Primary hyperparathyroidism: new concepts in clinical, densitometric and biochemical features

Abstract

Primary hyperparathyroidism (PHPT) is characterized most commonly now as an asymptomatic disorder with hypercalcaemia and elevated levels of parathyroid hormone (PTH). The elevation in PTH is detected by both the standard immunoradiometric assays (IRMA) and a more recent IRMA that detects only the 1-84 full-length PTH molecule. The serum calcium concentration is usually <1 mg dL )1 above normal. Recently, another variant of PHPT (normocalcaemic PHPT) has been described in which the serum calcium is normal but the serum PTH is elevated, in the absence of any secondary cause for PTH elevation. Although usually sporadic, PHPT also occurs in inherited syndromes. Skeletal manifestations are appreciated by densitometry showing a typical pattern in which cancellous bone of the lumbar spine is reasonably well preserved whilst the cortical bone of the distal third of the radius is preferentially reduced. Although reduced in incidence, renal stones remain the most common overt complication of PHPT. Other organs are theoretical targets of PHPT such as the neurobehavioural axis and the cardiovascular system. Vitamin D looms as an important determinant of the activity of the PHPT state. The 2002 NIH Workshop on asymptomatic PHPT has led to revised guidelines to help doctors determine who is best advised to have parathyroid surgery and who can be safely followed without surgery. New information about the natural history of PHPT in those who did not undergo surgery has helped to define more precisely who is at-risk for complications. At the NIH workshop, a number of items were highlighted for further investigation such as pharmacological approaches to controlling hypercalcaemia, elevated PTH levels and maintaining bone density.

Diagnosis and management of primary hyperparathyroidism: a scientific statement from the Department of Bone Metabolism, the Brazilian Society for Endocrinology and Metabolism

“…Specific markers of bone formation (osteocalcin, bone-specific alkaline phosphatase) or bone resorption (deoxypyridinoline, N-telopeptide and C-telopeptide) tend to be in the normal-high range or slightly above the reference values (1).…”

“…PHPT occurs due to unregulated and excessive parathyroid hormone (PTH) secretion by one or more parathyroid glands (1). Solitary parathyroid adenomas represent about 85% to 90% of PHPT cases (1,2) (C-4).…”

“…Although the clinical presentation is variable the asymptomatic hypercalcemia form, detected by routine screening, is the most common (50% to 80%) (2). However, the presentation is variable, with patients demonstrating a range from normocalcemia to severe hypercalcemic PHPT (1).…”

“…P rimary hyperparathyroidism (PHPT) is a disease caused by overactive parathyroid glands with consequent hypercalcemia (1). The main cause in 85%-90% of cases, is the presence of a solitary parathyroid adenoma (2,3).…”

Spontaneous Remission of Primary Hyperparathyroidism in a Patient with Neurofibromatosis Type 1: Case Report

“…It is the most common cause of hypercalcemia diagnosed in an ambulatory setting [7,8] and can occur at any age, but most frequently from 40 to 65 years, with a female:male predominance of 3:1. The incidence in Rochester-Minnesota during 1993-2001 was estimated to be 21.6 per 100,000 person-years [9].…”