Parathyroid adenoma (brief)

Question 1

How common is it?

Answer 1

Prevalence is highest among post-menopausal women, with 1:500 possibly being affected.

Question 2

What causes it?

Answer 2

Most of these tumours are small, less than 1g (normal glands are 30-50mg). Can be associated with MEN1.

Question 3

What risk factors are there?

Answer 3

MEN syndromes.

Question 4

How does it present?

Answer 4

Bones: Aches/pains localised in larger joints

Stones: Calcium based renal stones

Moans: Psychological/psychiatric symptoms (lethargy, depressed mood)

Groans: Non-specific GI symptoms (abdominal pain, constipation)

Question 5

Signs on examination?

Answer 5

Polyuria, polydipsia and nocturia are also common symptoms.

More than half of patients report no specific symptoms and accept it as getting older.

Hypercalcaemic crisis can occur in patients with PHPT exposed to severe dehydration (diarrhoea, vomiting). In severe cases, patients can present in a coma.

Question 6

Investigations

Answer 6

↑ corrected serum calcium is highly suggestive if unexplained, but not diagnostic.

↑ serum parathyroid hormone concentration (PTH) in the presence of hypercalcaemia confirms the diagnosis. (e.g. bone mets (breast, renal, thyroid carcinoma) have a low PTH concentration).

High resolution US may identify tumours. Sestamibi (radioisotope) scanning used to localize adenomas (accurate in 50% of cases).

Question 7

Treatment

Answer 7

Without localisation scans, then bilateral neck exploration and removing the enlarged ones has been standard treatment. Now if you know where the adenoma is patients can undergo minimally invasive parathyroidectomy. This is a focused neck operation.