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Gastrointestinal Bleeding The possibility of aortoenteric fistula should always be considered in patients who previously had aortic graft surgery and present with gastrointestinal bleeding because aortoen- teric fistula is life-threatening, with a mortality rate of 50% even with surgical intervention. When there is a high degree of suspicion for an aortoenteric fistula, CT with intravenous con- trast should be performed before endoscopy or other types of gastrointestinal evaluation.

The possibility of aortoenteric fistula should always be considered in patients who previously had aortic graft surgery and present with gastrointestinal bleeding because aortoen- teric fistula is life-threatening, with a mortality rate of 50% even with surgical intervention. When there is a high degree of suspicion for an aortoenteric fistula, CT with intravenous con- trast should be performed before endoscopy or other types of gastrointestinal evaluation. Postendoscopic Care Patients with peptic ulcer disease and low-risk stigmata can be fed within 24 hours of endoscopy, receive once-daily oral PPI therapy, and be discharged from the hospital. Patients with high-risk lesions and those with adherent clots requiring endoscopic treatment should receive intra- venous PPI therapy for 72 hours to decrease the risk for rebleeding and remain in the hospital for this interval. For high-risk lesions, twice-daily oral PPI therapy should con- FIGURE 42. Mallory-Weiss tear. This superficial linear mucosal tear (arrow) is tinue for 2 weeks. Intermittent intravenous dosing is as shown on endoscopic retroflexion in the proximal stomach. efficacious as continuous infusion and may be preferable Courtesy of Louis M. Wong Kee Song, MD, Mayo Clinic. from a cost and logistic standpoint. For discussion of man- agement of peptic ulcer disease, see Disorders of the Stomach and Duodenum. (Figure 42) stop bleeding spontaneously. Endoscopic tech- Nonselective B-blocker therapy (propranolol, nadolol, or niques, such as injection therapy, thermal devices, and endo- carvedilol) should be initiated in addition to endoscopic band clips, can be used for actively bleeding tears. ligation for secondary prophylaxis of variceal hemorrhage. The The most effective approach for control of acute variceal dosage of 8-blockers should be increased as tolerated to obtain hemorrhage (Figure 43) is combined therapy with octreotide a resting pulse rate of 55 to 60/min. Subsequent endoscopy and endoscopic therapy. Octreotide should be continued for 3 with further band ligation as needed to obliterate varices to 5 days after variceal hemorrhage. Endoscopic variceal liga- should also be performed every 2 to 4 weeks. Patients with tion within 12 hours of presentation is the endoscopic treat- cirrhosis and gastrointestinal bleeding should have antibiotic ment of choice for hemostasis of active variceal hemorrhage, therapy continued for 7 days after hemorrhage, even in the with a success rate of 90%. In patients with bleeding gastric absence of ascites. varices, endoscopic control may be difficult and transjugular Aspirin discontinued for secondary prevention of cardio- intrahepatic portocaval shunting may be considered if bleed- vascular disease should be restarted as soon as possible after ing persists despite octreotide. hemostasis is achieved. In patients with a recent acute coro-

