Small bowel ulcers and bleeding: An overlooked yet critical clinical challenge

Table 1 Causes of small bowel ulcers and bleeding

Category	Specific cause	Mechanism of bleeding/ulceration
Neoplastic	Gastrointestinal stromal tumor	Tumoral infiltration and mucosal ulceration
Neoplastic	Lymphoma	Infiltration and tissue necrosis
Neoplastic	Adenocarcinoma	Mucosal invasion and ulceration
Inflammatory	Crohn’s disease	Transmural inflammation and ulceration
Inflammatory	Behçet’s disease	Vasculitis involving submucosal vessels
Inflammatory	Systemic lupus erythematosus	Immune complex-mediated vasculitis
Infectious	Intestinal tuberculosis	Granulomatous inflammation and ulceration
Infectious	Cytomegalovirus infection	Direct viral effect and ulceration
Infectious	Histoplasmosis	Granulomatous infection with ulceration
Vascular	Angiodysplasia	Rupture of abnormal vessels
Vascular	Arteriovenous malformations	Bleeding from vascular malformations
Drug-induced	Nonsteroidal anti-inflammatory drug-induced enteropathy	Direct mucosal injury
Drug-induced	Chemotherapy/radiotherapy injury	Post-therapy mucosal injury
Idiopathic	Isolated nonspecific ulcers	Unknown cause
Idiopathic	Idiopathic chronic ulcerative enteritis	Chronic ulcerative process
Ischemic	Mesenteric ischemia	Mucosal necrosis due to hypoperfusion
Ischemic	Thrombotic microangiopathy	Microvascular lesions and ischemia
Miscellaneous	Radiation enteritis	Radiation-induced vascular/mucosal damage
Miscellaneous	Eosinophilic enteritis	Eosinophilic infiltration causing injury