A 67-year-old man presents to the emergency department with a 6-hour history of bleeding per rectum. The patient’s symptoms began after he developed an urge to defecate that was followed by several voluminous bowel movements containing maroon-colored stool mixed with blood clots. The patient complains of feeling light-headed just prior to arriving at the hospital but denies any abdominal pain. His past medical history is significant for borderline hypertension managed with diet control. His surgical history is significant for a right inguinal hernia repair 2 years ago. His blood pressure is 100/80 mm Hg, pulse rate 110 beats/min, and respiratory rate 20 breaths/min. The results of an examination of his abdomen are unremarkable. The rectal examination revealed no masses and a large amount of maroon-colored stool in the rectal vault.
What should be your next step?
What is the most likely diagnosis?
How would you confirm this diagnosis?
ANSWERS TO CASE 10: Lower Gastrointestinal Tract Hemorrhage
Summary: A 67-year-old man presents with acute lower gastrointestinal (GI) tract hemorrhage. The patient’s symptoms and vital signs indicate a significant acute hemorrhage, likely class II hemorrhagic shock.
• Next step: The patient’s presentation is highly suggestive of hypovolemic shock; therefore, the initial treatment should consist of volume resuscitation with isotonic crystalloid solution and close monitoring of his response to resuscitation.
• Most likely diagnosis: Acute lower GI tract hemorrhage.
• How to confirm the diagnosis: Place a nasogastric (NG) tube to sample the upper GI tract contents; the possibility of gastric bleeding can be eliminated if nonbloody, bilious material is recovered. Esophagogastroduodenoscopy (EGD) is the definitive method of evaluation to rule out a duodenal source of bleeding.
1. Learn to differentiate the clinical presentations of occult and acute anorectal, nonanorectal lower GI tract, and upper GI tract bleeding.
2. Learn a rational diagnostic and therapeutic approach to lower GI tract bleeding.
The passage of maroon-colored stool and blood clots generally indicates acute bleeding from a lower GI tract source (distal to the ligament of Treitz). Maroon-colored stool represents a mixture of fecal material and blood, indicating that the bleeding source is located proximal to the lower rectal segment and anus. The passage of blood clots can occur with brisk bleeding from an upper GI tract source. Placement of an NG tube is useful during the initial evaluation for possible upper GI tract bleeding, although up to 16% of patients may have nonbloody NG aspirate with upper GI tract bleeding originating from the duodenum. In patients older than 40 years, the most likely causes of acute lower GI tract bleeding are diverticulosis, angiodysplasia, and neoplasm, and these lesions are generally painless. When lower GI tract bleeding occurs in the presence of abdominal pain, the possibility of an ischemic bowel, inflammatory bowel disease, intussusception, and a ruptured abdominal aneurysm should be entertained. Following resuscitation, the primary goal in the treatment of a patient with acute and continued lower GI tract bleeding is localization of the bleeding site(colonoscopy, mesenteric angiography, and/or an isotope-labeled red blood cell [RBC] scan).
APPROACH TO: Lower GI Tract Bleeding
OCCULT GI TRACT BLEEDING: Slow bleeding originating anywhere along the upper aerodigestive or lower GI tract, most commonly associated with neoplasm, gastritis, and esophagitis. Patients generally do not report bleeding and commonly present with iron deficiency anemia, fatigue, and Hemoccult-positive stool.
OVERT LOWER GI TRACT BLEEDING: Hematochezia or melena. The most common causes in children and adolescents are Meckel diverticulum, inflammatory bowel disease, and polyps. In adults aged 20 to 60 years, the most common causes are diverticulosis, neoplasm, and inflammatory bowel disease. In older adults (>60 years), the most common causes are diverticulosis, angiodysplasia, and neoplasm. Overall, when adults present with hematochezia, the distribution of bleeding sources is diverticulum (17%-40%), angiodysplasia (9%-21%), colitis (2%-30%), neoplasia (11%-14%), anorectal (4%-10%), upper GI (0%-11%), and small bowel (2%-9%).
TAGGED RBC SCAN: Nuclear medicine imaging using RBCs labeled with technetium 99m. This technique is highly sensitive in identifying active bleeding at a rate of 0.1 mL/min or greater; however, the images obtained may not localize the GI tract bleeding site accurately. Some recommend this imaging modality as an initial screening study before performing mesenteric angiography.
CT SCAN WITH INTRAVENOUS CONTRAST: CT scan with intravenous contrast has been applied in some centers as an initial screening tool for patients with lower GI bleeding. This modality allows for the identification of intravenous contrast pooling in the GI tract at the site of the bleeding. Some centers have reported this approach to be highly specific in localizing the sites of active bleeding.
