IS Case 621: Gastrointestinal Bleeding: Etiology, Clinical Presentation, Diagnosis, Treatment and Management: A Review Article
2016, UR Imaging Sciences
Publication Date: 20161128
Gastrointestinal bleeding, also known as a GI bleed, is any type of bleeding that emerges from the GI tract. This includes the esophagus, stomach, small intestines, large intestine, and rectum. GI bleeds are characterized by the location of the bleeding source: upper GI bleed and lower GI bleed. Upper GI bleed includes the GI tract from esophagus to the duodenum. Lower GI bleed is defined as any from of bleeding from the small intestines to the anus. Typically, most forms of bleeding can be handled by simply applying pressure, however, this isn’t an option for GI bleeds due to their internal location. 
A Gastrointestinal bleed can originate anywhere from the mouth to the anus, and it can also include peripheral structures that are attached to the GI tract. These structures include: the pancreas, the liver, and many more. Due to the vast area that GI bleeds can occur over, diagnosing the location of the bleeding can be challenging. This article will provide an overall review of Gastrointestinal bleed including its etiology, diagnosis, treatment, and management in the United States.
Types of GI Bleed: Overt (acute), Occult (chronic) and Obscure
Due to the vast area in which GI bleeds can occur, they are split into two distinct categories, upper GI bleed and lower GI bleed. However, GI bleeds can also be characterized by the time course of the bleed. There is overt (or acute) GI bleeds, which are visible and are typically discovered from hematemesis (vomiting of red blood) or coffee ground emesis. However, there is also occult GI bleeds, which are persistent microscopic bleeds that can be challenging to identify, but can lead to a large amount of blood loss. This type of GI bleed typically presents as in hemoccult-positive stool or iron deficiency anemia, if there is no visible blood. The final type of GI bleed is obscure, which is a reoccurring bleed that has an unidentified source. Obscure GI bleeds can be occult or overt. These different categories are critical for physicians and their diagnosis and treatment of diseases, because each type has a unique treatment plan that may not be effective for another type of GI bleed.
According to recent surveys of GI bleeds, the occurrence of an upper GI bleed is about 40 to 150 people per 100,000 per year (0.04-0.15% of the population).  This is much more prevalent than a lower GI bleed which has an incidence rate of 20 to 30 people per 100,000 per year (0.02-0.03% of the population). Over the last few decades it was discovered that there is a direct correlation between age and the incidence rate of a GI bleed. This correlation is even more predominate in people over the age of 60 and in men.
The mortality of upper GI hemorrhaging was about 12% according to studies conducted in 1997. However, more recent data suggests that the mortality rate has decreased to around 7.4%. The mortality of lower GI bleeds ranges between 4- 10%. Regardless, there is call for more research in this area. [4,5]
Etiology of Upper GI Hemorrhaging vs. Lower GI Bleeds
Currently, the most frequent cause of Upper GI bleeds are peptic ulcers. These ulcers are erosions in the lining of the esophagus, stomach, or duodenum. Ulcers can form from a bacteria called H. Pylori that has infected the lining if the stomach or an overuse NSAID’s (Non-Steroid Anti-Inflammatory Drugs). NSAID’s disrupt the normal lining of the GI tract that helps protect itself from stomach acid. By disrupting this process, the lining of the GI tract is left vulnerable to tear easily. Additionally, these NSAID prevent blood clotting, which is obviously very important to the reparation of peptic ulcers. 
The next most prevalent cause of GI upper bleeds are arteriovenous malformations which are an abnormal connection of veins and arteries. If this malformation ruptures, it can cause a bleed. This is common in patients over the age of 70 and is typically discovered because of painless bleeding. [6,7]
Other causes of Upper GI bleeds include malignancies in any of the upper GI tract, gastritis, duodenitis, esophageal ulcers that are usually caused from indigestion or heartburn, and Mallory-Weiss tears from repeated vomiting. (Figure 1)
In regards to lower GI bleeds, the most common cause is diverticulosis, a condition where small pouches form along the digestive tract beginning at the small intestines. The reason for the formation of these diverticula (pouches) is still not quite comprehended. However, one hypothesis is that the weak spots of the digestive tract are more vulnerable to the extensive pressure exerted by the GI tract, which can cause these weak spots becoming diverticula. Diverticulosis of the small intestines and colon are the main causes of lower GI hemorrhaging. 
