What is the approach to managing hyperparathyroid (elevated parathyroid hormone) levels?

Management of Hyperparathyroidism

The management of elevated parathyroid hormone levels should be tailored to the specific type of hyperparathyroidism (primary, secondary, or tertiary) and underlying etiology, with treatment options ranging from medical therapy to surgical intervention depending on disease severity. 1, 2

Types of Hyperparathyroidism

Secondary Hyperparathyroidism

• Characterized by normal or low serum calcium with elevated PTH, commonly seen in chronic kidney disease (CKD), vitamin D deficiency, and malabsorption syndromes 2
• Results from reduced plasma levels of 1,25(OH)2D leading to decreased intestinal calcium absorption and impaired suppression of PTH synthesis 1

Tertiary Hyperparathyroidism

• Characterized by hypercalcemia with elevated PTH, often developing after longstanding secondary hyperparathyroidism 3
• Commonly seen in patients with end-stage renal disease, particularly after kidney transplantation 3, 4

Management Algorithm for Secondary Hyperparathyroidism

CKD-Related Secondary Hyperparathyroidism

1. First-line interventions:

   • Control serum phosphorus through dietary phosphorus restriction and phosphate binders 1
   • Target serum phosphorus within the normal range 1
   • Ensure adequate vitamin D status 1, 2

2. Vitamin D therapy:

   • Initiate active vitamin D analogs (calcitriol, paricalcitol, or doxercalciferol) 5, 1
   • For hemodialysis patients, intermittent intravenous administration is more effective than oral administration 5, 1
   • Adjust dosage according to severity of hyperparathyroidism 5
   • Monitor serum calcium and phosphorus every 2 weeks for 1 month after initiating therapy, then monthly 5, 6

3. Calcimimetic therapy:

   • Consider cinacalcet for persistent secondary hyperparathyroidism despite vitamin D therapy 1, 6
   • Starting dose is 30 mg once daily, taken with food 6
   • Titrate dose no more frequently than every 2-4 weeks through sequential doses of 30,60,90,120, and 180 mg once daily 6
   • Target iPTH levels of 150-300 pg/mL 6
   • Monitor serum calcium frequently during dose titration 6

Non-CKD Secondary Hyperparathyroidism

• For vitamin D deficiency: Provide vitamin D supplementation 1, 7
• For X-linked hypophosphatemia: Adjust active vitamin D and/or decrease phosphate supplements 2
• For malabsorption syndromes: Address underlying cause and provide calcium and vitamin D supplementation 7, 8

Surgical Management

• Consider parathyroidectomy for severe hyperparathyroidism with hypercalcemia that precludes medical therapy 1, 2

• Surgical options include:

  • Total parathyroidectomy (TPTX) 5, 1
  • Total parathyroidectomy with autotransplantation (TPTX+AT) 5, 1
  • Subtotal parathyroidectomy (SPTX) 5, 1

• TPTX+AT has become the first choice for treatment of secondary hyperparathyroidism in many clinical centers due to lower risk of permanent hypoparathyroidism 5

Post-Treatment Monitoring

• For patients on medical therapy:

  • Monitor serum calcium and phosphorus monthly 6
  • Measure iPTH every 1-3 months until target levels are achieved, then every 3 months 5

• For post-parathyroidectomy patients:

  • Monitor ionized calcium every 4-6 hours for the first 48-72 hours 1, 2
  • Provide calcium supplementation if hypocalcemia develops 1, 2

Common Pitfalls to Avoid

• Not assessing vitamin D status when interpreting PTH levels 2
• Excessive vitamin D therapy leading to hypercalcemia and worsening hyperparathyroidism 5, 1
• Inadequate monitoring of calcium levels during cinacalcet therapy, which can lead to hypocalcemia 6
• Delayed recognition of tertiary hyperparathyroidism in patients with longstanding secondary hyperparathyroidism 3, 4

Special Considerations

• For patients with X-linked hypophosphatemia and secondary hyperparathyroidism, consider cinacalcet with close monitoring, though it is not licensed for this indication 5
• Parathyroidectomy should be considered in patients with tertiary hypercalcemic hyperparathyroidism 5
• Cinacalcet is not indicated for use in patients with CKD who are not on dialysis due to increased risk of hypocalcemia 6