Quantitative bone histology in end-stage renal failure

Bone biopsies from 37 haemodialysis patients were embedded in a methyl methacrylate:hydroxyethylmethacrylate mixture and consecutive sections taken for: (1) acid phosphatase activity (osteoclasts), (2) pyronin stain for RNA (osteoblasts), and (3) fluorescence for tetracycline. Images of the three sections were traced using a camera lucida and the tracing quantitated with a digitiser. Osteomalacia (OM) was diagnosed by increased osteoid with decreased tetracycline and hyperparathyroidism (HPT) by an increased osteoclast count. OM was present in 8 patients, HPT in 11, OM + HPT in 16, and no disease in 2. Biochemistry could not predict the histology. Histologically, though HPT could be satisfactorily diagnosed, problems still remain in the definition of OM, particularly when combined with HPT.