US Pharm. 2009;34(12):HS12-HS16.
Gastrointestinal (GI) bleeding can originate anywhere from the pharynx to the rectum and can be occult or overt. It differs from internal bleeding, where blood leaks from the blood vessels in such a way that the bleeding cannot be seen outside of the body. GI bleeding has a variety of causes, and a review of patient medical history and a physical examination can distinguish between the macroscopic and microscopic forms. The manifestations depend on the location and rate of bleeding, from nearly undetectable to acute and life-threatening. Upper endoscopy or colonoscopy are generally considered the best methods to identify the source of bleeding.1
History of present illness should be reviewed to ascertain quantity and frequency of blood passage. However, quantity can be difficult to assess because even small amounts (5-10 mL) of rectal bleeding or modest amounts of vomited blood are alarming to a patient. Whether blood was passed with initial emesis or only after several nonbloody vomiting episodes could indicate different causes.1
To evaluate the patient, there are a number of symptoms that need to be reviewed after GI bleeding. These include presence of abdominal discomfort, weight loss, easy bleeding or bruising, previous colonoscopy results, and symptoms of anemia (weakness, fatigue, dizziness). Past medical history should also inquire about previously diagnosed or undiagnosed GI bleeding, inflammatory bowel disease (IBD), bleeding diatheses, and liver disease.
Several drugs increase the likelihood of bleeding, including nonsteroidal anti-inflammatory drugs (NSAIDs), warfarin, and heparin. Chronic liver disease due to excessive use of alcohol can also cause bleeding. GI bleeding may also precipitate hepatic encephalopathy (brain and nervous system damage caused by liver failure) or hepatorenal syndrome (kidney failure secondary to liver disease).2
Types of GI Bleeding
Upper GI Bleeding: Hematemesis is vomiting of red-colored blood and indicates upper GI bleeding, usually from an arterial source or varix. It is considered a medical emergency, and the most vital distinction is whether there is blood loss sufficient to cause shock. The bleeding is similar to dark brown emesis, with granular material that resembles coffee grounds. This results from upper GI bleeding that has slowed or stopped, with conversion of red hemoglobin to brown hematin by gastric acid.3
There are many causes for hematemesis, including irritation or erosion of the lining of the esophagus or stomach; bleeding ulcer located in the stomach, duodenum, or esophagus; vomiting of ingested blood after hemorrhage in the oral cavity, nose, or throat; vascular malfunctions of the GI tract; and tumors of the stomach or esophagus.
Minimal Blood Loss: In this case, the patient is administered a proton pump inhibitor such as omeprazole, given a blood transfusion, and kept nil per os (Latin, “nothing by mouth”) until endoscopy can be arranged for further investigation.
Significant Blood Loss: In a hemodynamically significant case of hematemesis (e.g., hypovolemic shock), resuscitation is an immediate priority to prevent cardiac arrest. Fluids and/or blood are administered, preferably by central venous catheter, and the patient is prepared for emergency endoscopy. If the source of bleeding cannot be identified endoscopically, a surgical option is usually sought for laparotomy.3
Lower GI Bleeding: Hematochezia is the passage of gross blood from the rectum and usually indicates lower GI bleeding. It is distinguished from melena, which is stool with blood that has been altered by the gut flora and appears “tarry” black. It is also different from bright red blood per rectum, which is caused by hemorrhoidal or fissure problems and is a local rectal bleeding. Hematochezia might also result from vigorous upper GI bleeding with rapid transit of blood through the intestines. Most common causes in adults are diverticulosis and hemorrhoids, both relatively benign, although this bleeding might be a warning sign for colorectal cancer.
