Hypercalcaemia Flashcards
What are the 2 main causes?
Primary hyperparathyroidism
Cancer - mets
Rarer causes:
Why does thyrotoxicosis cause it?
What vitamin taken in excess could also cause it?
Granulomatous diseases and lymphoproliferative diseases can cause it as they raise Calcitriol. Give an example of these diseases?
Thyroid hormones are known to cause bone resorption and mobilizing calcium from bone to circulation leading to hypercalcemia.
Vit D
Sarcoidosis and TB
Hypercalcaemia due to malignancy:
Why does this happen from a malignancy that is not even in the bone?
What cancers would cause bone lysis?
PTH-related protein (PTHrP_ is released from malignant cells, which has x100 potency than PTH
Bone mets, myeloma, leukaemia
Presentation - most asymptomatic:
- What neurological symptoms can it cause and why? - 2
- What psychological illness could it also cause?
- Why do they feel tired, weak and muscle and bone pain?
Hypercalcemia can interfere with how your brain works, resulting in confusion, lethargy and fatigue. It can also cause depression.
Confusion
Coma
Depression
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In most cases, the excess calcium in your blood was leached from your bones, which weakens them. This can cause bone pain and muscle weakness.
Presentation - most asymptomatic:
- Why do they polyuria, polydipsia and subsequent dehydration?
The calcium-sensing receptors (CaSRs) found in the kidney play a major role in volume status due to their expression in the thick ascending loop (TAL) of Henle and the collecting duct. Interestingly, hypercalcemia activates the CaSR in the medullary portion of TAL, causing inhibition of the same cotransporter (Na-K-2Cl) inhibited by furosemide and other loop diuretics (2-4)! Hypercalcemia also inhibits vasopressin action ( therefore urine concentration) by activating CaSR in the collecting duct (5). Lastly, inhibition of Na+-K+ ATPase in the proximal convoluted tubule may further contribute to natriuresis and subsequent polyuria.
Thus, hypercalcemia may lead to polyuria by interfering with the absorption of sodium as well as inhibiting the action of vasopressin.
Presentation - most asymptomatic:
- Why do they get abdo pain and N&V?
- Why do they get constipation?
Increased gastric acid secretion often accompanies hypercalcemia. Anorexia, nausea, and vomiting are made worse by increased gastric residual volume.
Constipation is worse due to dehydration associated with hypercalcemia.
Presentation - most asymptomatic:
- What does increased bone resorption cause? - 2
- What does increased bone resorption increase the risk of?
- What may increased calcium levels leave in the kidneys?
- Why does hypercalcaemia cause HTN?
Pain
Osteoporosis/osteopenia (a less severe form of osteoporosis)
Fractures
Kidney stones
An increase in vascular resistance mediated via the direct effect of calcium on vascular smooth muscle as well as the indirect effect of calcium-induced hypercatecholaminemia.
What is a good phrase to remember all the symptoms?
Which cause will have a more acute onset, malignancy or hyperparathyroidism?
‘Stones, bones, groans, and psychiatric moans’
Malignancy will cause more acute hypercalcaemia
Investigations:
Calcium levels are measured.
Which cause will have a very high level of calcium malignancy or hyperparathyroidism?
PTH is measured next to confirm hyperparathyroidism.
What protein in the blood is lowered in malignancy?
What does a raised alkaline phosphate (ALP) suggest? - 2
What do you expect the levels of phosphate to be?
Malignancy - calcium is higher
Albumin - this guides investigation
Increased bone breakdown - Cancer and hyperparathyroidism
Low phosphate levels
Management:
1st - You need to bring down the calcium concentration immediately. What can be done?
2nd - What can be given to inhibit bone resorption?
Long term treatment depends on the cause:
- LOOK AT ENDO FOR HYPERPARATHYRODISM
- What drug can be given for higher levels of Vit D or sarcoidosis?
Dehydration so give thems aline
Biphosphonates IV
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Prednisolone
Complications:
- Renal - 2
- Where are they likely to get fractures?
- What could happen to the cornea?
Renal stones and failure
Wrist and hips
In cancer, hypercalcaemia is a poor prognostic sign, with a life expectancy of < 2 months!
In cancer, hypercalcaemia is a poor prognostic sign, with a life expectancy of < 2 months!
