What are the steps to diagnose hyperparathyroidism?

From the Guidelines

Diagnosing hyperparathyroidism primarily involves biochemical testing, specifically measuring serum calcium and parathyroid hormone (PTH) levels, as imaging has no role in confirming or excluding the diagnosis. The diagnostic process begins with blood tests to assess calcium and PTH levels, where elevated serum calcium alongside inappropriately high PTH levels strongly suggests primary hyperparathyroidism 1. Additional diagnostic steps include:

• Measuring phosphorus levels, which are typically low in hyperparathyroidism
• Assessing vitamin D levels
• Conducting kidney function tests
• A 24-hour urine calcium collection to distinguish between primary hyperparathyroidism and familial hypocalciuric hypercalcemia
• Bone density testing (DEXA scan) to evaluate bone loss Imaging studies such as ultrasound, sestamibi scan, CT, or MRI are useful for preoperative localization of abnormal parathyroid glands, facilitating minimally invasive parathyroidectomy, especially in cases of primary hyperparathyroidism where a single parathyroid adenoma is suspected 1. Genetic testing may be considered if familial disorders are suspected. The diagnosis of hyperparathyroidism requires correlation between laboratory findings and clinical symptoms, which can include fatigue, bone pain, kidney stones, depression, and cognitive issues. Once diagnosed, treatment options, including parathyroidectomy, can be discussed, offering a curative approach for primary hyperparathyroidism in appropriate surgical candidates.

From the Research

Diagnostic Steps for Hyperparathyroidism

To diagnose hyperparathyroidism, the following steps can be taken:

• Measure parathyroid hormone (PTH) levels, as elevated PTH is a key indicator of primary hyperparathyroidism 2
• Assess calcium levels, as hypercalcemia is a common symptom of hyperparathyroidism 2, 3
• Evaluate kidney function through creatinine and glomerular filtration rate (GFR) measurements 2
• Measure phosphate, 25-OH vitamin D3, and 24-hour urine values to aid in differential diagnosis 2
• Perform kidney ultrasound to detect nephrocalcinosis or kidney stones 2
• Conduct dual-energy X-ray absorptiometry (DXA) to determine bone mineral density (BMD) at various sites 2

Imaging Studies for Hyperparathyroidism

Imaging studies can help locate the hyperfunctioning parathyroid gland or glands:

• Parathyroid ultrasound as a first-line exploration 4, 2
• Nuclear medicine examination, such as parathyroid scintigraphy (e.g., double isotope I/12399m Tc-sestamibi) or PET-CT scan with 18F-choline 4
• Additional investigations using 4D parathyroid CT or parathyroid MRI, fine-needle aspiration cytology, and determination of PTH in the flushing fluid may be necessary in difficult cases 4

Preoperative Evaluation and Surgical Planning

Before surgery, it is essential to:

• Normalize vitamin-D deficiency 2
• Perform presurgical diagnostic evaluation of the thyroid for surgical planning 2
• Consider postsurgical calcium and vitamin-D administration to prevent hypocalcemia and hungry-bone disease 2