Term
| How can metastases cause hypercalcaemia? |
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Definition
1) Direct tumour invasion
2) Secretion of osteoclast activating factors leading to local osteolytic hypercalcaemia
3) Metastases not in bone synthesise and secrete parathyroid hormone-related peptide. |
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Term
| What causes other than cancer can lead to hypercalcaemia? |
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Definition
1) Vitamin D-dependent hypercalcaemia
2) Hyperthyroidism
3) Acromegaly
4) Milk ingestion |
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Term
| How do you treat hypercalcaemia? |
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Definition
Patients are usually dehydrated:
1) Rehydrate and use a loop diuretic to promote calciuria
2) Use anti-resorptive agents (bisphosphonates and calcitonin)
3) Once calcium levels are normal treat the underlying disease. |
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Term
| What does hypocalcaemia result in? |
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Definition
Neuromuscular excitability:
1) Numbness, tingling, hyperventilation, tetany
2) Prolonged Q-T interval in an ECG. |
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Term
| What is PTH-deficient hypoparathyroidism (primary hypoparathyroidism)? |
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Definition
| Reduced or absent synthesis of PTH. It is often due to inadvertant removal of excessive parathyroid tissue during surgery. |
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Term
| What is the pathophysiology of PTH-deficient parathyroidism? |
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Definition
| Low PTH levels result in low 1, 25 DHCC production in the kidney. This leads to decreases in bone resorption, renal Ca2+ reasorption and GI Ca2+ absorption. |
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Term
| What are other causes of hypocalcaemia apart from PTH-dificient hypoparathyroidism? |
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Definition
1) PTH-ineffective hypoparathyroidism
2) PTH-resistant hypoparathyroidism
3) Secondary hyperparathyroidism. |
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Term
| How do you treat hypocalcaemia? |
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Definition
1) Ca2+ and calcitrol
2) Malabsorption is treated with dietary calcium and high doese of vitamin D. |
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Term
| How do you treat hypocalcaemia? |
|
Definition
1) Ca2+ and calcitrol
2) Malabsorption is treated with dietary calcium and high doese of vitamin D. |
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Term
| In practice how do you measure vitamin D levels? |
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Definition
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Term
| What are normal ranges of calcium and parathyroid hormone? |
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Definition
1) Calcium: 8-10 mg/dL
2) PTH: 20-60 pg/mL |
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Term
| What are the ranges for mild, moderate and severe hypercalcaemia? |
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Definition
1) Mild: 10-12 mg/dL
2) Moderate: 12-14 mg/dL
3) Severe: 15+ mg/dL |
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Term
| What is the effect of a tumour of the parafollicular cells of the thyroid gland? |
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Definition
| Hypercalcitonaemia. Calcitonin levels are high bt serum CA2+ is normal. |
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Term
| What is the effect of pregnancy on calcium levels? |
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Definition
1) Increased Ca2+ absorption from teh GI tract
2) Elevated levels of circulating 1,25 DHCC, calcitonin ant PTH. |
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