From the Guidelines
Elevated Parathyroid Hormone (PTH) levels with normal Calcium (Ca) levels and a 25-hydroxyvitamin D (25-OH Vit D) level of 90 may indicate normocalcemic primary hyperparathyroidism [ 1 ]. This condition is characterized by an elevated PTH concentration in combination with normal calcium values, and patients are still at risk for developing complications associated with classic primary hyperparathyroidism.
Key Considerations
- The patient's elevated PTH level is the primary concern, as it can lead to bone resorption and increased risk of osteoporosis [ 1 ].
- The normal calcium level does not rule out primary hyperparathyroidism, as some patients may have normocalcemic primary hyperparathyroidism [ 1 ].
- The 25-OH Vit D level of 90 is within the normal range, which suggests that vitamin D deficiency is not contributing to the elevated PTH level.
Recommendation
The patient should be monitored closely and considered for further evaluation, including:
- A repeat PTH measurement to confirm the elevation [ 1 ].
- Regular monitoring of calcium and phosphate levels.
- Assessment for symptoms of hyperparathyroidism, such as kidney stones, bone pain, or abdominal cramps.
Medication
No medication is recommended at this time, but the patient may be considered for:
- A bisphosphonate, such as alendronate 70mg weekly, if the PTH level remains elevated and the patient has symptoms or complications of hyperparathyroidism.
- A calcimimetic, such as cinacalcet 30mg daily, if the PTH level remains elevated and the patient has symptoms or complications of hyperparathyroidism.
Follow-up
The patient should have a follow-up appointment with their primary care physician or an endocrinologist in 3-6 months to:
- Monitor PTH and calcium levels.
- Assess for symptoms or complications of hyperparathyroidism.
From the Research
Interpretation of Elevated Parathyroid Hormone (PTH) Levels
Elevated PTH levels with normal calcium (Ca) levels can be caused by several conditions, including:
- Normocalcemic primary hyperparathyroidism (NPHPT) 2, 3
- Secondary hyperparathyroidism (SHPT) 4, 2 It is essential to exclude causes of SHPT, such as vitamin D deficiency or renal failure, before diagnosing NPHPT 2, 3.
Role of 25-Hydroxyvitamin D (25-OH Vit D) Levels
A 25-OH Vit D level of 90 is considered sufficient, and it is unlikely to be a contributing factor to SHPT in this case 4. However, it is crucial to consider other medical conditions and medications that can increase PTH secretion 2.
Clinical Implications
The presence of elevated PTH levels with normal calcium levels requires careful evaluation and management. A conservative approach to surgery may be advised in cases of NPHPT, and it is essential to monitor patients closely for any changes in their condition 2, 3. The diagnosis and management of PHPT after Roux-en-Y gastric bypass can be challenging due to the presence of SHPT, and surgery may be indicated in some cases 5.
Key Considerations
- Exclude causes of SHPT before diagnosing NPHPT 2, 3
- Consider medical conditions and medications that can increase PTH secretion 2
- Monitor patients closely for any changes in their condition 2, 3
- Surgery may be indicated in some cases of PHPT, including those with a history of Roux-en-Y gastric bypass 5