MESENTERIC ANGIOGRAPHY: Selective angiography of the superior and inferior mesentery arteries can localize bleeding from the midgut and hindgut. This procedure has greater specificity for bleeding localization than a tagged RBC scan. Selective injection of vasopressin or gel foam can be applied during angiography to treat active bleeding in patients who are not suitable surgical candidates. The bleeding generally has to be 0.5 to 1.0 mL/min to be visualized by angiography.
VIDEO CAPSULE ENDOSCOPY: A small capsular video camera can be swallowed to provide visualization of the entire GI tract lumen. This study is time consuming and does not offer therapeutic options for patients with acute bleeding.
RIGID PROCTOSIGMOIDOSCOPY: A simple bedside procedure in which a nonflexible endoscope is used to visualize the most distal 25-cm segment of the lower GI tract.
DIAGNOSTIC COLONOSCOPY: Flexible fiberoptic endoscopy that evaluates the entire colon and rectum and is reserved for hemodynamically stable patients. The reported success rate in identifying the bleeding source and site is as high as 75%, but this figure is highly variable depending on the operator and the timing. The advantages of this procedure are that it can rule out the possibility of a colorectal bleeding source and that identified bleeding angiodysplasia can be treated with epinephrine injection or coagulation.
ANGIODYSPLASIA: A common acquired degenerative vascular condition producing small, dilated, thin-walled veins in the submucosa of the GI tract. It occurs most commonly in the cecum and ascending colon of people older than 50 years. Approximately 50% of patients have associated cardiac disease. Up to 25% of patients with angiodysplasia have aortic stenosis. Most patients with angiodysplasia have chronic low-grade, self-limiting bleeding, although approximately 15% present with acute massive bleeding.
A patient presenting with overt lower GI tract bleeding should be quickly assessed for intravascular volume status and hemodynamic stability. A detailed history is important. The identification of coexisting medical problems may help identify patients whose bleeding is the result of coagulopathy, thrombocytopenia, or platelet dysfunction (medical causes of bleeding). If the patient has had a previous abdominal vascular reconstruction, the possibility of an aortoenteric fistula must be strongly considered and ruled out. The history elicited should include details regarding the quality and appearance of the bleeding. Melena (tarry stool) indicates the degradation of hemoglobin by bacteria and forms after blood has remained in the GI tract for more than 14 hours. Melena is usually associated with upper GI tract or small bowel bleeding but can occur with bleeding from the ascending colon. The passage of maroon-colored stools generally excludes a possible bleeding source in the rectum and anus. Bleeding from the rectum is usually characterized by the passage of formed stools streaked with blood or the passage of fresh blood at the end of a normal bowel movement. Most episodes of overt lower GI tract bleeding resolve spontaneously without specific therapy. It is important to rule out GI tract neoplasm as the source of bleeding in patients whose bleeding resolves. Patients whose bleeding creates adverse hemodynamic consequences or necessitates blood transfusion should undergo prompt evaluation to localize the source of bleeding so that operative excision can be accomplished. See Figure 10–1 for management strategy.
Figure 10–1. Algorithm for the management of hematochezia. Esophagogastroduodenoscopy (EGD), colonoscopy, and small bowel contrast radiography should be performed in patients whose gastrointestinal (GI) tract bleeding has resolved to eliminate the possibility of GI tract bleeding as the cause of bleeding. NG, nasogastric; RBC, red blood cell.
10.1 A 75-year-old man develops hematochezia and presents with blood pressure of 90/60 mm Hg and heart rate of 120 beats/min. His vital signs improve slightly with crystalloid and packed red cells infusion. Which of the following is considered the most appropriate next step(s) in management?
A. EGD, proctosigmoidoscopy, and a barium enema
B. NG tube, proctosigmoidoscopy, and a tagged RBC scan with or without mesentery angiography
C. NG tube, mesentery angiography, and colonoscopy
D. EGD and colonoscopy
E. Preparation of the patient for emergency operative intervention
10.2 Which of the following conditions is almost always associated with painless hematochezia?
A. Bleeding from Crohn colitis
B. Ischemic colitis involving the descending colon
C. Bleeding duodenal ulcer
D. Superior mesentery artery embolus
E. Aortoenteric fistula developing 1 year after an abdominal aortic aneurysm repair
10.3 Which of the following diagnostic modalities has the greatest specificity in identifying the source of lower GI tract bleeding?
A. Tagged RBC scan
B. Barium enema
D. Surgical exploration
E. CT scan
10.4 A 66-year-old woman presents to the emergency center with a history of having passage of several maroon-colored stools earlier in the day. She complains of feeling light-headed following these episodes. The patient has a history of hypertension and osteoarthritis. She takes metoprolol and NSAIDs daily. Her initial blood pressure is 100/85 mm Hg, and heart rate is 90 beats/min. Her initial hematocrit is 34%. The patient’s blood pressure improves with initial IV fluid resuscitation. An NG tube was placed and gastric lavage reveals only bilious fluid. During a 4-hour period of observation in the emergency center, the patient remains stable without further passage of bloody stools. Which of the following is the most appropriate next step?
