Radius Loading in Primary Hyperparathyroidism

Primary hyperparathyroidism (PHPT), a disease characterized by excess parathyroid hormone (PTH) and high blood calcium, is one of the most common endocrine disorders. PHPT is seen most often in post-menopausal women. Kidney stones and bone deformities were prominent manifestations of the disease in the past, however, PHPT is now primarily asymptomatic due to incidental detection of high blood calcium levels. Many patients with PHPT, however, have low bone mineral density (BMD) when bone mass is measured by dual energy x-ray absorptiometry (DXA), primarily at the forearm. There is no effective medical therapy which increases bone density at the forearm in patients with PHPT. PTH both builds and breaks down bone, and the pathways by which PTH mediates these actions are beginning to be identified. Prior research suggests that mechanical loading shifts PTH towards building bone. Arm exercise is an attractive option for the treatment of low forearm BMD in patients with PHPT since it is often the site most affected by excess PTH.