Normocalcemic primary hyperparathyroidism: a survey in a small village of Southern Italy

Abstract

We investigated the prevalence of normocalcemic primary hyperparathyroidism (NPHPT) in the adult population living in a village in Southern Italy. All residents in 2010 (n=2045) were invited by calls and 1046 individuals accepted to participate. Medical history, calcium intake, calcium, albumin, creatinine, parathyroid hormone (PTH) and 25OHD were evaluated. NPHPT was defined by normal albumin-adjusted serum calcium, elevated plasma PTH, and exclusion of common causes of secondary hyperparathyroidism (SHPT) (serum 25OHD <30 ng/ml, estimated glomerular filtration rate (eGFR) <60 ml/min per 1.73 m2 and thiazide diuretics use), overt gastrointestinal and metabolic bone diseases. Complete data were available for 685 of 1046 subjects. Twenty subjects did not meet the inclusion criteria and 341 could not be evaluated because of thawing of plasma samples. Classical PHPT was diagnosed in four women (0.58%). For diagnosing NPHPT the upper normal limit of PTH was established in the sample of the population (n=100) who had 25OHD ≥30 ng/ml and eGFR ≥60 ml/min per 1.73 m2 and was set at the mean+3s.d. Three males (0.44%) met the diagnostic criteria of NPHPT. These subjects were younger and with lower BMI than those with classical PHPT. Our data suggest, in line with previous studies, that NPHPT might be a distinct clinical entity, being either an early phenotype of asymptomatic PHPT or a distinct variant of it. However, we cannot exclude that NPHPT might also represent an early phase of non-classical SHPT, since other variables, in addition to those currently taken into account for the diagnosis of NPHPT, might cumulate in a normocalcemic subject to increase PTH secretion.

Normocalcemic Primary Hyperparathyroidism in Adults Without a History of Nephrolithiasis or Fractures: A Prospective Study

“…Finally, controversy exists regarding the exclusion of the 2 main causes of SHPT (chronic kidney disease and vitamin D insuf-ficiency). Some authors consider an estimated glomerular filtration rate (eGFR) > 40 ml/min/1.73 m 2 [11,12] for the diagnosis of NPHPT and others an eGFR > 60 ml/min/1.73 m 2 [1-4, 8, 9, 13, 14], as well as concentrations of 25-hydroxyvitamin D > 20 ng/dl [4,[9][10][11]13] or > 30 ng/dl [2,8,12,14].…”

Vocal cord paralysis due to ectopic parathyroid adenoma and function recovery: a case report and review of the literature

“…PHPT, usually caused by a single functioning PA, is an important clinical issue that affects 0.4% to 11% of the population [8][9][10]. PAs may occur anywhere along the embryologic path following the descent of the parathyroid glands, and the existence of ectopic PA remains a significant hurdle in the surgical management of hyperparathyroidism.…”

Elevated PTH with normal serum calcium level: a structured approach

“…In the absence of chronic kidney disease, malabsorption or deficiency of active vitamin D, normocalcaemic hyperparathyroidism may represent a subclinical form of PHPT, described as a forme fruste by Silverberg and Bilezikian; it is reported to be common in population studies, although prevalence rates vary according to the diagnostic criteria applied . A recent analysis of data from the Dallas Heart Study revealed a prevalence of normocalcaemic PHPT of 3·1% in a community population; in the longitudinal WHO MONICA study prevalence increased over 13 years of follow‐up from 2·0% to 11·0% in a study population aged 38–79 years .…”