Postendoscopic Care Patients with peptic ulcer disease and low-risk stigmata can be fed within 24 hours of endoscopy, receive once-daily oral PPI therapy, and be discharged from the hospital. Patients with high-risk lesions and those with adherent clots requiring endoscopic treatment should receive intra- venous PPI therapy for 72 hours to decrease the risk for rebleeding and remain in the hospital for this interval. For high-risk lesions, twice-daily oral PPI therapy should con- FIGURE 42. Mallory-Weiss tear. This superficial linear mucosal tear (arrow) is tinue for 2 weeks. Intermittent intravenous dosing is as shown on endoscopic retroflexion in the proximal stomach. efficacious as continuous infusion and may be preferable Courtesy of Louis M. Wong Kee Song, MD, Mayo Clinic. from a cost and logistic standpoint. For discussion of man- agement of peptic ulcer disease, see Disorders of the Stomach and Duodenum. (Figure 42) stop bleeding spontaneously. Endoscopic tech- Nonselective B-blocker therapy (propranolol, nadolol, or niques, such as injection therapy, thermal devices, and endo- carvedilol) should be initiated in addition to endoscopic band clips, can be used for actively bleeding tears. ligation for secondary prophylaxis of variceal hemorrhage. The The most effective approach for control of acute variceal dosage of 8-blockers should be increased as tolerated to obtain hemorrhage (Figure 43) is combined therapy with octreotide a resting pulse rate of 55 to 60/min. Subsequent endoscopy and endoscopic therapy. Octreotide should be continued for 3 with further band ligation as needed to obliterate varices to 5 days after variceal hemorrhage. Endoscopic variceal liga- should also be performed every 2 to 4 weeks. Patients with tion within 12 hours of presentation is the endoscopic treat- cirrhosis and gastrointestinal bleeding should have antibiotic ment of choice for hemostasis of active variceal hemorrhage, therapy continued for 7 days after hemorrhage, even in the with a success rate of 90%. In patients with bleeding gastric absence of ascites. varices, endoscopic control may be difficult and transjugular Aspirin discontinued for secondary prevention of cardio- intrahepatic portocaval shunting may be considered if bleed- vascular disease should be restarted as soon as possible after ing persists despite octreotide. hemostasis is achieved. In patients with a recent acute coro- nary syndrome or coronary stent placement in whom a P2Y12 receptor was discontinued, therapy should be reinitiated within 5 days. In patients in whom warfarin was discontinued, re-anticoagulation with low-molecular-weight heparin or unfractionated heparin should be considered within 48 hours in patients at high thrombotic risk (mechanical prosthetic heart valve in the mitral position, atrial fibrillation with pros- thetic heart valve or mitral stenosis, or recent venous throm- boembolism). Timing of resuming direct oral anticoagulants depends on the risk profile, but resumption generally should occur within 7 days. For all causes of UGIB, endoscopic therapy should be repeated if bleeding recurs, but routine second-look endoscopy is not recommended. Interventional radiology or surgery is reserved for cases of rebleeding despite endo- scopic treatment. For variceal bleeding, placement of a transjugular intrahepatic portocaval shunt is reserved for

nary syndrome or coronary stent placement in whom a P2Y12 receptor was discontinued, therapy should be reinitiated within 5 days. In patients in whom warfarin was discontinued, re-anticoagulation with low-molecular-weight heparin or unfractionated heparin should be considered within 48 hours in patients at high thrombotic risk (mechanical prosthetic heart valve in the mitral position, atrial fibrillation with pros- thetic heart valve or mitral stenosis, or recent venous throm- boembolism). Timing of resuming direct oral anticoagulants depends on the risk profile, but resumption generally should occur within 7 days. For all causes of UGIB, endoscopic therapy should be repeated if bleeding recurs, but routine second-look endoscopy is not recommended. Interventional radiology or surgery is reserved for cases of rebleeding despite endo- scopic treatment. For variceal bleeding, placement of a transjugular intrahepatic portocaval shunt is reserved for FIGURE 43. Acute esophageal variceal hemorrhage. A varix in the distal bleeding that is not controlled by drug and endoscopic esophagus is seen spurting bright red blood. therapy.

nary syndrome or coronary stent placement in whom a P2Y12 receptor was discontinued, therapy should be reinitiated within 5 days. In patients in whom warfarin was discontinued, re-anticoagulation with low-molecular-weight heparin or unfractionated heparin should be considered within 48 hours in patients at high thrombotic risk (mechanical prosthetic heart valve in the mitral position, atrial fibrillation with pros- thetic heart valve or mitral stenosis, or recent venous throm- boembolism). Timing of resuming direct oral anticoagulants depends on the risk profile, but resumption generally should occur within 7 days. For all causes of UGIB, endoscopic therapy should be repeated if bleeding recurs, but routine second-look endoscopy is not recommended. Interventional radiology or surgery is reserved for cases of rebleeding despite endo- scopic treatment. For variceal bleeding, placement of a transjugular intrahepatic portocaval shunt is reserved for FIGURE 43. Acute esophageal variceal hemorrhage. A varix in the distal bleeding that is not controlled by drug and endoscopic esophagus is seen spurting bright red blood. therapy. 78

