Download Triad of Intestinal Obstruction

PEDIATRIC SURGERY
Vomiting and GI Obstruction
Dr. Alberto P. Paulino, Jr
Group 2
Cajucom, Franch Jolly
Callang, Anna Katrina
Calma, Dorothy
Camarines, Belen
Camus, Erwin
Cantor, Margarita
Carubio, Dianne
TRIAD OF INTESTINAL OBSTRUCTION
Obstruction is associated with an accumulation of ingested food, gas, and intestinal secretions
proximal to the point of obstruction, leading to distention of the bowel. As the bowel dilates, intestinal
absorption decreases and secretion of fluids and electrolytes increases. The shift of fluids and electrolytes
result in isotonic intravascular depletion usually associated with hypokalemia. The gut proximal to
obstruction initially demonstrates an increase in contractile activity, which is followed by a marked decrease
with hypoactive bowel sounds. The combination of fluid accumulation and hypomotility is associated with
nausea and vomiting. Obstipation occurs with complete obstruction of the bowel leading to inability to pass
out flatus and stool.
Therefore, the triad of intestinal obstruction is nausea and vomiting, abdominal distention, and
obstipation.
High intestinal obstruction
High intestinal obstructions occur above the ligament of Treitz (located at 4 th part of duodenum).
With high intestinal obstruction, the vomiting appears early and has potential for aspiration. Early use of
NGT or decompression reduces the risk of aspiration. The vomitus can be bilious or non-bilious in relation
with the Ampulla of Vater. The pain is usually localized at the epigastrium or paraumbilical area and there is
minimal abdominal distention. On radiologic exam, there is paucity of gas and there is no distal air on
supine and upright films of the abdomen.
Conditions presenting with high intestinal obstruction includes hypertrophic pyloric stenosis,
congenital gastric outlet obstruction (pyloric atresia), duodenal atresia, gastric duplication, and gastric
volvulus.
Low intestinal obstruction
Low intestinal obstruction occurs below the ligament of Treitz. Vomiting appears later and feculent
in nature because of the action of colonic bacteria. It is usually associated with fluid and electrolyte
problems like isotonic or hypotonic dehydration. The pain is diffused over the entire abdomen and there is
marked abdominal distention. On radiologic exam, multiple air-fluid levels and distended bowel loops may
be seen.
MALROTATION
Disturbances in the normal intestinal positioning are mostly due to embryonic development
disturbances. Most abnormalities occur in the Midgut. Malpositions of the fore- and hindgut are extremely
rare thus it is out of practicality that the Midgut be the focus of this discussion. In order to fully understand
anomalies of rotation, it is necessary that the normal Midgut development be understood.
Embryology of Midgut
The Midgut is the most active part in embryological development. It starts from the apex of the
duodenal loop and ends at the last third of the Transverse colon. The Midgut will give rise to the inferior part
of the duodenum with the duodeno-jejunal bend, the Jejunum, the Ileum with the iliocaecal valve, the
Cecum with its vermiform appendix, the Ascending colon and the proximal two-thirds of the Transverse
colon. Its blood supply is from the Superior Mesenteric artery and it is innervated by the Vagus nerve.
Midgut Herniation and Rotation
By the fourth week of fetal gestation the primitive gut is a straight tube. Around the fifth week, the
midgut rapidly increases in length and eventually forms a loop. The midgut loop has two parts which are the
(1) Cranial and the (2) Caudal limb. The cranial limb of the midgut loop will give rise to the distal duodenum,
jejunum and the proximal ileum while the Midgut loop caudal limb will give rise to the distal ileum and
proximal two-thirds of the transverse colon. Along with the increase in the Midgut loop length is its herniation
together with a pouch of peritoneum into the elastic umbilical cord. This phenomenon is a physiologic
herniation that occurs because the relatively small abdominal cavity becomes crowded with the enlarging
liver thus is not able to accommodate the rapidly elongating Midgut. Between the fifth and the tenth week, a
counter-clockwise rotation of the Midgut along the axis of the Superior Mesenteric Artery occurs.
