Primary Hyperparathyroidism
The parathyroid glands may start to produce too much hormone - this will increase the blood calcium levels. Because many patients remain genuinely asymptomatic the reported incidence varies. The prevalence in older women might be up to 1%.
Causes:
Adenomas - in 80% of patients.
Double adenomas - uncommon but 2 of the glands may be affected.
Hyperplasia - can be found in 15-20% of patients. All 4 glands are affected. It can be difficult to diagnose - even at operation.
Carcinomas - 1% of all patients. Men and women are affected equally. Usually after the age of 50 years.
Ectopic hormone production - is rare. The hormone is produced by other tissues such as small cell lung cancer and cancer of the ovary.
MEN syndromes - multiple endocrine neoplasia where the parathyroid glands are involved together with other endocrine glands.
Presentation:
Asymptomatic disease - up to 50% patients may have no symptoms. Picked up on routine blood tests.
Kidney manifestation - producing large quantities of urine, back pain, colic and haematuria (blood in the urine). Stones may develop as well as problems with the function of the kidney.
Bone involvement - thinning of the bone occurs making it more susceptible to fractures.
'Nerve' involvement - weakness, fatigue, wasting of muscles, depression, lethargy, confusion and memory impairment.
Gut involvement - loss of appetite, nausea, dyspepsia, constipation and abdominal pains. Stomach ulcers may occur as may pancreatitis secondary to the high calcium levels.
High blood pressure
Investigations
Blood tests will show high parathormone levels in the presence of high calcium levels.
Ultrasound scan is not very good at locating small adenomas.
CT/MRI scans can be used to look for parathyroid tissue in unusual places such as in the chest.
Sestamibi scan - this is a substance that concentrates in the parathyroid glands. It is combined with technitium and can be detected with special cameras.
In most cases once the diagnosis is made on blood tests an operation is recommended without the need for further tests. These further scans are needed in the unusual cases when the gland cannot be found at the time of initial surgery.
Treatment
Surgery to remove the parathyroid adenoma is the treatment of choice. Primary neck exploration will result in a cure in more than 95% of cases.