Gastrointestinal Bleeding Lower Gastrointestinal Bleeding e The most common causes of upper gastrointestinal Twenty percent of all cases of gastrointestinal bleeding origi- bleeding include peptic ulcer disease, gastroesophageal nate in the colon or rectum. Most cases of LGIB stop spontane- varices, and Mallory-Weiss tear. ously and have good outcomes; however, morbidity and ° Tachycardia (pulse rate >100/min), hypotension (systolic mortality are higher in older patients and those with comorbid blood pressure <100 mm Hg), age older than 60 years, conditions. Patients with LGIB usually present with sudden and major comorbid medical conditions are associated onset of hematochezia (maroon or red blood per rectum). with increased risk for rebleeding and death in patients Occasionally, bleeding from the cecum or right colon may with upper gastrointestinal bleeding. appear black and tarry, like melena. LGIB may also present with pain, diarrhea, or change in bowel movements. © Octreotide should be initiated if variceal hemorrhage is suspected, and initiation of antibiotics is recommended for all patients with cirrhosis. Causes e Endoscopic variceal ligation within 12 hours of presenta- The most common cause of minor LGIB is hemorrhoidal tion is the endoscopic treatment of choice for hemostasis bleeding. This is usually characterized by a small volume of of active variceal hemorrhage. bright red blood and usually does not cause hemodynamic HVC e Patients with peptic ulcer disease and low-risk stig- instability or significant volume loss (see Disorders of the mata can be fed within 24 hours of endoscopy, receive Small and Large Bowel for discussion of hemorrhoids). once-daily oral PPI therapy, and be discharged from the Causes of severe LGIB that may lead to clinical instability

HVC e Patients with peptic ulcer disease and low-risk stig- instability or significant volume loss (see Disorders of the mata can be fed within 24 hours of endoscopy, receive Small and Large Bowel for discussion of hemorrhoids). once-daily oral PPI therapy, and be discharged from the Causes of severe LGIB that may lead to clinical instability hospital. include diverticular bleeding, colonic angiodysplasia, post- polypectomy bleeding, Dieulafoy lesion, rectal varices, and e Patients with high-risk peptic ulcer lesions and those malignancy (Table 42). Fifteen percent of patients with with adherent clots requiring endoscopic treatment hematochezia, however, are found to have an upper gastroin- should receive intravenous PPI therapy for 72 hours. testinal source. TABLE 42. Causes of Severe Lower Gastrointestinal Bleeding | Bleeding Source Pathogenesis Presentation Treatment Diverticulosis Segmental weakness of arteries Painless hematochezia or self- Endoscopic, interventional coursing over the dome ofthe limited massive bleeding radiologic, and surgical diverticulum Aortoenteric fistula Erosion of aortic aneurysm Minor hemorrhage (herald Aggressive resuscitation and (primary) into Gl tract orfollowing bleeding) or massive bleeding emergent surgical repair surgical or endovascular grafting (secondary) Rectal varices Portal hypertension Episodic hematochezia or severe Endoscopic therapy and treatment bleeding (rare) of portal hypertension

Aortoenteric fistula Erosion of aortic aneurysm Minor hemorrhage (herald Aggressive resuscitation and (primary) into Gl tract orfollowing bleeding) or massive bleeding emergent surgical repair surgical or endovascular grafting (secondary) Rectal varices Portal hypertension Episodic hematochezia or severe Endoscopic therapy and treatment bleeding (rare) of portal hypertension Dieulafoy lesion Erosion of an aberrant dilated Recurrent hematochezia or Endoscopic therapy submucosal blood vessel massive bleeding Neoplasm Tumor invasion Recurrent episodes of Radiographic or endoscopic hematochezia or melena or iron techniques or surgery deficiency Colonic ischemia Colonic hypoperfusion Abdominal pain and Supportive care; surgical hematochezia intervention for cases of irreversible ischemia Inflammatory bowel Mucosal inflammation and Bloody diarrhea and abdominal Medical therapy for underlying disease ulceration pain disease Infectious colitis Mucosal invasion of infectious Bloody diarrhea Treatment of causative organism organism Intussusception Intestinal wall ischemia from Hematochezia in setting of bowel Surgical underlying obstruction obstruction

