From the Guidelines
Checking parathyroid hormone (PTH) levels in a patient with weight loss is crucial because hyperparathyroidism, which can be indicated by elevated PTH, is a potential cause of unexplained weight loss, and early detection can lead to effective treatment and prevention of complications. Hyperparathyroidism is defined as excessive parathyroid hormone production, typically resulting in hypercalcemia 1. Primary hyperparathyroidism (PHPT) is the most common form, occurring when parathyroid glands autonomously overproduce PTH. The condition can lead to various symptoms, including fatigue, weakness, bone pain, kidney stones, cognitive issues, and unintentional weight loss.
Some key points to consider in the diagnostic workup of hyperparathyroidism include:
- Serum PTH measurement alongside calcium levels is essential, as the combination of elevated PTH and hypercalcemia strongly suggests hyperparathyroidism 1.
- PHPT is more common in women, with an incidence of 66 per 100,000 person-years, and 25 per 100,000 person-years in men 1.
- Treatment of PHPT typically involves surgical removal of the affected parathyroid gland(s), which resolves symptoms in most patients 1.
- Weight loss in hyperparathyroidism may result from the metabolic effects of excess calcium, increased energy expenditure, or gastrointestinal symptoms like nausea and decreased appetite that often accompany the condition.
The role of imaging in PHPT is to localize the abnormally functioning gland or glands with high accuracy and high confidence to facilitate targeted curative surgery 1. Therefore, checking PTH levels in a patient with weight loss is a critical step in diagnosing and managing hyperparathyroidism, and it should be done in conjunction with serum calcium measurement and other diagnostic tests as needed.
From the Research
Parathyroid Hormone and Weight Loss
- Weight loss can be a non-specific symptom of various conditions, including primary hyperparathyroidism (PHPT) 2, 3
- PHPT is characterized by excessive secretion of parathyroid hormone (PTH), which can lead to hypercalcemia, skeletal fragility, and other symptoms 2, 3
- Although weight loss is not a typical symptom of PHPT, it can be associated with the condition, particularly in cases where hypercalcemia leads to gastrointestinal symptoms such as nausea, vomiting, and abdominal pain 3
Diagnosis and Management of PHPT
- The diagnosis of PHPT typically involves measurement of serum calcium and PTH levels 2, 3
- In patients with weight loss and suspected PHPT, checking PTH levels can help establish a diagnosis and guide management decisions 2, 3
- Management of PHPT may involve surgery, medical therapy, or a combination of both, depending on the severity of the condition and the presence of symptoms or target organ damage 2, 3
Vitamin D and PHPT
- Vitamin D deficiency is common in patients with PHPT and can stimulate parathyroid secretion 4, 5
- Correction of vitamin D deficiency in patients with PHPT may help reduce PTH levels and alleviate symptoms, but the optimal approach to vitamin D supplementation in this context is still a topic of debate 4, 5
- Further research is needed to fully understand the relationship between vitamin D and PHPT, particularly in patients with normocalcemic PHPT 5, 6