Browse the corpus

498 SECTION 9: Gastrointestinal Disorders with decreased in-hospital mortality, a significant cost reduction, and decreased length of stay.19,20,44-47 Endoscopic treatment options commonly used for variceal bleeding include variceal ligation and sclerotherapy. Clips, thermocoagulation, and sclerosant injections alone or in combination with epinephrine injections are commonly used in ulcerative lesions. In some practices, the ED physician is asked to provide sedation for the endoscopist. Pretreat with an antiemetic such as ondansetron. Use short-acting titratable drugs with both analgesic properties (fentanyl) and sedative properties (midazolam or propofol). Ideal agents can be reversed if the patient’s condition changes. 48-50 In unstable patients, consider using cardiovascular stable agents such as etomidate or ketamine. While providing sedation, consider that the most noxious part of the procedure is when the scope is passed around the tongue. BALLOON TAMPONADE Balloon tamponade is an effective short-term solution for life-threat ening variceal bleeding. Today, it is generally reserved for temporary stabilization of patients for transfer to an appropriate institution or until endoscopy can be done. The Sengstaken-Blakemore tube (which has a 250-mL gastric balloon, an esophageal balloon, and a single gastric suc tion port) and the Minnesota tube (with an added esophageal suction port above the esophageal balloon) are examples of balloons that have been used. Tube placement is discussed in Chapter 86, “Gastrointestinal Procedures and Devices. ”  SURGERY Patients who do not respond to both pharmacologic and endoscopic treatments may require emergent surgery. In patients with variceal bleeding, there are two basic types of operations: shunt operations (transjugular intrahepatic portosystemic shunt procedure) and nonshunt operations (esophageal transection or gastroesophageal junction devascularization). In nonvariceal bleeding, percutaneous embolization or subtotal or total gastrectomy can be performed. Emergent surgical consultation is considered prudent in case of uncontrolled bleeding. DISPOSITION AND FOLLOW-UP Patients with significant upper GI bleeding require intensive care unit admission and early endoscopy. Very-low-risk patients (Table 75-1) may be eligible for ED observation or be discharged home with adequate outpatient follow-up. REFERENCES The complete reference list is available online at www.TintinalliEM.com. Lower Gastrointestinal Bleeding Bruce Lo INTRODUCTION AND EPIDEMIOLOGY Historically, lower GI bleeding is the loss of blood from the GI tract distal to the ligament of Treitz. However, management and outcomes differ if the bleeding originates from the small intestine compared with the colon. 1 Nevertheless, lower GI bleeding is a common problem in emergency medicine and should be considered potentially life threatening until proven otherwise. Lower GI bleeding occurs more often than upper GI bleeding, with an annual incidence of approximately 109 per 100,000 and a mortality of <1%.2 Because blood must travel through the upper GI tract down to the lower GI system, upper GI bleeds are the most common source for all causes of blood detected in the lower GI system. Among patients with an established lower GI source of bleeding, the most common cause is diverticular disease, followed by colitis, hemorrhoids, and adenomatous polyps/malignancies. About 80% of episodes of lower GI bleeding resolve spontaneously.

