Primary hyperparathyroidism

Diagnosis of primary hyperparathyroidism is confirmed biochemically with synchronous elevation of serum calcium and inappropriate elevation of parathyroid hormone (PTH).

Normal serum intact PTH in the setting of hypercalcemia does not rule out disease.

Depression, cognitive changes, change in sleep pattern, fatigue, and myalgia or muscle weakness are nonspecific subjective complaints. There may be a history of nephrolithiasis or low bone mineral density.

Physical examination is usually normal, but examination of the neck is essential to look for a hard, dense mass, suggestive of parathyroid carcinoma.

Parathyroidectomy is the only definitive cure. Monitoring is an option for patients who have mild hypercalcemia without surgical indications, which include lack of ensured follow-up, renal stones, impaired renal function, or osteoporosis.

Primary hyperparathyroidism (PHPT) is an endocrine disorder in which autonomous overproduction of parathyroid hormone (PTH) results in derangement of calcium metabolism. In approximately 80% of cases, over-production of PTH is due to a single parathyroid adenoma and, less commonly, multi-gland involvement may occur. Diagnosis occurs through testing for a concurrent elevated serum calcium level with a higher or inappropriately normal (i.e., non-suppressed) plasma PTH level.[1]Wilhelm SM, Wang TS, Ruan DT, et al. The American Association of Endocrine Surgeons guidelines for definitive management of primary hyperparathyroidism. JAMA Surg. 2016 Oct 1;151(10):959-68. http://jamanetwork.com/journals/jamasurgery/fullarticle/2542667 http://www.ncbi.nlm.nih.gov/pubmed/27532368?tool=bestpractice.com [2]Khan AA, Hanley DA, Rizzoli R, et al. Primary hyperparathyroidism: review and recommendations on evaluation, diagnosis, and management. A Canadian and international consensus. Osteoporos Int. 2017 Jan;28(1):1-19. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5206263 http://www.ncbi.nlm.nih.gov/pubmed/27613721?tool=bestpractice.com Inherited forms, affecting a minority of patients, lead to hyperfunctioning parathyroid glands. Importantly, hyperparathyroidism is rarely caused by parathyroid cancer characterized by severe hypercalcemia.[3]Fang SH, Lal G. Parathyroid cancer. Endocr Pract. 2011;17(suppl 1):36-43. http://www.ncbi.nlm.nih.gov/pubmed/21454239?tool=bestpractice.com

Normocalcemic PHPT is recognized as a variant of PHPT, and has yet to be thoroughly characterized.[4]Bilezikian JP. Primary Hyperparathyroidism. J Clin Endocrinol Metab. 2018 Nov 1;103(11):3993-4004. https://www.doi.org/10.1210/jc.2018-01225 http://www.ncbi.nlm.nih.gov/pubmed/30060226?tool=bestpractice.com It presents with high levels of parathyroid hormone, in the setting of normal serum and ionized calcium levels, after secondary causes of PTH elevation have been excluded.[5]Zavatta G, Clarke BL. Normocalcemic Hyperparathyroidism: A Heterogeneous Disorder Often Misdiagnosed? JBMR Plus. 2020 Aug;4(8):e10391. https://www.doi.org/10.1002/jbm4.10391 http://www.ncbi.nlm.nih.gov/pubmed/32803112?tool=bestpractice.com It is sometimes detected during the evaluation of patients with low bone mineral density.[6]Walker MD, Silverberg SJ. Primary hyperparathyroidism. Nat Rev Endocrinol. 2018 Feb;14(2):115-25. https://www.doi.org/10.1038/nrendo.2017.104 http://www.ncbi.nlm.nih.gov/pubmed/28885621?tool=bestpractice.com Some, but not all, patients will go on to develop PHPT.[1]Wilhelm SM, Wang TS, Ruan DT, et al. The American Association of Endocrine Surgeons guidelines for definitive management of primary hyperparathyroidism. JAMA Surg. 2016 Oct 1;151(10):959-68. http://jamanetwork.com/journals/jamasurgery/fullarticle/2542667 http://www.ncbi.nlm.nih.gov/pubmed/27532368?tool=bestpractice.com [2]Khan AA, Hanley DA, Rizzoli R, et al. Primary hyperparathyroidism: review and recommendations on evaluation, diagnosis, and management. A Canadian and international consensus. Osteoporos Int. 2017 Jan;28(1):1-19. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5206263 http://www.ncbi.nlm.nih.gov/pubmed/27613721?tool=bestpractice.com [5]Zavatta G, Clarke BL. Normocalcemic Hyperparathyroidism: A Heterogeneous Disorder Often Misdiagnosed? JBMR Plus. 2020 Aug;4(8):e10391. https://www.doi.org/10.1002/jbm4.10391 http://www.ncbi.nlm.nih.gov/pubmed/32803112?tool=bestpractice.com