The midgut while contained in the umbilical hernia turns 90 degrees around the axis of the Superior
Mesenteric artery. This torsion is classified as the
first stage of rotation. After the completion of this stage, the midgut is found suspended from the narrow
duodenocolic isthmus. Rotational Standstills at this point give rise to an unchanged condition at birth with
the second and third stages having failed to follow.
By the tenth week of development, a comparatively sudden expansion of the abdominal cavity
occurs which produces a negative pressure thus, suctioning the extruded gut back into the cavity. Along
with this return of abdominal contents, the second stage of rotation occurs. The completed second stage of
rotation amounts to 180 degrees. By the end of this stage, the midgut is found to have completely reentered
the abdominal cavity, the small intestine has crossed the mesocolon posteriorly and has rotated behind the
proximal colon and the cecum is found just below the liver.
The third stage of rotation is the final stage of the midgut rotation which occurs between the
eleventh week and in some cases some time after birth. This stage involves the final descent of the cecum
and the final permanent fixation of the intestines. By the end of this stage, the normal midgut rotation has
completed a 270 degree rotation along the axis of the Superior Mesenteric Artery.
Midgut Malrotation
With the complexity of the Midgut development a number of rotational anomalies may occur. A
midgut Malrotation is broadly defined as any deviation from the normal 270° counterclockwise rotation of the
midgut during embryologic development. Such can occur at a wide range of locations which may lead to a
variety of both acute and chronic presentations of disease. Midgut Malrotation can be broadly categorized
into to (1) Complete Nonrotation and (2) Incomplete rotation.
Complete Nonrotation
Nonrotation of the midgut happens when the second stage of rotation fails to occur. In this case,
the small intestine occupies the right side and the colon occupies the left side of the abdominal cavity. The
duodenal C loop fails to form and the ligament of Treitz is positioned at the right abdomen. The small
intestine and the proximal part of the colon are suspended from the same mesentery. This type of
Malrotation can lead to volvulus and subsequent ischemic necrosis. According to Sabiston Textbook of
Surgery 17th Ed, this type of Malrotation is the most common.
Incomplete Rotation
Incomplete rotation of the midgut refers to the spectrum of partial rotational
Anomalies possible with either the duodenum or the right colon, the most common of which is the failure of
the cecum to descend to the right lower quadrant. Intestinal obstruction is one of the common complications
of this type of Malrotation. According to Nelson Textbook of Pediatrics 17th Ed, this type is the most
common.
Nonrotation:
Arrest in development at stage I results in nonrotation. Subsequently, the duodenojejunal junction
does not lie inferior and to the left of the SMA, and the cecum does not lie in the right lower quadrant. The
mesentery in turn forms a narrow base as the gut lengthens on the SMA without rotation, and this narrow
base is prone to clockwise twisting leading to midgut volvulus. The width of the base of the mesentery is
different in each patient, and not every patient develops midgut volvulus.
Incomplete rotation:
Stage II arrest results in incomplete rotation and is most likely to result in duodenal obstruction.
Typically, peritoneal bands running from the misplaced cecum to the mesentery compress the third portion
of the duodenum. Depending on how much rotation was completed prior to arrest, the mesenteric base may
be narrow and, again, midgut volvulus can occur. Internal herniations may also occur with incomplete
rotation if the duodenojejunal loop does not rotate but the cecocolic loop does rotate. This may trap most of
the small bowel in the mesentery of the large bowel, creating a right mesocolic (paraduodenal) hernia.
History: History of present illness varies according to acute or chronic presentation as well as according to
type of rotational defect.
Acute midgut volvulus
 Most patients present in the first year of life.

The primary presenting sign of acute midgut volvulus is sudden onset of bilious emesis.
Chronic midgut volvulus
 Chronic midgut volvulus is due to intermittent or partial twisting that results in lymphatic and venous
obstruction.
 Multiple case reports show that 2 of the main presenting features are recurrent abdominal pain and
malabsorption syndrome.
