Acute Lower Gastrointestinal Bleeding

• Amanda Box, M.D., M.S.,
• J. Richard Walker III, M.D., M.S.

 Basic Information

Definition

Acute lower gastrointestinal bleeding is defined as sudden colonic blood loss.

Synonyms

1. Acute colonic bleeding

2. Gastrointestinal hemorrhage

3. Melena

4. Hematochezia

ICD-10CM CODES
K92.2	Gastrointestinal hemorrhage, unspecified
K92.1	Melena
K62.5	Hemorrhage of rectum and anus

Epidemiology & Demographics

Incidence

1. •

   Annual incidence in U.S. of lower gastrointestinal (GI) bleeding is 72/100,000.

2. •

   Annual incidence in U.S. of hospitalization is 36/100,000 (about half of that for upper GI bleeding).

Peak Incidence

1. •

   The rate of lower GI bleeding, including that necessitating hospitalization, is higher in the elderly.

Predominant Sex and Age

1. •

   24.2/100,000 in males versus 17.2/100,000 in females. This increases 200-fold by 9th decade of life

Risk Factors

1. •

   Risk factors include nonsteroidal antiinflammatory drug (NSAID) use, aspirin use, alcohol abuse, GI malignancy, atrial fibrillation, coagulopathies, prior GI bleed, cirrhosis, constipation, congenital malformations, radiation exposure, recent infectious illness, recent travel, abdominal aortic aneurysm (AAA) repair, and inflammatory bowel disease.

Physical Findings & Clinical Presentation

1. •

   Attention should be paid in the history to details suggesting the location and etiology of the bleed. For instance, weight loss and abdominal pain suggest inflammatory bowel disease; recent AAA repair, especially with history of a sentinel bleed, raises suspicion for aortoenteric fistula; a history of cirrhosis suggests bleeding from portal hypertension, e.g., varices. Bright red blood is typically from a brisk upper GI bleed, distal colon, or anorectal disease. Melena arises from the upper GI tract, small bowel, or proximal colon. Take a detailed medication history, noting NSAIDs or other drugs that may cause or mimic GI bleeding as well as beta blockers that may mask tachycardia in the setting of significant blood loss.

2. •

   The clinician should first and foremost check vital signs, including orthostatics, if stable. Perform ABCs as indicated. Check for pallor and signs of volume depletion, such as delayed capillary refill and skin tenting. Observe for stigmata of liver disease, such as telangiectasias and jaundice. Auscultate for bowel sounds. Absence of bowel sounds may indicate perforation. Palpate the abdomen for pain, masses, and hepatosplenomegaly. Rectal exam should be performed, noting the presence of blood, rate of bleeding, masses, fissures, hemorrhoids, tenderness, and skin changes. If no gross bleed is seen, perform hemoccult testing. Ensure that the bleeding is, in fact, gastrointestinal, excluding hematuria, vaginal bleeding, and wounds.

Etiology

1. •

   Diverticulosis is the most common cause of lower GI bleeding at 30%. Internal hemorrhoids are the second most common cause. 15% of lower GI bleeds are due to upper GI bleeding.

Diagnosis

Differential Diagnosis

1. •

   Upper GI bleed

2. •

   Diverticulosis

3. •

   Diverticulitis

4. •

   Ischemic colitis

5. •

   Postpolypectomy bleeding

6. •

   Vascular ectasias (angiodysplasia, arteriovenous malformation)

7. •

   Anal fissure

8. •

   Rectal ulcer

9. •

   Colonic polyps

10. •

    Advanced neoplasms

11. •

    Hemorrhoids

12. •

    Intussusception

13. •

    Coagulopathies

14. •

    Infectious colitis (E. coli, Shigella, Salmonella, Giardia)

15. •

    Autoimmune (hemolytic uremic syndrome)

16. •

    Radiation colitis or proctitis

17. •

    Aortoenteric fistula

18. •

    Vasculitis

19. •

    Inflammatory (ulcerative colitis, Crohn’s disease)

20. •

    Colonic varices

21. •

    Drugs (iron, NSAIDs)

22. •

    Foreign body

Work-Up

1. •

   Establish large-bore intravenous access. If the patient has significant hematochezia without hematemesis, consider performing nasogastric lavage to evaluate for upper GI bleeding.

Laboratory Test(S)

1. •

   Complete blood count may reveal anemia and/or thrombocytopenia. The hematocrit and hemoglobin should generally be trended every 4 to 6 hours to document the status of the bleed.

