Primary hyperparathyroidism the condition in which there are high levels of serum calcium due to non-suppressed parathyroid hormone (PTH) levels. Most cases are sporadic, although it can also be acquired ( as with lithium treatment) or inherited ( as in MEN I and IIA syndromes). The sporadic disease is a common disorder, and its prevalence has been reported to be as high as 2% in the women population in the USA. 80% of cases are caused by a single parathyroid adenoma, 10% by more than one adenoma, less than 10% by hyperplasia of all four glands, and less than 1% are due to parathyroid cancer.
The majority of patients present with hypercalcemia but remain asymptomatic. In cases of symptomatic disease, the most common symptoms include impaired skeletal health and nephrolithiasis. Primary hyperparathyroidism causes a resorptive bone status, which increases the risk of bone loss and fragility fractures. It has been reported that the most affected bones are those of the wrist, rib, spine, and pelvis. There is an increased risk of nephrolithiasis, together with more unusual symptoms such as fatigue, depression, anxiety, impaired memory, cardiovascular disease, constipation, or increased risk of acute pancreatitis.
The process of diagnosis must be standardized and include laboratory tests that show serum calcium levels above the normal range with an inappropriately high PTH. However, normocalcemic primary hyperparathyroidism with high PTH levels can also be found. Causes of secondary and tertiary hyperparathyroidism must be excluded.
Surgery is strongly recommended in the following situations:
– Patients < 50 years old
– Men and peri/post-menopausal women with T scores of -2.5 or lower densitometry at any site, or with a recent fragility fracture
– Patients with serum calcium level > 1.0 mg/dL above the upper limit of normal
– In primary hyperparathyroidism with a glomerular filtration rate < 60 ml/min
- Presence of kidney stones or hypercalciuria > 400 mg/day
However, there will always be patients who are not candidates for or who refuse surgery. In those cases, treatment is fundamentally medical and focuses on the symptoms, and includes calcimimetics that suppress the secretion of PTH, diets with sufficient calcium and Vit D, bisphosphonates, thiazide diuretics such as hydrochlorothiazide to reduce urinary calcium excretion, and appropriate hydration to reduce the risk of kidney stones.