Tessa Davis. 6 PEM papers that could change your practice – #3 – Intussusception and ultrasound, Don't Forget the Bubbles, 2014. Available at:
Simon Binks, an Emergency Medicine doc in Wollongong Hospital recently gave an awesome talk on six papers that changed his paediatric emergency medicine practice in the last year. This week we are posting one each day.
You can hear the talk on Joe Lex’s Free Emergency Medicine Talks site.
See all the papers and discussion:
Here I summarise the third paper he identified and his key points.
3. Intussusception – do you have to transfer to a tertiary hospital for ultrasound?
Often ultrasound is not available when you have a suspicion of intussusception – so what are the likely presenting symptoms and can we use x-ray to rule out intussusception?
Paper 1 – prevalence of clinical findings in intussusception (Pediatric Emergency Care)
This was a case series of 219 patients in a US ED
All the patient had confirmed intussusception and required an air enema or surgery.
More than 50% were <1 year old.
97% had ileo-colic intussusception (terminal ileum and ascending colon). Intussusception can also be ileo-ileal or colo-colic but most commonly is ileo-colic.
83% of children under 1 year old had bloody stools on presentation.
It was less common to have bloody stools in over 1 year olds – the most common complaint in this age group was abdo pain.
Not many had an ultrasound but in those that did, it was positive in 92% of cases.
Quite a few had abdo x-rays.
So, are abdo x-rays any use?…
Paper 2 – use of plain radiographs to exclude the diagnosis of intussusception (Pediatric Emergency Care).
This was a prospective study in the US.
It looked at children aged 3 months to 3 years with a clinical suspicion of intussusception.
Each child had three plain abdo x-ray views – supine, prone and left lateral decubitus. The authors looked to see air in ascending colon (remember that 97% of intussusceptions are ileo-colic and in these you wouldn’t see air in ascending colon). So, air in the ascending colon was a negative predictor. They also looked at positive predictors – target sign, meniscus sign or evidence of small bowel obstruction.
A blinded paediatric radiologist interpreted the films.
There were 190 patients eligible and 146 enrolled.
19 patients had intussusception,109 didn’t.
In patients with intussusception, none had air in the ascending colon in all three views. This was not a large study, but it showed a negative predictive value of 100% (i.e. if you have air in the ascending colon in all three views, you do not have intussusception).
If they only saw air in ascending colon on two views but not the third view, this was less effective. In these patients 2 out of 19 cases were missed (a 96% negative predictive value).
Abdominal x-ray is a good tool if you aren’t sure about intussusception and can be used to rule it out before initiating a transfer. All three views are needed for maximum negative predictive value.
Bottom line – plain abdo x-rays can be used to exclude intussusception when ultrasound is not available.