 Several patients presented with acute midgut volvulus, but further history revealed they had had
chronic symptoms with misdiagnoses.
 Other clinical features include recurrent bouts of diarrhea alternating with constipation, intolerance
of solid food, obstructive jaundice (1 case), and gastroesophageal reflux.
Acute duodenal obstruction
 This anomaly usually is recognized in infants and is due to compression or kinking of the
duodenum by peritoneal bands (Ladd bands).
 Patients present with forceful vomiting, which may or may not be bile stained depending on
location of the obstruction with respect to the entrance of the common bile duct (ampulla of Vater).
Chronic duodenal obstruction
 The typical age at diagnosis ranges from infancy to preschool.
 The most common symptom is vomiting, which is usually bilious.
 Patients may also have failure to thrive and intermittent abdominal pain (frequently diagnosed as
colic).
Physical: Physical examination findings may vary depending on the type of rotational defect. Acute and
chronic presentations also differ. Each is discussed below.
Acute midgut volvulus
 Abdominal distention is frequently present, and the infant appears in acute pain.
 As vascular compromise persists, intraluminal bleeding may occur, which leads to blood per
rectum and sometimes hematemesis.
 Abdominal guarding is usually present and prevents palpation of intestinal loops.
 As symptoms persist, the infant may develop signs of shock, including poor perfusion, decreased
urine output, and hypotension.
 Patients also have signs of peritonitis, including abdominal tenderness and discoloration of the
skin.
Chronic midgut volvulus
 Physical examination results may be completely normal if the patient presents during a period
when the obstruction is relieved.
 If partial twisting is present at the time of examination, the patient may have signs and symptoms
equivalent to those of acute midgut volvulus.
 Abdominal tenderness and guarding is usually present, as well as abdominal distention.
Acute duodenal obstruction
 Abdominal distention and gastric waves may be present.
 Passage of meconium or stool can be present.
 These patients usually do not have signs of peritonitis or shock unless volvulus is also present
distal to the obstruction.
Chronic duodenal obstruction
 Physical examination results may be completely normal at the time of presentation.
 Abdominal distention and tenderness may be present.
 Diagnosis is usually made by history and enough suspicion to obtain radiologic studies; physical
examination findings are very unreliable.
Common Complications:
 Intestinal necrosis
 Short gut syndrome due to extensive intestinal ischemia from volvulus
 Persistent symptoms after repair of malrotation should suggest a pseudo- obstruction-like motility
disorder.
Diagnostic Procedures:
Upper gastrointestinal series
 Gold standard for the diagnosis
 If contrast ends abruptly or tapers in a corkscrew pattern, midgut volvulus or some other form of
proximal obstruction may be present.
 “ Bird’s beak” appearance seen in volvulus, if the obstruction is on the 3rd portion of duodenum.
Plain Abdominal Radiographs
 Plain radiography has limited use for defining obstruction because infants may have a gasless
abdomen or one that is almost normal.
 The classic pattern for duodenal obstruction, if present, is the double-bubble sign produced by an
enlarged stomach and proximal duodenum with little gas in the remainder of the bowel.
Management
Ladd Procedure
 Volvulus occurs clockwise and is therefore untwisted counterclockwise (“turning back the hand’s of
time)
 Bands between the cecum and the abdominal wall between the duodenum and terminal ileum are
divided sharply to slay out the SMA and its branches. This would bring the duodenum into RLQ
and cecum into the LLQ.
 Appendectomy
INTUSSUSCEPTION
Intussusception is a process in which a segment of the intestine invaginates into the adjoining
intestinal lumen causing a bowel obstruction. It is the leading cause of intestinal obstruction between 3
months and 6 years of age. It develops in males 4 times than females. It is a common cause of abdominal
pain in children. There are three types of intussusception: Ileocolic – the small intestine telescopes into the
colon; Ileoileal – the small intestine telescopes into itself; Colocolic – the large intestine telescopes into
itself. The ileocolic type occurs more frequently than the other two.
