Calcium/parathyroid Flashcards
What is parathyroid hormone released in response to?
Low calcium
How does PTH act to normalise calcium levels?
Increases bone resorption
Acts on the kidney to enhance reabsorption of calcium and production of calcitriol
How does calcitriol enhance calcium levels?
Increases absorption of calcium from the gut
How does hypercalcaemia present acutely?
Thirst, confusion, polyuria
How does hypercalcaemia present chronically?
Depression, renal stones, pancreatitis, myopathy, osteopenia, fractures
What are the main causes of hypercalcaemia?
Malignancy
Primary hyperparathyroidism
What are most cases of primary hyperparathyroidism caused by?
Solitary parathyroid adenoma (80%); hyperplasia (20%)
How is hypercalcaemia managed?
Fluid resus with 0.9% saline
Bisphosphonates
What are the indications for surgery in primary hyperparathyroidism?
End organ damage
eGFR 2.85mmol/l
age < 50
What are secondary and tertiary hyperparathyroidism?
Secondary is physiological response to low calcium; tertiary is a sequel to secondary, and results from the development of an autonomous gland uninhibited by -ve feedback (Calcium high, PTH also high)
Name three signs of hypocalcaemia
Chvostek’s sign- tapping the facial nerve induces facial spasm
Long QT on ECG
Trosseau’s sign- spasm of the hand/wrist after occlusion of the brachial artery
How is hypocalcaemia managed acutely?
IV 10% calcium gluconate, 10mls over 10 minutes
Name three possible causes of hypoparathyroidism
Di George syndrome, destruction by radiotherapy/surgery, hypomagnesia
What is brachydactyly of the 3rd and 4th metacarpals (shortness of the digits) a sign of?
Pseudohypoparathyroidism
What are ricketts and osteomalacia caused by?
Deficiency of Vit D
