Endgames Case Report

A few hours from disaster

BMJ 2012; 345 doi: http://dx.doi.org/10.1136/bmj.e4441 (Published 09 July 2012) Cite this as: BMJ 2012;345:e4441
  1. Rami Radwan, foundation year 1, paediatric surgery,
  2. Ashok Daya Ram, specialist registrar, paediatric surgery,
  3. Simon N Huddart, consultant, paediatric surgery
  1. 1University Hospital of Wales, Cardiff CF14 4XW, UK
  1. Correspondence to: R Radwan ramiradwan{at}hotmail.com

A 4 month old boy was brought to our children’s assessment unit with a 12 hour history of multiple green bilious vomits and irritability. He was not tolerating anything orally and had last opened his bowels two days ago. Birth had been at term by normal vaginal delivery, with no complications. He was taking no regular drugs and had no family or social history of note.

When he was 2 weeks old he had been seen by his general practitioner for bilious vomiting and had been sent home on antacids. A week later, he presented with further bilious vomiting, now associated with constipation, and was treated conservatively with guidance given to his mother on diet. During a third presentation at the age of 2 months, this time for irritability and constipation, his mother was advised that this was a common symptom of colic in newborns.

When we examined him, his temperature was normal, his heart rate was 121 beats/min (normal range 100-160), and his respiratory rate was 40 breaths/min (30-60). His mucous membranes were dry, and capillary refill time was 3 s. On auscultation he had normal heart sounds and his chest was clear. His abdomen was soft, mildly tender, and he had no palpable masses. Routine blood tests showed a normal white blood cell count and a C reactive protein concentration of <1 mg/L.

Questions

  • 1 What are the differential diagnoses of neonatal bilious vomiting?

  • 2 What is malrotation and why does it predispose to midgut volvulus

  • 3 How should this patient be investigated?

  • 4 How is this condition managed?

Answers

1 What are the differential diagnoses of neonatal bilious vomiting?

Short answer

Bilious vomiting in a neonate should be treated as a surgical emergency until proved otherwise. The causes include intestinal malrotation and volvulus, duodenal atresia, jejunoileal atresia, meconium ileus, and necrotising enterocolitis.

Long answer

Neonatal bilious vomiting is always a worrying sign. All cases require rapid investigation and diagnosis to exclude an underlying surgical emergency. Malrotation is the most worrying differential diagnosis.1 The pathophysiology is incomplete rotation of the normal bowel during fetal development. As a consequence, the bowel is suspended on a narrow mesenteric base, which is prone to twisting. This can cause midgut volvulus with occlusion of the superior mesenteric artery.1 2 Bilious vomiting is the initial symptom in 90-95% of patients; immediate surgical intervention is needed to preserve the bowel.2

Another cause of bilious vomiting is duodenal atresia. It is a form of congenital obstruction to the second part of the duodenum, thought to result from failure of recanalisation of this segment of the duodenum during fetal development.1 Because the obstruction often lies just distal to the papilla of Vater, duodenal atresia presents with bilious vomiting. The incidence is about one in 5000-10 000 live births in the developed world, and it is slightly more common in boys.1 Diagnosis is often made by abdominal radiography, which shows a characteristic “double bubble” sign.1 Jejunoileal atresia is similar in some respects; it is the result of a mesenteric vascular event, such as volvulus or intussusception, that occurs during fetal development. The more proximal the lesion, the earlier the symptoms of bilious vomiting become apparent. Diagnosis is again through abdominal radiography, with erect imaging showing air fluid levels proximal to the level of obstruction.1

Meconium ileus is another condition that is associated with neonatal bilious vomiting. Meconium, which is normally passed within the first few days of life, becomes thickened and congested within a segment of the bowel. This phenomenon results in obstruction, with subsequent abdominal distension and bilious vomiting; 80-90% of newborns who present with meconium ileus have cystic fibrosis.1

Necrotising enterocolitis is a severe condition in which there is extensive necrosis to the bowel. Its cause is not yet fully understood, but symptoms often present within the first two weeks of life.1 It is common in premature babies and babies with a low birth weight. Between 20% and 50% of patients require surgical intervention, but despite this mortality is high and many patients develop long term complications.1

2 What is malrotation and why does it predispose to midgut volvulus?

Short answer

Intestinal malrotation is a congenital anomaly of midgut rotation. Malrotation, with or without volvulus, is responsible for a large proportion of cases of neonatal bilious vomiting and should always be excluded first.