2. •

   Order a comprehensive metabolic panel to evaluate the following: elevated blood urea nitrogen, which indicates reabsorption of red blood cells; elevated creatinine, which indicates poor renal perfusion; liver function tests, which could reveal liver disease that is exacerbating bleeding.

3. •

   International normalized ratio, especially if patient is taking warfarin.

4. •

   Partial thromboplastin time, especially if the patient is on heparin.

5. •

   Type and screen/cross in anticipation of the need for blood products.

6. •

   Stool studies, including white blood cell count, gram stain, culture, and pathogen-specific testing to identify infectious etiologies.

Imaging Studies

1. •

   Computed tomography (CT) angiography can potentially identify the location of the bleed as well as abnormal vasculature.

2. •

   Perform a tagged red blood cell scan if source is not identified on CT angiography.

3. •

   CT scan of the abdomen and pelvis may identify malignancy as the source of bleeding.

4. •

   If free air is suspected from perforation, an abdominal or chest plain film should be ordered immediately. An abdominal plain film can also identify radiopaque foreign bodies.

5. •

   Abdominal ultrasound if intussusception is suspected.

6. •

   Meckel (technetium-99) scan if Meckel’s diverticulum is suspected.

Treatment

1. •

   Begin crystalloid bolus to maintain a systolic blood pressure of at least 100 mm Hg. Transfuse for hemoglobin and hematocrit of 7 and 21, respectively, or less. If the patient has coronary artery disease or multiple medical comorbidities and is older than 65 years, the goal hemoglobin and hematocrit are 8 and 24, respectively. Platelets should be maintained above 50,000 mm and international normalized ratio 1.5 or less.

Nonpharmacologic Therapy

1. •

   Colonoscopy defines the colonic anatomy, can identify the source of bleeding, and allows for potential therapy.

2. •

   Endoscopy can be performed if the source of the bleed is suspected to be proximal to the ligament of Treitz.

3. •

   Anoscopy can be performed for bleeding internal hemorrhoids or other anorectal disorders.

4. •

   Balloon tamponade of esophageal or anorectal bleeds

5. •

   Perform surgery if the source of the bleed cannot be otherwise identified, for aortoenteric fistula, or if air enema for intussusception is unsuccessful.

6. •

   Interventional radiology for embolization

7. •

   Ablation

Acute General Rx

1. •

   Proton pump inhibitor, histamine 2 blocker

Chronic Rx

1. •

   Avoid NSAIDs and alcohol. Treat the underlying cause of the bleed, e.g., coagulopathy, portal hypertension, etc. Most patients are prescribed daily proton pump inhibitors. Fiber, stool softeners, and analgesic creams may alleviate development and/or symptoms of hemorrhoids.

Disposition

1. •

   Most cases of acute lower GI bleeding will resolve spontaneously. Therefore, if the patient is hemodynamically stable without symptomatic anemia or brisk bleeding, he or she may follow up with his or her primary care physician or a gastroenterologist. However, patients with shock or other hemodynamic compromise, severe bleeding, or significant comorbidities should be admitted to the intensive care unit. These patients are at high risk for acute decompensation and as such require close monitoring and aggressive resuscitation; furthermore, they will require urgent diagnosis and intervention to stop the bleeding. Clinical factors predictive of severe colonic bleeding include aspirin use, at least two comorbid illnesses, pulse greater than 100 beats/minute, and systolic blood pressure <115 mm Hg. The overall mortality rate from colonic bleeding is 2.4% to 3.9%. Independent predictors of in-hospital mortality are age over 70 years, intestinal ischemia, and two or more comorbidities.

Referral

Patients should be referred to gastroenterology for follow-up.

Suggested Readings

• B. Cagil: Lower gastrointestinal bleeding, Practice Essentials, Background, Anatomy . Medscape. 06 Jan. 2017 Web. 01 Aug. 2017

• K.A. Ghassemi, D.M. Jensen: Lower GI bleeding: epidemiology and management. Curr Gastroenterol Rep. 15 (7)2013

• I.M. Gralnek, et al.: Acute lower gastrointestinal bleeding. N Engl J Med. 376:1054–1063 2017 28296600

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1. Bleeding, Gastrointestinal (Algorithm)

2. Colorectal Cancer (Related Key Topic)

3. Diverticular Disease (Related Key Topic)

4. Meckel Diverticulum (Related Key Topic)