Gastrointestinal Bleeding

Gastrointestinal Bleeding: Introduction


Gastrointestinal (GI) bleeding can be occult (not readily visible) or overt. This chapter will focus on overt GI bleeding that is acute or subacute. Separate chapters (e.g., Chapters 13 and 16) will cover aspects of chronic or occult GI blood loss in more detail. The source of visible blood in stool or vomit may be from the upper GI (UGI) tract, lower GI (LGI) tract, extraintestinal (e.g., swallowed blood from a nosebleed), or an exogenous substance (e.g., red-colored foods). Regardless of the source, obvious blood from the GI tract tends to be a very distressing problem for patients and their families that quickly bring them to medical attention. GI bleeding can be serious and life threatening. Thankfully, serious GI bleeding is uncommon in the pediatric age group and the problem often resolves without specific intervention. The key to approaching a patient with GI bleeding is a rapid assessment of the severity of bleeding and hemodynamic status of the child. Given the nature of the content, this chapter will focus on differential diagnosis, diagnostic approach, and treatment based on clinical presentation: hematemesis or coffee ground emesis, hematochezia, and melena.



UGI bleeding is defined as a source proximal to the ligament of Treitz (where the duodenum meets the jejunum). LGI bleeding is from a source distal to the ligament of Treitz (see Figure 6–1).


Position of ligament of Treitz. Bleeding above this point is considered upper GI and below is lower GI.

Hematemesis refers to vomiting bright red blood, usually indicating fairly brisk bleeding. Coffee ground emesis usually occurs with slower bleeding and coagulation of blood after exposure to gastric acid. Melena refers to stools that are jet black and tarry, and often have a distinctive foul odor. Melena occurs when intestinal bacteria have time to oxidize heme to hematin, usually indicating a relatively slow bleed proximal to the cecum. Hematochezia refers to bright red or maroon blood in stools, usually from a colonic bleed but can occur with high-volume UGI bleeding with rapid transit time. Bleeding, if severe, can also become symptomatic (dizziness, syncope, pallor, tachycardia, and hypotension) before the passage of a bloody stool.



The pathogenesis of true GI bleeding varies greatly by etiology. A few broad categories of pathology underlie most causes of bleeding. Vascular anomalies (e.g., arteriovenous malformations or hemangiomas), collateral vessel formation (e.g., esophageal varices), or erosion of the intestinal mucosa (e.g., inflammation, ulceration, sloughing, and perforation) bring blood vessels in close proximity to the intestinal lumen and may make them prone to rupture. Acute or chronic vascular congestion, thrombosis, and/or ischemia may also lead to bleeding. Any illness (most often viral gastroenteritis) that causes persistent retching and vomiting can cause bleeding from mucosal tears in the lower esophagus and upper stomach (Mallory–Weiss tears) and/or broken capillaries in the gastric mucosa (emetogenic gastropathy).

Key Initial Steps in the Evaluation of GI Bleeding


Determine the Severity of the Bleeding

Different diagnoses may be suggested by not only presenting signs and symptoms, but also patient age. Although the history is paramount, the initial history should be very brief followed by an assessment of vital signs and hemodynamic status. If it is obvious the child is ill or there is a large amount of bleeding, it is appropriate to initiate supportive management before completing the history and evaluation. Tachycardia is a sensitive indicator of blood loss but orthostasis tends to be more useful in assessment of hemodynamic status and response to therapy. Pulse and blood pressure should be obtained while supine. The patient then stands for at least 1 minute and measurements are repeated while standing. This must be done in a consistent manner (supporting staff may not do this correctly and specific instructions are a good idea). A pulse increase over 20 beats/minute or systolic blood pressure decrease of 10 mm Hg indicates intravascular volume depletion. Children have incredible reserve and although pulse may increase significantly, blood pressure may be stable in spite of severe blood loss. Dizziness, lethargy, pallor, diaphoresis, and nausea often accompany significant blood loss.

