Hypercalcaemia Flashcards
1
Q
What does PTH do?
A
- Reabsorption of calcium at distal tubule
- Internalises sodium-phosphate co-transporters at proximal tubule
- Inhibits Na+/H+ leading to bicarbonate wasting
- Increased number and activity of osteoclasts in continuous PTH exposure
- Intermittent exposure increases anabolic activity of osteoblasts
- Stimulates synthesis of active form of Vit D in kidney (1,25 dihydroxy cholecalciferol)
- Thereby increases calcium absorption from the gut
2
Q
How is calcium regulated?
A
3
Q
What are the signs and symptoms of hypercalcaeima?
A
- Muscle weakness
- Bone pain
- Osteoporosis
- Anorexia
- Nausea
- Constipation
- Pancreatitis
- Confusion
- Depression
- Fatigue
- Come
- Shortening of QTc
- Bradycardia
- HTN
- Polyuria
- Nephrogenic GI
- Stones
- Nephrocalcinosis
4
Q
How is hypercalcaemia investigated?
A
- FBC
- U&Es
- LFTs
- Bone profile
- PTH
- ECG
- Chest X-ray
5
Q
What are the roles of vitamine D in bone metabolism?
A
- Increases calcium and phosphate absorption from the gut
- Bone mineralisation and mobilises calcium stores
- Immunomodulation (B and T lymphocytes)
- Increases muscle strength
- Reduces insulin resistance
- Interacts with RAAS
6
Q
How is hypercalcaemia treated?
A
- Stop offending medications
- Rehydration
- Bisphosphonates
- Steroids
- Management of primary hyperparathyroidism (parathyroidectomy, medical treatment)
7
Q
What are the features of osteomalacia?
A
- Classically associated with very low levels of vitamin D
- Failure to ossify bones in adulthood as a result of Vit D deficiency
- Hypo-mineralisation of trabecular and cortical bone
- Presents insidiously with bone pain; proximal myopathy; hypocalcaemia
- Low calcium; low phosphate; high alk phos; Low Vit D; elevated PTH
