Intussusception
- Intussusception is the invagination (or telescoping) of one part of bowel into another.
- Most typically it involves the ileum into the caecum however can occur anywhere in the bowel.
- The risk is ischemia of the ‘trapped’ bowel leading to necrosis and sepsis.
- It may occur at any age but commonly occurs in the 2 month to 2 year age group with a peak incidence at 5 to 9 months.
- Most common cause of bowel obstruction in children < 3yr old. M > F
- Fatal if untreated.
Patho-physiology of Intussusception
CAUSES
- Idiopathic/Unknown etiology.
- In a small percentage, there may be a ‘lead point’. This is an anatomical or pathological structure contributing the the intussusception. EG tumor, meckles diverticulum or haematoma. Non surgical resolution is less successful when a lead point is present.
SIGNS AND SYMPTOMS
- Acute onset of severe pain (spasmodic, but increasing in frequency)
- May be a palbable mass.
- Mixture of blood and mucous causes ‘current jelly’ stools. Occurs as the condition advances. Does not have to be present.
- Most common cause of bowel obstruction in children < 3yr old. M > F
Scanning Protocol
Preparation & Equipment
- No preparation is needed.
- Supine.
- Begin with a curvilinear probe to obtain an overview of the abdomen for masses and free fluid.
- A linear probe (largest foot print available). Ideally 8-12MHz.
- A curve-linear probe for larger/deeper structures depending on the age and habitus of the pediatrics patient.
- Warm gel and warm environment.
Scan technique
- Be as gently as possible.
- Begin with a curvilinear probe to obtain an overview of the abdomen for masses and free fluid.
- If there is a palpable mass or painful focus, scan directly on that area.
- If not, scan medially in the RIF.
- Begin at the level to ASIS in a transverse plane.
- Slide superiorly looking for the caecum.
- Sweep superiorly and inferiorly in a progressive manner towards umbilicus.
- If no pathology/cause for symptoms is identified, assess all the viscera (liver, kidneys, adrenals etc).
- Also check the orientation of superior mesenteric artery to be left of the superior mesenteric vein. Image in a transverse plane. If reversed, suspect volvulus. and look for “bowel whirlpool”.
- If intussusception or other bowel pathology identified, ensure vascularity is present in the bowel wall using color doppler.
Differential diagnoses
There are many causes of abdominal pain in an infant. These include:
- Appendicitis
- Colic
- Constipation
- Mass
- Infection
Basic Hardcopy Imaging
An intusseption series is an urgent, targeted scan & is actually an examination for the cause for abdominal pain. It should include images of the relevant anatomy investigated:
- SMA, SMV orientation
- Color doppler of bowel wall.
- Any pathology identified
- Any free fluid identified.