Gastrointestinal bleeding.

Gastrointestinal bleeding can occur at any level from the mouth to the anus and may be overt or covert. There are many possible causes, which divide bleeding into upper (above the ligament of Treitz) and lower GI bleeding.

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What causes gastrointestinal bleeding?

Bleeding of any etiology is more likely and potentially more dangerous in patients with chronic liver disease or inherited coagulation disorders and in patients taking potentially dangerous drugs. Drugs that can cause gastrointestinal bleeding include anticoagulants (e.g., heparin, warfarin), those that affect platelet function (e.g., aspirin, some nonsteroidal anti-inflammatory drugs, clopidogrel, selective serotonin receptor inhibitors), and those that affect mucosal defenses (e.g., nonsteroidal anti-inflammatory drugs).

Common Causes of Gastrointestinal Bleeding

Upper gastrointestinal tract

• Duodenal ulcer (20-30%)
• Erosions of the stomach or duodenum (20-30%)
• Esophageal varices (15-20%)
• Gastric ulcer (10-20%)
• Mallory-Weiss syndrome (5-10%)
• Erosive esophagitis (5-10%)
• Diaphragmatic hernia
• Angioma (5-10%)
• Arteriovenous malformations (< 5%)

Lower gastrointestinal tract

• Anal fissures
• Angiodysplasia (vascular ectasia)
• Colitis: radiation, ischemic
• Colon cancer
• Colon polyposis
• Diverticular disease (diverticulosis)
• Inflammatory bowel diseases: ulcerative proctitis/colitis, Crohn's disease, infectious colitis

Diseases of the small intestine (rare)

• Angiomas
• Arteriovenous malformations
• Meckel's diverticulum
• Tumors

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Symptoms of gastrointestinal bleeding

Symptoms of gastrointestinal bleeding depend on the location of the source and the extent of the bleeding.

Hematemesis is the vomiting of fresh blood and indicates bleeding from the upper gastrointestinal tract, usually from an arterial source or varices. "Coffee-ground" vomiting indicates bleeding that has stopped or slowed and is due to the conversion of hemoglobin to brown-colored hydrochloric hematin by hydrochloric acid.

Bloody stool is the release of "dirty" blood from the rectum and usually indicates bleeding from the lower gastrointestinal tract, but can also be a consequence of massive bleeding from the upper gastrointestinal tract with rapid transit of blood through the intestines.

Melena is a black, tarry stool and definitely indicates upper GI bleeding, but the source of bleeding may also be in the small intestine or the right colon. Approximately 100-200 ml of blood from the upper GI tract causes melena, which may persist for several days after the bleeding. Black stools that do not contain occult blood may be due to iron, bismuth, or foods that can stain the intestinal contents black and should be differentiated from melena.

Chronic occult bleeding can develop in any part of the gastrointestinal tract and is detected by chemical analysis of stool.

Severe bleeding may present with symptoms of shock (eg, tachycardia, tachypnea, pallor, diaphoresis, oliguria, confusion). Patients with underlying coronary artery disease may develop angina or myocardial infarction due to hypoperfusion.

Patients with less severe bleeding may have only moderate tachycardia (HR > 100). Orthostatic changes in pulse (increase of > 10 beats/min) or blood pressure (decrease of 10 mmHg) often occur after acute loss of 2 units of blood. However, orthostatic measurements are not useful in patients with severe bleeding (possibly due to syncope) and are unreliable as a measure of intravascular volume in patients with moderate bleeding, particularly in elderly patients.

Patients with chronic bleeding may have symptoms and signs of anemia (eg, weakness, easy fatigability, pallor, chest pain, dizziness). Gastrointestinal bleeding may precipitate hepatic encephalopathy or hepatorenal syndrome (secondary renal failure in liver failure).

Diagnosis of gastrointestinal bleeding

Stabilization of the patient's condition with intravenous fluids, blood, and other therapy is necessary before and during diagnostics. In addition to the anamnesis and physical examination, laboratory and instrumental examination are necessary.

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Anamnesis

History suggests the diagnosis in approximately 50% of patients, but confirmation by testing is required. Epigastric pain that is relieved by food or antacids suggests peptic ulcer disease. However, many patients with bleeding ulcers have no history of pain syndrome. Weight loss and anorexia suggest a gastrointestinal tumor. A history of cirrhosis or chronic hepatitis is associated with esophageal varices. Dysphagia suggests esophageal cancer or stricture. Nausea and forceful vomiting before bleeding suggests Mallory-Weiss syndrome, although approximately 50% of patients with Mallory-Weiss syndrome do not have a history of these features.

