Gastrointestinal Bleeding as Initial Manifestation of Injection Drug Use-Associated Amyloidosis.

Systemic amyloidosis has been reported in the context of injection drug use, usually related to ongoing chronic inflammation and persistent cutaneous infections. The kidneys are almost always the first organs affected in that setting. Involvement of the gastrointestinal tract is less common and rarely the initial site of presentation. We present a case of systemic amyloidosis that primarily manifested in the gastrointestinal tract, occurring in the setting of chronic injection drug use. The patient's hemoglobin level dropped progressively over time due to ongoing, slow gastrointestinal bleeding, prompting an endoscopic examination that ultimately confirmed the presence of gastrointestinal amyloidosis. As the overall prognosis for gastrointestinal amyloidosis is poor, early diagnosis and treatment are essential to decelerate the progression of the disease.