemia:
- Primary Hyperparathyroidism
- Malignancy
- Granulomatous disease
- Familial Hypocalciuric Hypercalcaemia
What drugs can cause hypercalcaemia?
Thiazide diuretics
Vitamin D
How is hypercalcaemia treated?
- rehydrate with IV fluids
- flush Ca out with loop diuretics (NOT thiazide)
- bisphosphonates
Why is Calcium raised in Familial Hypocalciuric Hypercalcaemia? How is diagnosis confirmed?
- Calcium detection level by Calcium Sensing Receptors in parathyroid glands is raised
- negative feedback occurs at higher plasma calcium
If PTH and serum Ca are raised, confirm FHH by checking if urine calcium
-if low, it’s FHH
What are the symptoms/signs of Hypocalcaemia?
- loss of sensation in peripheries
- muscle cramps and weakness
- fits
- QT prolongation on ECG
Name 3 causes of Hypocalcaemia.
- Hypoparathyroidism
- Vitamin D deficiency
- Chronic renal failure
What is the treatment of acute Hypocalcaemia?
Emergency!
-IV calcium gluconate
What are the causes of Hypoparathyroidism?
- congenital (DiGeorge syndrome - congenital absence)
- Surgical/radiotherapeutic /autoimmune desctruction
- Hypomangesaemia
Why is PTH release inhibited in Hypomagnasaemia?
- Calcium release from cells is Mg-dependent
- Intracellular calcium is high
- PTH release is inhibited by high Ca
What is the cause of Pseudohypoparathyroidism?
PTH resistance
-does not induce desired resorption/absorption of Ca
Describe the biochemistry of Primary Hyperparathyroidism?
Calcium: high
PTH: high
ALP: normal
Phosphate: low
Describe the biochemistry of bone malignancy.
Calcium: high
PTH: low (suppressed)
ALP: v. high
Phosphate: normal
Describe the biochemistry of Familial Hypocalciuric Hypercalcaemia.
Calcium: high (mild) PTH: normal/mild elevation ALP: normal Phosphate: normal/mild elevation Urine Calcium: low
Describe the biochemistry of Hypoparathyroidism.
Calcium: low
PTH: low
ALP: normal
Phosphate: normal/mild elevation
Describe the biochemistry of osteomalacia.
Calcium: low
PTH: high
ALP: v. high
Phosphate: low
Describe the biochemistry of Paget’s disease?
Calcium: normal (slightly high)
PTH: normal
ALP: High
Phosphate: normal
