[Secondary (AA) amyloidosis in Crohn's disease].

Amyloidosis is a clinical entity that results from deposition of an extracellular protein material that causes disruption in normal architecture and impairs function of multiple organs and tissues. Secondary amyloidosis (AA) is a rare but serious complication that occurs in the context of cancer, chronic inflammation and chronic infectious diseases, including inflammatory bowel disease, mainly long-standing Crohn's disease. Renal failure is the most common clinical presentation of AA, ranging from nephrotic syndrome and impaired renal function to renal failure, with a potential for high morbidity. The incidence of the association of secondary amyloidosis in patients with Crohn's disease has been reported to be 0.5%-8%. We present a case of a 39-year-old male patient diagnosed with Crohn's disease at age 21 and submitted to right hemicolectomy because of ileus 17 years before. Thereafter, he was treated with corticosteroids for 15 years and with azathioprine for a short period; in the last three years he was on therapy with mesalazine alone. He was hospitalized due to worsening clinical condition and re-evaluation of the underlying disease. Physical examination revealed marked peripheral edema in both lower extremities. Endoscopic and radiographic examinations confirmed the underlying disease activity. Laboratory tests showed an increase of inflammatory reactants, anemia, hypocalcemia, and severe hypoalbuminemia and hypoproteinemia. He had proteinuria over 24 g/L and creatinine clearance of 66 mL/min, falling within second grade of chronic kidney disease. Renal biopsy was performed for evaluation of renal insufficiency with nephrotic range proteinuria. Congo red staining showed the presence of characteristic amyloid deposition; deposits immunoreacted with the antibody against amyloid A protein, confirming the diagnosis of secondary amyloidosis. The patient was suggested active induction treatment with corticosteroids and azathioprine to achieve remission of Crohn's disease, thereafter treatment with infliximab, but he did not consent with this therapy at that time. Studies with infliximab have demonstrated a decrease in SAA circulating levels and proteinuria, as well as stabilization of renal function. Amyloidosis is frequently described as a major cause of death in patients with Crohn's disease, with long-term mortality between 40% and 60%. Various therapeutic attempts such as azathioprine, colchicine, dimethyl sulfoxide, infliximab, and elemental diets have been tried but there is no definite treatment for secondary amyloidosis in Crohn's disease. Kidney transplantation may offer the best prospects for patients with Crohn's disease who develop amyloidosis and end-stage renal failure.