Infectious colitis Mucosal invasion of infectious Bloody diarrhea Treatment of causative organism organism Intussusception Intestinal wall ischemia from Hematochezia in setting of bowel Surgical underlying obstruction obstruction | Meckel diverticulum Ulceration of small bowel from Chronic and insidious bleeding or Surgical resection of the ectopic gastric mucosa-produced acute massive bleeding diverticulum acid Angiodysplasia Ectatic, dilated, thin-walled blood Chronic and insidious bleeding or Endoscopic; interventional vessels acute and massive bleeding radiography and surgery in refractory cases 79

Gastrointestinal Bleeding Diverticular bleeding is arterial and stops spontaneously in Radiographic studies should be considered in patients 75% of cases. In patients with diverticulosis, risk for bleeding is who cannot tolerate colonoscopy or colon preparation or in estimated at 0.5 per 1000 person-years. For further discussion of patients in whom a source of bleeding is not identified endo- diverticular disease, see Disorders of the Small and Large Bowel. scopically. Techniques include CT angiography, angiography, Angiodysplasia, also known as angiectasia or arterio- and, less frequently, tagged red blood cell scintigraphy. venous malformation, can occur throughout the colon but is Catheter-based angiography with embolization should be most common in the right colon. Elderly patients, patients with performed as soon as possible if active bleeding is noted on CT end-stage kidney disease, and patients receiving anticoagula- angiography. Angiographic embolization is also frequently tion therapy are at highest risk. Patients with cardiac disease, used to stop persistent or recurrent diverticular bleeding especially valve dysfunction, and patients with left ventricular because of the limitations of endoscopic approaches. Surgical assist devices may be at increased risk for gastrointestinal consultation is reserved for patients who do not respond to bleeding secondary to acquired von Willebrand disease. endoscopic or interventional radiologic hemostatic measures. Postpolypectomy bleeding can occur immediately after The risk for rebleeding is highest in patients with diver- polyp removal or days or weeks later. Risk is increased in ticular bleeding (9% to 47%) and angiodysplasia bleeding (37% patients with polyps larger than 2 cm or polyps in the right to 64%). To prevent recurrent LGIB, nonaspirin NSAIDs should colon and with resumption of antithrombotic therapy. be avoided, particularly after diverticular or angiodysplasia Diarrhea, abdominal pain, and hematochezia can occur bleeding. Management of antiplatelet and anticoagulant medi- with inflammatory bowel disease and infectious colitis; ischemic cations is similar to that in patients with UGIB. colitis may also present with these symptoms, although the bleeding is rarely significant. LGIB from a colon malignancy may ¢ CT angiography is the initial diagnostic test in patients be painless or associated with obstructive symptoms. who have lower gastrointestinal bleeding, are hemody-

