Pediatric emergency medicine trisk 945
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Gastrointestinal Emergencies further discuss the diagnosis and management of
patients with GI bleeding.
FIGURE 116.17 Causes of rectal bleeding in children.
CLINICAL PEARLS AND PITFALLS
Blood per rectum can be a sign of ischemic bowel
Meckel diverticulum can present with brisk, painless rectal bleeding
Small amounts of blood mixed in the stool of an otherwise healthy,
asymptomatic infant is generally due to allergic colitis
Fissures
An anal fissure is probably the most common cause of bleeding, especially in
infants. However, fissures may occur at any age. The child usually has a history
of passing a large, hard stool with anal discomfort. Often, the child has a history
of chronic constipation with progressive reluctance to pass stool because of the
associated discomfort. If bleeding occurs, it usually involves streaking of bright
red blood on the outside of the stool or red blood on the toilet tissues. The
diagnosis can easily be made by inspection or anoscopic examination and
appropriate measures taken to relieve the chronic constipation (see Chapter 18
Constipation ). Rarely does a child require hospitalization or surgery.
Juvenile Polyps
Older infants and children can develop either single or multiple retention polyps.
Usually, the polyps occur in the lower portion of the colon and can often be
palpated on rectal examination. Polyps bleed, but they rarely cause massive
hemorrhage. They may intermittently prolapse at the anus or on occasion come
free and be passed as a fecal mass associated with bleeding. Colonic polyps may
be lead points for intussusception. Usually, however, polyps are asymptomatic
except for the associated bleeding. These are not premalignant lesions, and they
tend to be self-limiting ( Fig. 116.18 ) although they can be easily removed by
colonoscopy.
FIGURE 116.18 Juvenile polyp. Double air-contrast barium enema shows a single polyp with
long stalk in transverse colon (arrows ).
Meckel Diverticulum
Two percent of the population is born with a Meckel diverticulum. This is the
most common omphalomesenteric duct remnant. The diverticulum is usually
located 50 to 75 cm proximal to the terminal ileum. Only 2% of persons with a
Meckel diverticulum manifest any clinical problems. The most common
complication of a Meckel diverticulum is a bleeding ulcer, typically presenting as
painless rectal bleeding. Ectopic gastric mucosa in such patients is usually present
in the diverticulum. The acid secretion produces ulceration at the junction of the
normal ileal mucosa with the ectopic mucosa. Currant jelly stools or hemorrhage
may be present. Other modes of presentation include diverticulitis, perforation
with peritonitis, or intussusception with the diverticulum serving as a lead point.
Enteral contrast studies usually fail to outline a Meckel diverticulum. The
imaging modality of choice for detection of ectopic gastric mucosa in a bleeding
Meckel diverticulum is nuclear scintigraphy. A well-defined focal accumulation
of radionuclide (99m-technetium pertechnetate) usually appears at or about the
same time as activity in the stomach and gradually increases in intensity ( Fig.
116.19 ). A duplication cyst with gastric mucosa shows the same focal
accumulation of radionuclide. Preoperative differentiation between two lesions as
a cause of GI bleeding is not important. The accuracy of scintigraphy in detection
of ectopic gastric mucosa in Meckel diverticula is approximately 95%. Falsenegative results may rarely occur in patients with rapidly bleeding Meckel
diverticula and with those diverticula that do not contain gastric mucosa.
In any child with a major rectal bleed and a negative scan, further workup is
required, including an arteriogram if the bleeding continues to be active or
colonoscopy when the bleeding is not active.
