GI Pathology: Gastrointestinal bleeding
Hematemesis means vomiting blood ("heme" = blood; "emesis" = vomit).
When the bloody vomit has a dark, mottled
"coffee ground" appearance, this means that the blood flow has slowed or stopped.
Melena refers to black, tarry stools with blood.
Hematochezia refers to the passage of bright red fresh blood.
Bleeding in the upper gastrointestinal tract can produce hematemesis and/or melena; bleeding in the lower gastrointestinal tract can produce melena or hematochezia.
Defining Upper vs. Lower GI tract:
The Upper Gastrointestinal tract lies proximal to the duodenal attachment of the
ligament of Treitz (aka, the
suspensory ligament of the duodenum) and the Lower Gastrointestinal tract lies distal to it.
Key causes of Upper GI Bleeding
These pathologies produce hematemesis and/or melena.
Esophagitis is inflammation of the esophagus, and can lead to erosion of the esophageal lining and bleeding. - Erosion is most often associated with severe acid reflux and alcohol consumption.
Mallory-Weiss tears are another cause of esophageal bleeding; these tears occur in the distal esophagus, and are the result of fits of violent vomiting or coughing. They are rare.
Duodenal and gastric ulcers & erosion are most common cause of upper GI bleeding. Most often the result of
H. pylori infection, drugs, stress, or autoimmune disorders.
Varcies in the esophagus and proximal stomach are enlarged, swollen veins that can rupture and cause bleeding. They are most often associated with cirrhosis and
portal hypertension, and can cause potentially life-threatening hemorrhages.
Key causes of Lower GI Bleeding
Produce melena and/or hematochezia.
Infectious colitis, particularly when caused by bacteria, can produce fever, tenesmus, abdominal pain, and purulent, loose bloody stools.
An example of bacterial colitis is
C. difficile infection following antibiotic use.
In contrast,
viral colitis is often associated with watery diarrhea and is more common in infants and children;
amoebic colitis is associated with diarrhea and mucoid discharge.
Inflammatory bowel disease, particularly
ulcerative colitis, causes bloody diarrhea when active.
- We show that ulcerative colitis is characterized by mucosal and submucosal inflammation with sunken ulcers that create a friable or crumbly appearance.
Acute and chronic intestinal ischemia can cause lower GI bleeding, along with nausea, vomiting, and abdominal pain.
Diverticular hemorrhage is a top cause of lower GI bleeding and is characterized by brisk hematochezia with the possibility of massive bleeding.
We show a diverticulum in the colon wall with vascular rupture; note that the diverticula are not necessarily inflamed when the bleeding occurs.
Anal fissures are tears in the anal sphincter that produce bright, fresh blood and cause pain during and after bowel movements.
Hemorrhoids are swollen veins in the rectum and perianal region; these can rupture and produce hematochezia.
Key causes of Upper And/Or Lower GI Bleeding
Neoplasms can occur anywhere along the GI tract; in fact, they are often the presenting sign.
We show a tumor with a leaking vascular system.
Vascular lesions in the GI tract, including
arteriovenous malformations, can cause upper and lower GI bleeding.
We show that arteriovenous malformations are atypical arrangements of blood vessels that divert blood from their proper targets; the tangled vessels can rupture and cause bleeding. These are rare.
