Diagnosis and management of primary hyperparathyroidism

Abstract

Primary hyperparathyroidism is the most common cause of hypercalcaemia in the ambulatory setting. 1 2 Although this condition can occur at any age, it commonly affects people over the age of 50 years and postmenopausal women. 2 3 Over the past few decades it has changed from being a condition usually defined by its symptoms to one that is often discovered on routine screening tests while the patient is still largely asymptomatic. In light of advances in research, new guidelines on the diagnosis and management of asymptomatic primary hyperparathyroidism have recently been developed. We review the presentation, diagnosis, and management of primary hyperparathyroidism for the generalist doctor, with evidence drawn from randomised controlled trials, cohort studies, and the most recent consensus guidelines.The four parathyroid glands are situated behind the thyroid gland. Parathyroid hormone (PTH) secreted by the chief cells regulates calcium homeostasis. Decreases in serum ionised calcium are sensed by the calcium sensing receptor on the chief cells, which increase the production and secretion of PTH, thereby enhancing renal tubular calcium reabsorption and osteoclast mediated bone resorption. PTH also enhances the conversion of 25-hydroxyvitamin D 3 into 1,25-hydroxyvitamin D 3 , which in turn increases the efficiency of calcium absorption from the bowel. 1 Rising calcium concentrations decrease the release of of PTH, normalising serum calcium values. What causes primary hyperparathyroidism? Tumours and hyperplasiaAbout 85% of cases are caused by a sporadic PTH secreting solitary adenoma of parathyroid chief cells. 1 Multiglandular parathyroid hyperplasia occurs in 1-15% of patients with primary hyperparathyroidism. 1 Parathyroid carcinoma is rare and occurs in less than 1% of cases. Adenomas may be found in ectopic locations in about 16% of cases-commonly the thymus, trachea-oesophageal groove, mediastinum, and the thyroid. 4 Familial disordersPrimary hyperparathyroidism may also be associated with uncommon familial disorders, including multiple endocrine neoplasia type 1 and type 2A syndromes, familial hyperparathyroidism-jaw tumour syndrome, neonatal severe hyperparathyroidism, and familial isolated hyperparathyroidism. In addition, familial hypocalciuric hypercalcaemia is a benign cause of hypercalcaemia, and it is inherited as an autosomal dominant condition that mimics primary hyperparathyroidism. It is caused by an inactivating mutation of the calcium sensing receptor gene that makes the receptor less sensitive to calcium in the parathyroid glands and the kidneys. Normally, activation of the calcium sensing receptor in the kidney enhances renal calcium clearance. An inactivating mutation leads to decreased sensing of calcium in the kidney and decreased renal calcium clearance, with relative hypocalciuria. 5 6 Drugs and radiation exposureDrugs such as thiazide diuretics and lithium may also alter calcium homeostasis. Thiazides may unmask underlying primary hyperparathyroidism because they reduce urinary calciu...

Detection and Characterization of Parathyroid Adenoma/Hyperplasia for Preoperative Localization: Comparison Between 11C-Methionine PET/CT and 99mTc-Sestamibi Scintigraphy

“…Current imaging techniques such as 99m Tc-sestamibi (MIBI) or 99m Tc-tetrofosmin scintigraphy with single photon emission computed tomography (SPECT) as well as ultrasonography (USG), computed tomography (CT), and magnetic resonance imaging (MRI) are not always successful in the localization of parathyroid tissues [4,5]. Recently, it was reported that MIBI scintigraphy is useful to differentiate benign from malignant parathyroid lesions as well as to detect parathyroid lesions [6].…”

Nephrolithiasis in primary hyperparathyroidism: a contemporary look

“…По оценкам разных авторов, в исследованиях 70-80-х годов нефролитиаз выявлялся в 40-60% [31], в то время как в работах последних лет частота конкрементов почек, как правило, не превы-шает 20-30% [32]. Характеристика состояния почек у пациентов с ПГПТ существенно меняется в зависи-мости от возраста, пола, а также применяемых мето-дов диагностики.…”

Primary hyperparathyroidism – a diagnostic approach

“…A 24-hour urine calcium measurement is necessary to rule out familial hypocalciuric hypercalcemia (FHH). Other laboratory findings include mild hyperchloremic acidosis, hypophosphatemia, increased alkaline phosphatase and mild-to-moderate increase in urinary calcium and inorganic phosphorus excretion rate (1,2,3,7).…”

“…With increased detection by means of routine calcium screening, the clinical profile of primary hyperparathyroidism in Western countries has shifted from a symptomatic disease, characterized by hypercalcemic symptoms, nephrolithiasis, overt bone disease, and neuromuscular symptoms to one with subtle or no specific symptoms ("asymptomatic" primary hyperparathyroidism) (2,3,4). In the developing world, the symptomatic variant still dominates (6).…”

“…The frequency of primary hyperparathyroidism is 1-4/1000 individuals in the general population (1,2). Women are twice as likely to be affected as men, and the commonest age of presentation in between 50 and 60 years of age (3).…”