Primary Hyperparathyroidism

Primary hyperparathyroidism is a condition where calcium levels in the blood are elevated (hypercalcaemia) due to high secretion of parathyroid hormone (PTH) produced by parathyroid gland/s.  It used to be a very rare condition as it was only diagnosed on Xrays and manifestations of high calcium levels.  Since discovery of PTH as well as development of a blood test for detecting PTH levels, it was found that approximately 1 in 200 people will develop hyperparathyroidism.  Primary hyperparathyroidism is more common in females. 

Patients with primary hyperparathyroidism may have no or minimal symptoms, or these symptoms may be due to severe hypercalcaemia (excessive thirst, dehydration, kidney stones, muscle weakness or bone fractures).  Most common symptom is  tiredness. 

The diagnosis is confirmed with elevated calcium levels in the blood associated with high levels of PTH. 

Most commonly the cause of primary hyperparathyroidism is single gland parathyroid adenoma (85-90% of cases).  Multiple adenomas are present in approximately 3% of cases, parathyroid hyperplasia in 9% and parathyroid cancer is very rare, less then 1% of cases of hyperparathyroidism. 

Distinction between adenoma and hyperplasia is sometimes very hard even for dedicated parathyroid pathologists.  Hyperplasia often involves all 4 parathyroid glands, but at times, one gland may appear to be larger than rest. 

Diagnosis of parathyroid cancer is also difficult, unless it is already invading surrounding structures and causes dense scarring. 

Treatment of primary hyperparathyroidism is primarily surgical with either unilateral or bilateral parathyroid surgery depending on localization studies and cause. 

Secondary Hyperparathyroidism

Secondary hyperparathyroidism is caused by when other factors rather than primary hyperparathyroidism cause high levels of PTH.  The most common cause is chronic renal failure.  Other causes are high magnesium levels, osteoporosis, osteomalacia and rickets.
The secondary hyperparathyroidism is primarily treated by either renal physicians or endocrinologists with use of medication.  At times surgical treatment may include parathyroidectomy where majority of parathyroid glands are removed (1 or half gland are left). 

Tertiary Hyperparathyroidism

Patients who have chronic kidney failure may be treated with kidney transplant.  Often these patients will have secondary hyperparathyroidism.  Following kidney transplant in majority of patients this secondary hyperparathyroidism resolves.  Sometimes it does not, and this is called tertiary hyperparathyroidism.   This is rare.  Even in these situations, the condition will spontaneously resolve.  If it does not, these patients may require parathyroidectomy.