REVIEW

A pattern-based approach to bowel obstructionin the newborn

Charles M. Maxfield & Brett H. Bartz & Jennifer L. Shaffer

Received: 22 June 2012 /Revised: 21 October 2012 /Accepted: 29 October 2012 /Published online: 12 December 2012# Springer-Verlag Berlin Heidelberg 2012

Abstract Intestinal obstruction is common in newborns,and the radiologist plays a critical role in the care of thesechildren. Diagnosing and managing the potentiallyobstructed newborn can be challenging, especially giventhe myriad underlying pathologies that range from benignto acutely life-threatening. A familiarity with the most com-mon diagnoses is essential, but equally important to theradiologist is a systematic approach to management of thechild in this setting. We propose an approach based on therecognition of eight radiographic patterns, five upper gas-trointestinal examination (UGI) patterns and four contrastenema patterns. Recognition of these patterns directs furtherimaging when necessary and allows triage of children whocan be managed medically, those requiring elective or ur-gent surgery and those requiring emergent surgery.

Keywords Newborn . Neonatal . Obstruction .

Gastrointestinal

Introduction

The radiologist plays a crucial role in the diagnosis andmanagement of the vomiting newborn. This common andpotentially life-threatening presentation is not limited tochildren’s hospitals. All radiologists must be familiar withthe workup and management of potential bowel obstructionin the newborn. Etiologies of vomiting in the newborn

include surgical and non-surgical causes ranging from thebenign and nearly universal gastroesophageal reflux (GER)to life-threatening midgut volvulus [1]. In between the be-nign and the life-threatening are myriad etiologies of vomit-ing that produce different patterns on abdominalradiographs, contrasted upper gastrointestinal examination(UGI), and contrast enema. A familiarity with these patternsallows triage of cases that can be managed medically, thoserequiring elective surgery and those requiring emergentsurgery.

We present a pattern-based approach to the workup andmanagement of the vomiting newborn. Through identifica-tion of eight patterns on abdominal radiograph, five patternson UGI and four patterns on contrast enema, the radiologistcan competently and confidently manage this common andpotentially life-threatening clinical presentation.

Clinical presentation

Vomiting newborns sometimes present with additional signsand symptoms, such as feeding intolerance, abdominal disten-sion, failure to pass meconium and peritoneal signs [2]. Thesymptoms do not reliably discriminate the causes of vomiting,although they can provide clues to the underlying etiology.

Vomiting typically presents earlier with proximalobstructions than it does with more distal obstructions [3].Duodenal atresia, for example, typically presents with thefirst feeding. The various causes of duodenal stenosis,whether intrinsic or extrinsic, present at more variable times,depending on the degree of stenosis. Distal obstructions(ileal and colonic) progress over the first 24–48 h of life,often with more abdominal distension [2]. Midgut volvuluspresents more variably, 50% during the first week and 60%by the end of the first month [2], often with a sudden onsetof bilious vomiting after initially tolerating feeds.

CME activity This article has been selected as the CME activity forthe current month. Please visit the Society for Pediatric Radiology Website at www.pedrad.org on the Education page and follow theinstructions to complete this CME activity.

C. M. Maxfield (*) : B. H. Bartz : J. L. ShafferDepartment of Radiology, Duke University Medical Center,Box 3808, Durham, NC 27710, USAe-mail: charles.maxfield@duke.edu

Pediatr Radiol (2013) 43:318–329DOI 10.1007/s00247-012-2573-1

The bilious or non-bilious character of the vomiting is nota reliable discriminator for the presence of midgut volvulus.Most neonates with bilious emesis do not, in fact, havemidgut volvulus [2]. The presence of bile simply reflectsthat the obstruction is below the ampulla of Vater. Forinstance, the vomiting in 70% of cases of duodenal atresiais bilious [3], and in distal (ileal and colonic) obstructionsbilious vomiting [4] typically develops over hours to days.

Meconium passage can provide additional clues to diag-nosis. Normal newborns pass meconium in the first 24 h oflife. Non-passage of meconium suggests a complete distalobstruction. Infants with Hirschsprung disease or functionalobstructions might pass small amounts of meconium [5].

