Intussusception
is invagination of a segment of intestine, called the intussusceptum,
into a more distal bowel segment, known as the intussuscipiens. 90%
of intussusceptions are ileocolic. 90% have no lead point. When a
lead point is present, the most common cause is a Meckel's
diverticulum. Other causes include: polyps, enteric duplication
cysts, an inflamed appendix, or lymphoma. Most commonly occur in
male infants less than 2 years old. Patients present with pain,
vomiting, or blood per rectum. Intussusception will lead to
obstruction and ischemia of bowel.
Causes of Intussusception
In infants, the causes of intussusception are unknown, although
there are some theories about why it occurs. Because intussusception
is seen most often in spring and fall, this seems to suggest a
possible connection to the kinds of viruses that children catch
during these seasons, including upper respiratory infections.
In some cases, intussusception may follow a recent bout of
gastroenteritis (sometimes called stomach flu). Gastrointestinal
infections may cause swelling of the infection-fighting lymph tissue
that lines the intestine, which may pull one part of the intestine
into the other. Intussusception is most common around the age that
infants are being introduced to solid foods. It has been suggested
that the introduction of new foods may also cause some swelling of
the lymph tissue in the intestines, increasing the chance of
developing an instussusception.
Recently, there has also been some investigation into the
rotavirus vaccine and its possible connection to intussusception,
although the number of reported cases of intussusception among
babies who received the vaccine is quite small. According to the
U.S. Centers for Disease Control and Prevention (CDC), it has
not been established that the vaccine causes
intussusception, but the CDC and the U.S. Food and Drug
Administration have suspended the vaccine until they're able to
gather more information. Babies who received the rotavirus vaccine
before its suspension have no increased risk of developing
intussusception now.
Usually when an adult or a child older than
3 develops an intussusception, it's often the result of enlarged
lymph nodes, a tumor, or a polyp in the intestine.
Signs and Symptoms
Children with an intussusception have intense abdominal pain,
which often begins so suddenly that it causes loud, anguished crying
and causes the child to draw the knees up to the chest. The pain is
usually intermittent, but recurs and becomes stronger. As the pain
subsides, a child with an intussusception may stop crying and seem
fine.
Other common symptoms include:
- abdominal swelling or distension
- passing stools (or poop) mixed with blood and mucus, known as
currant jelly stool (60% percent of infants with an
intussusception will pass currant jelly stool)
- vomiting
- vomiting up bile, a bitter-tasting fluid secreted by the liver
that's often golden-brown to greenish in color
- lethargy (i.e., drowziness or sluggishness)
- shallow breathing
- grunting
As the illness progresses, a child will become progressively
weaker and may develop a fever and appear to go into shock. Symptoms
of shock include lethargy, rapid heartbeat, weak pulse, low blood
pressure, and rapid breathing.
Complications of Intussusception
If left untreated, intussusception can cause severe
complications. Complications are directly related to the amount of
time that passes from when the intussusception occurred until it's
treated. Most infants who are treated within the first 24 hours
recover completely from an intussusception with no problems. Further
delay increases the risk of complication which include irreversible
tissue damage, perforation of the bowel, infection, and death.
Radiologic Overview of the Diagnosis:
Approximately 50% of plain film radiographs of the abdomen are
normal. Plain film findings include: an intraluminal convex filling
defect in an air-filled loop of bowel or an abnormal bowel gas
pattern with lateralization of the distal small bowel. If plain
films cannot completely exclude intussusception or if clinical
correlation is high, an ultrasound or an enema may be performed. On
ultrasound, a target or doughnut sign is characteristic with a
hypoechoic ring surrounding an echogenic center. Air (pneumatic) or
contrast (hydrostatic) reduction enema may be performed for both
diagnosis and therapy (if successful). If there is free flow of air
or contrast into the termimal ileum, the exam is negative and
terminated. However, if positive, an convex intraluminal filling
defect will be seen, most commonly in the transverse colon. Constant
pneumatic or hydrostatic pressure should be maintained to reduce the
intussusception. Free flow of contrast or air into the terminal
ileum indicates successful reduction. There is a 5-10% recurrence
rate. Complication of enema reduction includes perforation (1:300
cases).
Key Points:
90% of intussusceptions are ileocolic. 90% have no lead point.
When an intussusception is encountered during an enema, a convex
intraluminal filling defect is seen, usually in the transverse
colon.
Contraindications to intussusception reduction include perforation
or peritonitis Definition
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Images
 This abdominal
X-ray shows an intestinal condition in which a loop of bowel has
slipped into another section of bowel (intussusception), causing
swelling, reduced blood flow, obstruction, and tissue damage.
Intussusception requires emergency treatment (barium enema or
surgery) to prevent intestinal tissue death (necrosis), intestinal
perforation, peritonitis, and death |