Diverticular bleeding is arterial and stops spontaneously in Radiographic studies should be considered in patients 75% of cases. In patients with diverticulosis, risk for bleeding is who cannot tolerate colonoscopy or colon preparation or in estimated at 0.5 per 1000 person-years. For further discussion of patients in whom a source of bleeding is not identified endo- diverticular disease, see Disorders of the Small and Large Bowel. scopically. Techniques include CT angiography, angiography, Angiodysplasia, also known as angiectasia or arterio- and, less frequently, tagged red blood cell scintigraphy. venous malformation, can occur throughout the colon but is Catheter-based angiography with embolization should be most common in the right colon. Elderly patients, patients with performed as soon as possible if active bleeding is noted on CT end-stage kidney disease, and patients receiving anticoagula- angiography. Angiographic embolization is also frequently tion therapy are at highest risk. Patients with cardiac disease, used to stop persistent or recurrent diverticular bleeding especially valve dysfunction, and patients with left ventricular because of the limitations of endoscopic approaches. Surgical assist devices may be at increased risk for gastrointestinal consultation is reserved for patients who do not respond to bleeding secondary to acquired von Willebrand disease. endoscopic or interventional radiologic hemostatic measures. Postpolypectomy bleeding can occur immediately after The risk for rebleeding is highest in patients with diver- polyp removal or days or weeks later. Risk is increased in ticular bleeding (9% to 47%) and angiodysplasia bleeding (37% patients with polyps larger than 2 cm or polyps in the right to 64%). To prevent recurrent LGIB, nonaspirin NSAIDs should colon and with resumption of antithrombotic therapy. be avoided, particularly after diverticular or angiodysplasia Diarrhea, abdominal pain, and hematochezia can occur bleeding. Management of antiplatelet and anticoagulant medi- with inflammatory bowel disease and infectious colitis; ischemic cations is similar to that in patients with UGIB. colitis may also present with these symptoms, although the bleeding is rarely significant. LGIB from a colon malignancy may ¢ CT angiography is the initial diagnostic test in patients be painless or associated with obstructive symptoms. who have lower gastrointestinal bleeding, are hemody- Evaluation namically unstable, or have rapid ongoing bleeding, fol-

Diverticular bleeding is arterial and stops spontaneously in Radiographic studies should be considered in patients 75% of cases. In patients with diverticulosis, risk for bleeding is who cannot tolerate colonoscopy or colon preparation or in estimated at 0.5 per 1000 person-years. For further discussion of patients in whom a source of bleeding is not identified endo- diverticular disease, see Disorders of the Small and Large Bowel. scopically. Techniques include CT angiography, angiography, Angiodysplasia, also known as angiectasia or arterio- and, less frequently, tagged red blood cell scintigraphy. venous malformation, can occur throughout the colon but is Catheter-based angiography with embolization should be most common in the right colon. Elderly patients, patients with performed as soon as possible if active bleeding is noted on CT end-stage kidney disease, and patients receiving anticoagula- angiography. Angiographic embolization is also frequently tion therapy are at highest risk. Patients with cardiac disease, used to stop persistent or recurrent diverticular bleeding especially valve dysfunction, and patients with left ventricular because of the limitations of endoscopic approaches. Surgical assist devices may be at increased risk for gastrointestinal consultation is reserved for patients who do not respond to bleeding secondary to acquired von Willebrand disease. endoscopic or interventional radiologic hemostatic measures. Postpolypectomy bleeding can occur immediately after The risk for rebleeding is highest in patients with diver- polyp removal or days or weeks later. Risk is increased in ticular bleeding (9% to 47%) and angiodysplasia bleeding (37% patients with polyps larger than 2 cm or polyps in the right to 64%). To prevent recurrent LGIB, nonaspirin NSAIDs should colon and with resumption of antithrombotic therapy. be avoided, particularly after diverticular or angiodysplasia Diarrhea, abdominal pain, and hematochezia can occur bleeding. Management of antiplatelet and anticoagulant medi- with inflammatory bowel disease and infectious colitis; ischemic cations is similar to that in patients with UGIB. colitis may also present with these symptoms, although the bleeding is rarely significant. LGIB from a colon malignancy may ¢ CT angiography is the initial diagnostic test in patients be painless or associated with obstructive symptoms. who have lower gastrointestinal bleeding, are hemody- Evaluation namically unstable, or have rapid ongoing bleeding, fol- An initial patient assessment and hemodynamic resuscitation lowed by immediate upper endoscopy if CT angiography

