This is a new guideline from NICE on managing high calcium (Ca) levels and hyperparathyroidism. It was published in May 2019.
I am doing a general summary of the guideline. Although some of this is going to be managed in secondary care, I have also summarised these bits of the guideline as we will be responsible for following up the patients.
When should you measure calcium levels?
- Symptoms of hypercalcaemia (e.g. thirst, frequent or excessive urination or constipation)
- Osteoporosis or fragility fracture.
- Renal stone.
- Incidental finding of Ca 2.6 mmol/L or more.
Also consider measuring it if there are 'chronic non-differentiated symptoms'.
You should repeat it at least once if:
- Ca 2.6 mmol/L or more OR
- Ca 2.5 mmol/L or more and there are any features of primary hyperparathyroidism.
When should you measure parathyroid hormone PTH?
- Ca 2.6 mmol/L or more on at least 2 separate occasions.
- Ca 2.5 mmol/L or more on at least 2 separate occasions and any features of primary hyperparathyroidism.
When should you seek further advice?
Seek guidance if PTH is:
- Above the mid-point of the reference range and primary hyperparathyroidism is suspected OR
- Below the mid-point of the reference range and the Ca is 2.6 mmol/L or above.
The advice here at first glance seems a bit odd. Surely you need a raised PTH to have primary hyperparathyroidism? However the reasoning behind this is twofold. Firstly PTH levels can vary considerably from one individual to another. Secondly there is quite a lot of debate about what level of PTH you need to rule out primary hyperparathryoidism. So if you use the normal reference ranges, you are going to miss some people with primary hyperparathyroidism.
Thankfully, they are reassuring in that if the PTH is below the mid-point of the reference range and the Ca is less than 2.6 mmol/L, we don't need to investigate further for primary hyperparathyroidism...
If there is a raised Ca and PTH is below the lower limit for the reference range, then consider other causes, such as malignancy.
What about measuring Vitamin D?
In the NICE guideline this is listed as a secondary care investigation. They advise that this is because in some areas it is not easy to get it tested, so the delay can then lead to a delay in diagnosis for patients. We will have to make our own minds up about whether we feel it is reasonable to check for it prior to referral in our own areas.
What will secondary care do?
- Check renal function (though how they could have got as far as secondary care without this being checked, I'm not sure...).
- Renal scan.
- Exclude familial hypercalciuric hypercalcaemia (urine and blood tests).
Who should be referred for surgery?
Referrals will be made by secondary care if:
- Symptoms of hypercalcaemia.
- End organ disease (eg osteoporosis/fragility fractures/renal stones).
- Ca 2.85 mmol/L or above.
They do however advise that we should consider referring all patients with primary hyperparathyroidism for surgery.
What non-surgical management is there?
This is cinacalcet. It should be used if surgery is declined, not suitable or is unsuccessful. It will be used for patients with higher levels of hypercalcaemia.
Consider if there is primary hyperparathyroidism AND an increased fracture risk.
What monitoring will patients need?
We need to be aware of this, as I suspect most of this will come our way.
After successful surgery:
- Calcium/UE annually (and refer if Ca rises again as per the initial advice).
- Osteoporosis. A DEXA should be considered every 2-3 yrs.
- Renal stones. An USS should be done at presentation and thereafter if a further stone is suspected.
NICE advises to monitor in accordance with the SPC. The BNF advises checking Ca every 2-3m.
What about patients considering pregnancy?
If patients are considering pregnancy, they should be offered surgery.
If pregnant, they should be under MDT care. They should not be given bisphosphonates or cinacalcet.
There is a higher risk of hypertension for pregnant patients with primary hyperparathyroidism.