While the exact cause of intussusception is unknown, it often follows an intestinal virus or other
viral illness such as a respiratory infection. In response to the virus, the normal lymphatic components of the
intestinal wall, known as Peyer's patches, enlarge significantly. This increase causes a thickening of the
intestinal wall that encourages intussusception. When older children develop intussusception, it is usually
due to what is referred to as a pathologic lead point. A lead point is a recognizable anatomic abnormality
that obstructs the bowel, thus initiating the process of intussusception. Meckel's diverticulum and lymphoma
of the intestine are two classic examples of lead points. Intestinal tumors and polyps may also act as lead
points.
Clinical Presentation
The patient usually develops a colicky, severe and intermittent abdominal pain in which the child
may cry and draw his knees to his chest. The patient may be normal or quiet between intervening periods.
Vomiting and fever usually occur and the child may have a normal or loose bowel movement. The stool may
then become mixed with sloughed mucosa, blood and mucus – currant jelly stool. As the condition worsens,
vomiting may increase and the child may become pale and weak showing signs of dehydration or shock.
Lethargy is a relatively common presenting symptom with intussusception. In some patients, lethargy can be
the sole presenting symptom, which makes the diagnosis challenging.
Upon physical examination, the pulse is weak and thready. Respiration is shallow and grunting.
The patient may also be diaphoretic and hypotensive if shock has occurred.
The hallmark physical findings in intussusception is a right hypochondrium sausage-shaped mass and
emptiness in the right lower quadrant. This is what we call the Dance sign. This is hard to detect and is best
palpated when the infant is quiet between spasms of colic. Abdominal distention frequently is found if
obstruction is complete. If intestinal gangrene and infarction have occurred, peritonitis can be suggested on
the basis of rigidity and involuntary guarding. Fever and leukocytosis are late signs and can indicate
transmural gangrene and infarction. A rare presentation of intussusception is prolapse of the
intussusceptum through the anus. This prolapse can be confused with rectal prolapse. Careful examination
can differentiate between the 2 presentations. The anal crypts are everted with prolapse and not with
intussusception. An examining finger can pass between the prolapse and the anus in patients with
intussusception but not in patients with rectal prolapse.
Pathogenesis
The pathogenesis of intussusception is believed to be secondary to an imbalance in the
longitudinal forces along the intestinal wall. This imbalance can be caused by a mass acting as a lead point
or by a disorganized pattern of peristalsis. As a result of the imbalance, an area of the intestinal wall
invaginates into the lumen, with the rest of the intestine following. The invaginating portion of the intestine,
intussusceptum, completely invaginates into the receiving portion of the intestine, intussuscipiens. This
process continues and more proximal areas follow, allowing the intussusceptum to proceed along the lumen
of the intussuscipiens. If the mesentery of the intussusceptum is lax and progression is rapid, the
intussusceptum can proceed to the distal colon or sigmoid and even prolapse out of the anus. The
mesentery of the intussusceptum is invaginated with the intestine, leading to the classic pathophysiologic
process of any bowel obstruction.
Early in this process, lymphatic return is impeded then with the rise in the pressure within the wall
of the intussusceptum, venous drainage is impaired. Finally, the pressure reaches a point at which arterial
inflow is inhibited, and infarction ensues. The mucosa is most sensitive to ischemia because it is farthest
away from the arterial supply. Ischemic mucosa sloughs off, which initially leads to the heme-positive stools
and then the classic currant jelly stool. If untreated, the process progresses to transmural gangrene and
perforation of the leading edge of the intussusceptum.
Diagnostic Exams
Imaging Studies
After obtaining a thorough history and performing a careful physical examination, plain radiographs
of the abdomen with the patient in the supine and upright positions is obtain. Plain radiograph findings may
be normal early in the course of intussusception. As the disease progresses, earliest radiographic evidence
includes an absence of air in the right lower and upper quadrants and a right upper quadrant soft tissue
density present in 25-60% of patients. These findings are followed by an obvious pattern of small bowel
obstruction, with small bowel dilatation and air-fluid levels in the small bowel only. If the distention is
generalized and the air-fluid levels are also present in the colon, the findings more likely represent acute
gastroenteritis than intussusception. A left lateral decubitus view is also helpful. If the view exhibits air in the
cecum, the presence of ileocecal intussusception is highly unlikely.
