Lower Gastrointestinal Bleeding Clinical Presentation

Updated: Jul 26, 2019
  • Author: Burt Cagir, MD, FACS; Chief Editor: BS Anand, MD  more...
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A detailed history and physical examination are essential parts of an initial evaluation of lower gastrointestinal bleeding (LGIB). These can provide valuable clues to the etiology and anatomic source of the bleeding. Document whether this is a first or recurrent episode of GI bleeding as well as any significant medical history (including peptic ulcer disease, liver disease, cirrhosis, coagulopathy, inflammatory bowel disease [IBD]) and previous medication use (eg, nonsteroidal anti-inflammatory drugs [NSAIDs] and/or warfarin). In patients with cancer, the history of radiation, chemotherapy, or both should be considered.

The clinical presentation of LGIB varies with the anatomic source of the bleeding as well as with the etiology. Commonly, LGIB from the right side of the colon can manifest as maroon stools, whereas a left-sided bleeding source may be evidenced by bright red blood per rectum. In practice, however, patients with upper GI bleeding (UGIB) and those with right-sided colonic bleeding may also present with bright red blood per rectum if the bleeding is brisk and massive. Similarly, cecal bleeding may present with melena, which is typically seen with UGIB, suggesting no distinct method exists for determining the anatomic source of bleeding based solely on stool color.

The presentation of LGIB can also vary depending on the etiology. A young patient may present with fever, dehydration, abdominal cramps, and hematochezia caused by infectious or noninfectious (idiopathic) colitis. An older patient may present with painless bleeding and minimal symptoms caused by diverticular bleeding or angiodysplasia. LGIB can be mild and intermittent, as often is the case with angiodysplasia, or it may be moderate or severe, as may be the situation in diverticula-related bleeding.

Symptoms are also important in identifying the source of bleeding. Young patients may present with abdominal pain, rectal bleeding, diarrhea, and mucous discharge that may be associated with IBD. However, elderly patients presenting with abdominal pain, rectal bleeding, and diarrhea may have ischemic colitis, or elderly patients with atherosclerotic heart disease may present with intermittent LGIB and syncope that may be due to angiodysplastic lesions. Stools streaked with blood, perianal pain, and blood drops on the toilet paper or in the toilet bowl may be associated with perianal pathology, such as anal fissure or hemorrhoidal bleeding.

Massive LGIB is a life-threatening condition in which patients present with a systolic blood pressure (SBP) below 90 mm Hg and a hemoglobin (Hb) level of 6 g/dL or less. Affected patients are usually aged 65 years and older, have multiple medical problems, and are at risk of death from acute hemorrhage or its complications. The passage of maroon stools or bright red blood from the rectum is usually indicative of massive lower GI hemorrhage.

Diverticular bleeding

Although diverticular bleeding is painless, patients may experience mild abdominal cramping due to the intraluminal blood that triggers spasmodic contractions of the colonic wall. Bleeding is usually acute, without antecedent symptoms, and it is self-limited in about 70%-80% of cases. Rebleeding can occur in up to 25% of patients. [25]

If the bleeding is brisk and voluminous, patients may be hypotensive and display signs of shock. In patients with diverticular disease, consider the possibility of complicated diverticulitis in the presence of tachycardia and hypotension. [26] Patients with diverticular bleeding or unstable vital signs should undergo rapid assessment and resuscitation before diagnostic testing. [27]

Chronic, intermittent, minimal blood loss per rectum is unlikely to be caused by diverticular bleeding, because diverticular bleeding is arterial in origin. [5]


Significant angiodysplasia-related bleeding, like diverticular bleeding, presents as painless, self-limited hematochezia or melena; angiodysplasia-related bleeding is venocapillary. Unlike diverticular bleeding, angiodysplasia tends to cause slow but repeated bleeding episodes. Therefore, patients may present with guaiac-positive stools, iron-deficiency anemia, and syncope. Occasionally, patients can present with large-volume bleeding.


Ischemic colitis may or may not present with abdominal pain and associated bloody diarrhea. The bloody diarrhea is self-limited but can recur if the underlying cause is not corrected. Although the clinical presentation is indistinguishable at times from that of infectious colitis, idiopathic colitis, and radiation-induced colitis, patients with ischemic colitis are usually older and have cardiovascular comorbidities. Ischemic colitis may be fulminant, presenting with acute abdominal pain, rectal bleeding, and hypotension, or this condition may be insidious, presenting with pain and rectal bleeding over several weeks.