Another major cause of lower GI bleeds is inflammatory bowel disease. The main types of inflammatory bowel disease are: Crohn disease, ulcerative colitis, and noninfectious colitis. Each of these diseases typically causes bleeding in the colon or the small intestines. [8,9]
The last major cause of lower GI bleeds is angiodysplasia. This is the most common vascular anomaly found in the GI tract. Unlike, diverticulosis this venocapillary malformation causes less aggressive bleeding but has a higher reoccurrence rate. 
Other causes of lower GI bleeds include: anorectal disease (fistulas, hemorrhoids, and fissures), infectious colitius (E. coli and Salmonella), and neoplasia (bleeding from polyps or malignant tumors, such as those of colon cancer). (Figure 2)
Upper GI bleeds typically present with hematemesis (vomiting of fresh blood), “coffee-ground” emesis (vomiting of dark digested blood), and/or melena (dark/tarry stool). These are the most common signs of an upper GI bleed. While hematemesis typically points to a more active and severe bleed, “coffee-ground” emesis usually indicates that the bleed is less active or is an acute GI bleed.
Lower GI bleeds are most commonly diagnosed by hematochezia (bleeding from the anus). However, melena can also indicate a lower GI bleed, which indicates the source of bleeding is most likely the right colon or the small intestines. [10,11] If the blood appears bright red, then the bleeding is most likely occurring from the left portion of the colon.
Other indicators of GI bleeds can include: hemodynamic instability, abdominal pain, and symptoms of anemia such as lethargy, fatigue, and angina. If the patient presents with normocytic red blood cells this typically indicates an acute GI bleed. Where microcytic red blood cells and iron deficiency anemia indicate that the GI bleed is chronic. In general, anatomic and vascular causes of bleeding present with painless, large-volume blood loss, whereas inflammatory causes of bleeding are associated with diarrhea and abdominal pain.
An upper endoscopy consists of inserting a camera via the mouth and down the esophagus. This minimally invasive technique proves the most successful in diagnosing upper GI bleeds. Doctors can then use the imaging to manage the bleed and sometimes even stop it. This diagnostic technique is usually the first choice when a patient presents the typically symptoms of an upper GI bleed such as hemostasis or “coffee-ground” emesis.  (Figure 3A&B.)
Physicians will use a pill camera, that patients will swallow.The camera transmits video of the GI tract to determine the source of bleeding. This can be used for either upper or lower GI bleeds. But, this technique gives doctors the best look at the small intestines an area that is typically not accessible via an upper endoscopy or a colonoscopy. (Figure 4)
This procedure involves inserting a tube with a camera attached to the end into the rectum to examine the large intestine and rectum. This diagnostic technique is the most commonly used tool when a patient present with hematochezia, blood in stool. In most cases this indicates that the source of the GI bleed is after the duodenum on the GI tract, therefore it is considered a lower GI bleed. (Figure 5)
Balloon Assisted Enteroscopy
This diagnostic technique involves the use of balloons attached to an endoscopeto better reach the small bowel, which is typically a difficult area to access via endoscopy. This new technique is becoming more widely used as a source of viewing the small intestines, which proves to be extremely challenging to view using minimally techniques.
If initial findings of an upper endoscopy or a colonoscopy are inconclusive, then many doctors use an angiography to determine the source of the GI bleed. This technique is most widely used in patients that have persistent and reoccurring GI bleeds, which can indicate that the bleed is of an arterial source. Through this technique doctors will insert a contrast dye into an artery and use x-rays or a CT to view these arteries. Physicians will use this method if they suspect that source of bleeding is originating from the vascular system of the GI tract. The most common cause would then be a vascular malformation that is causing the GI bleed.  (Figures 6A-C)
A majority of GI bleeds can be treated or managed using a variety of endoscopic techniques. These techniques include: thermocoagulation, laser photocoagulation, epinephrine injections, band ligation, endoclips, rubber band ligation, and biologic glue.
