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Primary hyperparathyroidism (PHPTH)

Checked: 23-08-2021 by Vicky Ryan Next Review: 23-08-2022

Overview

These guidelines have been provided by the Endocrinology Team at NBT so pathways might be slightly different at UHBW

Definition

An elevated serum calcium in the context of an inappropriately normal or elevated parathyroid hormone (PTH) level
Normocalcaemic PHPTH has also been described but has yet to be fully characterised. Some, but not all patients will go on to develop overt PHPTH
In approximately 80% of cases, over production of PTH occurs due to a single parathyroid adenoma and less commonly parathyroid hyperplasia

Important points

Commonly asymptomatic and picked up on screening. Consider measuring a serum calcium (albumin adjusted) with any of the following features which might represent hypercalcaemia:

Symptoms suggestive of hypercalcaemia e.g. excessive thirst, polyuria, bone pain, lethargy, constipation
Osteoporosis or a previous fragility fracture
Renal stones
Severe hyperemesis in pregnancy

Who to refer

If Ca2+ 2.85-2.99 mmol/L or mild to moderate symptoms at any calcium level <3 mmol/L – routine Endocrine referral advised. Monitor Ca2+ every 2-3 months and if symptoms worsen or calcium rises to ≥3 mmol/L, manage as below.

If asymptomatic and Ca2+ ≤2.85mmol/L routine referral is recommended in the following cases:

Any patient requesting definite surgical management
Any patient with known end organ dysfunction from hypercalcaemia e.g. renal stones, osteoporosis
Age:

Any patient <50 years should be referred as surgery is often indicated
Most patients aged 50-75 should be referred unless they decline further investigation or are very frail (see below)
Those ≥75 years of age – there is some evidence that definitive treatment (e.g. parathyroidectomy) does not benefit long term mortality. However, the patient may have subtle symptoms of hypercalcaemia e.g. confusion, lethargy etc. which may resolve with normalisation of the calcium. In these patients, a detailed history of co-morbidities, frailty and patient preference for intervention are much more important than age.

Red Flags

If Ca2+ ≥ 3 mmol/L or severe symptoms and diagnosis in keeping with PHPT – discuss directly via the Endocrine mobile phone (after 1pm) and make an urgent referral. The patient may need treatment e.g. IV fluids, bisphosphonates or Cinacalcet whilst awaiting further investigation/definitive treatment

Before referral

Further investigation

If the serum adjusted Ca2+ is above the upper limit of the reference range, repeat the measurement alongside the following investigations:

Parathyroid hormone – if normal or above the upper limit of the reference range, consider PHPHT as the diagnosis. If the PTH is suppressed (<1.6pmol/L) investigate for other causes, particularly malignancy
Vitamin D – aim for a level >50nmol/L. Avoid high dose loading due to the risk of worsening the hypercalcaemia. For most people, 1000-2000iU daily is sufficient. NB. If the patient is severely vitamin D deficient e.g. <10nmol/L, this can impact on the PTH and 24 hour urine Ca2+ result. In these cases, repeat PTH and 24 hour urine collection once vitamin D replete
Myeloma screen
24 hour urine collection for Ca2+ (Appendix 2) – this will be interpreted in secondary care but will speed up definitive investigation if able to be completed in primary care
Ultrasound parathyroids – should not be routinely requested in primary care

Services

Endocrinology NBT

Endocrinology UHBW

Resources

References:

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