Intestinal Obstruction in a Term Stillborn Infant
Shaoying Li, MD, Ona Marie Faye-Peterson, MD, Stephanie Reilly, MD
(Department of Pathology, University of Alabama at Birmingham, Birmingham, AL)
Case History demise was diagnosed with delivery that Autopsy Findings
Patient same day. Images 1 and 2.
A 41-week estimated gestational-age
Caucasian female stillborn infant. Family History Postmortem examination revealed bowel
Noncontributory. distension by inspissated meconium with a
History of Present Illness mucosal web in the very distal ileum at the
A female infant was delivered stillborn at Physical Examination ileocecal valvar region that occluded the
term to a 24-year-old P1011 white female. Nondysmorphic, mildly-macerated female infant bowel lumen. The mesentery was intact and
Obstetrical history included an elective with anthropometry consistent with 41 weeks unremarkable. This was associated with an
first-trimester termination and a previous estimated gestational age. acute ileal perforation, meconium peritonitis,
uncomplicated term delivery. Routine prenatal and an underdeveloped, small-caliber colon.
care for this pregnancy began at 12 weeks of Radiologic Findings Microscopically, aside from the area of
gestation. There were no reported pregnancy Postmortem whole-body fetograms were perforation and the meconium peritonitis,
complications, but the woman had a 10 pack/ performed and no bony abnormalities were no significant histopathologic abnormality
year history of cigarette smoking and had identified. was identified along the bowel length or its
continued to smoke throughout this pregnancy. mesentery, either proximal or distal to the
She presented at 41 weeks of gestation for a Principal Laboratory Findings obstruction.
routine checkup, whereupon intrauterine fetal No abnormal laboratory results or infections
ganglion cells, both proximal and distal to the obstruction,
1. What are the leading causes of intrauterine fetal demise at which excluded coexisting Hirschsprung disease. No ischemic
term? changes or fibrosis were identified. Intestinal atresia is an un-
2. How do you explain this case of fetal death? common cause of stillbirth.3
3. What is the most likely diagnosis, and how commonly does
it result in stillbirth? 4. Intestinal atresia is a well-recognized cause of bowel
4. What are the types and pathogenesis of this abnormality? obstruction in a newborn. The classification of intestinal atresia
5. What are the clinical characteristics of this abnormality in varies with the location of the obstruction. There are 3 types of
live born infants? duodenal atresia.4 Type I atresia is caused by a mucosal web, or
6. How is this abnormality diagnosed in the neonate? diaphragm, in which the obstruction is produced by a mem-
7. What is the treatment and prognosis of this anomaly? brane formed of mucosa and submucosa, but the muscularis
8. Is maternal smoking associated with increased risks of this is not interrupted. In type II, the bowel is interrupted and a
fetal abnormality? fibrous cord separates the blind ends, but the mesentery is intact.
9. What other condition should be considered when bowel In type III, there is complete segmental absence of a portion of
distension and/or perforation with meconium peritonitis the intestine and the associated mesentery. In all 3 types, the
due to meconium inspissation is observed at autopsy of a intestinal segment proximal to the atresia is dilated, and the dis-
stillborn or neonate? tal segment is unexpanded or hypoplastic. The classification of
jejunoileal atresia and colonic atresia is modified: types I and II
are the same as above, type III is subdivided as IIIa and IIIb, and
a type IV is added. Type IIIa demonstrates an atretic segment of
Possible Answers bowel with a V-shaped mesenteric defect, while type IIIb is most
1. The leading causes of intrauterine fetal demise at term commonly called “apple peel” deformity, in which the proximal
include cord accidents, placental abruption, placental insuffi- end of the intestine is atretic and the distal segment of coiled
ciency, and intrauterine infection.1,2 intestine is supplied and connected to the mesentery by a single
vessel. Type IV is also described as “string of sausage” because
2. Postmortem examination revealed an intact mesentery there are multiple atresias involving different sites of the intes-
and proximal intestine with bowel obstruction at the ileocecal tine.5 The most frequent sites of atresia are the proximal ileum
junction resulting in underdevelopment of the colon distal to and the duodenum; the least frequent site is the colon. Type I
the obstruction and dilatation of the small bowel proximal to mainly occurs in the duodenum, and the most common type of
the obstruction with ileal perforation and meconium peritonitis, colonic atresia is type IIIa. Although very rare, atresia may occur
causing the intrauterine fetal demise. at the ileocecal valve.4 The pathogenesis of intestinal atresia may
vary considerably according to the location of the obstruction.
