Gastrointestinal bleeding

Gastrointestinal bleeding or gastrointestinal hemorrhage describes every form of hemorrhage (loss of blood) in the gastrointestinal tract, from the pharynx to the rectum. It has diverse causes, and a medical history, as well as physical examination, generally distinguishes between the main forms. The degree of bleeding can range from nearly undetectable to acute, massive, life-threatening bleeding.

Initial emphasis is on resuscitation by infusion of intravenous fluids and blood transfusion, treatment with proton pump inhibitors and occasionally with vasopressin analogues and tranexamic acid. Upper endoscopy or colonoscopy are generally considered appropriate to identify the source of bleeding and carry out therapeutic interventions.

Definition
Gastrointestinal bleeding can range from microscopic bleeding, where the amount of blood is so small that it can only be detected by laboratory testing (in the form of iron deficiency anemia), to massive bleeding where pure blood is passed and hypovolemia and shock may develop, risking death.

Cause
The causes of upper GI bleed is different from that for lower GI bleeds.

Differential diagnosis
Gastrointestinal bleeding can be roughly divided into two clinical syndromes.

Upper gastrointestinal
Upper gastrointestinal bleeding is from a source between the pharynx and the ligament of Treitz. An upper source is characterised by hematemesis (vomiting up blood) and melena (tarry stool containing altered blood).

Lower gastrointestinal
Lower gastrointestinal bleeding may be indicated by red blood per rectum, especially in the absence of hematemesis. Isolated melena may originate from anywhere between the stomach and the proximal colon.

Diagnostic approach
Diagnosis is often based on direct observation of blood in the stool. This can be confirmed with a fecal occult blood test.

Initial
Initial focus in any patient with a form of gastrointestinal hemorrhage is on resuscitation, as any further intervention is precluded by the presence of intravascular depletion or shock.
 * Fluid resuscitation: intravenous fluids and blood transfusion may be administered.
 * Acid suppression: in an upper GI source, proton pump inhibitors reduce gastric acid production and enhance healing of bleeding lesions.
 * Inhibition of fibrinolysis: in ongoing bleeding, tranexamic acid reduces fibrinolysis and may decrease blood product requirements.
 * Correction of coagulopathy: if coagulation parameters (e.g. prothrombin time) are deranged, vitamin K or fresh frozen plasma may need to be administered.
 * Reduction of portal pressure: if the bleeding is thought to be due to esophageal varices (a complication of cirrhosis of the liver), vasopressin analogues and rarely octreotide may be administered. Rarely, a Sengstaken-Blakemore tube or Minnesota tube may be inserted to mechanically compress varices.
 * Urgent endoscopy: if the bleeding cannot be managed medically an urgent esophagogastroduodenoscopy (EGD/OGD) may identify sources of bleeding. This is a high-risk procedure best performed under safe circumstances in the intensive care unit or operating theatres.
 * Surgical intervention: in extreme cases of bleeding, laparotomy may be required to identify the bleeding source.

Endoscopy
After adequate stabilization, endoscopy (upper endoscopy and/or colonoscopy) are used to identify the source of bleeding. Injection, sclerotherapy, electrocoagulation, vascular clipping and biopsy may be performed.

Endoscopy is also useful in setting the indication for therapy, e.g. the need for long-term proton pump inhibitor therapy, presence of esophageal varices, adenomatous polyps and so on.