Similarly, the surgeon’s physical exam is not always areliable discriminator. Even in cases of midgut volvulus, theabdomen is typically soft and non-tender until ischemia devel-ops [2]. These relatively benign symptoms and physical examfindings prior to the onset of catastrophic bowel infarctionjustify a high index of suspicion and explain the centralimportance of the radiologist in managing the vomiting infant.

With near-universal utilization of prenatal US screening,many congenital bowel obstructions are detected in utero[6]. Duodenal atresia, as manifested by a fluid-filled doublebubble plus polyhydramnios, is more reliably detected thanduodenal stenosis, malrotation and distal obstructions [7].Pitfalls in the diagnosis of congenital obstructions are welldocumented and necessitate a post-natal imaging workupbefore surgery is contemplated [6].

Eight patterns on radiographs: definitions

The postnatal imaging workup of the vomiting infant oftenbegins with an abdominal radiograph. We propose thatrecognition of the eight patterns on the frontal supine ab-dominal radiograph shown in Fig. 1 helps narrow the dif-ferential diagnosis and, more important, triage the neonatewith bowel obstruction to the next phase of management—either additional imaging or admission to the medical orsurgical team for treatment.

Significance of the eight patterns and associatedmanagement

Normal (Fig. 1)

A normal abdominal radiograph might seem reassuring inthis setting until one realizes that many cases of midgutvolvulus present with a normal abdominal radiograph [8].If the vomiting is bilious or if there is another reason tosuspect malrotation with midgut volvulus, the workupshould proceed to UGI.

Double bubble (Fig. 1)

The true double bubble—two upper abdominal gas bubbles,one on each side of the midline, and no distal gas—can beconsidered diagnostic of duodenal atresia (Fig. 2) [9]. AUGI is unnecessary, both because this pattern is highlyspecific for duodenal atresia and because contrast (bariumor iodinated) will not characterize the abnormality any betterthan does air.

Because the obstruction caused by duodenal atresia isalready long-standing at birth, the proximal duodenum ismarkedly dilated. This is in contradistinction to midgutvolvulus, an acute obstruction that does not distend theduodenum significantly.

The treatment for duodenal atresia is elective surgicalrepair. The critical question, however, is whether this patternwarrants any concern for midgut volvulus, which wouldnecessitate emergent, rather than elective, surgery. There isconsiderable debate in the literature concerning whethermidgut volvulus needs to be excluded in the setting of anewborn with a double bubble, because of concern thatmidgut volvulus could either produce a double bubble pat-tern [10] or complicate duodenal atresia [11]. Some believesuch concern is unwarranted [12, 13]. What is undeniable isthat if air is not passing distal to the duodenum, neither willcontrast material; a UGI would not rule out malrotation.

The single bubble (Fig. 1)

The true single bubble, with no gas beyond a distendedstomach, is characteristic of gastric (antral or pyloric) atresia[14]. It is important to note, however, that gastric atresia isexceedingly uncommon. More often, this pattern is character-ized by a stomach that is partially decompressed by vomitingor a nasogastric tube, with no gas distally. In such cases, thepattern must be considered incompletely characterized. Fre-quently, a subsequent radiograph will reveal better distension.If not, the pattern might be fully characterized by a portableradiograph obtained following insufflation of the stomachwith approximately 10–20 ml of air through the nasogastrictube. One of three patterns will then become manifest, two ofwhich establish diagnoses and obviate UGI evaluation: (1) asingle bubble with distal gas (discussed below), which shouldprompt an emergent UGI; (2) a true double bubble, diagnosticof duodenal atresia, an indication for elective surgery (Fig. 3);(3) a true single bubble, distended andwithout any distal gas, afinding indicative of a complete gastric outlet obstruction,such as the rare gastric atresia.

Triple bubble (Fig. 1)

If confidently identified, this pattern is indicative ofjejunal atresia [15], with dilation of the stomach,

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duodenum and a jejunal bowel loop just proximal to theatretic segment (Fig. 4). One might argue that the con-fident recognition of this pattern obviates UGI examina-tion, but if all three loops are not distended, this patternis easily confused with other radiographic patterns thatnecessitate UGI to exclude malrotation and midgutvolvulus.

