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CHAPTER 61

Neonatal Intestinal Obstruction

Daniel Sidler
Miliard Debrew
Kokila Lakhoo

Introduction The midgut comprises the jejunum and ileum as well as the
Neonatal intestinal obstruction (NIO) is one of the most common ascending and proximal transverse colon. These are supplied by the
emergency conditions a paediatric surgeon is called upon to assess superior mesenteric vessels.
during the neonatal period. Successful management of NIO depends The hindgut comprises the distal colon, which is supplied by the
on timely diagnosis and referral for therapy. The diagnosis is based inferior mesenteric vessels, and the rectum, which is supplied by the
on history (symptoms) and physical examination (signs) confirmed by internal iliac vessels.
some investigations such as radiographic and histopathological stud- Aberrations of foregut formation include duodenal stenosis, duodenal
ies. Catastrophic events such as volvulus, ischaemic loop of bowel, atresia, and annular pancreas. Maldevelopment of the midgut includes
pneumoperitoneum, and/or pneumonia from aspiration and malnutri- malrotation as well as jejunal and ileal atresia. Meconium ileus involves
tion could be overcome through efficient and timely resuscitation and the distal ileum. Hirschsprung’s disease (aganglionic megacolon),
urgent transport to a specialised unit. meconium plug syndrome, and imperforate anus involve the hindgut.
The desired goal of healthy survival of neonatal intestinal Enteric duplications occur in all three locations.
obstruction requires a coordinated interaction of medical, nursing, Jejunoileal atresia is a condition acquired during foetal development
and rehabilitative specialties in an organised team. Early surgical due to disruption of the mesenteric blood supply. In their classic work on
intervention is paramount and may mean all the difference between foetal dogs in 1955, Louw and Barnard from Cape Town, South Africa,
intestinal salvage and crippling short gut syndrome. The typical case clarified the pathophysiology of jejunoileal atresia. Other abdominal
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of neonatal bowel obstruction is generally straightforward, and the conditions occurring in utero, such as gastroschisis, volvulus, or intus-
outcome is potentially excellent. Only very preterm babies and those susception, may be associated with intestinal atresia due to kinking,
of extremely low birth weight may succumb. However, in Africa, late stretching, or otherwise disrupting the blood flow to the foetal bowel.
presentations and poor resources lend to a mortality of up to 50%. Chromosomal anomalies are rare (<1%) in babies with jejunoileal atresia.
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Few dedicated paediatric hospitals exist in developing countries. 2
Intestinal obstruction can be complete (atresia, anorectal Meconium ileus is the earliest manifestation of cystic fibrosis (CF),
malformation (ARM)) or incomplete (stenosis, web). Obstruction an autosomal recessive condition characterised by abnormalities in cel-
may be intraluminal (meconium ileus or meconium plug syndrome) lular membrane physiology and chloride ion transport that contribute to
or functional (Hirschsprung’s disease (HD)). Proximal obstruction progressive respiratory failure, derangements in cellular secretory pat-
presents with earlier vomiting and less abdominal distention, whereas terns, and diminished mucosal motility. In developed countries, 10–20%
distal bowel obstruction lends itself to late emesis and greater abdominal of newborns with CF present with meconium ileus, an association first
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distention. This chapter provides an overview on neonatal bowel described by Landsteiner in 1905. A cystic fibrosis gene that is different
obstruction. Each specific condition is covered in chapters elsewhere from that in the caucasian population has been identified in the black
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in this book, specifically, Chapter 58 (inguinal and femoral hernias African population; however, the incidence in Africa is much reduced,
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and hydroceles), Chapter 62 (duodenal atresia and stenosis), Chapter and in many sub-Saharan countries, the disease is not reported.
63 (intestinal atresia and stenosis), Chapter 65 (intestinal malrotation Abnormalities in the cystic fibrosis transmembrane regulator
and midgut volvulus), Chapter 67 (meconium disease), Chapter 76 (CFTR) disrupt transmembrane flux of the chloride ion, which
(Hirschsprung’s disease), and Chapter 77 (anorectal anomalies). subsequently affects sodium transport as well. The meconium of
affected babies is thick and sticky; this, coupled with the poor motility
Demographics of an immature intestine, leads to intraluminal obstruction of the
The incidence of NIO is approximately 1 in 5,000 live births. The true terminal ileum. A contrast enema might reveal the characteristic finding
incidence in Africa is unknown, but a recent report from Tanzania has of a microcolon. It is essential to push the contrast up to the level of
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shown that it is still the most common neonatal surgical emergency. obstruction, namely, the distal ileum to be therapeutic by flushing out
Many cases still die undiagnosed and untreated. the meconium plugs (Figures 61.1 to 61.4).
Aetiology/Pathophysiology Meconium plug syndrome refers to inspissated meconium obstruct-
Neonatal intestinal obstruction has varied aetiology, so the patho- ing the colon; it may denote HD but not CF. Conditions that predispose
physiology is diverse. to dysmotility of the neonatal bowel (e.g., maternal pre-eclampsia,
The gastrointestinal tract (GIT) arises from the yolk sac. At 3 diabetes mellitus, administration of magnesium sulfate, prematurity,
to 4 weeks’ gestation, it becomes a distinct entity. A connection, sepsis, and hypothyroidism) may be responsible for the formation of the
the vitelline (omphalomesenteric) duct, may persist as a Meckel’s meconium plug. A water-soluble contrast enema can be both diagnostic
diverticulum. The alimentary tube is divided according to its blood and therapeutic for this condition.
supply into the foregut, midgut, and hindgut. Hirschsprung’s disease is a disorder of the neuroenteric pathways
The foregut comprises the oesophagus, stomach, and duodenum. in the distal colon that results in a bowel that is tonically contracted.
These are vascularised by multiple sources—the thyrocervical, Bowel peristalsis is controlled by neuroenteric ganglion cells, which
intercostal, celiac axis, and superior mesenteric vessels.