Submitted by Ricky Kaneshiro, MD and Thomas Learch, MD.
30-year old female with PMH of hyperparathyroidism presents to the ED with right knee pain after a mechanical fall.
Knee x ray was done which showed no fractures or soft tissue swelling. There was, however, thickening of the patellar and quadriceps tendons with suggestion of intra-tendinous dystrophic calcifications.
MRI was performed and re-demonstrated thickening of the patellar and quadriceps tendons with focal calcifications within the proximal patellar tendon.
Parathyroid hormone (PTH) is produced by the parathyroid glands and helps to maintain serum calcium levels. When calcium levels are low PTH is secreted. Osteoclast activity is increased which in turn leads to bone resorption and release of calcium. Hyperparathryoidism is a condition of excess parathyroid hormone and is classified as either primary, secondary or tertiary. Excess PTH can lead to intra-tendinous dystrophic calcifications and subperiosteal bone resorption which ultimately results in tendinopathy with increased risk of rupture.