t common source for all causes of blood detected in the lower GI system. Among patients with an established lower GI source of bleeding, the most common cause is diverticular disease, followed by colitis, hemorrhoids, and adenomatous polyps/malignancies. About 80% of episodes of lower GI bleeding resolve spontaneously. 4 However, one cannot predict which episodes will spontaneously resolve or which episodes will result in complications. This is partly due to the difficulty in establishing a pathophysiologic diagnosis. In one study, a cause for bleeding was found in <50% of the cases. PATHOPHYSIOLOGY Hematochezia is either bright red or maroon-colored rectal bleeding. If hematochezia originates from an upper GI source, it indicates brisk upper GI bleeding, which may be accompanied by hematemesis and hemodynamic instability. Approximately 10% of hematochezia episodes may be associated with upper GI bleeding. 6 Melena is dark or blackcolored stools and usually represents bleeding from an upper GI source (proximal to the ligament of Treitz) but may also represent slow bleeding from a lower GI source.  DIVERTICULOSIS Diverticular bleeding is usually painless and results from erosion into the penetrating artery of the diverticulum. Diverticular bleeding may be massive, but up to 90% of episodes will resolve spontaneously. Bleeding can recur in up to half of patients. 7,8 Although most diverticula are located on the left colon, right-sided diverticula are thought to be more likely to bleed. 9 Elderly patients with underlying medical illnesses, those with increased needs for transfusion, and those taking anticoagulants or NSAIDs have increased morbidity and mortality.  VASCULAR ECTASIA Vascular ectasia, which includes arteriovenous malformations and angiodysplasias of the colon, is a common cause of lower GI bleeding. Vascular ectasia can also be present in the small bowel and is difficult to diagnose. The development of vascular ectasia in the large bowel seems to be due to a chronic process and increases with aging. Inherited con ditions can also give rise to arteriovenous malformations. There is also a suggestion that valvular heart disease is a risk factor for developing bleeding vascular ectasias, although this is an area of debate.  ISCHEMIC COLITIS AND MESENTERIC ISCHEMIA Ischemic colitis is the most common cause of intestinal ischemia and is usually transient. The colon is predisposed to ischemia because of its poor vascular circulation and high bacterial content. Aneurysmal rupture, vasculitis, hypercoagulable states, prolonged strenuous exercise, cardiovascular insult, irritable bowel syndrome, and certain medica tions that cause vasoconstriction or slow bowel motility are known risk factors. Diagnosis is usually made by endoscopy. Although most cases will resolve on their own, some patients require surgical intervention. Mesenteric ischemia can lead to bowel necrosis. Causes include thrombosis or embolism of the superior mesenteric artery, mesenteric venous thrombosis, and nonocclusive mesenteric ischemia associated with low arterial flow with vasoconstriction. Diagnosis is difficult, and the presentation can mimic other intra-abdominal pathologies. Diagnosis requires a high index of suspicion, especially in patients >60 years old and in those with atrial fibrillation, congestive heart failure, recent myocardial infarction, postprandial abdominal pain, or unexplained weight loss. CT has a specificity of 92% but a sensitivity of only 64%. Angiography remains the diagnostic study of choice. Despite aggressive treatment, prognosis is poor, with a survival of 50% if diagnosed within 24 hours.  MECKEL’S DIVERTICULUM Meckel’s diverticulum consists of embryonic tissue, most commonly found in the terminal ileum.

ecificity of 92% but a sensitivity of only 64%. Angiography remains the diagnostic study of choice. Despite aggressive treatment, prognosis is poor, with a survival of 50% if diagnosed within 24 hours.  MECKEL’S DIVERTICULUM Meckel’s diverticulum consists of embryonic tissue, most commonly found in the terminal ileum. More than half of lesions contain ectopic CHAPTER Tintinalli_Sec09_p0473-0562.indd 498 8/2/19 6:49 PM

ecificity of 92% but a sensitivity of only 64%. Angiography remains the diagnostic study of choice. Despite aggressive treatment, prognosis is poor, with a survival of 50% if diagnosed within 24 hours.  MECKEL’S DIVERTICULUM Meckel’s diverticulum consists of embryonic tissue, most commonly found in the terminal ileum. More than half of lesions contain ectopic CHAPTER Tintinalli_Sec09_p0473-0562.indd 498 8/2/19 6:49 PM CHAPTER 76: Lower Gastrointestinal Bleeding 499 TABLE 76-1 Causes of Lower GI Bleeding •  Upper  GI bleed •  Diverticulosis •  GI  carcinoma •  Angiodysplasia •  Arteriovenous  malformations •  Mesenteric  ischemia •  Ischemic  colitis •  Meckel’s  diverticulum •  Hemorrhoids •  Infectious  colitis •  Inflammatory  bowel disease •  Polyps •  Radiation  colitis •  Rectal  ulcers •  Trauma •  Foreign  bodies •  Carcinoma •  Prostate  biopsy sites •  Endometriosis •  Dieulafoy  lesions •  Colonic  varices •  Portal  hypertensive enteropathy gastric tissue, which can secrete gastric enzymes, eroding the mucosal wall and causing bleeding. It is a rare but important condition, especially in the younger population.  HEMORRHOIDS Although hemorrhoids are the most common source of anorectal bleeding, massive hemorrhage is unusual.10 Bleeding is usually associated with bowel movements and is usually painless. Diagnosis can sometimes be made at the bedside as a cause for lower GI bleeding. For further discussion of hemorrhoids, see Chapter 85, “ Anorectal Disorders. ”  OTHER CAUSES OF LOWER GI BLEEDING Numerous other lesions may result in lower GI hemorrhage (Table 76-1), including infectious colitis, radiation colitis, rectal ulcers, trauma, and inflammatory bowel disease. Polyps and carcinomas can cause lower GI bleeding and are usually a source of chronic anemia. Delayed hemorrhage can occur up to 3 weeks after polypectomy. Patients with left ventricular assist devices are prone to GI bleeding especially due to anticoagulation, risk of arteriovenous malformations, and acquired von Willebrand’s disease. DIAGNOSIS As with any emergency, the medical history, physical examination, and diagnostics often must be accomplished simultaneously with resuscitation and stabilization. Factors associated with a high morbidity rate are hemodynamic instability, repeated hematochezia, gross blood on initial rectal examination, initial hematocrit <35%, syncope, nontender abdomen (predictive of severe bleeding), history of diverticulosis or angioectasia, elevated creatinine, aspirin or NSAID use (predictive of diverticular hemorrhage), and more than two comorbid conditions. 1,3,13  HISTORY Although most patients will volunteer complaints of hematochezia or melena, signs and symptoms of hypotension, tachycardia, angina, syn cope, weakness, or altered mental status can all occur as a result of lower GI bleeding. Ask about previous GI bleeding as well as a history of pain, trauma, ingestion or insertion of foreign bodies, and recent colonoscopies. Weight loss and changes in bowel habits may suggest malignancy. A history of an aortic graft may suggest the possibility of an aortoenteric fistula. Medications, such as antiplatelets (e.g., salicylates, clopidogrel), NSAIDs, and anticoagulants (e.g., warfarin, rivaroxaban, apixaban), increase the risk of lower GI bleeding. 1,14-16 Ingestion of iron or bismuth can simulate melena, and certain foods, such as beets, can simulate hematochezia. However, stool guaiac testing in those cases will be negative.  PHYSICAL EXAMINATION Hypotension and tachycardia, or decreased pulse pressure or tachypnea, develop with significant bleeding. However, changes in vital signs may be masked by concurrent medications, such as β-blockers, or medical conditions, such as poorly controlled hypertension. Thus, relative tachycardia and hypotension may represent subtle clues to ongoing bleeding.

