GI bleeding Flashcards
What features on physical examination of skin can help identify an unknown cause of GI bleeding?
Skin Signs of chronic liver disease (e.g., spider angiomas, venous distention, caput medusae, jaundice)
Signs of coagulopathy (e.g., petechiae, purpura)
Signs of vascular dysplasias (e.g., telangiectasia, hemangiomas)
Signs of vasculitis (e.g., palpable purpura on legs and buttocks suggests Henoch-Schönlein purpura)
Dermatologic manifestations of IBD (e.g., erythema nodosum, pyoderma gangrenosum)
What features on physical examination of head and neck can help identify an unknown cause of GI bleeding?
Signs of epistaxis (especially before placing a nasogastric tube, which can induce bleeding)
Hyperpigmented spots on the lips and gums (suggests Peutz-Jeghers syndrome, which is associated with multiple intestinal polyps)
Webbed neck (suggests Turner syndrome, which is associated with gastrointestinal vascular malformations and IBD)
Lesions on buccal mucosa (suggests trauma)
What features on physical examination of lung and heart can help identify an unknown cause of GI bleeding?
Hemoptysis (tuberculosis, pulmonary hemosiderosis
Murmur of aortic stenosis (in adults, associated with vascular malformations of the ascending colon, although this association is not certain in children)
What features on physical examination of abdomen, perianal and joints can help identify an unknown cause of GI bleeding?
Splenomegaly or hepatomegaly (suggests portal hypertension and possible esophageal varices)
Ascites (suggests chronic liver disease and possible varices)
Palpable or tender loops of intestine (suggests IBD)
Perianal ulcerations and skin tags (suggest IBD)
Perianal abscess (suggests IBD, chronic granulomatous disease immunodeficiency)
Fissure (suggests constipation)
Hemorrhoids (suggests constipation, portal hypertension)
Rectal mass on digital examination (suggests polyp)
Arthritis (Henoch-Schönlein purpura, IBD)
How does the type of bloody stool help pinpoint the location of a GI bleed?
- Hematochezia (bright red blood): Normal stool spotting on toilet tissue likely suggests distal bleeding (e.g., anal fissure, juvenile colonic polyp). Mucous or diarrheal stools (especially if painful) indicate left-sided or diffuse colitis.
- Melena (black, tarry stools) indicates blood denatured by acid and usually implies a lesion, likely before the ligament of Treitz. However, melena can be seen in patients with Meckel diverticulum as a result of denaturation by anomalous gastric mucosa.
- Currant jelly (dark maroon) stools usually come from the distal ileum or colon and often are associated with ischemia (e.g., intussusception).
What can cause false-negative and false-positive results when stool testing for blood?
Hemoglobin and its various derivatives (e.g., oxyhemoglobin, reduced hemoglobin, methemoglobin, carboxyhemoglobin) can serve as catalysts for the oxidation of guaiac (Hemoccult) or benzidine (Hematest) when a hydrogen peroxide developer is added, thereby producing a color change. Of note, iron does not cause false-positive results.
False negatives: Ingestion of large doses of ascorbic acid; delayed transit time or bacterial overgrowth, allowing bacteria to degrade the hemoglobin to porphyrin
False positives: Recent ingestion of red meat or peroxidase-containing fruits and vegetables (e.g., broccoli, radishes, cauliflower, cantaloupes, turnips)
How do the causes of lower GI bleeding vary by age group?
Newborn and infant:
• Mucosal: Peptic ulcer disease, necrotizing enterocolitis, infectious colitis, eosinophilic or allergic colitis, Hirschsprung enterocolitis, anal fissure
• Structural: Intestinal duplication, Meckel diverticulum, intussusception
Child:
- Mucosal: Anal fissure, juvenile polyp, infectious colitis, inflammatory bowel disease, solitary rectal ulcer, lymphonodular hyperplasia
- Structural: Intestinal duplication, Meckel diverticulum, intussusception, volvulus, Dieulafoy malformation (large tortuous arteriole in the stomach that erodes and bleeds)
- Other: Hemolytic-uremic syndrome, Henoch-Schönlein purpura, Munchausen syndrome by proxy, arteriovenous malformation, vascular malformation
A previously asymptomatic 18-month-old child has large amounts of painless rectal bleeding (red but mixed with darker clots). What is the likely diagnosis?
Although juvenile polyps can also cause painless rectal bleeding, the likely diagnosis is a Meckel diverticulum . This outpouching occurs from the failure of the intestinal end of the omphalomesenteric duct to obliterate. Up to 2% of the population may have a Meckel diverticulum, and about half contain gastric mucosa; most are usually silent throughout life. Meckel diverticulum is twice as common in males and usually appears during the first 2 years of life as massive painless bleeding that is red or maroon in color. Tarry stools are observed in about 10% of cases. A history of previous minor episodes may be obtained. The presentation can range from shock to intussusception with obstruction, volvulus, or torsion. Meckel diverticulitis, which occurs in 10% to 20% of cases, may be indistinguishable from appendicitis.
Worldwide, what is the most common cause of GI blood loss in children?
Hookworm infection. Caused by the parasites Necator americanus and Ancylostoma duodenale , this infection is often asymptomatic. Progressive microscopic blood loss often leads to anemia as a result of iron deficiency
How do the causes of upper GI bleeding vary by age group?
- Newborns: Swallowed maternal blood, vitamin K deficiency, stress gastritis or ulcer, vascular anomaly, coagulopathy, milk-protein sensitivity
- Infants: Stress gastritis or ulcer, acid-peptic disease, Mallory-Weiss tear, vascular anomaly, GI duplications, gastric or esophageal varices, duodenal or gastric webs, bowel obstruction
- Children: Mallory-Weiss tear, acid-peptic disease, varices, caustic ingestion, vasculitis, hemobilia, tumor
What is the most likely cause of hematemesis in a healthy term infant?
Swallowed maternal blood. The Apt test can be used to differentiate maternal from infant blood. Fetal hemoglobin resists denaturation with alkali better than adult hemoglobin does. Therefore, exposure of adult blood to sodium hydroxide will result in a brown color, whereas the newborn infant’s blood will remain pink.
What are the two most likely causes of visible blood in the stool of an otherwise healthy infant?
Anal/rectal fissure and milk/soy protein allergy . A physical exam and rectal exam are of particular importance in making the diagnosis.
What are the six most common causes of massive GI bleeding in children?
- Esophageal varices
- Meckel diverticulum
- Hemorrhagic gastritis
- Crohn disease with ileal ulcer
- Peptic ulcer (mainly duodenal)
- Arteriovenous malformation