The unstable or actively bleeding patient should be resuscitated. Venous access is secured with two large-bore IV catheters or central venous access. Initial blood work should include type and cross to expedite transfusion if necessary. Key laboratory data include hemoglobin, platelets, coagulation studies, and complete metabolic profile (see Table 6–1). The goal is to stabilize the patient for controlled evaluation. Transfer to the intensive care unit and/or a facility with surgical and endoscopic services is often warranted (see Box 6–1). Surgical consultation should be obtained early for patients who are hemodynamically unstable, especially if they have abdominal tenderness, distension, fever, or signs of obstruction on upright or decubitus abdominal films. Surgical exploration is indicated for signs of obstruction or ongoing blood loss (i.e., patient remains unstable requiring frequent blood transfusion, ≥85 mL/kg).1,2

Table 6–1. Appropriate Considerations for Initial Evaluation of GI Bleeding

Box 6–1. When to Refer—ICU, Surgeon, and Gastroenterologist

For stable and/or asymptomatic patients, a thorough history is likely to be the most important part of the assessment. This should include a focused family history based on presentation (inflammatory bowel disease, atopic disease, polyposis or early colon cancer, bleeding disorders, and Hirschsprung’s disease). For bloody diarrhea, recent antibiotic use and infectious exposures should be queried. Questions in plain English yield the most detailed information. Instead of asking about blood or bile in vomit, it is often more helpful to ask if they have seen anything that looks pink, red, bright yellow, bright green, or like coffee grounds. Similarly, for stool, ask about bright red, dark red (maroon), or tarry (jet) black color. Anxious patients or families often overestimate the amount of blood but a general approximation can be made. The severity of the bleeding is often reflected in the clinical presentation and hemodynamic status of the patient. In a clinically stable patient, minimal amounts of red blood or coffee grounds usually indicate slow bleeding (although large-volume bleeds can present with coffee ground vomit). Clots of blood or red blood mixed in the vomit may indicate higher volume bleeds. Melena may be slow or brisk bleeding depending on location and transit time. Large amounts of bright red blood in stool or pure blood usually are high-volume bleeds.

Determine If It Is Blood

Exogenous substances may mimic blood. Identifying sources of confusion can appropriately redirect evaluation and management or avoid concern altogether (see Table 6–2). A commonly used antibiotic, cefdinir (Omnicef), may turn stool red causing concern. This is distinguished from Clostridium difficile colitis by the lack of ill appearance, fever, abdominal pain, and diarrhea.

Table 6–2. Substances that May Mimic Appearance of GI Bleeding

Guaiac testing can usually determine if what we are seeing is blood or an exogenous substance. Guaiac is a natural resin that turns blue when oxidized after exposure to substances with peroxidase activity (e.g., heme) followed by hydrogen peroxide. The substance to be tested is placed on paper impregnated with guaiac followed by hydrogen peroxide after a few minutes. Gastroccult (Beckman Coulter, Inc., Fullerton, CA) is designed to detect heme in vomit with a low pH. Hemoccult (Beckman Coulter, Inc.) is used for stool. Hemoccult may produce false negatives if used to test vomit but a positive test should be reliable if Gastroccult is not immediately available. These tests are inexpensive and reliable for the most part. False positives no longer occur with iron preparations. However, since the reaction is based on peroxidase activity, rare false positives may occur with certain foods (e.g., red meats, turnips, horseradish, artichokes, mushrooms, radishes, broccoli, bean sprouts, cauliflower, melons, and grapes). Newer immunochemical or heme-porphyrin tests can detect human blood more specifically but are not in wide use due to higher cost, slower turnaround, and possible false positives due to high sensitivity.2,3

Determine If Blood Originated from the GI Tract

Extraintestinal sources of blood can include spit or swallowed blood (nasopharyngeal, oropharyngeal, and hemoptysis) and blood that only appears to come from the rectum (anal fissure, excoriated skin, and vaginal or urinary tract bleeding). The history is key in determining the origin of the blood. Clues to nasopharyngeal origin include frequent nosebleeds, recent surgery (e.g., tonsillectomy or adenoidectomy), dental work, facial trauma, or traumatic nasogastric tube placement. Infants with denuded skin from diaper dermatitis may have intermittent bleeding. Vaginal bleeding may be normal in the first week of life and is sometimes mistaken for LGI bleeding. Similarly, onset of menstruation in adolescents may be confused with hematochezia.

