How to manage hyperparathyroidism?

Management of Elevated PTH (166 pg/mL)

For a PTH level of 166 pg/mL, the recommended approach is to increase active vitamin D (calcitriol) dosage and/or decrease phosphate supplement dosage to manage secondary hyperparathyroidism. 1

Initial Evaluation

When faced with a PTH of 166 pg/mL, it's essential to determine the underlying cause of hyperparathyroidism:

• Check serum calcium, phosphorus, 25-hydroxyvitamin D, and kidney function
• Determine if this represents primary, secondary, or tertiary hyperparathyroidism
• Assess for symptoms (bone pain, muscle weakness, kidney stones, neuropsychiatric symptoms)

Treatment Algorithm Based on Type of Hyperparathyroidism

For Secondary Hyperparathyroidism (most common with kidney disease):

1. First-line approach:

   • Increase active vitamin D (calcitriol) dosage (start with 0.25-0.5 μg daily) 2
   • Decrease phosphate supplement dosage if patient is on supplements 1
   • Ensure adequate native vitamin D (cholecalciferol) supplementation if deficient 2

2. If PTH remains elevated despite above measures:

   • Consider adding calcimimetic (cinacalcet) starting at 30 mg once daily 3
   • Titrate cinacalcet every 2-4 weeks through sequential doses (30,60,90,120,180 mg) to target PTH 150-300 pg/mL 3
   • Monitor serum calcium weekly after initiation or dose adjustment 3

3. For persistent hyperparathyroidism despite medical therapy:

   • Consider parathyroidectomy (surgical options include subtotal or total parathyroidectomy with autotransplantation) 1

For Primary Hyperparathyroidism:

1. If symptomatic or meeting surgical criteria:

   • Parathyroidectomy is the treatment of choice 4
   • Minimally invasive approach if single adenoma is identified 5

2. If surgery is contraindicated:

   • Cinacalcet starting at 30 mg twice daily 3
   • Bisphosphonates may help preserve bone density 6

For Tertiary Hyperparathyroidism:

1. If persistent hypercalcemic hyperparathyroidism despite optimized therapy:
   • Parathyroidectomy is recommended 1, 7

Monitoring and Follow-up

• Measure serum calcium and phosphorus within 1 week of treatment initiation or adjustment 3
• Measure PTH 1-4 weeks after treatment changes 3
• Once stable, check calcium monthly and PTH every 3 months 2
• For patients on cinacalcet, monitor for hypocalcemia, especially during dose titration 3

Common Pitfalls to Avoid

1. Overlooking vitamin D deficiency: Always check and correct vitamin D deficiency, which can contribute to secondary hyperparathyroidism 2

2. Excessive phosphate supplementation: Avoid doses >80 mg/kg daily of elemental phosphorus to prevent gastrointestinal discomfort and worsening hyperparathyroidism 1

3. Ignoring hypercalcemia: If present with elevated PTH, this strongly suggests primary hyperparathyroidism requiring surgical evaluation 8

4. Inadequate monitoring: Failure to monitor calcium levels can lead to hypercalcemia or hypocalcemia, especially when using active vitamin D or cinacalcet 3

5. Delaying surgical referral: For patients with severe hyperparathyroidism (PTH >800 pg/mL) with hypercalcemia and/or hyperphosphatemia refractory to medical therapy, surgical referral should not be delayed 1

A PTH of 166 pg/mL requires thorough evaluation and targeted treatment based on the underlying cause, with careful monitoring of calcium, phosphorus, and PTH levels to guide therapy adjustments and prevent complications.