Next, you are taking a more detailed history about eight month old Timmy. He has a one day history of screaming inconsolably and poor feeding. He has also vomited breast milk twice over the past few hours. His mother has not measured any fever; there is no diarrhoea and no cold symptoms. When Timmy’s mother last changed the nappy, she noted some 'red currant jelly-like' substance. She has noted that between bouts of screaming, Timmy has been calm and at times quite sleepy.
The following five questions refer to Timmy’s clinical scenario.
| Question 07 Which one of the following is the most likely diagnosis in Timmy’s case? |
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| Food intoxication |
| Gastroenteritis |
| Intussusception |
| Constipation |
| Appendicitis |
| Check answer |
ExplanationIntussusception describes the invagination of the proximal bowel into a distal segment. As the trapped section of bowel may have its blood supply cut off, there is resultant ischemia (lack of oxygen in the tissues). The mucosa (gut lining) is very sensitive to ischemia, and responds by sloughing off into the gut. This creates the classically described "red currant jelly" stool, which is a mixture of sloughed mucosa, blood and mucus. A study reported that only a minority of children with intussusception had stools that could be described as "red currant jelly". Hence, intussusception should be considered in the differential diagnosis of children passing any type of bloody stool. |
Question 08 You have now examined Timmy. He is calm in his mother’s arms and in no distress, however, he looks pale. His tummy is soft, yet you can palpate a 'sausage' in his right upper quadrant. Which one of the following next steps is the LEAST urgent in Timmy’s case? |
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| Get a catheter urine sample |
| Call the paediatric surgical registrar |
| Obtain IV access |
| Obtain abdominal ultrasound imaging |
| Tell the nurse and parents to keep the baby nil by mouth |
| Check answer |
ExplanationEven though vomiting can be a sign of urinary tract infection, the other four steps are more important as this presentation is very likely to be intussusception. Timmy’s condition might warrant surgical intervention, therefore notification of the surgeon, IV access and fasting are mandatory. Ultrasound imaging is helpful in confirming the clinical diagnosis. Ultrasound is today considered the imaging modality of choice for diagnosis and exclusion of intussusception due to its high accuracy and lack of radiation. A target-like mass, usually around 3 cm in diameter, confirms the diagnosis. An x-ray of the abdomen may be indicated for evaluation of intestinal obstruction or the presence of free intraperitoneal gas; the latter finding would imply that bowel perforation has already occurred. |
Question 09 You have arranged for an abdominal ultrasound for Timmy. Which one of the following findings would NOT be consistent with your provisional diagnosis of intussusception? |
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| Target sign |
| Pseudokidney sign |
| Crescent in a doughnut sign |
| Double bubble sign |
| Doughnut sign |
| Check answer |
ExplanationDouble bubble sign. The diagnosis of duodenal atresia is usually confirmed by radiography. An x-ray of the abdomen shows two large air filled spaces, the so-called 'double bubble' sign. The air is trapped in the stomach and proximal duodenum, which are separated by the pyloric sphincter, creating the appearance of two bubbles visible on x-ray. Since the closure of the duodenum is complete in duodenal atresia, no air is seen in the distal duodenum. There are many target signs (A), one of which gives the appearance of intestinal intussusception, also known as the doughnut sign (E). The appearance is generated by concentric alternating echogenic and hypoechogenic bands. The echogenic bands are formed by mucosa and muscularis, whereas the submucosa is responsible for the hypoechoic bands. The Pseudokidney of intussusception sign (B) refers to the longitudinal ultrasound appearance of the intussuscepted segment of bowel. The fat containing mesentery dragged into the intussusception, which contains vessels, resembles the renal hilum. The renal parenchyma is formed by the oedematous bowel. The crescent in a doughnut sign (C) refers to the transverse ultrasound appearance of intestinal intussusception and is a variation of the target (or doughnut) sign. The crescent is formed by mesentery dragged into the intussusception. It is only on one side of the bowel and therefore forms a crescent that is echogenic. It is the transverse equivalent of the pseudokidney sign. |
Question 10 Ultrasound imaging suggests intussusception. Which one of the following is your next step? |
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| Air enema |
| Emergency laparotomy |
| Admit to the ward for observation |
| Child can eat and drink |
| Notify the gastroenterologist |
| Check answer |
ExplanationIntussusception warrants urgent resuscitation and reduction. It is not usually immediately life-threatening and can be treated with an air enema, which confirms the diagnosis of intussusception and in most cases successfully reduces it. The success rate is over 80%. However, approximately 5–10% of these recur within 24 hours. The main contra-indication for an enema is a perforation. If the intussusception cannot be reduced by an enema or if the intestine is damaged, a surgical reduction (B) is necessary. In a surgical reduction, the abdomen is opened and the part that has telescoped in is squeezed out (rather than pulled out) manually by the surgeon. If the surgeon is unable to successfully reduce it or the bowel is damaged, the affected section will be resected. More often, the intussusception can be reduced by laparoscopy, whereby the segments of intestine are pulled apart by forceps. |
Question 11 Intussusception can occur anywhere. In children, which one of the following is the most frequent location? |
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| Ileoileal and colocolic |
| Ileoileocolic |
| Ileocolic |
| Location will always depend on the location of a lead point lesion |
| Gastric intussusception |
| Check answer |
ExplanationIntussusception most commonly involves ileum passing into the caecum and colon through the ileo-caecal valve (75 - 95%), presumably due to the abundance of lymphoid tissue related to the terminal ileum and the anatomy of the ileocaecal region. B) Ileoileocolic is the second most common. A) Ileoileal, colocolic and gastric are uncommon. Almost all intussusceptions occur with the intussusceptum having been located proximally to the intussuscipiens. The reason for this is that peristaltic action of the intestine pulls the proximal segment into the distal segment. There are, however, rare reports of the opposite being true. D) An anatomic lead point (= a piece of intestinal tissue which protrudes into the bowel lumen) is present in approximately 10% of intussusceptions e.g Meckel’s diverticulum and polyp. Although infectious agents, including rotavirus, have been suspected by some researchers to be a possible causative factor, studies and analysis have not conclusively identified them to be such. A review of sparse data on the possible association between natural rotavirus and intussusception has not demonstrated a possible association until very recently. In addition, ecological studies revealed that no seasonality exists for intussusception in the United States, whereas rotavirus has distinct peaks in winter. In developing countries, patterns of intussusception may be quite variable and different from developed countries. A likely reason for this may be incomplete reporting of cases. Rates of intussusception may also vary according to socioeconomic status in developing countries. The typical age group for intussusception is two months to two years. |