Determine If It Is the Child’s Blood

Infants may swallow maternal blood during birth or breastfeeding. Physiologic reflux (normal infant spitting) is common, so this is often spit up. It may also manifest as hematochezia or melena. For breastfeeding infants, the mother should be asked if she has had any breast tenderness, sores, or bleeding (blood on the bra or seen in the baby’s mouth before spitting up are useful clues). Significant anxiety can be avoided by distinguishing fetal from maternal blood early by this history or diagnostic testing.

The Apt–Downey Test can be used to detect maternal hemoglobin in vomit or stool containing bright red blood. This is based on the fact that fetal hemoglobin is resistant to alkali denaturation. The bloody vomit or stool is mixed with 1–5 mL of water and centrifuged yielding a pink hemolysate; 1 mL of 1% NaOH is then added and the solution’s color is observed after a few minutes. Fetal hemoglobin is alkali resistant and the solution remains pink. Maternal hemoglobin A is denatured and the solution turns yellow to dark brown indicating that further evaluation in a well-appearing infant is unnecessary. The test requires grossly visible bright red blood. Melena or coffee grounds contain already denatured blood and may falsely indicate maternal hemoglobin. The infant’s blood (especially for older breastfeeding infants) can be tested as a control to exclude the presence of significant hemoglobin A in which case the test would not be helpful.

Clinical Presentation


Upper GI Bleeding

Table 6–3 lists common diagnoses and typical characteristics of presentation for both UGI and LGI bleeding. Most patients with overt UGI bleeding present with hematemesis or coffee ground emesis. This can include bleeding from the intestinal tract and rarely from the biliary system (hemobilia) or pancreatic ductal system (hemosuccus pancreaticus). Occasionally, UGI bleeding will present as melena without vomiting. If there is massive UGI bleeding and/or rapid intestinal transit (e.g., infants, short bowel), hematochezia may be seen. Finally, a severe bleed may present with hypovolemic shock before hematemesis or the passage of a bloody stool. Depending on the etiology and severity of bleeding, children may appear completely asymptomatic or quite ill.

Table 6–3. Typical Presentations of Common Diagnoses

Lower GI Bleeding

Overt LGI bleeding can present as hematochezia or melena depending on etiology and severity. The amount and character of blood loss (bright red, black, or currant jelly) is important in suggesting specific diagnoses and possible need for urgent intervention. Stool frequency and consistency (normal, large and hard, or loose) should be investigated. Streaks of red blood coating hard or normal stool suggest a distal source (e.g., anal fissure and polyp). Presence of abdominal or anal pain can also be helpful. Non-bloody vomiting may occur with certain etiologies (e.g., bowel obstruction and inflammatory bowel disease). As with UGI bleeding, LGI bleeding can present with signs of severe blood loss before passage of a bloody stool.

Differential Diagnosis Based on Presentation


Memorizing the differential diagnosis for UGI and LGI bleeding is less useful than a thoughtful approach based on the clinical presentation. Tables 6–4 and 6–5 provide a guide for hematemesis and hematochezia, respectively. It should be remembered that some diagnoses can have variable presentations and occur in different age groups. Tables 6–6 and 6–7 list rare causes separately. Variables besides presentation may include the age of the patient, the type and character of bleeding, and the clinical status of the child. The key initial steps described above should be undertaken no matter the presentation.

Table 6–4. Etiology of Hematemesis or Coffee Ground Emesis by Age and Presentation

Table 6–5. Hematochezia or Melena by Age and Presentation (Always Consider UGI Sources)
Jan 21, 2019 | Posted by in GASTROENTEROLOGY | Comments Off on Gastrointestinal Bleeding
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