Bone scan in chronic dialysis patients with evidence of secondary hyperparathyroidism and renal osteodystrophy

Bone scans in 13 of 14 patients on chronic dialysis were found to be abnormal. Symmetrical increased activity was noted in the calvarium, mandible, sternum, shoulders, vertebrae, and the distal aspects of the femur and tibia, as well as the patella. The scan abnormality is felt to be most likely the result of secondary hyperparathyroidism because of clinical and laboratory data, and, in four, confirmatory tissue diagnoses. The scan findings support the data of some earlier investigations on bone isotopic accretion in hyperparathyroidism. However, co-existing osteomalacia giving rise to abnormal activity in some of the patients cannot be excluded. Dihydrotachysterol may have minimized the extent of osteomalacia in these patients. Osteoporosis was probably present in some patients, but it appears differently on scan. Osteosclerosis was not detected on radiographic examination. Scan manifestations, especially mandibular activity, were pronounced and appeared earlier than the radiographic changes. The degree and extent of abnormal activity correlated with the length of dialysis and the level of alkaline phosphatase.