Gastrointestinal manifestation of secondary (AA) amyloidosis with GI symptoms
Amyloidosis is a disorder of the gastrointestinal tract that causes extracellular deposition of abnormal fibrillar protein. The deposition then interferes with the structure and function of organs. Amyloidosis is either hereditary, systemic or localised to a single organ, for example, the gastrointestinal tract. It can be divided into six types, hemodialysis-related, hereditary, senile, and localized amyloidosis.
This article highlights the case of amyloidosis in a 60-year-old woman who presented to the rheumatology clinic with complaints of diarrhoea, weight loss and anorexia with a history of 3 months. On inquiring, the patient told the doctors that she had been diagnosed with rheumatoid arthritis 35 years ago. For which she was currently on treatment with tacrolimus and methotrexate. However, despite being on treatment, her disease activity was not well controlled. The patient’s physical examination was significant for swelling and tenderness in the metacarpophalangeal joints and the wrists.
Doctors further advised an endoscopy for the upper and lower gastrointestinal tract which showed edematous, granular lesions with erosions in the transverse and ascending colon.
Based on the investigations findings, the patient was diagnosed with AA amyloidosis. Biopsy of the specimens showed deposits of amyloid with apple-green birefringence on Congo red staining under polarized light. The findings were consistent with the diagnosis of gastrointestinal AA amyloidosis associated with a high activity level of rheumatoid arthritis.
Secondary (AA) amyloidosis is a secondary manifestation of chronic inflammatory, neoplastic and infectious disorders. In 60% of the patients it affects the GI tract, whereas only 1% to 8% of patients with primary amyloidosis have GI involvement. However, cases of amyloidosis confined to only the GI tract are extremely rare. The deposition of amyloid proteins interferes with the structure and function of organs. The clinical presentation of intestinal amyloidosis varies from asymptomatic to fetal forms. Although AA amyloidosis is caused by extracellular deposition of amyloid fibrils derived from serum amyloid A protein, it is often also associated with familial Mediterranean fever, Crohn’s disease, ankylosing spondylitis and juvenile idiopathic arthritis.
Doctors initiated treatment with monoclonal antibody against interleukin-6 receptor. The patient showed significant improvement in both the gastrointestinal symptoms, joint pain and swelling after several days of initiation of therapy.
Gastrointestinal Amyloidosis https://www.nejm.org/doi/full/10.1056/NEJMicm2034179