Many surgeons also request a contrast enema to excludean additional colonic atresia (which would change surgery)or meconium ileus (which might obviate surgery). A searchfor additional atresias is reasonable because jejunal atresia isthought to be most often secondary to a vascular insult [16],which can cause more than a single atresia. This is incontradistinction to duodenal atresia, which is thought to

be caused by failure of recanalization [3] and is thereforetypically an isolated atresia.

Single bubble with distal gas (Fig. 1)

Gastric distention out of proportion to non-distendeddistal bowel loops is a very common and typicallybenign finding at any age, including the neonatal peri-od. However, in the setting of bilious vomiting, thispattern must be considered as ominous, as it is welldescribed in association with midgut volvulus [8]. Eventhough midgut volvulus obstructs distal to the gastricoutlet, the obstruction is too acute to dilate the duode-num appreciably, and so the pattern frequently suggests

Fig. 1 The eight radiographic patterns. a Normal. Gas is distributeduniformly throughout non-dilated stomach and bowel. The L1 inter-pedicular distance can be used as an internal standard for the upperlimits of normal for bowel distension. b The double bubble. Thispattern consists of two large rounded lucencies (bubbles) in the upperabdomen, with no distal gas. The left-side bubble is larger and moresuperiorly located. The right-side bubble is slightly smaller but clearlydistended, with its epicenter to the right of the spine. c The singlebubble. Gas is limited to the stomach. The stomach may be distendedor may be decompressed by an enteric tube or vomiting. The key torecognizing this pattern is the absence of any gas distal to the stomach.d Triple bubble. There are three lucencies in the upper abdomen. Thethird bubble is dilated and is often oriented horizontally. There is nogas distal to the three large bubbles, which rarely extend below the

level of the iliac crests. To assign this pattern with confidence, the thirdgas bubble must be contiguous with the more superior bubbles. eSingle bubble with distal gas. Gas is present in the stomach,which is sometimes distended. There is also a small amount ofgas distal to the stomach in a limited number of decompressedbowel loops. f Double bubble with distal gas. This pattern impliesthe presence of gas distal to an otherwise classic double bubblepattern. Distal gas is variable in amount, but distal loops aretypically decompressed. g Diffusely dilated loops. In this pattern,dilated, non-separated bowel loops fill the distended abdomen andextend into the pelvis. h Dilated, scattered bowel loops. Thispattern is characterized by bowel loops that are mildly dilatedbut noncontiguous, featureless in appearance and scattered ran-domly throughout the abdomen and pelvis

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a gastric outlet obstruction. This pattern should triggerUGI examination in this clinical setting.

Double bubble with distal gas (Fig. 1)

Whether one is dealing with a single or double bubble, thepresence of even a tiny amount of distal gas is a criticalfinding that alters the differential diagnosis and necessitiesUGI examination.

In the setting of the double-bubble pattern, the identifi-cation of distal gas (Fig. 5) virtually excludes duodenalatresia (exception being the rare case of the bifid commonbile duct inserting above and below the atretic segment) [17]and widens the differential diagnosis to include midgutvolvulus, along with duodenal stenosis/web.

Ultimately, the vomiting infant with a double bubbleneeds surgery, whether there is distal gas or not. It is theradiologist’s role to assist the surgeon in determining wheth-er the surgery is elective/urgent or emergent. This is deter-mined with the help of UGI.

Diffusely dilated loops (Fig. 1)

It can be impossible to distinguish colon from small bowelin infants, particularly when the bowel is distended. Theappearance of multiple (four or more) dilated (wider thanthe L1 interpedicular distance) loops of bowel throughoutthe abdomen and extending into the pelvis (Fig. 6) is sug-gestive of a low obstruction, typically at the level of theileum or colon. Contrast enema is indicated to evaluate

Fig. 2 Double bubble in a newborn boy intolerant of first feed.Abdominal radiograph demonstrates dilated stomach and duodenumwith no distal gas. Elective surgery was performed without additionalimaging and confirmed duodenal atresia

Fig. 3 Duodenal atresia initiallypresenting as a single bubble. aInitial abdominal radiographobtained after newborn girlvomited first feed demonstratesno air distal to a decompressedstomach. b The subsequentradiograph demonstratesgaseous distension of stomachand distended duodenum, withno distal gas. Notice thenasogastric tube had migratedout of the stomach, allowing thedistension, and demonstration ofthe classic double bubble pattern

Fig. 4 Triple bubble in a newborn girl who had abnormal prenatal US.Initial radiograph demonstrates three rounded upper abdominal lucen-cies and no distal gas. Elective surgery confirmed jejunal atresia

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further. A contrast enema is usually diagnostic and can betherapeutic in the case of meconium ileus.