Diverticular bleeding is arterial and stops spontaneously in Radiographic studies should be considered in patients 75% of cases. In patients with diverticulosis, risk for bleeding is who cannot tolerate colonoscopy or colon preparation or in estimated at 0.5 per 1000 person-years. For further discussion of patients in whom a source of bleeding is not identified endo- diverticular disease, see Disorders of the Small and Large Bowel. scopically. Techniques include CT angiography, angiography, Angiodysplasia, also known as angiectasia or arterio- and, less frequently, tagged red blood cell scintigraphy. venous malformation, can occur throughout the colon but is Catheter-based angiography with embolization should be most common in the right colon. Elderly patients, patients with performed as soon as possible if active bleeding is noted on CT end-stage kidney disease, and patients receiving anticoagula- angiography. Angiographic embolization is also frequently tion therapy are at highest risk. Patients with cardiac disease, used to stop persistent or recurrent diverticular bleeding especially valve dysfunction, and patients with left ventricular because of the limitations of endoscopic approaches. Surgical assist devices may be at increased risk for gastrointestinal consultation is reserved for patients who do not respond to bleeding secondary to acquired von Willebrand disease. endoscopic or interventional radiologic hemostatic measures. Postpolypectomy bleeding can occur immediately after The risk for rebleeding is highest in patients with diver- polyp removal or days or weeks later. Risk is increased in ticular bleeding (9% to 47%) and angiodysplasia bleeding (37% patients with polyps larger than 2 cm or polyps in the right to 64%). To prevent recurrent LGIB, nonaspirin NSAIDs should colon and with resumption of antithrombotic therapy. be avoided, particularly after diverticular or angiodysplasia Diarrhea, abdominal pain, and hematochezia can occur bleeding. Management of antiplatelet and anticoagulant medi- with inflammatory bowel disease and infectious colitis; ischemic cations is similar to that in patients with UGIB. colitis may also present with these symptoms, although the bleeding is rarely significant. LGIB from a colon malignancy may ¢ CT angiography is the initial diagnostic test in patients be painless or associated with obstructive symptoms. who have lower gastrointestinal bleeding, are hemody- Evaluation namically unstable, or have rapid ongoing bleeding, fol- An initial patient assessment and hemodynamic resuscitation lowed by immediate upper endoscopy if CT angiography should be performed simultaneously. The timing and quality does not reveal a source of bleeding.

Evaluation namically unstable, or have rapid ongoing bleeding, fol- An initial patient assessment and hemodynamic resuscitation lowed by immediate upper endoscopy if CT angiography should be performed simultaneously. The timing and quality does not reveal a source of bleeding. of any previous colonoscopy should be assessed, particularly e Catheter-based angiography with embolization should for a report of polypectomy or biopsies. A careful assessment be performed as soon as possible if active bleeding is should be performed for use of antithrombotic or antiplatelet noted on CT angiography. agents as well as for a personal history of or risk factors for e In hemodynamically stable patients with lower gastro- liver disease, other comorbidities, or recent illness. Special intestinal bleeding but no evidence of rapid bleeding, attention should be paid to the factors that suggest an upper colonoscopy is the first study of choice and should be gastrointestinal source of hematochezia, including concomi- performed within 24 hours of presentation. tant melena, liver disease, and hemodynamic instability.

