To whom should patients with parathyroid hormone (PTH) problems be referred for evaluation and treatment?

Referral Recommendations for Parathyroid Hormone Problems

Patients with parathyroid hormone (PTH) problems should be referred to an endocrinologist, with cases requiring surgical intervention being referred to an experienced parathyroid surgeon. The specific referral pathway depends on the type of PTH disorder, severity, and associated complications.

Types of PTH Disorders and Appropriate Referrals

Primary Hyperparathyroidism

• Patients with confirmed primary hyperparathyroidism should be referred to an endocrinologist for initial evaluation and management planning 1
• Surgical referral to a high-volume parathyroid surgeon is indicated for:
  • Significant hypercalcemia (>0.25 mmol/L above upper limit of normal) 1
  • Impaired renal function (GFR <60 mL/min/1.73 m²) 1
  • Patients with symptomatic disease (kidney stones, bone disease, etc.) 2
  • Most asymptomatic patients, as surgery is more cost-effective than observation or pharmacologic therapy 2

Secondary Hyperparathyroidism

• Patients with CKD-related secondary hyperparathyroidism should be managed by a nephrologist in coordination with an endocrinologist 3
• Referral to parathyroid surgery is recommended for:
  • Severe hyperparathyroidism with persistent hypercalcemia that precludes medical therapy 4
  • Cases that fail to respond to medical therapy with calcimimetics, vitamin D analogs, or combination therapy 3
  • Tertiary hyperparathyroidism (persistent hypercalcemic hyperparathyroidism) despite optimized medical management 4

X-Linked Hypophosphatemia with PTH Abnormalities

• These patients should be managed in a multidisciplinary team setting including an endocrinologist and nephrologist 3
• Parathyroidectomy should be considered for tertiary hyperparathyroidism despite optimized active vitamin D and cinacalcet therapy 3

Timing of Referral

• Immediate referral is warranted for:

  • Serum calcium >1 mg/dL above normal range 2
  • PTH levels persistently >800 pg/mL with hypercalcemia and/or hyperphosphatemia refractory to medical therapy 1
  • Evidence of end-organ damage (kidney stones, osteoporosis, fragility fractures) 2

• Delayed referral leads to increased morbidity:

  • Studies show an average delay of almost 5 years in referral to specialists for patients with primary hyperparathyroidism who meet surgical criteria 5
  • Only 22% of patients with classic hyperparathyroidism (abnormal calcium and PTH) are referred to surgeons 6

Specialist Selection Considerations

• Endocrinologists with high case volume (≥12 PHPT cases per year) demonstrate better awareness of management guidelines 7
• Parathyroid surgeons who perform a high volume of operations have better outcomes 2
• For complex cases such as familial hyperparathyroidism, reoperative parathyroidectomy, or parathyroid carcinoma, referral to specialized centers with appropriate expertise is recommended 2

Pre-Referral Evaluation

• Before referral, primary care physicians should obtain:
  • Serum calcium (total and ionized) and phosphate levels 3
  • Intact PTH measurement using appropriate assay 1
  • 25-hydroxyvitamin D levels to assess for vitamin D deficiency 1
  • 24-hour urine calcium measurement 2
  • Renal function tests (creatinine, GFR) 1
  • Dual-energy x-ray absorptiometry (DEXA) scan for bone density assessment 2

Common Pitfalls in Referral Process

• Failure to recognize hypercalcemia as a sign of hyperparathyroidism (only 31% of hypercalcemic patients have PTH levels measured) 6
• Not assessing vitamin D status when interpreting PTH levels, which can lead to misdiagnosis 1
• Using different PTH assay generations without considering their varying sensitivity to PTH fragments 1
• Performing parathyroid biopsy before surgical referral, which should be avoided 2
• Inadequate documentation of hypercalcemia/hyperparathyroidism in medical records (only 28% of hypercalcemic patients have documented diagnosis) 6

By following these referral guidelines, clinicians can ensure timely and appropriate care for patients with PTH disorders, potentially reducing morbidity and improving outcomes.