A history of bleeding (eg, purpura, ecchymosis, hematuria) may indicate a bleeding diathesis (eg, hemophilia, liver failure). Bloody diarrhea, fever, and abdominal pain suggest inflammatory bowel disease (ulcerative colitis, Crohn's disease) or infectious colitis (eg, Shigella, Salmonella, Campylobacter, amebiasis). Bloody stools suggest diverticulosis or angiodysplasia. Fresh blood only on toilet paper or on the surface of formed stool suggests internal hemorrhoids, whereas blood mixed with stool indicates a more proximal source of bleeding.

Analysis of medication use records may reveal the use of drugs that disrupt the protective barrier and damage the gastric mucosa (eg, aspirin, nonsteroidal anti-inflammatory drugs, alcohol).

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Physical examination

Blood in the nasal cavity or flowing down to the pharynx suggests a source in the nasopharynx. Spider veins, hepatosplenomegaly, or ascites are associated with chronic liver disease and therefore may originate from esophageal varices. Arteriovenous malformations, especially of the mucous membranes, suggest hereditary hemorrhagic telangiectasia (Rendu-Osler-Weber syndrome). Nailfold telangiectasias and gastrointestinal bleeding may indicate systemic sclerosis or mixed connective tissue disease.

A digital rectal examination is necessary to assess the color of the stool, identify rectal masses, fissures, and hemorrhoids. A stool test for occult blood completes the examination. Occult blood in the stool may be the first sign of colon cancer or polyposis, especially in patients over 45 years of age.

Study

Patients with a positive fecal occult blood test should have a complete blood count. Bleeding also requires a hemocoagulation test ( platelet count, prothrombin time, activated partial thromboplastin time ) and liver function tests ( bilirubin, alkaline phosphatase, albumin, AST, ALT ). If there are signs of ongoing bleeding, it is necessary to determine the blood type and Rh factor. In patients with severe bleeding, hemoglobin and hematocrit should be determined every 6 hours. Additionally, the necessary set of diagnostic tests should be performed.

Nasogastric intubation, aspiration, and gastric lavage should be performed in all patients with suspected upper GI bleeding (eg, hematemesis, coffee-ground emesis, melena, massive rectal hemorrhage). Aspiration of blood from the stomach indicates active upper GI bleeding, but approximately 10% of patients with upper GI bleeding may not aspirate blood on nasogastric aspiration. Coffee-ground contents indicate slow or stopped bleeding. If there are no signs suggesting bleeding and the contents are bile-stained, the nasogastric tube is removed; the tube may be left in the stomach to monitor ongoing or recurrent bleeding.

In cases of upper GI bleeding, endoscopy should be performed to examine the esophagus, stomach, and duodenum. Since endoscopy can be both diagnostic and therapeutic, the examination should be performed promptly if bleeding is significant, but can be delayed for 24 hours if bleeding has stopped or is minor. Barium X-ray of the upper GI tract has no diagnostic value in acute bleeding. Angiography has limited value in the diagnosis of upper GI bleeding (mainly in the diagnosis of bleeding from hepatobiliary fistulas), although it allows in some cases to perform certain therapeutic manipulations (e.g., embolization, administration of vasoconstrictors).

Flexible sigmoidoscopy with rigid anoscope may be performed in all patients with acute symptoms suggestive of hemorrhoidal bleeding. All other patients with bloody stools require colonoscopy, which may be done when indicated after routine preparation if there is no ongoing bleeding. In such patients, prompt bowel preparation (5-10 L of polyethylene glycol solution via nasogastric tube or orally over 3-4 hours) often allows adequate evaluation. If no source is found at colonoscopy and bleeding is still severe (>0.5-1 mL/min), the source may be identified by angiography. Some angiologists first perform radionuclide scanning to preliminarily evaluate the source, but the effectiveness of this approach is unproven.

