Gastrointestinal Amyloidosis as a Cause of Anemia: Rare and Rarely Considered.

Gastrointestinal involvement in amyloidosis is reported in 3% of cases, mostly associated with multiple myeloma. An elderly man with chronic kidney disease presented to the hospital after a large melenic bowel movement. The patient was tachycardic and anemic to 3.8 g/dL on admission and was transfused blood. Endoscopy and colonoscopy were unremarkable. Subsequently, the patient had 2 more admissions for severe anemia requiring blood transfusion. Repeat esophagoduodenoscopy with capsule endoscopy were unremarkable. The patient was diagnosed with monoclonal gammopathy of undetermined significance by hemoglobin electrophoresis, and endoscopy biopsy revealed intestinal amyloidosis in a duodenal specimen. The patient's recurrent anemia was attributed to bleeding from gastrointestinal amyloidosis, in the absence of other identifiable sources of anemia, and was managed with intravenous iron infusions.