17. Gastrointestinal Bleeding / R.R. Gillies 

Blood issuing from the GI tract is a cause for alarm, and justifiably so! The visible evidence is described as hematemesis, hematochezia and/or melena. 

Hematemesis ^_ vomited blood, either red (fresh) or dark brown (altered by reaction with HCl) ^_ comes from a source proximal to the duodenojejunal junction. 

Hematochezia ^_ blood in the stool ^_ comes from the left colon, or even above if the volume of blood is large and the transit rapid. 

Melena ^_ black, tarry, smelly stool, looser and larger with larger hemorrhages ^_ comes from the upper GI tract, in which case bacterial action has longer to break down the blood. It may even come from the lower tract when transit is delayed. The important causes of upper gastrointestinal bleeding are shown in Table 3, and of lower gastrointestinal bleeding in Table 4.   

TABLE 3. The important causes of upper GI bleeding

TABLE 4. The important causes of lower GI bleeding

Vomiting blood usually signifies a major hemorrhage. In a briskly bleeding duodenal ulcer, rapid transit may result in passage of red blood and clots per rectum without vomiting. Even before being passed per rectum, a large hemorrhage into the upper tract will announce itself by hyperactive bowel sounds. It is obvious that such a large-volume blood loss will have major cardiovascular effects compared to a rectal lesion causing passage of red blood and clots. 

The symptoms associated with blood loss may occur before any blood appears externally (e.g., the features of an acute anemia ^_ weakness, faintness, sweating, pallor, thirst and collapse). While the first clues as to the site of bleeding are gathered, we need to know more about how the patient is tolerating the blood loss. A rapid, thready pulse; hypotension; cold, sweaty skin; and pallor tell us that emergency restoration of blood volume is needed to keep the patient alive. Vital signs may be normal while the patient is recumbent, but a blood pressure fall of 15 mm Hg when the patient sits up indicates a significant blood loss. Cardiovascular compensation may be perfect ^_ for the moment! A large-diameter IV line (at least 18 gauge) must be inserted. The patient should be given first saline or plasma and then, as soon as it is available, blood as indicated by any features of hypovolemia. 

Once resuscitation is under way, one can assess the site and etiology of the bleeding. First, take a detailed history, particularly noting upper and lower GI symptoms, previous episodes of bleeding, previous GI surgery, ASA or NSAID intake, ethanol abuse, and diseases or treatments that could cause clotting defects. Ulcer pain often stops as bleeding starts; ulcer pain does not precede ulcer bleeding in 20-25% of cases. 

Next, do a thorough physical examination, with attention to vascular lesions of the skin and mucosa, ecchymoses, the liver, peripheral signs of cirrhosis, splenomegaly and prominent superficial abdominal veins. Inspection of the nares and oropharynx avoids the embarrassment of missing epistaxis as a source of swallowed blood. Rectal examination allows stool examination. 

When the passage of blood from either end of the GI tract has been reported but not observed, or when hematochezia or melena without hematemesis has been observed, the passage of a nasogastric tube for a single aspiration will help determine if bleeding is proximal or distal to the pylorus. Providing the patient’s response to IV volume replacement is satisfactory, one can make a decision as to the timing and type of investigation needed to identify the cause of bleeding. Upper GI endoscopy is the most reliable technique to detect lesions proximal to the duodenojejunal junction. Sometimes perendoscopic injection, heater probe application or snare-cautery polypectomy may be employed to stop bleeding from identified lesions. Whether endoscopy is emergent, urgent or elective depends on the status of the patient. Remember that the status may rapidly deteriorate. One must be prepared to change the plan just as rapidly. 

Bleeding lower GI tract lesions may be identified and treated endoscopically. Usually this is feasible only later, after proper bowel preparation removes the accumulated blood. When active bleeding continues from the small or large bowel, mesenteric angiography is the best choice to discover the bleeding site. If the bleeding is less brisk and is intermittent, radionuclide imaging may point to the site. Bleeding must occur during either test to make it useful. 

When all else fails, total enteroscopy ^_ endoscopy of the entire small bowel ^_ should be done. Usually this is more efficient at laparotomy where the surgeon can assist by manipulating the loops of bowel over the advancing scope. 

Remember that the objective is a live patient. Continued, careful assessment of the patient’s cardiovascular response to blood loss and replacement will guide interventions, including surgical. Specific treatment depends upon the underlying disease and will be dealt with in subsequent sections.