From the Guidelines
Parathyroid hormone (PTH) levels should be evaluated in the context of serum calcium levels to diagnose and manage hyperparathyroidism, with treatment aimed at normalizing calcium levels and preventing long-term complications, as emphasized in the 2021 study on acr appropriateness criteria for parathyroid adenoma 1.
Diagnosis and Treatment
When diagnosing hyperparathyroidism, it is crucial to measure both PTH and calcium levels simultaneously. Elevated PTH can result from parathyroid adenomas, chronic kidney disease, or vitamin D deficiency, leading to high calcium levels, bone loss, kidney stones, and neurological symptoms.
- Normal PTH levels range from 10-65 pg/mL, though this may vary by laboratory.
- Primary hyperparathyroidism often requires surgical removal of abnormal parathyroid tissue, with two accepted curative operative strategies being bilateral neck exploration (BNE) and minimally invasive parathyroidectomy (MIP) 1.
- MIP is less invasive than BNE and is often performed when preoperative imaging confidently localizes a single parathyroid adenoma, offering benefits such as shorter operating times, faster recovery, and decreased perioperative costs 1.
Management Considerations
Treatment of hyperparathyroidism depends on the underlying cause, with secondary hyperparathyroidism being managed by addressing the underlying condition with vitamin D supplements, phosphate binders, or calcimimetics like cinacalcet.
- In cases of persistent or recurrent hyperparathyroidism, preoperative imaging is essential to localize the target parathyroid lesion and identify postoperative changes from previous parathyroid explorations that can impact subsequent surgery 1.
- Hypoparathyroidism treatment includes calcium supplements (1-3g daily) and active vitamin D (calcitriol 0.25-2.0 mcg daily) to maintain normal calcium levels.
Clinical Implications
Given the potential negative effects of long-term hypercalcemia, treatment of primary hyperparathyroidism is typically indicated even in asymptomatic cases, with the goal of preventing complications such as bone demineralization, fractures, nephrolithiasis, and neurocognitive disorders 1.
From the Research
Parathyroid Hormone (PTH) Regulation and Conditions
- PTH helps regulate calcium homeostasis in a complex relationship with the gastrointestinal tract, kidneys, bone, and parathyroid glands 2.
- Abnormalities in PTH production can result in many conditions, including hypoparathyroidism, and primary, secondary, and tertiary hyperparathyroidism 2.
Hypoparathyroidism
- Hypoparathyroidism is a metabolic disorder in which hypocalcemia and hyperphosphatemia occur either from a failure of the parathyroid glands to secrete sufficient amounts of biologically active PTH, or from an inability of PTH to appropriately induce a biological response in its target tissues 3.
- The most common cause of acquired hypoparathyroidism is surgery, accounting for 75% of all cases 3.
- Patients with chronic hypoparathyroidism are treated with a combination of calcium, vitamin D analogs, and, occasionally, exogenous PTH 2.
Hyperparathyroidism
- Primary hyperparathyroidism is often caused by a single parathyroid adenoma, with multiglandular disease and cancer as other possible etiologies 2.
- Secondary and tertiary hyperparathyroidism are often caused by chronic kidney disease-mineral and bone disorder (CKD-MBD), in which hypocalcemia stimulates PTH production 2.
- Severe calcium or vitamin D deficiency can also cause secondary hyperparathyroidism and is managed with calcium and vitamin D replacement 2.
PTH Therapy
- PTH therapy has been shown to achieve a small improvement in physical health-related quality of life in patients with chronic hypoparathyroidism 4.
- PTH therapy results in more patients reaching 50% or greater reduction in the dose of active vitamin D and calcium 4.
- PTH therapy may increase hypercalcemia, but the evidence is limited due to short duration and small sample size of studies 4.