Findings: A radiograph of both hands and an AP radiograph of the spine were obtained. The radiograph of the hand demonstrates osteopenia. Multiple lytic and somewhat expansile lesions with well-defined borders, that are in part sclerotic, are present bilaterally. These lesions are present in the distal aspects of the metacarpals and in the proximal, mid and distal phalanges. Subperiosteal resorption is present along the radial aspect of the proximal and mid phalanges bilaterally involving the first through fifth fingers. Generalized thinning of the cortices is present of all the metacarpals suggestive of endosteal bone resorption.

The radiograph of the spine demonstrates extensive erosions of both SI joints, which are widened bilaterally and symmetrically.

Diagnosis: Secondary hyperparathyroidism related to renal osteodystrophy.

Discussion: Renal osteodystrophy results from chronic renal failure by abnormal metabolism of vitamin D. The kidney is unable to hydroxylate vitamin D to form the active compound. This results in sustained hypocalcemia resulting in secondary hyperparathyroidism. Secondary hyperparathyroidism can also result from malabsorption of vitamin D, osteomalacia, and pseudohyperparathyroidism. Clinical findings in hyperparathyroidism are related to renal, skeletal and gastrointestinal changes. Symptomatic bone disease is present in 25% of patients and often progress to pain, swelling, and deformity.

Secondary hyperparathyroidism results in bone resorption from the osteoclastic activity. Subperiosteal bone resorption is often found at the radial aspect of the phalanges of the hand. Subperiosteal resorption of bone also occurs near articular surfaces, particularly at the acromioclavicular joint, sternoclavicular joint, and sacroiliac joints as well as the pubic symphysis. Bone resorption also occurs at subligamentous and subtendinous areas. Brown tumors, which are lytic lesions, occur related to accumulation of fibrous tissue as well as giant cells. These can be single or multiple and can also be expansile. Bone sclerosis also occurs in secondary hyperparathyroidism at the superior and inferior end plates of the spine resulting in "Rugger Jersey" spine. The mechanism of bony sclerosis is not well established. Chondrocalcinosis is another finding, resulting from calcium pyrophosphate dihydrate crystal deposition. This often results in CPPD arthropathy. Pathologic fractures occur, particularly in the spine and in regions of Brown tumors. Both soft tissue and vascular calcification may also occur.

Reference:
Resnick D. Bone and Joint Imaging. 1996.

Return to Musculoskeletal Teaching File Page