What are the investigation and management strategies for hyperparathyroidism?

From the Guidelines

Hyperparathyroidism investigation and management should prioritize a systematic approach based on clinical presentation and laboratory findings, with initial investigation including serum calcium, parathyroid hormone (PTH), phosphate, vitamin D, and renal function tests, as well as imaging studies such as neck ultrasound, sestamibi scan, and sometimes CT or MRI to localize parathyroid adenomas, as recommended by the most recent guidelines 1.

Key Components of Investigation and Management

• Initial investigation should include:
  • Serum calcium
  • Parathyroid hormone (PTH)
  • Phosphate
  • Vitamin D
  • Renal function tests
• Imaging studies:
  • Neck ultrasound
  • Sestamibi scan
  • CT or MRI (in some cases)

Treatment Approaches

• For primary hyperparathyroidism, parathyroidectomy is the definitive treatment for symptomatic patients or those meeting surgical criteria (calcium >1 mg/dL above normal, age <50, osteoporosis, kidney stones, or creatinine clearance <60 mL/min) 1.
• In non-surgical candidates, medical management includes:
  • Cinacalcet (30-90 mg daily) to lower calcium levels
  • Bisphosphonates like alendronate (70 mg weekly) for bone protection
  • Adequate hydration with target urine output >2 L/day
• Secondary hyperparathyroidism, often seen in renal disease, requires treating the underlying cause, vitamin D supplementation (cholecalciferol 1000-2000 IU daily), phosphate binders like sevelamer (800-1600 mg with meals), and calcimimetics such as cinacalcet 1.

Monitoring and Dietary Considerations

• Regular monitoring of calcium, PTH, and renal function every 3-6 months is essential for all patients.
• Dietary calcium should be maintained at 1000-1200 mg daily while avoiding excessive intake. These approaches target the underlying pathophysiology of excessive PTH secretion and its effects on calcium homeostasis, bone metabolism, and renal function, prioritizing morbidity, mortality, and quality of life outcomes, as supported by the most recent and highest quality study 1.

From the FDA Drug Label

The recommended starting oral dose of cinacalcet tablets is 30 mg once daily for secondary hyperparathyroidism in patients with chronic kidney disease on dialysis. The dose of cinacalcet tablets should be titrated every 2 to 4 weeks through sequential doses of 30,60,90,120, and 180 mg once daily to target iPTH levels of 150 to 300 pg/mL. For patients with parathyroid carcinoma and primary hyperparathyroidism, the recommended starting oral dose of cinacalcet tablets is 30 mg twice daily. The dose of cinacalcet tablets should be titrated every 2 to 4 weeks through sequential doses of 30 mg twice daily, 60 mg twice daily, and 90 mg twice daily, and 90 mg 3 or 4 times daily as necessary to normalize serum calcium levels.

Investigation and Management Strategies:

• Serum Calcium Monitoring: Monitor serum calcium levels within 1 week after initiation or dose adjustment of cinacalcet tablets.
• iPTH Monitoring: Measure intact parathyroid hormone (iPTH) levels 1 to 4 weeks after initiation or dose adjustment of cinacalcet tablets.
• Dose Titration: Titrate the dose of cinacalcet tablets every 2 to 4 weeks to target iPTH levels of 150 to 300 pg/mL for secondary hyperparathyroidism.
• Combination Therapy: Cinacalcet tablets can be used alone or in combination with vitamin D sterols and/or phosphate binders.
• Hypocalcemia Management: Monitor for hypocalcemia and take appropriate steps to increase serum calcium levels if necessary, such as providing supplemental calcium or initiating vitamin D sterols. 2 2 2

From the Research

Investigation Strategies for Hyperparathyroidism

• Imaging modalities for identification of parathyroid adenoma include ultrasonography, parathyroid scintigraphy, four-dimensional computed tomography, and magnetic resonance imaging 3
• Sestamibi and ultrasound scans are commonly used to locate hyperfunctioning glands, but can fail to do so in some cases 4
• When both preoperative studies are non-localizing, options include referral to a surgeon for a bilateral neck examination or additional preoperative imaging 4
• Neck ultrasound and sestamibi scans have limited utility in patients with secondary and tertiary hyperparathyroidism, and rarely change the conduct of a standard four-gland exploration 5

Management Strategies for Hyperparathyroidism

• Treatment for primary hyperparathyroidism (PHPT) is surgical excision, with parathyroidectomy (PTx) indicated for those with symptomatic disease 6
• For asymptomatic patients, recent guidelines have recommended criteria for surgery, but PTx can also be considered in those who do not meet criteria and prefer surgery 6
• Non-surgical therapies are available when surgery is not appropriate 6
• In cases where preoperative localization studies are non-localizing, bilateral neck examination with intraoperative PTH assay is a proposed course of action 4
• The use of a gamma-detecting probe during operation can be beneficial in identifying parathyroid glands, especially in cases of parathyroid hyperplasia 7