Hematochezia in newborn infants may be due to swallowed maternal blood at the time of delivery. In the most serious cases, it can also be an initial symptom of necrotizing enterocolitis, a serious condition affecting premature infants. In young adults, IBD, particularly ulcerative colitis, is a serious cause of hematochezia that must be further investigated for rapid treatment.1-3
Melena: Melena is a black, tarry stool that is caused by GI bleeding. The black color is due to the oxidation of blood hemoglobin during the bleeding in the ileum and colon. Melena also refers to stools or vomit stained black by blood pigment or dark blood products and may indicate upper GI bleeding. Bleeding from a lower source that occurs slowly enough to allow for oxidation is also associated with melena. About 100 to 200 mL of blood in the upper GI tract is required to cause melena, which can remain for several days after bleeding has stopped.4
Black stool that does not contain occult blood may result from ingestion of iron, bismuth, or various foods and should not be mistaken for melena. Peptic ulcer disease is the main cause of melena, but secondary causes include bleeding from the upper GI tract as in gastritis or esophageal varices or even from the ascending colon. Overdosing of certain drugs (e.g., warfarin, clopidogrel, or long-term use of NSAIDS) may also be a cause. Melena is not considered a medical emergency, but patients should be carefully monitored to find the cause and assessed for further treatment.3
GI bleeding of any cause is more likely and severe in patients with chronic liver disease from alcohol abuse or hepatitis. It also occurs more commonly in patients with hereditary coagulation disorders or in those taking certain drugs. Drugs associated with GI bleeding include heparin, warfarin, aspirin, certain NSAIDs, clopidogrel, and selective serotonin reuptake inhibitors, which cause platelet depletion and reduce the ability to form clots. About 20% to 30% of GI bleeding is due to duodenal ulcers and gastric or duodenal erosions.4
Varices and erosive esophagitis are responsible for 10% to 20% of upper GI bleeds. For the lower GI, the bleeding depends on the age group, but it is mainly due to anal fissures, diverticulitis, irritable bowel syndrome, colitis, Crohn’s disease, and colonic polyps or carcinoma.5
Evaluation and Diagnosis
The first step in the diagnosis of GI bleeding is to stabilize the patient’s airways and administer IV fluids or transfuse blood. Bloody nasogastric aspirate indicates active upper GI bleeding, but about 10% of patients have no blood in the nasogastric aspirate.4 Then the focus should be on vital signs and any indication for hypovolemia (e.g., tachycardia, tachypnea, oliguria, confusion) or anemia (e.g., fatigue, pale skin, headache, coldness in the hands and feet, diaphoresis). In cases of lesser bleedings, the tachycardia and orthostatic changes (i.e., pulse, blood pressure) are milder but need immediate attention, especially in the elderly.6
When the patient is stable, the signs and symptoms of external bleeding disorders, such as black and blue spots on the skin (petechiae, ecchymoses), are sought. Other signs to look for are ascites and erythema (chronic liver disease) and splenomegaly and dilated abdominal wall veins (portal hypertension).
In all patients with GI bleeding, a digital rectal examination is necessary to search for stool color, masses, and fissures. Anoscopy is done to diagnose hemorrhoids. Chemical testing of a stool specimen for occult blood completes the examination if gross blood is not present. In about 50% of patients, peptic ulcer can be the cause of GI bleeding.4 Epigastric abdominal discomfort that is relieved by food or antacids suggests peptic ulcer disease. These patients may or may not have pain.6
Bloody diarrhea, fever, and abdominal pain suggest ischemic colitis, ulcerative colitis, Crohn’s disease, or an infectious colitis. Fresh blood only on stools suggests rectal hemorrhoids or fissures, whereas blood mixed with the stool indicates bleeding from a distal or farthest area of the colon. Occult blood in the stool may be the first sign of a polyp, particularly in middle-aged patients. A CBC should be obtained in patients with occult blood loss.6
With more significant bleeding, coagulation monitoring such as platelet count, prothrombin time (PT), and partial thromboplastin time (PTT), and liver function tests such as aspartate aminotransferase (AST), alanine aminotransferase (ALT), bilirubin, alkaline phosphatase (ALP), and albumin, are done in certain patients. In most cases, one or more diagnostic procedures are required.
Although endoscopy is therapeutic as well as diagnostic, it should be done rapidly for significant upper GI bleeding. Angiography is useful in the diagnosis of upper GI bleeding and permits certain therapeutic maneuvers (e.g., embolization, vasoconstrictor infusion).