Injection Therapy: Physicians can inject a dose of epinephrine (diluted to 1:10,000)  and injected in a dose of 0.5ml- 1ml aquilots. Scientists still debate whether the hemostatic effect of epinephrine is due to induced vessel vasoconstriction and subsequent platelet aggregation or to the tamponade effect produced by injecting the volume of drug into the tissue surrounding the bleeding lesion. 
Epinephrine clears the area surrounding the lesion which in turn allows better visualization of the lesion. Doctors now have a clearer view of the site of the bleeding and can stop the bleeding using other techniques such as heat probes, biologic glue, etc.
Laser Therapy: Using a focused line of photons, doctors can treat a vessel with the laser causing hemostasis by direct vessel coagulation. This technique is not as effective as other treatments such as coaptive coagulation which induces the tamponade effect that helps reduce bleeding. Laser therapy doesn’t cause this tamponade effect because it does not come in contact with the lesion and the surrounding area. 
Band and Rubber Band Ligation: When there is serious lower GI bleed and the cause is a hemorrhoid then this technique is most often used. Doctors can place bands on the base of the hemorrhoid, cutting off circulation to the hemorrhoid and stopping the bleeding. This will cause the hemorrhoid to shrink and fall off the lining of the GI tract. 
Hemoclips and Endoclips: There are multiple different types of clips that can be applied to a wide variety of lesions along the GI tract that are now available in the US. The clips are applied to the lesion to cause hemostasis. Originally these clips proved difficult to place in the right positon endoscopically, but now the reinvented designs of these clips has made it easier to position. 
Biologic Glue: Cyanoacrylates are the type of compound that is used. This tissue adhesive can provide hemostasis. Essentially, these are glues for the wound. Once it’s injected it coagulates and solidifies forming a type of cast over the wound. This induces hemostasis and heals the lesion.
The previously mentioned methods are the most widely used treatment techniques for both upper and lower GI bleeds. These therapeutic techniques are the first steps doctors take to localize the bleeding and stop it, however if bleeding persists and there seems to be no stop, emergent surgery is the last option. This exploratory surgery searches along a majority of the bowel looking for the source of bleeding. This is typically used for an occult or obscure GI bleed. 
The following flow charts provide an overview of the way in which doctors approach both upper and lower GI bleeds. Each flow chart shows the steps that physicians take to treat and manage GI bleeding. (Figures 7-9)
The digestive tract is the largest portion of the body, running over 30 feet in length. So, in order to treat diseases within the tract, such as gastrointestinal bleeding, doctors must classify the area from where the issue has originated. Therefore, Gastrointestinal Bleeding comes in many different forms: upper, lower, occult, obscure, and overt. Even though there are many different types of GI bleeds, these are classifications that allow doctors to better diagnose and treat the bleed. GI bleeds are special because they are not diseases in themselves. These bleeds are symptoms or effects of other conditions or diseases, such as arteriovenous malformations, cancer, or other diseases. Regardless of the underlying disease or issue, doctors have to deal with the short term problem, which is the bleeding, because if this is not dealt with, it will prove fatal.
- Upper Gastrointestinal Bleeding. AHC Media Continuing Medical Education Publishing RSS. http://www.ahcmedia.com/articles/102700-upper-gastrointestinal-bleeding?trendmd-shared=1. Accessed September 7, 2016.
- Pirastehfar M, Azari A, Saberifiroozi M, Kaviani M. Etiology and outcome of patients with upper gastrointestinal bleeding: A study from South of Iran. Saudi Journal of Gastroenterology Saudi J Gastroenterol. 2010;16(4):253. doi:10.4103/1319-3767.70608.
- El-Tawil AM. Trends on gastrointestinal bleeding and mortality: Where are we standing? World Journal of Gastroenterology : WJG. http://www.ncbi.nlm.nih.gov/pmc/articles/pmc3309903/. Published 2012
- Ghassemi KA, Jensen DM. Lower GI Bleeding: Epidemiology and Management. Current gastroenterology reports. http://www.ncbi.nlm.nih.gov/pmc/articles/pmc3857214/. Published 2013. Accessed September 7, 2016.