B. Mesenteric angiography
C. Abdominal CT scan
10.5 A 72-year-old man presents to the emergency center with abdominal pain and the passage of bloody stools. His past medical history is significant for hypertension, non–insulin-dependent diabetes, and coronary artery disease. His blood pressure is 90/60 mm Hg, with a pulse rate of 120 beats/min. His temperature is 38.8°C. Palpation of his abdomen reveals tenderness in the left upper and lower quadrants. There is no evidence of peritonitis. Which of the following is the most appropriate next step?
B. Abdominal CT scan with oral and intravenous contrast
D. Tag RBC scan
E. Abdominal CT scan with intravenous contrast only
10.1 B. In an initially unstable patient with overt GI bleeding, who has only partial response to initial resuscitation, it is critical to rapidly differentiate between upper and lower GI bleeding sources, and this is most rapidly accomplished with NG placement and gastric lavage. A proctosigmoidoscopy could be performed at the bedside to evaluate the anorectal segment of the GI tract. If no bleeding sources are identified with these initial bedside evaluations, a tagged RBC scan and mesenteric angiography may be most appropriate to localize the site of bleeding. Bleeding from an unknown source leading to hemodynamic instability is unusual for lower GI bleeding sources, and it generally occurs as the result of delayed identification and resuscitation rather than continued brisk bleeding. Surgery should not be contemplated in any patients with lower GI bleeding prior to adequate localization of the bleeding site.
10.2 E. Aortoenteric fistula following aortic reconstruction is nearly always associated with painless hematochezia while all the other conditions are likely to have pain and bleeding. All the other listed sources generally are associated with some symptoms.
10.3 C. Colonoscopy has the highest specificity in identifying the source of lower GI tract bleeding (ie, the lowest false-positive rate for bleeding source identification). CT scan can identify pooling of contrast in the lumen, which then can help identify the GI tract segment from which bleeding is occurring. Proper localizations require precise timing and brisk active bleeding.
10.4 D. This patient appears to have had a significant lower GI bleeding episode, which has either stopped or slowed. At this time, colonoscopy may be the best initial diagnostic modality to evaluate and potentially treat the cause of her bleeding. Because the bleeding has apparently stopped or slowed, a tagged RBC scan sensitive in localizing bleeding that is more than 0.1 mL/min may not be helpful. Similarly, mesentery angiography sensitive in localizing bleeding sources that is more than 0.5-1.0 mL/min is not likely to be helpful. An abdominal CT helpful in identifying overt anatomic changes would not be helpful for the identification of lower GI bleeding sources, which are most commonly colonic diverticulosis and angiodysplasia.
10.5 B. This patient’s clinical presentation is atypical for lower hemorrhage, because the most common causes of lower GI hemorrhage are angiodysplasia and diverticulosis that do not produce pain. Given his picture of lower GI bleeding, fever, left-sided abdominal pain, and a history of atherosclerotic cardiac disease, the possibility of ischemic colitis needs to be entertained. Another diagnosis to consider is intestinal intussusception, which is uncommon in adults but would produce pain and mucosal sloughing that manifest as bloody mucus in the stool. CT scan with oral contrast and intravenous contrast in this setting may be useful to help identify the source of inflammatory changes that is producing the patient’s abdominal pain, bleeding, and septic picture. With acute inflammatory process, colonoscopy is associated with an increased risk of perforation and is a less ideal diagnostic tool in this setting. CT scan with intravenous contrast only is less helpful because this modality would not allow for proper visualization of GI pathologies.
The primary goal in the treatment of a patient with acute and continued lower GI tract bleeding is localization of the bleeding site.
The ability to localize the bleeding during an abdominal exploration is greatly compromised. Exploratory laparotomy thus should be avoided prior to precise localization of the bleeding site.
Tagged RBC scan results should be interpreted with great caution because localization of bleeding to a region of the abdomen does not necessarily localize bleeding from a specific segment of the GI tract.
Colonoscopy is the diagnostic and therapeutic modality of choice for stable patients with lower GI tract bleeding.
Visceral angiography is the preferred diagnostic and therapeutic approach for hemodynamic unstable patients with lower GI bleeding.
Surgery is rarely necessary for patients with lower GI bleeding, and this approach should be applied only when the location of the bleeding source has been identified.
Barnert J, Messmann H. Diagnosis and management of lower gastrointestinal bleeding. Nat Rev Gastroenterol Hepatol. 2009;6:637-646.
Lucas CE, Ledgerwood AM, Sugawa C. Approach to lower gastrointestinal bleeding. In: Cameron JL, ed. Current Surgical Therapy. 9th ed. Philadelphia, PA: Mosby Elsevier; 2008:306-310.