Amyloidosis for the Gastroenterologist: A Comprehensive Systematic Review of Diagnosis and Management of Gastrointestinal Manifestations

Amyloidosis is a rare, multisystem disorder characterized by extracellular deposition of misfolded protein fibrils. Gastrointestinal (GI) amyloidosis is uncommon but under-recognized due to nonspecific symptoms, but early diagnosis is critical to improve quality of life and prognosis. This comprehensive systematic review aimed to summarize current literature on GI and hepatic manifestations of amyloidosis, highlighting diagnostic and management strategies across the major subtypes of amyloidosis, in particular AL (immunoglobulin light chain), ATTR (transthyretin), and AA (serum amyloid A) amyloidosis. A systematic search of MEDLINE, Embase, and PubMed conducted for studies published between January 2014 and December 2024 identified 77 studies meeting inclusion criteria. GI symptoms occur in approximately 1 in 6 patients with amyloidosis, but symptoms correlate poorly with gastrointestinal deposition. Current literature suggests that duodenal biopsy is the most reliable diagnostic site. Fibroscan shows promise in detecting hepatic amyloid involvement. Management is subtype specific. However, supportive care, particularly nutritional intervention, is essential across all subtypes. GI amyloidosis presents diversely with nonspecific symptoms. Standardized diagnostic algorithms, targeted therapies, and nutritional support can lead to improved outcomes and enhance quality of life.