Rectal bleeding is one of the most common symptoms warranting referral to a pediatric gastroenterologist. The presence of blood in the stool is often an alarming symptom for parents, and usually pediatricians are asked to see the patient right away. Below are some tips to help referring doctors assess the severity of the problem, and whether urgent referral is indicated.
Important questions for evaluating pediatric patients with blood in the stool
Is it really blood?
Even the brightest of physicians have been fooled at times. Certain dyes (such as the red coloring found in some brands of juice) and medications (e.g., cefdinir) can result in a stool that appears bloody.) If a family brings a diaper in, use a guaiac test to confirm the presence of blood.
Believe it or not, the guaiac test is over 100 years old; Sir Arthur Conan Doyle had Sherlock Holmes use it to solve a crime in his first published Holmes mystery, “A Study in Scarlet.” The paper of the guaiac test contains alpha-guaiaconic acid, while the liquid in the developer contains hydrogen peroxide. In the presence of hemoglobin, the hydrogen peroxide rapidly oxidizes the guaiaconic acid into a blue-colored quinone, thus giving the characteristic blue color on the paper.
How old is the patient?
In babies 0-3 months, the most common causes of rectal bleeding are anal fissure or allergic colitis. In contrast, older infants and toddlers are more likely to have constipation, Meckel’s diverticulae or polyps. In school-aged children and teenagers, constipation, polyps, infections, and inflammatory bowel disease (IBD) are more common.
Is the bleeding painless or painful?
Painless rectal bleeding usually implies a lesion that is not inflamed, such as a polyp or Meckel’s diverticulae. In contrast, bleeding associated with pain suggests either ischemia or inflammation. Bleeding that is peridefecatory (i.e., occurring around the time of stooling) suggests colitis, infection or IBD. Severe, poorly localizing abdominal pain combined with bleeding should make the physician consider a rarer condition, like intussusception or volvulus.
What color is the stool?
Black blood (melena) implies bleeding in the esophagus, stomach or duodenum. Maroon-colored stool suggests small intestinal bleeding (e.g., from a Meckel diverticulum). Bright red blood suggests a colonic or rectal source.
Is the patient ill?
If the patient is in severe pain, if there is a large amount of rectal bleeding or if the vital signs suggest hypotension, this is an indication for urgent referral.
The importance of a physical examination for children with rectal bleeding
Physical examination of the patient with rectal bleeding involves examining the stool, assessing the patient’s hemodynamic stability (pulse, heart rate and orthostatic blood pressures), and then inspecting the skin to look for signs of pallor or hemangiomas. Assuming the patient is stable, then feel the abdomen for masses or tenderness and then examine the anal area for fissures, polyps or hemorrhoids. The rectal examination is the most important part of the physical; one needs to feel for polyps, assess the patient for any discomfort out of proportion to the exam and test the stool in the rectal vault.
Other diagnostic tools you might employ include:
- Lab work: If an obvious source of bleeding (e.g., hemorrhoid,constipation) is not apparent, laboratory work may be indicated. Consider ordering a complete blood count, prothrombin time, partial thromboplastin time, erythrocyte sedimentation rate and C-reactive protein. The latter two tests screen for inflammatory bowel disease. In a patient with large volume bleeding, type and screen are important. Further testing depends on the suspected differential diagnosis. For example, intussusception is often evaluated with an ultrasound first, while a patient with suspected Meckel diverticulum is evaluated with a technetium scan.
- Colonoscopy: This is the most useful test in evaluating long-standing rectal bleeding. Colonoscopy with biopsy can identify polyps, inflammatory bowel disease or vascular malformations.
Treatment for rectal bleeding in children
Treatment depends on the exact cause of rectal bleeding found. In some cases such as polyps, a bleeding lesion can be removed with the colonoscope. Other times, medical treatment (e.g., aminosalicylates for ulcerative colitis) or dietary modification (e.g., cow milk elimination in infants with allergic colitis) is required.
Athos Bousvaros, MD, MPH, is associate chief of the Division of Gastroenterology, Hepatology and Nutrition and associate director of the Inflammatory Bowel Disease Center at Boston Children’s Hospital, and an associate professor of pediatrics at Harvard Medical School.
For more information on rectal bleeding or to refer a patient, call Boston Children’s Hospital’s Division of Gastroenterology, Hepatology and Nutrition at 617-355-6058.