Ultrasonography is a noninvasive modality that can aid in making the diagnosis of intussusception.
Hallmarks of ultrasonography include depiction of the intussusceptum and its mesentery within the
intussuscipiens that will appear like a target or doughnut.
` CT scan has also been proposed to be useful making the diagnosis of intussusception. However,
CT findings are unreliable and carries the risks associated with intravenous contrast administration,
radiation exposure, and sedation.
The traditional and most reliable way to make the diagnosis of intussusception in children is to
obtain a contrast enema. Contrast enema is quick and reliable and has the potential to be therapeutic.
Exercise caution when performing contrast enema in patients older than 3 years because most patients
older than 3 years have a surgical lead point in the small bowel, and the diagnostic and therapeutic yield of
the enema is lower in these patients. There are two types of barium enemas.
a. Single-contrast study - the colon is filled with barium, which outlines the intestine and reveals large
abnormalities.
Double-contrast or air-contrast study - the colon is first filled with barium and then the barium is
drained out, leaving only a thin layer of barium on the wall of the colon. The colon is then filled with
air. This provides a detailed view of the inner surface of the colon, making it easier to see colon
polyps, colorectal cancer, or inflammation.
In some cases, the single-contrast study may be preferred for specific medical reasons or for older people
who may not be able to tolerate the time-consuming and somewhat more uncomfortable double-contrast
study. However, if the results are not clear or there is a strong suspicion of colorectal cancer, a doublecontrast study may also be done.
b.
Treatment
There are two approaches used in treating intussusception a. nonoperative reduction and b.
surgery.
a. Nonoperative reduction
After the diagnosis is confirmed, intussusception is generally reduced by gentle pressure exerted
within the intestine, using barium or air enemas. However, this technique is not effective for ileoileal
intussusceptions which usually require surgery. Also, if the child is ill with an abdominal infection or has
other complications, surgery is preferred. Both barium and air enemas have a low risk of less than 2% of
complications.
b. Surgery
For children who are too ill to undergo contrast enema, who may have significant infection in the
abdomen, or in whom intussusception does not resolve with the enema, surgery is necessary. If the child
has several episodes of intussusception, a surgical procedure may be performed in an attempt to determine
the cause of the recurrent intussusception. The intussusception is located and the bowel is pushed back to
return to its normal position.
HIRSCHSPRUNG’S DISEASE
It is also known as Congenital Aganglionic Megacolon.
Pathology
Its incidence is sporadic which is 1:5000 live births. It is characterized by absent ganglion cells in the
myenteric (Auerbach’s) & submucosal (Meissner’s) plexus. The nerve fibers are large and excessive in
number. It is often associated with muscular spasm of the distal colon & internal anal sphincter resulting in a
functional obstruction. The distal segment is the abnormal bowel which is contracted and the proximal
segment is normal which is dilated. There is this Transition Zone which is the area between the contracted &
dilated area. In this region the ganglion cells begin to appear but reduced in number. There is usually
aganglionosis in the distal rectum. The percentage that the rectosigmoid is affected is 75%, while the
splenic flexure and/or tranverse colon is 17% and the entire colon is about 8%. Its cause remains
incompletely understood. But there are suggestions that the disease results from the defect in the migration
of neural crest which is the embryonic precursor of intestinal ganglion. The normal neural crest migration is
cephalad to caudal. The migration process of the neural crest is usually completed by 12th week of
gestation. The migration from midtransverse colon to anus is about 4 weeks. In the latter period the fetus is
most vulnerable to defect that’s why mostly the rectum & rectosigmoid is involved.
Clinical Presentation
In the neonates the clinical manifestations are: failure to pass meconium in the 1 st 24 hr - 48 hr, abdominal
distention and bilious emesis. While in the infants, its presentation is abdominal distention, diarrhea which
usually results from enterocolitis, failure to thrive and lethargy. Lastly the manifestations in older children are
history of poor feeding, chronic abdominal distention, history of significant constipation, slow growth, bouts
of diarrhea (overflow soiling), malnutrition and poor weight gain.