- Straube S, Tramèr MR, Moore RA, Derry S, McQuay HJ. Mortality with upper gastrointestinal bleeding and perforation: effects of time and NSAID use. BMC Gastroenterology. http://www.ncbi.nlm.nih.gov/pmc/articles/pmc2698873/. Published 2009. Accessed September 7, 2016.
- Kim BSM, Li BT, Engel A, et al. Diagnosis of gastrointestinal bleeding: A practical guide for clinicians. World Journal of Gastrointestinal Pathophysiology. http://www.ncbi.nlm.nih.gov/pmc/articles/pmc4231512/. Published 2014. Accessed September 7, 2016.
- THAD WILKINS, MD; NAIMAN KHAN, MD; AKASH NABH, MD; and ROBERT R. SCHADE, MD, Georgia Health Sciences University, Augusta, Georgia. Diagnosis and Management of Upper Gastrointestinal Bleeding. - American Family Physician. http://www.aafp.org/afp/2012/0301/p469.html. Accessed September 7, 2016.
- Peptic Ulcer Disease. ACG Patients. http://patients.gi.org/topics/peptic-ulcer-disease/. Accessed September 7, 2016.
- Lower Gastrointestinal Bleeding. : Practice Essentials, Background, Anatomy. http://emedicine.medscape.com/article/188478-overview#a5. Accessed September 7, 2016.
- By a Friend', artTitle = $(. Gastrointestinal Bleeding (GI) Causes, Symptoms, Treatment - What are causes of lower GI bleeding? - eMedicineHealth. eMedicineHealth. http://www.emedicinehealth.com/gastrointestinal_bleeding/page3_em.htm#what_are_causes_of_lower_gi_bleeding. Accessed September 7, 2016.
- Edelman DA, Sugawa C. Lower gastrointestinal bleeding: a review. Surgical Endoscopy Surg Endosc. 2007;21(4):514-520. doi:10.1007/s00464-006-9191-7.
- Adang RP, Vismans JF, Talmon JL, Hasman A, Ambergen AW, Stockbrügger RW. Appropriateness of indications for diagnostic upper gastrointestinal endoscopy: association with relevant endoscopic disease. Gastrointest Endosc. 1995;42:390–397.
- Staff BMC. Capsule endoscopy. - Mayo Clinic. http://www.mayoclinic.org/tests-procedures/capsule-endoscopy/basics/definition/prc-20012773. Accessed September 7, 2016.
- Smith M. Balloon Assisted Enteroscopy. American Society for Gastrointestinal Endoscopy. http://www.asge.org/press/press.aspx?id=8138. Accessed September 7, 2016.
- Upper Gastrointestinal Bleeding Imaging. : Overview, Radiography, Computed Tomography. http://emedicine.medscape.com/article/417980-overview pa=p/3xx9952wcycwy4xxntt2hwot2iawtsxgbdf4qtrrp4thsiqmjjg55on4nevndsnijsqiyx7fhbya43yrtbron5lpyw/tq7z8woozpssmw=. Accessed September 7, 2016.
- Upper Gastrointestinal Bleeding Treatment & Management. Upper Gastrointestinal Bleeding Treatment & Management: Approach Considerations, PPIs, Therapeutic Endoscopy. http://emedicine.medscape.com/article/187857-treatment?pa=3mze1os5ntjl9n8u8exreof8phr6f8sc9fhlqwb4itb2aozjilmwgwwqhcu9gm/q/pwyoumuxcva2vwj1vkvn/zf93fvbcpwxd4yvpu7ryc=#d10. Accessed September 7, 2016.
- Bhat YM, Banerjee S, Barth BA, et al. Tissue adhesives: cyanoacrylate glue and fibrin sealant. Gastrointestinal Endoscopy. 2013;78(2):209-215. doi:10.1016/j.gie.2013.04.166.
- Strate LL, Gralnek IM. ACG Clinical Guideline: Management of Patients With Acute Lower Gastrointestinal Bleeding. Am J Gastroenterol The American Journal of Gastroenterology. 2016;111(5):755-755. doi:10.1038/ajg.2016.155.
- National Center for Biotechnology Information. https://www.ncbi.nlm.nih.gov/pubmed/9299669. Accessed October 14, 2016.