Intestinal Malrotation Workup

Updated: Dec 08, 2016
  • Author: Denis D Bensard, MD, FACS, FAAP; Chief Editor: Carmen Cuffari, MD  more...
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Workup

Laboratory Studies

The following studies may help facilitate the diagnosis and guide treatment in patients with suspected intestinal malrotation:

CBC count

An elevated or decreased WBC count may indicate systemic inflammation and/or sepsis.

Thrombocytopenia may indicate a platelet consumptive process (eg, necrotizing enterocolitis); additionally, platelets are an acute phase reactant with thrombocytosis indicating systemic inflammation.

A decreased hemoglobin/hematocrit gives evidence of blood loss, possibly through GI bleeding.

Arterial, capillary, or venous blood gas and lactate

Metabolic acidosis provides evidence for ongoing ischemia as observed with necrotizing enterocolitis or strangulated bowel (volvulus). This is demonstrated on serum laboratory studies with an elevated lactate and/or base deficit

Blood chemistries

Patients with volvulus and resultant bowel ischemia can develop severe metabolic derangements, which should be corrected, if possible, prior to operative intervention.

Ongoing sodium, chloride, and bicarbonate losses can occur through suctioned GI secretions.

Hyperkalemia may occur secondary to metabolic acidosis and hemolysis.

Urinalysis and urine culture

These may be useful to rule out other infectious causes if the differential remains unclear.

Type and screen

A current type and screen must be available because these patients often require emergent operative intervention which may or may not require blood transfusion.

Prothrombin time (PT) and activated partial thromboplastin time (aPTT)

These should be obtained in patients with sepsis, if ongoing blood loss is a concern and prior to operative intervention.

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Imaging Studies

The following imaging studies may be helpful in clarifying the diagnosis:

Plain abdominal radiography

Plain radiography has limited use for defining intestinal obstruction. The classic pattern for duodenal obstruction, if present, is the double-bubble sign produced by an enlarged stomach and proximal duodenum with little gas in the remainder of the bowel. Distended bowel loops with or without pneumatosis intestinalis may be seen. If pneumoperitoneum is suspected, a left lateral decubitus film can be obtained to better visualize this process

Upper GI series

Upper GI series is the criterion standard to diagnose intestinal malrotation, with a sensitivity of 93-100%. However, upper GI but should only be obtained in patients who are hemodynamically stable. [22, 23, 24]

Normal rotation is present if the duodenal C-loop crosses the midline and places the duodenojejunal junction to the left of the spine at a level equivalent or superior to the pylorus. If the contrast ends abruptly or tapers in a corkscrew pattern, midgut volvulus or some other form of proximal obstruction may be present. Barium is the contrast of choice in patients who are stable or have chronic symptoms

Contrast studies may not be possible in patients who are actively vomiting or are otherwise unstable and need immediate surgical exploration. Water-soluble agents should be used if the study must be performed prior to emergent operative intervention. See the image below.

In this upper GI series with abnormal results, the In this upper GI series with abnormal results, the duodenum does not cross the midline, and the small bowel is present only in the right side of the abdomen.

In this upper GI series with abnormal results, the duodenum does not cross the midline, and the small bowel is present only in the right side of the abdomen.

Lower GI series (contrast enema)

Occasionally, upper GI series may fail to define the location of the duodenojejunal junction, in which case, a contrast enema may be helpful to identify the location of the cecum.

A normally placed cecum does not unequivocally rule out intestinal malrotation and clinical judgment must be exercised. See the image below.

These 2 lower GI series show the cecum (arrows) in These 2 lower GI series show the cecum (arrows) in the right upper quadrant, indicative of malrotation.

Ultrasonography

Ultrasonography is quickly becoming a useful imaging modality in infants and children with abdominal pain and has been used to accurately diagnose intestinal malrotation with or without midgut volvulus. [25, 26]

In the hands of experienced ultrasonographers, ultrasonography has been shown to have false positive rate of 0% and a false negative rate of 0-30%. [27, 28]

Findings indicative of malrotation include inversion of the superior mesenteric artery (SMA) and the superior mesenteric vein (SMV) and a retroperitoneal position of the duodenum after fluid bolus via a nasogastric tube. [27]

Other diagnostic findings include fixed midline bowel loops and duodenal dilation with distal tapering. The finding of the SMV coiled around the SMA is suggestive of intestinal volvulus The presence of ascites and thickened bowel wall were not found to be statistically significant predictors of malrotation with midgut volvulus

CT scanning

CT scanning is not well developed for diagnosing malrotation and midgut volvulus.

Scattered case reports of its use are noted, but it is not recommended as the principal diagnostic tool.

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Procedures

The following procedures may be helpful:

NG tube insertion

Insert an NG tube in all patients with bilious emesis and suspected malrotation.

Adjust the NG tube to low intermittent suction in order to decompress the bowel proximal to any obstruction that may be present.

Central venous catheter placement

Most patients require long-term intravenous access after surgery, especially if midgut volvulus is present.

Because intravenous nutrition is likely to be necessary, central line access is preferable over peripheral access so that parenteral nutrition can be delivered.

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