Inflammatory Bowel Disease and Systemic AA Amyloidosis

Background Systemic AA amyloidosis is a recognised complication of inflammatory bowel disease. AA amyloidosis is a potential cause of end-stage renal failure and mortality but little is known of the natural history of this condition in inflammatory bowel disease. Methods We evaluated the clinical phenotype, disease progression and outcome amongst 26 patients with inflammatory bowel disease and AA amyloidosis followed prospectively at a single center between 1989 and 2010. Results Twenty-two patients had Crohn's disease and four had ulcerative colitis. Fistulae and abscesses occurred in ten cases, all of whom had Crohn's disease. Amyloidotic proteinuric renal dysfunction occurred in all of the cases. It resolved in five patients with well-controlled inflammation, but was progressive in all of the other patients. Fifteen patients reached end-stage renal disease after a median time of 6.3 years from development of renal dysfunction (by Kaplan-Meier estimate), six of whom subsequently proceeded to renal transplantation. There were five functioning grafts at census 0.8, 3.2, 4.2, 20.1 and 24.6 years after transplantation. One graft failed 14.5 years after renal transplantation because of amyloid recurrence in a patient with sustained chronic inflammatory activity. Conclusions AA amyloidosis remains a serious complication of both Crohn's disease and ulcerative colitis, and is characterized by proteinuric renal dysfunction that may resolve following suppression of inflammatory activity. Patient and graft survival are excellent in patients who undergo renal transplantation.