Flexible sigmoidoscopy and ano-scopy may be all that is required acutely for patients with symptoms typical of hemorrhoidal bleeding. All other patients with hematochezia should have a colonoscopy, which can be done electively after routine preparation unless there is significant ongoing bleeding. If colonoscopy cannot visualize the source and ongoing bleeding is sufficiently rapid (>0.5 to 1 mL/min), angiography may localize the source.5,6
Endoscopy is the preferred choice for occult bleeding, because diagnosis of this type of bleeding may be difficult, due to heme-positive stools from bleeding anywhere in the GI tract. Double-contrast barium enema and sigmoidoscopy can also be used for the lower tract when colonoscopy is unavailable or the patient refuses the procedure.4
Both hematemesis and hematochezia should be considered an emergency. Admission to an intensive care unit, with consultation by a gastroenterologist and a surgeon, is recommended for all patients with severe GI bleeding. General treatment is directed at maintenance of the airway and restoration of circulating volume. Hemostasis and other treatments depend on the cause of the bleeding.7,8
Airway: A major cause of morbidity and mortality in patients with active upper GI bleeding is aspiration of blood with subsequent respiratory problems. To prevent these issues, endotracheal intubation should be considered in patients who have inadequate gag reflexes or are obtunded or unconscious—particularly if they will be undergoing upper endoscopy.4
Fluid Replacement: IV fluids are initiated for any patient with hypovolemia or hemorrhagic shock. Patients requiring further resuscitation should receive transfusion with packed red blood cells (RBCs). Transfusions continue until intravascular volume is restored and then are given as needed to replace ongoing blood loss. Platelet count should be monitored closely, since platelet transfusion may be required with severe bleeding. Patients who are taking antiplatelet drugs (e.g., clopid-ogrel) and aspirin may have platelet dysfunction, often resulting in increased bleeding. Platelet transfusion should be considered when patients taking these drugs have severe, ongoing bleeding. Fresh frozen plasma should be transfused after every 4 units of packed RBCs.4
Hemostasis: Early intervention to control bleeding is important in order to minimize mortality, particularly in elderly patients. Specific therapy depends on the bleeding site. For peptic ulcer, ongoing bleeding or rebleeding is treated with endoscopic coagulation. Nonbleeding vessels that are visible within an ulcer crater are also treated. If endoscopy does not stop the bleeding and medical management does not control gastric acid secretion, then surgery is performed.4
Severe, ongoing hematochezia from diverticula or angiomas can sometimes be controlled colonoscopically by electrocautery, coagulation with a heater probe, or injection with dilute epinephrine. Polyps can be removed by snare or cautery. If these methods are ineffective or unfeasible, angiography with embolization or vasopressin infusion may be successful.4 Angiography can also be used to localize the source of bleeding more accurately. Surgery may be used in patients with continued bleeding, but localization of the bleeding site is very important. Acute or chronic bleeding of internal hemorrhoids stops spontaneously in most cases. Patients with refractory bleeding are treated via anoscopy with rubber band ligation, injection, coagulation, or surgery.8
Typically, a healthy person can endure a loss of 10% to 15% of the total blood volume without serious medical difficulties, and blood donation typically takes 8% to 10% of the donor’s blood volume.4
GI Bleeding in the Elderly
In the elderly (age ≥65 years), hemorrhoids and colorectal cancer are the most common causes of minor bleeding. Peptic ulcer, diverticular disease, and angiodysplasia are the most common causes of major bleeding. Approximately 35% to 45% of all cases of acute upper GI hemorrhage occur in elderly persons. These patients increasingly account for the 10% of deaths that result from a bleeding episode each year.4
Elderly patients tolerate massive GI bleeding poorly. Diagnosis must be made quickly, and treatment must be started sooner than in younger patients, who can better tolerate repeated episodes of bleeding.9
Although upper endoscopy and colonoscopy are generally considered to be safe in the elderly, the risk of complications (including hemorrhage, aspiration pneumonia, myocardial infarction, and perforation) is greater than that with younger patients. Approximately 30% to 40% of patients who undergo GI endoscopy are older than 70 years.4
On an emergency basis, therapeutic endoscopy is generally riskier than diagnostic endoscopy. Therefore, elderly patients—especially those with such comorbidities as obesity and cardiovascular, pulmonary, renal, hepatic, metabolic, or neurologic disorders—require careful evaluation before, and intensive monitoring during, the procedure. Endoscopy can be done in patients taking aspirin or NSAIDs who do not have a preexisting bleeding disorder.
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4. Gastrointestinal bleeding. MedlinePlus. www.nlm.nih.gov/medlineplus/ 2002;78:4-14.
5. Raju GS, Nath SK. Capsule endoscopy. Curr Gastroenterol Rep. 2005;7:358-364.
6. Triester SL, Leighton JA, Leontiadis GI, et al. A meta-analysis of the yield of capsule endoscopy compared to other diagnostic modalities in patients with obscure gastrointestinal bleeding. Am J Gastroenterol. 2005;100:2407-2418.
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8. Gastrointestinal bleeding. Mayo Clinic. www.mayoclinic.org/
9. Allison JE, Tekawa IS, Ransom LJ, Adrain AL. A comparison of fecal occult-blood tests for colorectal-cancer screening. N Engl J Med. 1996;334:155-159.
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