From the Guidelines
The next step for a patient with elevated parathyroid hormone (PTH) and calcium levels but normal vitamin D should be to evaluate for primary hyperparathyroidism, as suggested by the most recent and highest quality study 1. This evaluation should include a comprehensive metabolic panel to confirm hypercalcemia, 24-hour urine calcium measurement to rule out familial hypocalciuric hypercalcemia, and parathyroid imaging studies such as a sestamibi scan and/or ultrasound of the neck to localize potential parathyroid adenomas. Additional blood tests should include phosphorus levels (typically low in primary hyperparathyroidism) and renal function tests. If primary hyperparathyroidism is confirmed, referral to an endocrinologist and potentially an endocrine surgeon is warranted, as surgical removal of the abnormal parathyroid gland(s) is the definitive treatment for most cases. Some key points to consider in the evaluation and management of primary hyperparathyroidism include:
- Surgery is generally indicated for patients with significant hypercalcemia (>1 mg/dL above normal), osteoporosis, kidney stones, or age under 50 years, as noted in the guidelines 1.
- For patients who are poor surgical candidates or have mild, asymptomatic disease, medical management with monitoring and possibly cinacalcet (a calcimimetic that lowers PTH and calcium levels) may be appropriate.
- The elevated PTH with hypercalcemia and normal vitamin D strongly suggests autonomous PTH secretion from one or more parathyroid glands rather than secondary hyperparathyroidism, which is why focused evaluation for primary hyperparathyroidism is the appropriate next step. It's worth noting that the choice of surgical approach, such as subtotal parathyroidectomy (SPTX), total parathyroidectomy (TPTX), or total parathyroidectomy with autotransplantation (TPTX + AT), may depend on various factors, including the patient's overall health and the surgeon's experience, as discussed in the study 1. However, the most recent and highest quality study 1 suggests that TPTX may have advantages over SPTX and TPTX + AT in reducing the relapse of SHPT, which should be taken into consideration when making treatment decisions.
From the FDA Drug Label
The FDA drug label does not answer the question.
From the Research
Next Steps for Raised Parathyroid Hormone and Normal Calcium Levels
- Evaluate the patient's medical history and current medications to exclude causes of secondary hyperparathyroidism (SHPT) 2, 3
- Consider measuring 25-hydroxyvitamin D levels, as low levels are common in patients with primary hyperparathyroidism (PHPT) 4
- Assess for symptoms such as kidney stones or osteoporosis, which may be related to elevated parathyroid hormone levels 3
- Consider surgical evaluation for patients with normocalcemic primary hyperparathyroidism (NPHPT) who have significant symptoms or end-organ damage 2
- Medical management with cinacalcet may be an option for patients with PHPT, including those with normal calcium levels, to reduce parathyroid hormone levels and alleviate symptoms 5, 6
Key Considerations
- Differentiation between SHPT and NPHPT can be challenging, and a thorough evaluation is necessary to determine the underlying cause of elevated parathyroid hormone levels 2
- Patients with NPHPT may have similar findings at surgery as those with hypercalcemic PHPT, despite normal calcium levels 4
- Cinacalcet has been shown to be effective in reducing hypercalcemia in PHPT patients across a wide spectrum of disease severity, and may be a useful treatment option for patients with normal calcium levels 6