Value of percutaneous core needle biopsy in the differential diagnosis of renal transplant dysfunction.

The value of percutaneous core needle biopsy in the differentiation of rejection from other causes of renal allograft dysfunction, and its subsequent effect on patient management were assessed in 64 consecutive biopsies performed on 34 patients in whom the clinical diagnosis was was uncertain. A complete clinical, biochemical and radiographic assessment was made in each patient before biopsy. Only 1 biopsy (1.6 per cent) yielded tissue inadequate for evaluation, while another biopsy caused a renal artery pseudoaneurysm that ruptured and resulted in graft loss. In 27 of these 64 biopsies (42 per cent) the results differed from the pre-biopsy diagnosis and directly affected patient management, particularly the use of steroids. The remaining biopsy specimens were helpful to confirm uncertain clinical impressions, and allowed accurate counseling for patients and family. Biopsies were of special usefulness in separating acute rejection from complications, such as acute tubular necrosis, cytomegalovirus infections, recurrence of original disease, cyclosporin toxicity and acute superimposed-upon chronic rejection. Of 64 biopsies 22 (34.3 per cent) demonstrated the absence of rejection and 8 demonstrated chronic rejection (12.5 per cent), thereby averting the use of steroids in 46.8 per cent of the patients. All patients with evidence of severe small vessel disease and/or antibody-mediated rejection eventually lost the grafts, including 2 with cytomegalovirus glomerulopathy who also suffered such vascular changes. These data highlight the extreme usefulness of needle biopsy in the evaluation and management of renal allograft dysfunction.