Bowel Blockage Without a Block: Amyloidosis Presenting as Chronic Intestinal Pseudo-Obstruction

We present the case of a 61-year-old man with a history of schizophrenia and non-ischemic cardiomyopathy who was admitted with chronic nausea, vomiting, and abdominal pain. His clinical course was marked by recurrent hospitalizations due to persistently dilated small bowel and multiple exploratory laparotomies, all failing to yield a definitive diagnosis, raising suspicion for chronic intestinal pseudo-obstruction. Extensive testing for vascular, paraneoplastic, infectious, and autoimmune causes was unremarkable. Given his unexplained cardiomyopathy and elevated serum light chains with a mild M spike, amyloidosis was suspected. A biopsy of the abdominal fat pad with Congo red staining confirmed amyloid deposition. His symptoms showed partial improvement with prucalopride, but he continues to require total parenteral nutrition and a venting gastrostomy tube for symptom management. Amyloid subtyping and a bone marrow biopsy are pending to determine the underlying etiology.