Small Intestinal Bleeding: Causes, Symptoms, Diagnosis & Treatment

pediagenosis    October 13, 2026    Digestive , Organ , science    Comment   

VASCULAR MALFORMATION OF SMALL INTESTINE AND OTHER CAUSES OF SMALL INTESTINAL BLEEDING

Approximately 5% of cases of gastrointestinal bleeding occur in the small bowel, defined as the region between the ampulla of Vater and the ileocecal valve. Small intestinal vascular malformations are responsible for the majority of cases of small intestinal bleeding. They are more often seen in elderly patients, as is enteropathy induced by nonsteroidal antiinflammatory drugs (NSAIDs). Small intestinal tumors, Crohn disease, and nonspecific enteritis are more common in individuals under 40 years of age. Rarer causes include Meckel diverticulum, hemobilia, hemosuccus pancreaticus, and aortoenteric fistula.

 

Small Intestinal Vascular Malformations

Vascular malformations of the small bowel are rare, yet they account for 5% of cases of gastrointestinal bleeding. They are more commonly encountered in elderly persons and vary in size and distribution. Most vascular lesions present with obscure gastrointestinal bleeding, but the severity of the symptoms and signs ranges from hemepositive stool to profound anemia requiring recurrent blood transfusion.

 

Angiodysplasia (Angioectasia Or Vascular Ectasia)

Angiodysplasias are pathologically dilated and tortuous, thin-walled vessels, involving small capillaries, veins, and arteries, visualized within the mucosal and submucosal layers of the gut. They are the most common cause of small bowel bleeding, accounting for 50% of cases. The jejunum is the most common location in the small intestine, followed by the ileum and duodenum. Approximately 40% to 60% of patients will have more than one lesion. Aortic stenosis has long been associated with angiodysplasia (Heyde syndrome). The high stress in aortic stenosis was thought to cause shear-dependent cleavage of high-molecular-weight multimers of von Willebrand factor, leading to acquired deficiency of the factor; findings in recent large-scale studies have questioned this association, however. Chronic renal failure with or without hemodialysis is another condition associated with increased frequency of gastrointestinal angiodysplasia. Other reported risk factors include hypertension, ischemic heart disease, arrhythmias, valvular heart disease, congestive heart failure, chronic respiratory conditions, previous venous thromboembolism, and use of anticoagulants.

Angiodysplasias commonly present with anemia with or without iron deficiency. The stool is frequently hemepositive, but rarely, melena may develop. Capsule endoscopy has a high diagnostic yield and allows visualization of the entire small intestine. Small intestinal angiodysplastic lesions typically have a round, stellate, or spidery mucosal appearance with a distinct zone of pallor surrounding the margins. Biopsy is not recommended and carries a bleeding risk.

Deep enteroscopy is the best choice for short-term and initial therapy. Single-balloon enteroscopy, doubleballoon enteroscopy, or spiral enteroscopy can be used; once lesions have been identified, they can be cauterized using argon plasma coagulation. For patients with diffuse lesions or patients who are unfit for invasive therapies, various pharmacologic agents have been studied. Hormonal therapy (estrogen and progesterone), thalidomide (a vascular endothelial growth factor inhibitor), and octreotide have been shown to be beneficial in several case series, but randomized trials are lacking.

 

Telangiectasia

Telangiectasias of the small bowel are essentially similar to angiodysplasias, but they can involve all the layers of the bowel, unlike angiodysplasias, which are limited to the mucosa and submucosa. Additionally, telangiectasias often occur as part of a systemic disorder and involve cutaneous and other mucus membrane surfaces.

Gastrointestinal telangiectasias are associated with hereditary hemorrhagic telangiectasia, scleroderma, CREST syndrome, and, possibly, Turner syndrome. Hereditary hemorrhagic telangiectasia (Osler-Weber-Rendu syndrome) is an autosomal dominant disorder with a prevalence of 1:5000 to 1:8000. Individuals with the disease can have vascular lesions, including gastrointestinal telangiectasias and arteriovenous malformations of the liver, lung, and central nervous system. The most common clinical findings are epistaxis and iron deficiency anemia, but patients may be asymptomatic. Life-threatening bleeding can arise from visceral vascular lesions. The management is directed toward the organ involved and requires a multidisciplinary team approach. Endoscopic ablation is used to manage bleeding from gastrointestinal lesions. Surgery or embolization may be useful for life-threatening hemorrhage from localized lesions. A vascular endothelial growth factor antagonist such as bevacizumab, sprayed topically or injected locally, has shown promise in reducing bleeding episodes.

 

NSAID ENTEROPATHY

Intestinal injury related to the use of nonsteroidal antiinflammatory drugs (NSAIDs) is common and is one of the commonest causes of obscure gastrointestinal bleeding. The distal small bowel is often involved, but lesions can be diffuse and range from erosions or ulcers to stricture to frank bowel perforation. Enteric-coated aspirin was originally designed to decrease adverse effects on the stomach, but its use may have shifted the damage to the distal small bowel. The pathogenesis of NSAID-induced enteropathy is distinct from that of NSAID-induced gastropathy. Local mucosal damage induced by NSAIDs appears to increase intestinal permeability and weaken the mucosal barrier, allowing bile acid, proteolytic enzymes, intestinal bacteria, or toxins to penetrate epithelial cells, resulting in mucosal injury. Findings on capsule endoscopy or enteroscopy include reddened folds, a denuded area, red spots, a sharply demarcated ulcer, and blood; the pathognomonic finding of NSAID enteropathy, however, is diaphragmlike strictures. The strictures are caused by scarring from recurrent ulcerative injury and appear as thin, concentric, diaphragmlike septa with pinholesized lumen. They are usually multiple and are found mostly in the midintestine, but they have also been described in the ileum and colon. They are histologically characterized by submucosal fibrosis and thickening of the muscularis mucosa, with normal overlying epithelium. These strictures can rarely lead to entrapment of a capsule endoscopy. Endoscopically accessible strictures or diaphragms may be amenable to through- the-scope balloon dilatation, with retrieval of the retained capsule; surgical intervention may still be required, however. Cessation of NSAID use is the mainstay of management; complete resolution of most lesions usually follows.

Hemosuccus pancreaticus refers to bleeding from the peripancreatic blood vessel into the pancreatic duct, most often in the setting of acute or chronic pancreatitis or, rarely, following therapeutic endoscopy of the pancreas. Selective arteriography of the celiac trunk and superior mesenteric artery is the most sensitive diagnostic tool. Hemobilia, or bleeding from the hepatobiliary system, usually presents as melena, hematemesis, biliary colic, or jaundice and should be suspected after recent instrumentation of the hepatic parenchymal or biliary tract or blunt trauma to the abdomen. Sideviewing endoscopy can directly visualize the clot extrusion or blood oozing from the papilla of Vater.

Aortoenteric fistula is a rare, life-threatening condition and is almost always seen secondary to reconstructive aortic aneurysmal surgery. It typically involves the third portion of the duodenum and presents with herald bleeding, followed by massive life-threatening bleeding. The best diagnostic modality is abdominal CT scanning.