Intestinal obstruction is where the passage of food, fluids and gas through the intestines becomes blocked. Small bowel obstruction is more common than large bowel obstruction.
The obstruction results in a build-up of gas and faecal matter proximal (before) to the obstruction, causing dilation of the proximal bowel and vomiting. It also causes absolute constipation, where the patient is unable to pass stools or wind. Children with partial obstruction may still pass small amounts of stool.
Causes
The top causes of bowel obstruction in children are:
- Intussusception
- Hirschsprung’s disease
- Meconium ileus (usually caused by cystic fibrosis)
- Adhesions (e.g., previous surgery or intra-abdominal inflammation)
- Volvulus caused by congenital malrotation of the intestines
- Incarcerated hernia (e.g., inguinal hernia)
Adhesions are pieces of scar tissue that bind the abdominal contents together. They can cause kinking or squeezing of the bowel, leading to obstruction. Adhesions typically cause obstruction in the small bowel, rather than the large bowel. They are most often caused by previous abdominal surgery or intra-abdominal inflammation (e.g., appendicitis or peritonitis).
Congenital malrotation occurs when the normal rotation or coiling of the intestines at around 10-12 weeks of gestation is incomplete or faulty. This increases the risk of the child developing volvulus, where the bowel twists around itself and the mesentery it is attached to, causing intestinal obstruction.
Presentation
The key presenting features of bowel obstruction are:
- Generalised abdominal pain and distension
- Persistent bilious (green-coloured) vomiting
- Failure to pass stools or flatus (absolute constipation)
- Dehydration
- Shock (hypotension, tachycardia and pallor)
The abdomen gives a tympanic sound (hollow/drum-like) on percussion, due to the air-filled loops of bowel.
On auscultation, the bowel sounds are:
- Hyperactive, high pitched and “tinkling” early on in the obstruction
- Quiet or absent later in the obstruction
Diagnosis
Abdominal x-ray is the initial imaging in suspected bowel obstruction and shows distended loops of bowel.
Management
Bowel obstruction is a surgical emergency. They need to be transferred to the paediatric surgical unit.
As with any acutely unwell patient, the first step is an ABCDE assessment. Patients with bowel obstruction may be haemodynamically unstable and require urgent intervention if they have developed:
- Hypovolaemic shock
- Bowel ischaemia
- Bowel perforation
- Sepsis
The initial management of bowel obstruction involves:
- Nil by mouth (stop adding food or fluids when there is a blockage)
- IV fluids to hydrate the patient and correct electrolyte imbalances
- NG tube with free drainage to allow stomach contents to freely drain and reduce the risk of vomiting and aspiration
Definitive management depends on the underlying cause and often involves surgery.
Last updated February 2025
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