of any previous colonoscopy should be assessed, particularly e Catheter-based angiography with embolization should for a report of polypectomy or biopsies. A careful assessment be performed as soon as possible if active bleeding is should be performed for use of antithrombotic or antiplatelet noted on CT angiography. agents as well as for a personal history of or risk factors for e In hemodynamically stable patients with lower gastro- liver disease, other comorbidities, or recent illness. Special intestinal bleeding but no evidence of rapid bleeding, attention should be paid to the factors that suggest an upper colonoscopy is the first study of choice and should be gastrointestinal source of hematochezia, including concomi- performed within 24 hours of presentation. tant melena, liver disease, and hemodynamic instability. Management As with upper gastrointestinal bleeding, immediate attention Small-Bowel Bleeding should be paid to hemodynamic status, and resuscitative Small-bowel bleeding occurs secondary to a gastrointestinal measures must be initiated with the goal of hemodynamic bleeding source between the ampulla of Vater and ileocecal stabilization before endoscopy. The approach to management valve. It can be overt, in which visible bleeding (melena or of hemoglobin level and platelet count are as described for hematochezia) is present, or occult, which is characterized by UGIB, as are decisions regarding discontinuation and/or rever- anemia in the absence of gross signs of bleeding. Roughly 5% to sal of anticoagulant and antiplatelet agents. 10% of gastrointestinal bleeding is due to a small-bowel source. CT angiography is the initial diagnostic test in patients who are hemodynamically unstable after initial resuscitation Causes or have rapid ongoing bleeding, followed by immediate upper The causes of small-bowel bleeding vary with patient age endoscopy if CT angiography does not reveal a source of bleed- (Table 43). Angiodysplasia (Figure 44) is the most common ing. Upper endoscopy may also be a reasonable first choice in cause. Patients younger than 40 years are likely to have small- patients at risk for a rapidly bleeding upper gastrointestinal bowel bleeding due to inflammatory bowel disease, Dieulafoy source for hematochezia. lesions, neoplasia, Meckel diverticulum, or a polyposis syn- In hemodynamically stable patients without evidence of drome. Patients age 40 years and older are likely to have bleed- rapid bleeding, colonoscopy is the first study of choice in ing due to angiodysplasia, Dieulafoy lesions, neoplasia, or patients with LGIB. It should be performed within 24 hours of NSAID-related ulcers. Rare causes include Henoch-Schénlein presentation after adequate colon preparation, which may purpura, small-bowel varices or portal hypertensive enteropa- include rapid preparation. Colonoscopy identifies a source of thy, amyloidosis, blue rubber bleb nevus syndrome, aortoen- LGIB in two thirds of patients. teric fistula, and radiation enteritis.

Management As with upper gastrointestinal bleeding, immediate attention Small-Bowel Bleeding should be paid to hemodynamic status, and resuscitative Small-bowel bleeding occurs secondary to a gastrointestinal measures must be initiated with the goal of hemodynamic bleeding source between the ampulla of Vater and ileocecal stabilization before endoscopy. The approach to management valve. It can be overt, in which visible bleeding (melena or of hemoglobin level and platelet count are as described for hematochezia) is present, or occult, which is characterized by UGIB, as are decisions regarding discontinuation and/or rever- anemia in the absence of gross signs of bleeding. Roughly 5% to sal of anticoagulant and antiplatelet agents. 10% of gastrointestinal bleeding is due to a small-bowel source. CT angiography is the initial diagnostic test in patients who are hemodynamically unstable after initial resuscitation Causes or have rapid ongoing bleeding, followed by immediate upper The causes of small-bowel bleeding vary with patient age endoscopy if CT angiography does not reveal a source of bleed- (Table 43). Angiodysplasia (Figure 44) is the most common ing. Upper endoscopy may also be a reasonable first choice in cause. Patients younger than 40 years are likely to have small- patients at risk for a rapidly bleeding upper gastrointestinal bowel bleeding due to inflammatory bowel disease, Dieulafoy source for hematochezia. lesions, neoplasia, Meckel diverticulum, or a polyposis syn- In hemodynamically stable patients without evidence of drome. Patients age 40 years and older are likely to have bleed- rapid bleeding, colonoscopy is the first study of choice in ing due to angiodysplasia, Dieulafoy lesions, neoplasia, or patients with LGIB. It should be performed within 24 hours of NSAID-related ulcers. Rare causes include Henoch-Schénlein presentation after adequate colon preparation, which may purpura, small-bowel varices or portal hypertensive enteropa- include rapid preparation. Colonoscopy identifies a source of thy, amyloidosis, blue rubber bleb nevus syndrome, aortoen- LGIB in two thirds of patients. teric fistula, and radiation enteritis. 80

TABLE 43. Causes of Small-Bowel Gastrointestinal Bleeding Differential Patient Clinical Clues Diagnosis Age (y) Angiodysplasia >60 Intermittent, usually occult bleeding; may also occur in colon Peutz-Jeghers <20 Perioral pigmentation; syndrome obstructive symptoms Meckel 20-60 Possible abdominal pain diverticulum | Hemangioma <20 Possible cutaneous hemangiomas Malignancy >50 Weight loss; abdominal pain FIGURE 45. Hereditary hemorrhagic telangiectasia (Osler-Weber-Rendu Hereditary >50 Mucocutaneous syndrome) is a disorder of development of the vasculature characterized by hemorrhagic telangiectasias telangiectases and arteriovenous malformations in specific locations. The most telangiectasia common features of the disorder—nosebleeds and telangiectases on the lips, hands, and oral mucosa-are often subtle.

