Hyperparathyroidism is a disorder caused by an elevated parathyroid hormone (PTH) level. Patients generally present with hypercalcemia. An elevated PTH level accompanied by an elevated calcium level or an inappropriately normal PTH level in the setting of hypercalcemia is usually diagnostic of the disorder. Differential diagnosis includes familial hypocalciuric hypercalcemia (FHH). It’s important to distinguish these two disorders as FHH is a benign condition that normally doesn’t need therapy. FHH may be differentiated from primary hyperparathyroidism by a low urine calcium excretion.

The main therapy for hyperparathyroidism is surgery. Symptomatic patients with hyperparathyroidism should be referred for surgery. However, many patients present with asymptomatic hyperparathyroidism. The 2002 NIH Workshop on Asymptomatic Hyperparathyroidism developed criteria for surgical intervention. The guidelines state that asymptomatic patients with the following criteria should be referred for surgery:

1) Serum calcium 0.25 mmol/L or more above the upper limit of normal;

2) creatinine clearance that’s < 60 ml/min;

3) Bone density at the hip, lumbar spine or distal radius that’s more than 2.5 standard deviations below peak bone mass and/or a fragility fracture;

4) age < 50 years.

For patients who refuse or are not surgical candidates a number of recommendations should be made including to avoid factors that can aggravate hypercalcemia such as thiazide diruetics and lithium, dehydration, and prolonged bedrest. A moderate vitamin D intake should be maintained as vitamin D deficiency can further elevate PTH. Certain medications such as bisphosphonates, estrogen-progesterone therapy, and calcimemetics may also be useful as medical therapy.

Hypoparathyroidism is characterized by hypocalcemia accompanied by hyperphosphatemia and a low or undetectable PTH level. Main causes are usually surgical destruction or autoimmune destruction of the parathyroid glands. Hypoparathyroidism is treated by replacing calcium and vitamin D. The primary goal of therapy is to raise the calcium to low normal range and to relieve symptoms. Calcitriol is generally the treatment of choice for replacing vitamin D in this disorder.

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