decreased pulse pressure or tachypnea, develop with significant bleeding. However, changes in vital signs may be masked by concurrent medications, such as β-blockers, or medical conditions, such as poorly controlled hypertension. Thus, relative tachycardia and hypotension may represent subtle clues to ongoing bleeding. Some patients can tolerate substantial volume losses with minimal or no changes in vital signs. Cool, pale skin and an increase in capillary refill can be signs of shock. Physical findings of liver disease, as well as petechiae and pur pura, suggest an underlying coagulopathy. The abdominal examination may disclose tenderness, masses, ascites, or organomegaly. In patients with lower GI bleeding, a lack of abdominal tenderness suggests bleed ing from disorders involving the vasculature, such as diverticulosis or angiodysplasia. Inflammatory bowel disorders with lower GI bleeding are associated with abdominal tenderness on examination. Thorough examination of the rectal area may reveal an obvious source of bleeding, such as a laceration, masses, trauma, anal fissures, or external hemorrhoids. A vaginal or urinary source of bleeding mistaken for a GI source will be identified by examination and testing. Perform a digital rectal examination to detect gross blood (either bright red or maroon) and for guaiac testing. Rectal examination can also detect the presence of masses. Anoscopy can also be performed at the bedside. A source of bleeding such as hemorrhoids can sometimes be elucidated by anoscopy. How ever, blood originating beyond the level of visualization should raise the suspicion for other causes.  LABORATORY TESTING The most important laboratory tests are the CBC, coagulation studies, and typed and cross-matched blood. Coagulation studies, including prothrombin time, partial thromboplastin time, and platelet count, are of obvious benefit in patients taking anticoagulants or those with underlying hepatic disease. In addition, obtain BUN, creatinine, and electrolytes. In acute, brisk bleeding, the initial hematocrit level may not reflect the actual amount of blood loss. Bleeding from a source higher in the GI tract may elevate BUN levels through digestion and absorption of hemoglobin (BUN-to-creatinine ratio of >30:1).  IMAGING Routine abdominal radiographs are of limited value without specific indications such as perforation, obstruction, or foreign bodies. Similarly, routine admission chest radiographs for patients with acute GI hemor rhage, even those admitted to the intensive care unit, are of limited utility in the absence of known pulmonary disease or abnormal findings on lung examination. 17 Barium contrast studies are not helpful and can interfere with subsequent emergent endoscopy or angiography. The initial diagnostic procedure of choice—angiography, scintig raphy, or endoscopy—depends on resource ability and consultant preference. 18-21 Angiography can sometimes detect the site of bleed ing and help guide surgical management. Moreover, angiography permits therapeutic options such as transcatheter arterial emboli zation or the infusion of vasoconstrictive agents. However, angiographic diagnosis and therapy require a relatively brisk bleeding rate (at least 0.5 mL/min). Serious complications can also occur with angiography in up to 10% of cases. Technetium-labeled red cell scans can also localize the site of bleeding in obscure hemorrhage. Such localization can be used to help determine Tintinalli_Sec09_p0473-0562.indd 499 8/2/19 6:49 PM