A common theme of each week’s Ped EM Morsels seems to center around how difficult our jobs can be. I don’t want you to think that I am trying to accentuate a defeatist’s attitude, but rather highlight how the astute clinician continues to actively consider the most dangerous of entities even when faced with what appears to be benign. Continuing to actively search for the needles in the haystack sharpens your vision and improves your ability to find those most concerning conditions that present in the non-textbook fashion (which, by the way, is more common). Currently many ED’s are all dealing with a plethora of vomiting… so let’s not be cavalier and diagnose “gastroenteritis” prematurely (you can also refer to Intussusception Morsel).
- Consider Malrotation in patients with vomiting with or WITHOUT abdominal distension.
- Occurs in 1 in 500 births.
- “Malrotation” applies to a wide range of intestinal anomalies, in which the abnormal rotation and fixation of the midgut lead to narrow base of the small bowel mesentery and can allow volvulus to occur (often with disastrous results).
- Most frequently the cecum has failed to reach the right iliac fossa and lies, instead, in the subhepatic or central position.
- Often have dense fibrous bands that can further predispose to volvulus or occasionally cause obstruction themselves.
- The bowel’s abnormal position and connections lead to excessive mobility, which predisposes to bowel compression, kinking, or volvulus and also intussusception.
Presentation of Malrotation
- The Neonate (<30 days of age)
- Most malrotation present in this population.
- ~50% will present in first week of life and more than 60% before the end of the 1st month.
- Bilious emesis is the most frequent symptom (but not the sine qua non).
- Pain and irritability are not prominent clinical features in the neonate!
- Abdomen is soft and not tender (until there is strangulation).
- The older child
- 20% develop symptoms after 1 year of age (even into adulthood)!
- Diagnosis is more difficult
- Larger Differential Dx to conside
- Pain and irritability are more prevalent in toddlers and older children.
- Vomiting may be non-bilious in up to 50% initially.
- Diarrhea may even be present (16% in one study, 23% in another).
- Abdomen may still be soft and not tender (until there is strangulation).
- Stuttering attacks or pain and vomiting can occur and may lead to alternative Dx:
- “Cyclical vomiting”
- “Abdominal migraines”
- Abdominal Xray
- May show dilated duodenum
- May show air-fluid levels
- Can be read as “normal” 20% of the time.
- Reliance on AXR can lead to delayed diagnosis!
- “Barium Swallow” (AKA Upper GI Series)
- Can define the size, shape, rotation, and presence of obstruction
- If volvulus is present, may show dilated duodenum and “Corkscrew” of contrast projecting away from the posterior abdominal wall.
- Sensitivities for detecting malrotation are reported at 93-100%.
- “The normal position of the duodenojejunal junction is to the left of the left-sided pedicles of the vertebral body and at the level of the duodenal bulb on frontal views and posterior on lateral views.” (see Applegate Reference for great pictures).
- Gastroesophageal reflux can be present on Upper GI… but a complete study must demonstrate the duodenal anatomy.
- Is a useful adjunct, but not good enough to exclude the diagnosis.
- Able to depict flow in mesenteric vessels and can reveal the position of a volvulus.
- Barium Enema is not reliable as the position of the cecum is too variable.
MORAL of the Story: Be ever vigilant even in the patient with repeat episodes of abdominal pain and vomiting that has been labeled as “cyclical vomiting.” Don’t allow diagnostic momentum obscure your view of the needle in this haystack. Has this patient had an appropriate evaluation or have we just labeled them? Diarrhea, unfortunately, does not exclude the diagnosis either. Sorry, what can I say? … Your job is difficult.
Millar AJW, Rode H, Cywes S. Malrotation and Volvulus in Infancy and Childhood. Seminars in Pediatric Surgery, Vol 12, No 4 (November), 2003: pp. 229-236.