In infectious colitis, the clinical examination findings vary depending on the volume status, amount of blood loss, extent of abdominal pain, and accompanying peritoneal signs. The clinical presentation of fever, diarrhea, dehydration, and abdominal pain can be caused by any of a number of bacterial, viral, or parasitic pathogens. The specific etiology can only be determined by isolating the organism from the stool, blood, or other tissue fluid. Patients may be quite ill and may experience intravascular volume depletion, abdominal pain, and generalized malaise, but blood loss is usually mild and a minor factor in symptomatology.

The clinical presentation of ulcerative colitis depends on whether the disease is mild, moderate, or severe. Although bleeding is minimal to none in people with mild disease, those with moderate to severe ulcerative colitis present with bloody diarrhea with pus, abdominal cramps, and dehydration. Symptoms of weight loss and fever occur in those with severe disease. Patients with Crohn disease usually present with fever, nonbloody diarrhea, and abdominal pain. However, patients with Crohn colitis can present with bloody diarrhea.

Colon carcinoma

The bleeding associated with colon cancer, particularly right-sided bleeding, can be insidious, with patients presenting with iron-deficiency anemia and syncope. Right-sided colon cancer may also present with maroon stools or melena, whereas left-sided colonic neoplasms can present as bright red blood per rectum, which can sometimes be confused with hemorrhoidal bleeding.

Anorectal disease

Hemorrhoidal bleeding is most often painless, whereas bleeding secondary to fissures tends to be painful. Hemorrhoids can also present with strangulation, hematochezia, and pruritus. Typically, bright red blood coats the stool at the end of defecation or blood may stain the toilet paper. Rarely, the bleeding may be copious and distressing to the patient.


Physical Examination

The physical examination should be thorough and include assessment of the skin, oropharynx, nasopharynx, abdomen, perineum, and anorectum to evaluate for sources of bleeding.

Because brisk upper gastrointestinal bleeding (UGIB) can present as lower GI bleeding (LGIB), placement of a nasogastric (NG) tube may be necessary, with the aspirate or lavage examined for the presence of blood and/or bile. These aspirates usually correlate well with upper gastric hemorrhage proximal to the Treitz ligamentum; therefore, insert an NG tube to confirm the presence or absence of blood in the stomach.

If necessary, perform gastric lavage with warm isotonic fluids to obtain bilious discharge; an aspirate that is positive for bile is comprehensive in that it includes fluid even beyond the pylorus. In such a scenario, if no blood is present, a UGIB source only makes sense if the bleeding has stopped. If this possibility exists, an esophagogastroduodenoscopy (EGD) should be performed to obtain a more specific evaluation of the upper GI tract. Place a Foley catheter to monitor urine output. Careful digital rectal examination, anoscopy, and rigid proctosigmoidoscopy should exclude an anorectal source of bleeding.

Patients who have rectal varices with portal hypertension may develop painless massive LGIB; therefore, examining the anorectum early in the workup is important. If active bleeding is identified, treat it aggressively. Note that the discovery of a benign anorectal disease does not exclude the possibility of more proximal bleeding from the lower GI tract.

Once the bleeding is determined to be from the lower GI tract as opposed to an upper GI source, the tempo of the bleeding and the extent of blood loss should be quickly estimated so that a precise and targeted algorithm is adopted (see an example in the image below). Patients with massive LGIB usually present with bright red blood per rectum, hypotension, and a markedly reduced hematocrit in contrast to patients with mild bleeding who may present with intermittent passage of maroon stools. The emergency implementation of aggressive resuscitation, diagnostic evaluation, and early involvement of a gastroenterologist (and surgeon in the case of a rapid LGIB) is key to reducing morbidity and mortality and to improving outcomes.

Algorithm for massive lower gastrointestinal (GI) Algorithm for massive lower gastrointestinal (GI) bleeding, surgical perspective. EGD = esophagogastroduodenoscopy; NG = nasogastric; 99mTc RBC = technetium-99m pertechnetate–labeled autologous RBC.