Diagnostic Examinations
Barium enema is the initial diagnostic test. It demonstrates the location of transition zone which usually is a
cone shape. Normally rectum is wider than the sigmoid colon but in this disease due to the spasm of the
distal rectum, it usually results in smaller caliber compared with the more proximal sigmoid colon. Also
barium enema is use to exclude other causes of constipation or obstruction.
Radiographs may be of good help. It may show dilated loops of bowel proximal to the aganglionic area and
paucity of rectal air. Also Anorectal Manometry is being utilized. A special balloon is passed into the child’s
bottom and then inflated. This checks the pressure within the internal anal sphincter (muscle). And this
disease may show failure of the internal sphincter to relax when the rectum is distended w/ a balloon. A high
pressure may indicate Hirschsprung’s disease.
Rectal biopsy is the Gold standard. The procedure usually obtains sample at least 2cm above the dentate
line, this is to avoid sampling of the normal transition from the ganglionated bowel to the paucity or absence
of ganglia in the internal sphincter. The biopsy may show absence of ganglion cells, presence of
hypertrophied nerve bundles and Increased in acetylcholinesterase activity.
Complications
The most common complications are inflammation and infection of the intestines (enterocolitis), perforation
of the intestine and short bowel syndrome, a condition that can lead to malnourishment & dehydration.
Treatment
There can be two approaches in the management, a conservative and a non conservative which is surgery.
In the Conservative approach, there is a Non-operative treatment which consists of daily rectal washouts
with warm saline solution and continues for as long as this is effective at enabling complete bowel
evacuation (emptying). This method is usually more suitable for those children who have short segment
disease. If this method alone fails to resolve the constipation then the child will require surgical intervention.
This is also considered as a planned short-term measure until the surgery can be carried out.
The mainstay of treatment is surgery. The Goal is to preserve sphincter function and bring normal bowel
close to normal bowel and resect abnormal bowel. The Conventional treatment includes the two step repair,
diverting colostomy to decompress bowel followed by delayed takedown and pull-through. In colostomy, the
large intestine is cut and an opening is made through the abdomen. This allows bowel contents to be
discharged into a bag. The pull-through procedure repairs the colon by connecting the functioning portion of
the bowel to the anus.
There are different types or techniques of pull through. Swenson’s operation involves an abdominal incision
to remove the part of the bowel that is affected by the disease and then pulling the cut ends of the bowel
through the child’s bottom (anus) and joining them together (coloanal anastomose). The Duhamel procedure
involves cutting the bowel at the level where it is normal and bringing it down to the level of the child’s anus
so that it lies along side the part of the bowel that is aganglionic (affected by the Disease). The double
length of bowel is then made into one by cutting through the connecting walls so that one side has a piece
of bowel that is normal and one side that is not. In Soave procedure, it involves pulling the bowel out
through the babies bottom (anus) and cutting away the affected part. The cut end of the bowel is then
stitched to the anus.
DUODENAL / INTESTINAL / COLONIC ATRESIA
Intestinal atresia (absence of a normal opening) is the failure of a portion of the intestinal tract to completely
form. It occurs most frequently in the ileum (lower part of the small intestine). It can also occur in the
duodenum (part of the intestine that empties from the stomach), jejunum (second part of the intestine
extending from the duodenum to the ileum), or the colon (large intestine). Diagnosis can be made by
ultrasound during pregnancy or can present on the first to second day of life. Abdominal distension
(inflation) increases, the infant fails to pass stools, and, finally, feedings are vomited. The cause of intestinal
atresia is not known.
Etiology
Multiple theories regarding the etiology of jejunoileal atresias have been studied. Recent work suggests that
some forms of atresia may be hereditary and result from dysregulation of proliferation and apoptosis of the
developing intestine through the fibroblast growth factor pathways. To date, the most accepted theory
regarding the etiology of jejunoileal atresia is that of an intrauterine vascular accident resulting in necrosis of
the affected segment, with subsequent resorption.
