Content – GI Bleeds

Upper GI Bleeds

Causes of upper GI bleeds include the following:

Esophageal Varices  The lower 1/3 of the esophagus is drained by many small veins, which are a site of portocaval anastomoses. The portal system, which must drain into the liver before returning to the inferior vena cava (IVC), can sometimes be backed up due to liver pathology. In the situation of a significant degree of obstruction, it is possible for blood to shunt out of the portal system and into the caval system at certain points in the body, therefore avoiding the liver. These small esophageal veins are one of the points, but the high pressure placed on the thin walled veins can cause them to swell and burst, which is known as bleeding esophageal varices.

Gastric or Duodenal Ulcers   The lumen of stomach and duodenum is highly acidified, so the gastric and intestinal mucosa must be protected by a thick layer of mucous secreted by specialized cells. Any interruptions to this balance, such as increased luminal acidity or damaged mucous barrier, can lead to an area of ulceration in the mucosa. This can continue into the regional blood vessels, leading to bleeding.

Mallory-Weiss Tears  At the junction of stomach and esophagus, trauma can occur due to extreme vomiting or retching. This most often presents with vomiting of bright red blood and pain.

Aortoenteric Fistulas   These can occur anytime there is a connection between any part of the intestines and the aorta. They most often occur after surgery for aortic aneurysm repair.

Other causes of both chronic and acute upper GI bleeding include: malignancy, portal hypertensive gastropathy, gastric antral vascular ectasia (GAVE), and iatrogenic.

Lower GI Bleeds

Causes of lower GI bleeds include:

Diverticulitis   Diverticulosis occurs with small outpouchings of the colonic wall, most commonly in the sigmoid colon. Their incidence increases with age and they are associated with impacted stool. Diverticulitis occurs when one of these areas becomes infected, often due to retained stool, and inflammation occurs. This can be severe enough to cause rupture and bleeding.

Hemorrhoids   These are due to bulging and prolapse of the rectal veins, and can be internal or external depending on which veins are affected. They most often present with bright red blood on the toilet paper or coating the stool. Pain can also be present if the external veins are the source due to the somatic innervation in this area.

Angiodysplasia   This is a small vascular lesion that can occur anywhere in the GI tract, but most commonly the cecum and ascending colon. The cause is unknown.

Other causes of both acute and chronic lower GI bleeding include: Colitis (ulcerative, ischemic, or infectious), Crohn’s disease, malignancy, and iatrogenic.

Small bowel bleeding is more difficult to locate and treat. Its causes include:

• Angiodysplasia
• Mekel’s diverticulum
• Malignancy
• Crohn’s disease
• Mesenteric infarction

History

GI bleeding is typically divided into upper vs lower, which can present with different symptoms.

Depending on severity, all GI bleeding can result in:

• bleeding in vomit or stool
• abdominal pain
• symptoms of hemodynamic instability, especially lightheadedness/dizziness or syncope

Acute bleeding causes symptoms that occur over hours to days. Chronic bleeding can cause a gradual increase in symptoms such as fatigue and lightheadedness.

Focused questions can help to determine potential sources and causes for bleeding. Important considerations include:

• History of reflux (ulcers)
• NSAID use (ulcers – especially duodenal)
• Alcohol abuse (liver cirrhosis)
• Chronic liver disease
• Prior surgeries (especially aortic aneurysm repair)
• Anticoagulation

Physical Exam

Important considerations for the physical exam include:

• Skin and conjunctiva: Pallor
• Vitals: Respiratory rate, pulse, and blood pressure for evidence of shock
• Cardiac and respiratory exams – look for complications
• Abdominal – focused on signs of bleeding or liver disease
• Digital rectal examination – can potentially palpate masses or hemorrhoids

Lab Tests

Lab tests to consider include:

• CBC, electrolytes, BUN, creatinine
• INR, liver enzymes, cardiac enzymes
• Urea to creatinine ratio – greater than 30 suggests an upper GI bleed

Chronic GI bleeding can result in a microcytic or normocytic anemia.

Imaging

Which tests are performed and the urgency with which they are scheduled depends on the history given by the patient and the hemodynamic status.

• Upper endoscopy or colonoscopy – if patient is stable enough to undergo the procedure
• Gastric aspiration and lavage – to determine if there’s blood in the stomach
• Tagged RBC scan – if bleeding isn’t located on scope and bleeding persists
• Angiography (of the mesenteric arteries) – if patient is unstable
• Alternate endoscopy can be used to view the small intestines including capsule endoscopy, push enteroscopy, and balloon enteroscopy
• ECG, CXR – to look for complications