3. Most likely diagnosis: Type I intestinal atresia caused by Since duodenal atresia is more commonly associated with Down
a mucosal web at the terminal ileum/ileocecal valve that occluded syndrome and other congenital anomalies, it is believed that ge-
the bowel lumen. Microscopically, there was a well-preserved netics play an important role in duodenal atresia.4 The exception
mucosal and mural structure with a normal distribution of is some familial cases of jejunoileal atresia and colonic atresia, in
410 LABMEDICINE j Volume 39 Number 7 j July 2008 labmedicine.com
Image 1_(A) Unopened bowel: ileocecal atresia resulting in a markedly dilated small bowel with inspissated meconium, perforation of the small
bowel (black arrow), and an underdeveloped small caliber colon (red arrowhead). (B) Opened bowel (probe at atretic ileocecal valve; arrow on the
appendix) demonstrating the inspissated green meconium in the terminal ileum (left) and scant white-tan mucus in the underdeveloped colon (right).
which genetic factors also play an important role.5 These familial cause jejunoileal and colonic atresias. These conditions include
cases demonstrate an autosomal recessive inheritance pattern, intestinal volvulus, strangulation through mesenteric apertures,
but with the exception of Down syndrome, no associated chro- constriction by mesenteric bands, internal hernia, etc.4,5
mosomal abnormalities have been identified.6 It is suggested that
a late intrauterine mesenteric vascular accident is the cause of 5. Intestinal atresia, regardless of type, manifests as bowel
most jejunoileal and colonic atresias, while the lack of recanali- obstruction, with bilious vomiting, abdominal distention,
zation is the probable cause of most cases of duodenal atresia.7 and/or failure to pass meconium.5 The estimated incidence of
Any conditions disrupting the blood supply to the bowel can intestinal atresia ranges from 1 in 20,000 births to 1 in 1,500
Image 2_(A) Low-power transmural section of the bowel distal to
C obstruction (H and E stain: 40x); Normal distribution of ganglion cells
both proximal (B) and distal (C) to the atretic ileocecal valve, which
excluded coexisting Hirschsprung disease. No ischemic changes or
fibrosis were identified, and no thrombi were seen in the mesentery
(H and E stain, 200x).
labmedicine.com July 2008 j Volume 39 Number 7 j LABMEDICINE 411
births.4 About 66% of the cases are found in full-term infants. stillborn or neonate. Cystic fibrosis is an autosomal recessive dis-
In some cases, especially those with duodenal atresia, there is order due to a defect of the cystic fibrosis transmembrane con-
a strong association with other anomalies or syndromes; these ductance regulator (CFTR) gene and is the most common lethal
include omphalocele, annular pancreas, imperforate anus, genetic disease affecting Caucasians.18 CFTR gene mutations
malformation of the bile ducts, esophageal atresia, congenital result in abnormal cell membrane chloride channel function
heart disease, gastroschisis, Hirschsprung disease, and Down and fluid secretion in exocrine glandular epithelia of the respira-
syndrome.4,8 There are case reports of ileocecal atresia associ- tory, gastrointestinal, and reproductive tracts. The abnormally
ated with the absence of the appendix.9,10 Our case did not viscid mucous secretions accumulate in and obstruct ducts,
have any other associated anomalies. airways, and lumina of hollow viscera. In the intestine, the
bowel becomes progressively distended by the accumulation of a
6. The diagnosis of intestinal atresia is challenging. An characteristic thick, markedly tenacious meconium. Peristalsis is
ultrasound is useful for prenatal diagnosis; it is more reliable compromised, intestinal obstruction occurs, and perforation can
in detection of duodenal atresia than more distal lesions.5 result. In our case, the mother is Caucasian and the intrauterine
Sonographic findings include the presence of polyhydramnios, fetal demise was due to bowel obstruction and perforation, but
abdominal distension, or distension of the bowel. If intes- the macroscopic and microscopic features of the bowel and all
tinal atresia is not diagnosed prenatally, the diagnosis must the other organs (exocrine glands, lung, pancreas, etc) excluded a
be made postnatally in the first few hours after the onset of diagnosis of cystic fibrosis. LM
symptoms of bowel obstruction for infant survival. The pres-
ence of a large amount of intestinal luminal air with intestinal
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