Table of contents
Primary hyperparathyroidism
Background
Overview
Definition
Primary hyperparathyroidism is an endocrine disorder of calcium metabolism resulting from an abnormal increase in the secretion of PTH from one or more of the parathyroid glands.
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Pathophysiology
Primary hyperparathyroidism is primarily caused by solitary parathyroid adenoma (80%), four-gland hyperplasia (10-15%), multiple adenomas (5%), and parathyroid cancer (< 1%).
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Epidemiology
The average incidence of primary hyperparathyroidism in men and women in the US is 24.7 and 65.5 cases per 100,000 person-years, respectively. The age-adjusted prevalence in men and women is 85.2 and 232.7 per 100,000 individuals, respectively.
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Disease course
The loss of homeostatic control of PTH synthesis and secretion causes an increase in PTH secretion by either single cell or parathyroid hyperplasia. Normally, there is an inverse sigmoid relationship between calcium concentration and parathyroid secretion; however, in primary hyperparathyroidism, parathyroid cells in adenomas become less sensitive to the inhibitory action of calcium resulting in hypercalcemia. Since the PTH plays an important role in bone homeostasis and calcium reabsorption in kidneys, the disease is characterized by skeletal deformities, pathological fractures, and kidney stones and may also lead to cardiac and neurocognitive manifestations.
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Prognosis and risk of recurrence
Parathyroidectomies have > 98% cure rates. The recurrence rates of double parathyroid adenoma, hyperplasia, and single adenoma are 4.0%, 2.2%, and 1.3%, respectively.
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Guidelines
Key sources
The following summarized guidelines for the evaluation and management of primary hyperparathyroidism are prepared by our editorial team based on guidelines from the American College of Radiology (ACR 2021), the Canadian Task Force on Hyperparathyroidism (CTFH 2017), the American Association of Endocrine Surgeons (AAES 2016), and the International Workshop on the Management of Asymptomatic PHPT (IWMAP 2014).
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Screening and diagnosis
Clinical presentation
As per CTFH 2017 guidelines:
Recognize that approximately 85% of patients in developed countries present with asymptomatic disease, and 20% present with renal complications (kidney stones, nephrocalcinosis), skeletal complications (fracture, osteitis fibrosa cystica, bone pain) or symptomatic hypercalcemia.
E
Recognize that the majority of patients in developing countries present with symptomatic disease.
E
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Diagnosis
Diagnostic investigations
Clinical history: as per AAES 2016 guidelines, elicit a personal and family history in patients with suspected primary hyperparathyroidism.
B
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Laboratory tests
Genetic testing
Parathyroid imaging
Abdominal imaging
Bone mineral density testing
Diagnostic procedures
Medical management
Indications for medical management: as per CTFH 2017 guidelines, insufficient evidence to recommend medical therapy currently as an alternative to surgery.
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Bisphosphonates
Cinacalcet
Vitamin D supplementation
Perioperative care
Preoperative planning: as per AAES 2016 guidelines, take into account the following in the preoperative planning:
multigland disease, as it affects approximately 15% of patients with primary hyperparathyroidism
exposure-related and genotype-phenotype correlations (these are predictive of parathyroid anatomical and pathophysiologic features), as they may affect the planning and conduct of surgery.
B
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Preoperative thyroid evaluation
Preoperative voice evaluation
Preoperative vitamin D/calcium supplementation
Intraoperative PTH monitoring
Postoperative monitoring
Surgical interventions
Parathyroidectomy, general principles: as per AAES 2016 guidelines, recognize that surgical management is more effective and cost-effective than long-term observation or pharmacologic therapy.
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Parathyroidectomy (indications)
Parathyroidectomy (bilateral exploration)
Parathyroidectomy (minimally invasive surgery)
Parathyroidectomy (autotransplantation)
Concomitant thyroidectomy
Recurrent laryngeal nerve reinnervation
Specific circumstances
Patients with multiple endocrine neoplasia
As per AAES 2016 guidelines:
Perform subtotal parathyroidectomy as the index surgery in patients with MEN1-associated primary hyperparathyroidism.
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Perform resection of only visibly enlarged glands in patients with MEN2A-associated primary hyperparathyroidism.
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Patients with parathyroid carcinoma
Follow-up and surveillance
Postoperative vitamin D/calcium supplementation: as per AAES 2016 guidelines, consider administering short-term calcium and/or vitamin D supplementation for prophylaxis against hypocalcemia after parathyroidectomy.
C
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Management of postoperative hypoparathyroidism
Follow-up
Management of persistent or recurrent disease