[Asymptomatic primary hyperparathyroidism : Operation or observation?]

In many cases primary hyperparathyroidism (PHPT) remains asymptomatic for years and is only detected by abnormalities in routine diagnostics. While symptomatic disease almost always requires surgical treatment, in symptom-free patients the question of whether and in what form treatment should be carried out is particularly important.

The aim of this review is to summarize the current recommendations regarding the diagnostics and treatment of asymptomatic PHPT, taking the existing evidence into account.

The diagnostics of asymptomatic PHPT is the same as for symptomatic disease. The diagnosis is made in the presence of elevated parathyroid hormone and balanced vitamin D levels when a combination of hypercalcemia, hypophosphatemia and hypercalciuria is present. Borderline laboratory findings occur especially in asymptomatic PHPT and the differential diagnosis of familial hypocalciuric hypercalcemia must be considered. Once the diagnosis is made sonography, radiography or computed tomography (CT) is used to search for nephrolithiasis or nephrocalcinosis. Regarding bone mineral density (BMD) measurements, in addition to routine measurements at the lumbar spine and femur, measurement at the distal radius is important as it is the most sensitive site for detecting osteoporosis in PHPT. An indication for parathyroidectomy is confirmed in the case of hypercalcemia > 1.0 mg/dl (>0.25 mmol/l) above the upper limit of normal, hypercalciuria > 400 mg/day (>10 mmol/day), renal insufficiency, proven osteoporosis or age < 50 years. If none of these criteria are fulfilled and surgery is not desired by the patient, annual laboratory check-ups and assessment of BMD every 1-2 years are recommended.