imperforate anus and colon atresia in a newborn
TRANSCRIPT
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Imperforate anus and colon atresia in a newborn
Sean Goodwin, Marc Schlatter*, Robert Connors
Department of Pediatric Surgery, DeVos Children’s Hospital/Spectrum Health, Pediatric Surgeons of West Michigan, Grand
Rapids, MI 49503, USA
0022-3468/$ – see front matter D 2006
doi:10.1016/j.jpedsurg.2005.11.055
* Corresponding author.
Index words:Imperforate anus;
Colon atresia;
Multiple intestinal atresias
Abstract Imperforate anus is an uncommon congenital anomaly. Colon atresia is even more infrequent.
This report describes a newborn with the simultaneous occurrence of these 2 anomalies, a condition that
is exceedingly rare.
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Imperforate anus is a congenital anomaly that occurs in
approximately 1 in 4000 to 5000 live births. Colon atresia
is much more uncommon, being reported in only 1 in
20,000 births. We describe an unusual case of these
2 conditions occurring in the same infant, although the
colon atresia was not recognized initially after repair of the
imperforate anus.
1. Case report
A Hispanic male newborn was delivered via a planned
repeat cesarean delivery to a 34-year-old, gravida 4, para 4
woman at 40 weeks’ gestation. His Apgar scores were 5 at
1 minute and 9 at 5 minutes, and he weighed 3025 g. Several
anomalies were noted on physical examination, including
low-set ears, a high-arched palate, a coloboma, a small
cataract of the left eye, a small phallus, and an imperforate
anus. The presence of a well-formed sacrum and midline
perineal mound suggested a low imperforate anus.
An abdominal x-ray was obtained (Fig. 1). Evaluation of
midline structures included cardiac, renal, and cranial
ultrasounds, which were normal. Because of his physical
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examination findings, a magnetic resonance imaging of the
brain was obtained and revealed bilateral optic nerve
hypoplegia and an enlarged anterior pituitary gland.
Laboratory studies evaluating anterior pituitary function
were normal. Normal chromosomes were identified.
The patient was taken to the operating room within
the first day of life for a posterior sagittal anorectoplasty.
A muscle stimulator demonstrated a well-developed sphinc-
ter mechanism. The rectal atresia was found approximately
1 cm deep to the perineal skin. No communication with
the urinary tract was identified. A small amount of white
mucus was encountered upon opening the rectum. A
neoanus was created that enabled the easy passage of a
Hagar no. 12 dilator.
Postoperatively, the patient failed to pass meconium over
the next 4 to 5 days. Abdominal x-rays demonstrated a
markedly dilated loop of bowel transversely in the upper
abdomen (Fig. 2). A contrast enema was performed, which
demonstrated a colonic obstruction near the splenic flexure
(Fig. 3). The patient returned to the operating room for an
exploratory laparotomy. An atresia of the distal transverse
colon with massive dilatation of the proximal colon was
discovered. An extended right hemicolectomy with a
primary hand-sewn ileocolic anastomosis was carried out.
The patient demonstrated bowel function on postoperative
Journal of Pediatric Surgery (2006) 41, 583–585
Fig. 1 Initial postnatal abdominal x-ray.Fig. 3 Detail of colon atresia on barium enema.
S. Goodwin et al.584
day 7, and feedings were readily advanced to goal. The
patient was eating and stooling well and demonstrated good
weight gain at the time of discharge on day of life 26.
2. Discussion
The incidence of imperforate anus is 1 in 4000 to 5000 live
births. Colon atresia occurs in only 1 in 20,000 live births.
Seeing the 2 anomalies in combination is extremely rare.
The etiology of imperforate anus is unknown [1-3].
There is some evidence for a sex-linked genetic predispo-
sition with a slight male predominance, yet no specific
Fig. 2 Postoperative day 5 abdominal x-ray.
genetic mutation has been identified [1]. Imperforate anus is
often associated with the VACTERL (vertebral, anal,
cardiac, tracheal, esophageal, renal, and limb) anomalies
prompting further evaluation postnatally. Cardiac and renal
anomalies are most common, and gastrointestinal anomalies
other than esophageal atresia are not typically found. High
imperforate anus malformations demonstrate a higher
incidence of other anomalies and have traditionally been
treated with an initial diverting colostomy at birth, followed
by a posterior sagittal anorectoplasty within the first year of
life. Low imperforate anus malformations, as in our patient,
can be definitively repaired shortly after birth [4]. Laparos-
copy-assisted repairs have also been described [5].
The incidence of intestinal atresias varies depending
upon their location in the gastrointestinal tract. Small bowel
atresias, presumed to be the result of a prenatal mesenteric
vascular event, affect the terminal ileum most often and
occur in 1 in 300 to 400 live births in the United States [1].
The incidence of colon atresia is widely referenced to be
1 in 20,000 live births [1]. Multiple areas of small bowel
atresia have been reported to occur in 14% of cases, nearly
all being small bowel [6]. A familial pattern of multiple
atresias affecting the stomach, duodenum, small bowel,
and colon and a high degree of consanguinity were observed
in a group of people near Quebec, raising the possibility of a
rare autosomal recessive gene expression in that unique
situation [7].
Imperforate anus and colon atresia in combination is
extremely rare. A review of the English literature found only
5 previously reported cases [8-12]. None of these previous
reports were from the United States. The presence of white
mucus in the atretic rectum noted during the repair of the
imperforate anus ideally should have prompted an earlier
radiographic study to rule out a more proximal obstruction.
Diagnosis of an isolated colon atresia is usually made in the
Imperforate anus and colon atresia in a newborn 585
presence of a bowel obstruction, followed by radiographic
confirmation revealing dilated loops of bowel with a gasless
distal colon and rectum. A contrast enema will confirm the
diagnosis by demonstrating a distal microcolon that is cut
off from the dilated proximal loops of bowel. We obtained a
contrast enema on postoperative day 5 when the patient
failed to stool and an abdominal film revealed a dilated loop
of bowel (Fig. 2). The patient did well clinically from a
gastrointestinal standpoint, but his other multiple anomalies
may require long-term medical follow-up care. This case
highlights the very rare simultaneous occurrence of both an
imperforate anus and colon atresia and underscores the
importance of a high index of suspicion for more proximal
atresias when mucus and no meconium are encountered
during initial anorectoplasty.
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