The diagnosis of occult bleeding can be difficult because a positive occult blood test may result from bleeding from any part of the gastrointestinal tract. Endoscopy is most informative when symptoms indicate the need for a primary evaluation of the upper or lower gastrointestinal tract. If colonoscopy is not feasible for the diagnosis of lower gastrointestinal bleeding, double-contrast barium enema and sigmoidoscopy may be used. If upper endoscopy and colonoscopy are negative and occult blood remains in the stool, a small bowel passage should be studied, small bowel endoscopy (enteroscopy), radioisotope colloid or technetium-labeled red blood cell scanning, and angiography should be performed.

Treatment of gastrointestinal bleeding

Hematemesis, bloody stools, or melena should be considered a critical condition. All patients with severe gastrointestinal bleeding should be referred to a gastroenterologist and surgeon and admitted to the intensive care unit. General treatment is aimed at maintaining airway patency and restoring circulating blood volume. Hemostatic therapy and other treatments for gastrointestinal bleeding depend on the cause of the bleeding.

Respiratory tract

An important cause of morbidity and mortality in patients with active upper gastrointestinal bleeding is aspiration of blood with subsequent respiratory distress. To prevent aspiration, endotracheal intubation is indicated in patients with impaired pharyngeal reflex, confusion, or unconsciousness, especially if endoscopy or placement of a Sengstaken-Blakemore catheter is necessary.

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Restoration of BCC

Intravenous fluids are indicated in all patients with hypovolemia or hemorrhagic shock: adults are given 500-1000 ml of normal saline intravenously to a maximum of 2 l until signs of hypovolemia are completely compensated (for children 20 ml/kg with possible repeat transfusion). Patients requiring further intensive care require transfusion of packed red blood cells. Transfusions are continued until intravascular volume is restored and then, if necessary, blood replacement therapy is administered. Transfusions can be stopped if the hematocrit is stable (30) and if the patient does not require symptomatic treatment. In patients with chronic bleeding, blood transfusions are usually not performed if the hematocrit is at least 21 or if symptoms such as dyspnea or coronary ischemia are observed.

Regular monitoring of platelet counts is necessary; platelet transfusions may be necessary if bleeding is severe. Platelet dysfunction has been observed in patients taking antiplatelet drugs (eg, clopidogrel, aspirin), often resulting in increased bleeding. Platelet transfusions are indicated for severe ongoing bleeding in patients taking such drugs, although residual circulating drug (especially clopidogrel) may inactivate transfused platelets.

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Hemostasis

Gastrointestinal bleeding stops spontaneously in approximately 80% of patients. The remaining patients require some form of intervention. Specific treatment for gastrointestinal bleeding depends on the source of the bleeding. Early intervention to stop the bleeding is aimed at reducing mortality, especially in older patients.

Continued bleeding in peptic ulcer or recurrent bleeding are indications for endoscopic coagulation (bipolar electrocoagulation, injection sclerotherapy, diathermy or laser). Non-bleeding vessels visualized in the ulcer crater are also subject to treatment. If endoscopic hemostasis is ineffective, surgical intervention is aimed at suturing the source of bleeding. In such situations, some surgeons perform operations aimed at reducing acidity.

Active bleeding from varices requires endoscopic suturing, injection sclerotherapy, or transjugular intrahepatic portosystemic shunt (TIPS).

In cases of severe, ongoing lower GI bleeding, bleeding from diverticula or angiomas, colonoscopic electrocautery, coagulation with diathermy, or epinephrine injection may be used. Polyps may be removed with a snare or by cauterization. If these methods are ineffective or not feasible, angiography with embolization or vasopressin administration may be effective. However, because collateral blood flow in the intestine is limited, angiographic methods have a significant risk of developing intestinal ischemia or infarction. Vasopressin administration is effective in about 80% of cases, but recurrent bleeding occurs in 50% of patients. In addition, there is a risk of hypertension and coronary ischemia. Surgery may be used in patients with ongoing bleeding (need for transfusion of more than 4 units of blood/24 hours), but localization of the bleeding source is very important. Selective hemicolectomy (without preoperative identification of the bleeding source) carries a much higher mortality risk than targeted segmental resection. Therefore, investigations should be as rapid as possible to avoid extensive surgery.

Acute or chronic gastrointestinal bleeding from internal hemorrhoids stops spontaneously in most cases. Patients with persistent bleeding require anoscopy with ligation of nodes with latex rings, injection therapy, coagulation or hemorrhoidectomy.