How to manage elevated parathyroid hormone (PTH) levels?

Management of Elevated Parathyroid Hormone (PTH) Levels

For patients with elevated PTH levels, treatment should be targeted to the underlying cause, with specific interventions based on kidney function, calcium and phosphorus levels, and vitamin D status. Management differs significantly between patients with chronic kidney disease (CKD) and those with normal kidney function.

Initial Assessment

• Measure serum calcium, phosphorus, 25(OH)D levels
• Assess kidney function (eGFR)
• Evaluate for modifiable factors: hyperphosphatemia, hypocalcemia, high phosphate intake, vitamin D deficiency 1

Management Algorithm Based on Kidney Function

For Patients Without CKD or Early CKD (Stages G1-G2):

1. Correct vitamin D deficiency:

   • Supplement with native vitamin D (cholecalciferol or ergocalciferol) to achieve 25(OH)D levels >30 ng/mL 1
   • Target normal calcium levels

2. If PTH remains elevated with normal vitamin D:

   • Consider primary hyperparathyroidism if calcium is elevated
   • Consider normocalcemic hyperparathyroidism if calcium is normal

For Patients with Moderate CKD (Stages G3a-G5 not on dialysis):

1. First-line interventions:

   • Correct vitamin D deficiency
   • Control serum phosphorus (<4.6 mg/dL) 1
   • Consider dietary phosphate restriction
   • Use phosphate binders if needed (preferably non-calcium based) 1

2. For progressive or persistently elevated PTH:

   • Do not routinely use calcitriol or vitamin D analogs 1
   • Reserve calcitriol/vitamin D analogs only for patients with CKD G4-G5 with severe and progressive hyperparathyroidism 1
   • When using calcitriol: start with 0.25 μg/day (can increase to 0.5 μg/day) 1
   • Monitor calcium and phosphorus levels monthly for first 3 months, then every 3 months 1

For Patients with End-Stage Kidney Disease on Dialysis (CKD G5D):

1. Target PTH range: 2-9 times the upper normal limit for the assay 1

2. Treatment options:

   • Calcimimetics (cinacalcet): Starting dose 30 mg once daily with food, titrate every 2-4 weeks 2
   • Vitamin D analogs: Calcitriol, alfacalcidol, paricalcitol, or doxercalciferol 1
   • Combination therapy: Calcimimetics with vitamin D analogs 1

3. Monitoring:

   • Measure calcium and phosphorus every 2 weeks for 1 month after starting/changing therapy, then monthly 1
   • Measure PTH monthly for 3 months, then quarterly once target levels achieved 1

4. For severe hyperparathyroidism unresponsive to medical therapy:

   • Consider parathyroidectomy 1

Dose Adjustments and Safety Monitoring

For Vitamin D Therapy:

• Hold therapy if:

  • PTH falls below target range
  • Serum calcium exceeds 9.5 mg/dL
  • Serum phosphorus rises above 4.6 mg/dL 1

• Resume at half the previous dose when parameters normalize 1

For Cinacalcet Therapy:

• Contraindicated if serum calcium is below normal range 2
• Monitor for hypocalcemia: Can cause paresthesias, muscle spasms, tetany, seizures, QT prolongation 2
• Adjust dose if serum calcium falls below 8.4 mg/dL:
  • Increase calcium-containing phosphate binders or vitamin D sterols
  • If calcium falls below 7.5 mg/dL, withhold cinacalcet until calcium reaches 8 mg/dL 2

Special Considerations

• X-linked hypophosphataemia: Requires specific management with phosphate supplements and active vitamin D 1

• Tertiary hyperparathyroidism: Consider parathyroidectomy for persistent hypercalcemic hyperparathyroidism despite optimized medical therapy 1

• Post-kidney transplant: Monitor calcium and phosphate weekly until stable, then adjust frequency based on CKD stage 1

Common Pitfalls to Avoid

1. Ignoring vitamin D status: Always check and correct vitamin D deficiency before escalating to other therapies

2. Overtreatment leading to adynamic bone disease: Avoid suppressing PTH below target range

3. Calcium-based phosphate binders in hypercalcemia: Can worsen hypercalcemia and increase risk of vascular calcification

4. Failure to recognize tertiary hyperparathyroidism: Persistent hypercalcemia with elevated PTH after kidney transplantation requires specific management

5. Simultaneous administration of aluminum and citrate: Can increase aluminum absorption and toxicity in CKD patients 1