Long answer

Between the fifth and 12th week of gestation the intestine undergoes a series of developmental changes. It initially elongates, before herniating through the umbilicus into the umbilical cord. The whole intestine rotates 270° anticlockwise, with the superior mesenteric artery as its axis, before returning to the abdomen and fixating itself to the posterior abdominal wall. If this process is interrupted, it results in incomplete rotation (malrotation) of the intestine.3 4 Peritoneal bands (Ladd’s bands) from the misplaced caecum can compress the duodenum, causing obstruction. As a consequence of incomplete rotation, the small intestine is left suspended on a very narrow mesenteric base. This base becomes prone to clockwise twisting, resulting in midgut volvulus and occlusion of the superior mesenteric artery that lies within it.3 5

Incidence varies greatly probably because the condition can be difficult to diagnose and it may even be missed, especially in patients with non-specific symptoms. A large proportion (25-30%) of babies present within the first week of life, and 50-75% are diagnosed during the first year of life. The remainder may present in adulthood or not at all.5

Bilious vomiting is the single most identifiable symptom of intestinal malrotation, being present in 90-95% of cases. Other symptoms and signs are non-specific and their presence varies greatly throughout the population. They include abdominal pain, abdominal distension, peritonitis, constipation, and shock. The older the child is, the more intermittent these symptoms can become, which further complicates diagnosis. Cases that are not detected by early adulthood may even become asymptomatic.1 2

3 How should this patient be investigated?

Short answer

All patients with suspected malrotation require an upper gastrointestinal contrast study, and this remains the investigation of choice. Several other modalities may be used, including radiography, ultrasound, and computed tomography, although these tests can appear normal and often require experienced interpretation.

Long answer

A thorough clinical examination is an important first step in any patient with suspected malrotation and can identify the presence of any abdominal tenderness; examination can however be within normal limits. Routine blood tests are often normal in cases of suspected malrotation. With prolonged volvulus, however, the white blood cell count may be raised. If ischaemia is present, blood gas analysis may show a metabolic acidosis.

An upper gastrointestinal contrast series is the most accurate investigation for malrotation with or without volvulus. In a normal bowel, contrast will pass through the duodenal C loop and cross the midline of the abdomen. When malrotation is present, contrast may be abruptly cut off in the second part of the duodenum. Such a defect may not always be present but the abnormal orientation of the C loop, which may not cross the midline or may remain more towards the right of midline, should strongly suggest a malrotation. There may also be associated tapering of the contrast in a corkscrew pattern, which is indicative of the presence of midgut volvulus. This investigation has a sensitivity of almost 95%.6 7

Plain abdominal radiography is of limited use and may appear normal. If duodenal obstruction is present, air collects in the stomach and proximal duodenum, giving a “double bubble” appearance proximally, with little gas present distally.1 6

Ultrasound is not routinely ordered in cases of suspected malrotation, but it can be used when an upper gastrointestinal contrast series is inconclusive. Malrotation can be identified by assessing the orientation of the superior mesenteric vein and superior mesenteric artery. The presence of their inversion, or the coiling of the superior mesenteric vein around the artery, points to a diagnosis of midgut volvulus.2 8

Computed tomography is not routinely used for the investigation of malrotation, although it may identify its presence when used to investigate abdominal pain without bilious vomiting. Similar to an upper gastrointestinal contrast series, contrast cut-off and tapering of contrast may be seen. Lower gastrointestinal contrast series can be used when an upper gastrointestinal series has been inconclusive, and it may show the presence of an abnormally located caecum.2 8

4 How is this condition managed?

Short answer

Intestinal malrotation is a surgical emergency. A Ladd’s procedure should be performed as urgently as possible. This procedure reduces any volvulus present and restores blood supply and function to the small bowel.

Long answer

Although the embryology of the intestines was well understood by the late 1800s, it was not until 1936 that an American paediatric surgeon, William E Ladd, first described the surgical treatment of intestinal malrotation.9 It revolutionised surgical practice worldwide and helped reduce death as a result of the condition.

The technique involves entering the abdominal cavity through a central midline or transverse supraumbilical incision, which allows the entire small and large intestine to be inspected for evidence of volvulus. If present, the volvulus is reduced by rotation in an anticlockwise direction. Peritoneal bands and Ladd’s bands at the base of the intestine are ligated and divided, widening the mesenteric axis and greatly reducing the risk of reoccurrence. As the intestine is returned to the abdomen, the small bowel is placed on the right and the large bowel on the left. The unusual placement of the internal organs also helps prevent recurrence and further malrotation. Because the caecum is positioned in the left upper quadrant, an appendicectomy is sometimes performed at the same time to prevent any difficulty in a later diagnosis of appendicitis.9 10

More recently, laparoscopic Ladd’s procedures have been performed successfully in patients with malrotation.11

Patient outcome

Our patient underwent an urgent upper gastrointestinal contrast study, which showed tapering with a corkscrew pattern to the contrast. He underwent a Ladd’s procedure, which identified a 360° malrotation and midgut volvulus. The bowel was congested but fortunately no ischaemia was present. Any further delay, even a matter of hours, could have led to complete necrosis of the midgut; this would have required bowel resection and caused subsequent short bowel syndrome. The operation itself was uncomplicated and he recovered well before being discharged later that week.

Notes

Cite this as: BMJ 2012;345:e4441

Footnotes

  • Competing interests: All authors have completed the ICMJE uniform disclosure form at www.icmje.org/coi_disclosure.pdf (available on request from the corresponding author) and declare: no support from any organisation for the submitted work; no financial relationships with any organisations that might have an interest in the submitted work in the previous three years; no other relationships or activities that could appear to have influenced the submitted work.

  • Patient consent obtained.

  • Provenance and peer review: Not commissioned; externally peer reviewed.

References