Frequent association of duodenal atresia or stenosis with other neonatal malformations suggests both
anomalies are due to a development error in the early period of gestation. Duodenal atresia differs from
other atresias of the small and large bowel, which are isolated anomalies caused by mesenteric vascular
accidents during later stages of development. No predisposing maternal risk factors are known. While one
third of patients with duodenal atresia have Down syndrome (trisomy 21), it is not an independent risk factor
for developing duodenal atresia.
Colonic atresia is believed to be caused by an in utero vascular accident resulting in ischemic injury, likely
after the midgut has returned to the coelomic cavity. Some animal evidence is noted, that ties colonic atresia
to a heritable defect in the FGF regulatory pathway. Colonic atresia is the least common and comprises 1.815% of all intestinal atresias and stenoses. Atresias may occur throughout the colon; however, lesions
proximal to the splenic flexure and distal to the vascular watershed area are the most common. Colonic
atresias are frequently associated with other anomalies, including jejunoileal atresia, Hirschsprung disease,
and genitourinary malformations. They can generally be classified in the same fashion as small intestinal
atresias.
Different Types
Type I: In type I atresias, the mucosa and submucosa form a web or intraluminal diaphragm, resulting in
obstruction. As in duodenal webs, a windsock effect may be evident secondary to an increase in intraluminal
pressure in the proximal bowel causing a prolapse of a portion of the web into the distal part of the bowel. A
mesenteric defect is not present, and the bowel length is not affected.
Type II: The mesentery is intact in type II atresias; however, the bowel is not joined. The dilated proximal
portion has a bulbous blind end connected by a fibrous cord to the blind end of the distal flattened bowel.
The overall length of the small bowel is not usually shortened.
Type IIIa: The defect in type IIIa is similar to that in type II in that both types have blind proximal and distal
ends; however, in type IIIa, no bridging fibrous cord is present, and a V-shaped mesenteric defect is
present. The proximal blind end is usually markedly dilated and aperistaltic. The intervening bowel has
undergone intrauterine resorption, and, as a result, the bowel in this category is variably shortened.
Type IIIb: In addition to a large defect of the mesentery, the bowel is significantly shortened in type IIIb. This
lesion is also known as a Christmas tree or apple peel deformity because of the appearance of the bowel as
it wraps around a single perfusing vessel. The distal small bowel receives its blood supply from a single
ileocolic or right colic artery because the better part of the superior mesenteric artery is absent. Prematurity,
malrotation, and subsequent short bowel syndrome have been linked to this deformity, with increased
morbidity and mortality rates.
Type IV: Type IV involves multiple small-bowel atresias of any combination of types I to III. This defect often
takes on the appearance of a string of sausages because of the multiple lesions. The cause is unknown,
and theories range from multiple ischemic infarcts, possibly from a more global placental insufficiency, to an
early embryologic defect of the GI tract, to an inflammatory process occurring in utero.
Imaging
Radiologic findings reveal dilated loops of intestine with air-fluid levels in upright films. Atresias show the
double bubble sign, representing the dilatation of the stomach and first portions of the duodenum with
complete obstruction beyond. Depending on the number of loops dilated, air-filled bowel differentiates high
from low obstruction. If the bowel obstruction is complete, no air is present distal to the obstruction.
Barium enema is used when there is diagnostic uncertainty, or when distal intestinal obstruction is apparent.
It is useful in establishing a microcolon and diagnosing the presence of meconium plugs, small colon
syndrome, Hirshprung’s disease, or meconium ileus.
Reference:
Behrman, R.E. et al (2004). Nelson Textbook of Pediatrics 17th ed. PA,USA: Elsevier.
Marx, R. (1939).Nonrotation of the intestine. Annals of Surgery. 109, 49–56.
Townsend, C.M. et.al(2004). Sabiston Textbook of Surgery 17th Ed. PA,USA: Elsevier.