SFEBES2016 Clinical Management Workshops Workshop 1: Endocrinology at the edge of the reference range (Supported by Endocrinology, Diabetes & Metabolism Case Reports) (3 abstracts)
University of Dundee.
Primary hyperparathyroidism (PHPT) has become more prevalent as routine screening for serum calcium became more widespread. The current prevalence of PHPT is about 0.51% and possibly higher. The majority of patients are asymptomatic or have relatively subtle symptoms. NIH criteria for surgery are mainly based on patient symptoms and/or signs of end-organ damage, and the majority of patients do not fulfil these criteria. However it has become apparent that patients not fulfilling the surgical criteria may have increased rates of cardiovascular disease and other adverse endpoints. As assays for plasma PTH and vitamin D assays have become more widely used, the condition of normo-calcaemic primary hyperparathyroidism (NCPHPT) has emerged. Patients with NCPHPT have a normal serum calcium but raised PTH concentration in the absence of vitamin D deficiency, chronic kidney disease or the use of thiazide diuretics or lithium. It is thought that NCPHPT may be a stage in the natural history before PHPT develops, although it may also reflect inappropriate reference ranges for older and obese individuals. Most studies of 117 years follow up show low levels of progression but in one study 19% progressed to PHPT at 3% years. Patients who progressed were older, and had higher baseline serum and urinary calcium concentrations. A small number of patients with NCPHPT have undergone parathyroidectomy, and histology has almost universally demonstrated an adenoma or hyperplasia. It is unclear whether NCPHPT is related to increased morbidity as most studies are observational have been done in selected patients, with small numbers of patients and with limited duration of follow up. The condition of normo-calcaemic hypoparathyroidism has also been described and investigated.