Malignancy >50 Weight loss; abdominal pain FIGURE 45. Hereditary hemorrhagic telangiectasia (Osler-Weber-Rendu Hereditary >50 Mucocutaneous syndrome) is a disorder of development of the vasculature characterized by hemorrhagic telangiectasias telangiectases and arteriovenous malformations in specific locations. The most telangiectasia common features of the disorder—nosebleeds and telangiectases on the lips, hands, and oral mucosa-are often subtle. Evaluation Important elements of the history include assessment for TABLE 44. Clinical Factors Suggesting Need for Second-Look Endoscopy, Push Enteroscopy, or Colonoscopy NSAID use; inflammatory bowel disease; prior aortic aneurysm in Suspected Small-Bowel Bleeding repair; prior pancreatitis; and recent liver trauma, tumor, or Fresh blood or clot on initial upper endoscopy and/or colonoscopy biopsy. Key physical findings may include perioral pigmenta- limiting visualization tion or mucocutaneous or cutaneous telangiectasia (Figure 45). Large hiatal hernia If a bleeding source is not identified on initial endoscopy History of NSAID use and colonoscopy and small-bowel bleeding is suspected, sec- ond-look upper endoscopy or colonoscopy should be done if Poor colon preparation for initial colonoscopy

Evaluation Important elements of the history include assessment for TABLE 44. Clinical Factors Suggesting Need for Second-Look Endoscopy, Push Enteroscopy, or Colonoscopy NSAID use; inflammatory bowel disease; prior aortic aneurysm in Suspected Small-Bowel Bleeding repair; prior pancreatitis; and recent liver trauma, tumor, or Fresh blood or clot on initial upper endoscopy and/or colonoscopy biopsy. Key physical findings may include perioral pigmenta- limiting visualization tion or mucocutaneous or cutaneous telangiectasia (Figure 45). Large hiatal hernia If a bleeding source is not identified on initial endoscopy History of NSAID use and colonoscopy and small-bowel bleeding is suspected, sec- ond-look upper endoscopy or colonoscopy should be done if Poor colon preparation for initial colonoscopy the initial studies were low quality or other clinical factors Incomplete colonoscopy exist, because missed lesions on the initial endoscopy are common (Table 44). Push enteroscopy may be pursued in lieu of endoscopy to visualize the distal duodenum and proximal endoscopically. Limitations include the inability to intervene jejunum. Repeat colonoscopy should include intubation of the therapeutically and precisely localize a lesion; lesions may also

the initial studies were low quality or other clinical factors Incomplete colonoscopy exist, because missed lesions on the initial endoscopy are common (Table 44). Push enteroscopy may be pursued in lieu of endoscopy to visualize the distal duodenum and proximal endoscopically. Limitations include the inability to intervene jejunum. Repeat colonoscopy should include intubation of the therapeutically and precisely localize a lesion; lesions may also terminal ileum. be missed. The primary complication is capsule retention due to obstruction or stricture. For suspected obstruction or altered Stable Patients anatomy (small-bowel Crohn disease, radiation enteritis, prior For evaluating stable patients suspected of having small-bowel small-bowel surgery), CT enterography or magnetic resonance bleeding, video capsule endoscopy is the preferred test after enterography should be performed instead. Barium-based nondiagnostic upper endoscopy and colonoscopy, with a diag- nostic yield of 56% to 67%. This test uses a nondigestible wire- less capsule camera (Figure 46) that is swallowed or placed FIGURE 46. Endoscopy capsule. FIGURE 44. Capsule endoscopy image of angiodysplasia. This red lesion (arrow) has a fernlike pattern. Courtesy of Elizabeth Rajan, MD, Mayo Clinic. 81