From the Guidelines
Elevated parathyroid hormone (PTH) levels can increase the risk of peripheral calcium buildup, particularly in blood vessels and soft tissues, as seen in conditions like primary hyperparathyroidism or secondary hyperparathyroidism due to kidney disease, which disrupts normal calcium metabolism. This occurs through a complex process where persistently high PTH leads to hypercalcemia and abnormal calcium deposition outside the skeletal system. The mechanism involves PTH-induced changes in calcium and phosphate balance, along with effects on vascular smooth muscle cells that can transform into bone-forming cells 1.
Key Points to Consider
- Elevated PTH levels are associated with an increased risk of cardiovascular complications, particularly in patients with chronic kidney disease, due to vascular calcification 1.
- Management of elevated PTH typically focuses on treating the underlying cause, which might include parathyroidectomy for primary hyperparathyroidism, or medications like cinacalcet, vitamin D analogs, or phosphate binders for secondary hyperparathyroidism in kidney disease patients 1.
- Regular monitoring of calcium, phosphate, and PTH levels is essential for patients with conditions associated with PTH abnormalities, as high and progressively increasing PTH levels warrant investigation 1.
- The optimal PTH level in patients with CKD not on dialysis remains undefined, but observational data suggest that high and progressively increasing PTH levels are independently associated with CKD progression and cardiovascular events, mortality, and fractures 1.
Clinical Implications
- Treating the underlying cause of elevated PTH is crucial to prevent peripheral calcium buildup and associated complications.
- Clinicians should be aware of the potential risks of elevated PTH levels and monitor patients regularly to prevent long-term consequences.
- The use of novel calcimimetics, such as etelcalcetide, evocalcet, and upacicalcet, may be beneficial in reducing PTH levels in patients with CKD G5D, although more research is needed to support survival benefits 1.
From the Research
Elevated pTH and Peripheral Calcium Buildup
- Elevated parathyroid hormone (pTH) levels can increase the risk of peripheral calcium buildup, as pTH promotes calcium release from the bone and renal calcium reabsorption 2.
- Primary hyperparathyroidism (PHPT) is characterized by hypercalcemia and elevated or inappropriately normal serum levels of pTH, which can lead to peripheral calcium buildup and vascular calcification 3.
- Chronic hypercalcemia associated with increased levels of pTH contributes to the development of calcification of vessel walls and atherosclerotic plaques, which can occur in the intima or media of the arterial wall 3.
- Vascular calcification can lead to stiffness of peripheral arteries, formation of atherosclerotic plaques, and narrowing of the vessel lumen, increasing the risk of cardiovascular morbidity and mortality 3.
Risk Factors and Complications
- Elevated pTH levels can increase the risk of nephrolithiasis, nephrocalcinosis, and osteoporosis, which are common complications of PHPT 4, 2, 5.
- Hyperparathyroidism can also increase the risk of cardiovascular disease, including peripheral arterial disease, due to the development of vascular calcification and atherosclerosis 3.
- The risk of peripheral calcium buildup and vascular calcification can be reduced by treating hyperparathyroidism, particularly with parathyroidectomy, which is the only curative treatment for PHPT 4, 3, 5.
Diagnosis and Management
- The diagnosis of PHPT is based on serum calcium and pTH levels, as well as clinical presentation and imaging studies 4, 2, 5.
- Medical therapies, such as calcimimetics and vitamin D receptor activators, can increase bone mineral density and reduce serum calcium levels, but parathyroidectomy remains the primary therapeutic option for PHPT 4, 3, 5.