Treatment of Secondary Hyperparathyroidism
The treatment of secondary hyperparathyroidism should begin with dietary phosphate restriction, phosphate binders, correction of hypocalcemia, and vitamin D supplementation, with calcimimetics added for persistent cases, and parathyroidectomy reserved for severe refractory cases. 1
Initial Medical Management
- Dietary phosphate restriction and phosphate binders (calcium-based or non-calcium based) are first-line treatments to control serum phosphorus levels within the normal range 1
- Vitamin D supplementation should target 25-OH vitamin D levels >20 ng/ml (50 mmol/l) to address vitamin D deficiency 2
- Active vitamin D therapy with calcitriol or vitamin D analogs is recommended to suppress PTH levels, with intravenous administration being more effective than oral administration in hemodialysis patients 1
- Vitamin D dosage should be adjusted according to the severity of hyperparathyroidism, with monitoring for hypercalcemia 1
Advanced Medical Management
- For persistent secondary hyperparathyroidism despite vitamin D therapy, calcimimetics such as cinacalcet may be considered 1
- Cinacalcet is FDA-approved for treatment of secondary hyperparathyroidism in adult patients with chronic kidney disease on dialysis, but not for those not on dialysis due to increased risk of hypocalcemia 3
- Cinacalcet should be initiated at 30 mg once daily and titrated every 2-4 weeks through sequential doses of 30,60,90,120, and 180 mg once daily to target iPTH levels of 150-300 pg/mL 3
- Etelcalcetide is an intravenous calcimimetic indicated for secondary hyperparathyroidism in adult patients with chronic kidney disease on hemodialysis 4
- Serum calcium and phosphorus should be monitored within 1 week and iPTH within 1-4 weeks after initiation or dose adjustment of calcimimetics 3
Surgical Management
- Parathyroidectomy should be considered for severe hyperparathyroidism (persistent serum levels of intact PTH >800 pg/mL) associated with hypercalcemia and/or hyperphosphatemia refractory to medical therapy 5, 1
- Surgical options include:
- Recent evidence suggests TPTX may be superior to TPTX+AT in terms of lower recurrence rates of secondary hyperparathyroidism (OR = 0.17; 95% CI, 0.06-0.54; P = 0.002) 6
- TPTX also offers shorter operative time compared to TPTX+AT (WMD = 17.30; 95% CI, 30.53 to 4.06; P < 0.05) 6
- While TPTX has a higher risk of hypoparathyroidism (OR = 2.97; 95% CI, 1.09-8.08; P = 0.01), studies have not shown development of permanent hypocalcemia or adynamic bone disease 6
Postoperative Management
- Monitor ionized calcium every 4-6 hours for the first 48-72 hours after surgery, then twice daily until stable 2, 5
- Initiate calcium gluconate infusion and adjust phosphate binders as needed based on serum phosphorus levels 5
- Hypocalcemia is a common complication after parathyroidectomy and can be managed with calcium and vitamin D supplementation 6
Monitoring and Follow-up
- For patients on medical therapy, monitor serum calcium approximately monthly for patients with secondary hyperparathyroidism with CKD on dialysis 3
- Serum iPTH levels should be assessed no earlier than 12 hours after dosing with cinacalcet 3
- Reduce or temporarily discontinue vitamin D therapy if serum calcium rises above the normal range 1
- For patients who have undergone parathyroidectomy, monitor for recurrence of hyperparathyroidism, which may require reoperation 5
Special Considerations
- Preoperative imaging with ultrasound, 99mTc-Sestamibi scan, CT scan, or MRI should be performed prior to reoperative parathyroid surgery to localize target parathyroid lesions 5
- For patients with secondary hyperparathyroidism due to insufficient calcium intake (with normal kidney function and vitamin D levels), calcium supplementation (600 mg twice daily) may normalize PTH levels 7
- The choice between medical management with calcimimetics versus surgical parathyroidectomy should consider the severity of hyperparathyroidism, patient's surgical risk, and potential for kidney transplantation 8