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390 Vitelline Duct Anomalies

Like the appendix, a Meckel’s diverticulum can become inflamed
when the lumen is obstructed, resulting in decreased mucosal perfusion,
tissue acidosis, and bacterial invasion of the wall. This can lead to
progressive inflammation, with tissue gangrene and perforation. It is
possible that the gastric or pancreatic mucosa contributes to the luminal
obstruction, or the gastric mucosa can lead to ileal mucosal ulceration
first, which facilitates bacterial invasion. Rarely, foreign bodies and
parasites may be trapped within the diverticulum and cause obstruction
7,8
of the diverticulum as does an enterolith. Diverticular torsion leads to
secondary ischaemia and inflammatory change. 7
Anomalies of the omphalomesenteric duct can result in umbilical
drainage from granulation tissue. Other anomalies include a duct extending
to the umbilicus but covered with skin (Figure 64.1(B)); diverticulum
attached to the umbilicus with a fibrous cord (Figure 64.1(C)), Littre’s (A) (B)
hernia, and intraabdominal cystic mass (Figure 64.1(D,E)). Figure 64.2: (A) Patent vitelline duct; (B) vitello-intestinal communication.
Some tumours can be found in ectopic tissues, such as nesidioblastosis
in ectopic pancreas tissue of a Meckel’s diverticulum or tumours such
as carcinoid, leiomyoma, neurofibroma, and angioma. 6–9 an omphalomesenteric duct remnant manifests as faeculent drainage
Associated congenital anomalies include cardiac defects, congenital (Figure 64.2). The most common umbilical lesion is an umbilical
diaphragmatic hernia, duodenal atresia, esophageal atresia, imperforate granuloma, which secretes a mucoid material. If the drainage persists
anus, gastroschisis, malrotation, omphalocele, Hirschsprung’s disease, despite cauterization of the presumed granuloma with silver nitrate,
and Down syndrome. or if the drainage is copious, imaging studies are indicated. Prolapse
of the ileum into the duct at the anterior abdominal wall presents as a
Clinical Presentation discoloured, mucosa-covered mass situated at the umbilicus.
The clinical presentation of vitelline duct abnormalities is variable and
depends on the configuration of the remnant of the vitelline duct and Diagnosis
whether it contains ectopic gastric or pancreatic tissues. In developed Diagnosis of a symptomatic vitelline duct malformation is dependent
countries, the main forms of presentation are haemorrhage in 40–60%, on the anatomic configuration and its presentation, signs, and symp-
obstruction in 25%, diverticulitis in 10–20%, and umbilical drainage. 3–5 toms. History and physical examination are important for the diagnosis.
The classic presentation is an older infant or young child with Some abnormalities are evident on physical examination (faecal fistula,
painless rectal bleeding. This usually consists of a large volume prolapse of ileum through a patent duct, and umbilical granulation tis-
of bright red bleeding but can occasionally also present as dark, sue with a small fistula). A fistulogram may be necessary to identify the
tarry stools in small amounts. The bleeding is often massive and part of the intestine involved preoperatively.
frequently requires transfusion. Melena may be episodic and usually A complete description of the quality and frequency of the bloody
ceases without treatment; sometimes the melena is insidious and not stools is necessary in patients with rectal bleeding. Rectal examination
appreciated by the family. In a young child with haemoglobin positive and lower endoscopy is useful to identify other causes of lower bleeding
stools and a chronic iron deficiency anaemia, the diagnosis of Meckel’s (polyps and rectal tears). The test of choice for a bleeding Meckel’s
diverticulum should be considered. diverticulum is a technetium-99m pertechnetate isotope scan (Meckel
Intestinal obstruction, usually due to intussusception, is the most typical scan), which preferentially concentrates the isotope in ectopic gastric
presentation in newborns and infants. The symptoms include crampy mucosa. The specificity of scintigraphy is 95%, but the sensitivity is
7
abdominal pain, bilious vomiting, currant-jelly stools, and abdominal 85%. A negative scan result does not, however, exclude a bleeding
distention. Intestinal obstruction may also be caused by a volvulus or Meckel’s diverticulum. Capsule endoscopy has proven to be of diagnostic
arterial band. Because the volvulus usually involves the distal small bowel value in some cases of bleeding Meckel’s diverticulum, but the reports
and the obstruction is most often a closed loop, there may be little emesis are very few. These tests are rarely available in developing countries. The
until late in the course. The sequelae of intestinal ischaemia, such as best diagnostic test may be a laparotomy to visually look for a Meckel’s
acidosis, peritonitis, and shock, may occur first, and can be fatal in infants. diverticulum in children with unexplained rectal bleeding.
Patients with Meckel’s diverticulitis often have symptoms that If obstruction from either intussusception or volvulus is suspected,
resemble appendicitis. They are usually older children. Periumbilical plain x-rays may reveal dilated bowel loops and multiple air-fluid
pain is the first symptom. They usually do not have the same amount or levels. An air enema or upper gastrointestinal study with small bowel
intensity of vomiting and nausea as do children with appendicitis. On follow-through is suggestive. Ultrasonography remains fairly reliable
physical examination, their point of maximal tenderness may migrate to diagnose intussusception.
across the abdomen as the child moves. About the same percentage of A sinogram will exclude intestinal communication in umbilical
1
patients with diverticulitis will present with perforation. A perforated sinuses, and abdominal ultrasonography should localise a cyst.
Meckel’s diverticulum is potentially more serious than a perforated Inflammatory symptoms are similar to those of appendicitis and are
appendix because the former is more difficult to wall off due to its diagnosed clinically.
more mobile position. This may explain why perforated diverticulitis Treatment
is more likely to result in diffuse peritonitis and pneumoperitoneum
Symptomatic children with omphalomesenteric duct remnants should
detectable on abdominal radiographs. For this reason, it is imperative to
be resuscitated before intervention. Those with significant haemor-
search carefully for a perforated Meckel’s diverticulum as the cause of
rhage should be transfused. Patients with obstructive symptoms should
peritonitis when no inflamed appendix is discovered at appendectomy.
be resuscitated as rapidly as possible to obviate the need for ischaemic
Other types of symptomatic omphalomesenteric duct malformations
bowel resection. The incision chosen varies with the symptoms and
can result in umbilical drainage as well. The quantity and character
the age of the patient. Children with faeculent umbilical drainage (see
of the drainage may indicate the origin of the lesion. Clear drainage
Figure 64.2) or prolapse of the omphalomesenteric duct remnant can be
or yellowish drainage signifies a probable urachal anomaly, whereas
explored by a small infraumbilical incision.