Radiographs demonstrating this pattern sometimes pro-vide additional clues to a specific diagnosis. For instance, asoap bubble appearance, or absence of air-fluid levels,

suggests meconium ileus [18]. Alternatively, multiple dilat-ed loops with a single disproportionately distended loop ofbowel suggest a distal atresia, often colonic [4]. These cluesdo not obviate a contrast enema, however.

If the infant with this radiographic pattern is very ill withbilious vomiting and peritoneal signs, midgut volvulusshould be considered. In this rare case, the diffuse dilationis not secondary to obstruction but rather to an ileus sec-ondary to ischemia or infarction [19]. It is therefore impor-tant in this setting that a normal contrast enema be followedimmediately by UGI to exclude midgut volvulus.

Dilated, scattered bowel loops (Fig. 1)

Whether encountered in the infant, the older child or the adult,this pattern can be recognized by the experienced radiologistas that of a “sick belly” (Fig. 7). The loops are dilated butnoncontiguous, featureless in appearance, and scattered ran-domly throughout the abdomen and pelvis. This pattern can beseen with distal obstruction (such as complicated meconiumileus), proximal obstruction (midgut volvulus) and in uterobowel perforation. The radiologist should be prepared toperform UGI and contrast enema before surgery.

Five UGI patterns

At least four and as many as six of the eight radiographicpatterns presented should prompt UGI as the next examination

Fig. 5 Double bubble with distal gas. This infant boy had vomitedsince birth, prompting this abdominal radiograph, which demonstratestwo rounded upper abdominal lucencies, with additional gas in non-dilated distal small bowel loops. UGI (not shown) demonstrated apartial duodenal obstruction and normally positioned DJJ. A duodenalweb was found at surgery 1 month later

Fig. 6 Pattern of diffusely dilated loops. This girl, born at 24 weeks’gestational age, had become progressively distended over the first 72 hafter birth. The abdominal radiograph demonstrates diffusely dilatedbowel caused by a functional obstruction of prematurity

Fig. 7 Pattern of dilated scattered bowel loops on abdominal radio-graph obtained in a 1-day-old girl with bilious vomiting. Based onphysical exam findings, the girl was taken directly to surgery, wheremidgut volvulus was found

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in the workup of the vomiting newborn. Clearly, the mostimmediate goal of the UGI examination is to exclude malro-tation with midgut volvulus. The radiologist must be aware ofthe various appearances of malrotation and midgut volvulusbut otherwise should not approach the UGI examination feel-ing the necessity to make a specific diagnosis. Rather, theradiologist’s goal in performance of the UGI in this settingshould be to categorize the vomiting infant into one of threegroups, based on clinical management: (1) those requiringemergent surgery, (2) those requiring elective surgery and(3) those who can be treated non-surgically.

We propose that the recognition of the following fivepatterns on the UGI series narrows the differential diagnosisand allows assignment into one of the three managementpaths (Fig. 8).

Significance of each of the five UGI patterns

Normal (Fig. 8)

A normal UGI excludes structural causes of vomiting. Vom-iting is presumed secondary to any of the large number of

possible non-surgical causes [20], the more common causesbeing gastroesophageal reflux and sepsis.

Malposition of the duodenojejunal junction (Fig. 8)

Given malposition of the duodenojejunal junction (DJJ) in avomiting infant (Fig. 9), one must assume that the vomitingis from intermittent midgut volvulus. While that is notalways the case, and should not necessarily be assumed inthe older child or in the absence of vomiting, this finding isan indication for emergent surgery in the infant with biliousvomiting. We acknowledge that the differentiation betweena malpositioned and a normally positioned DJJ can besubtle, particularly in the setting of ileus or distal bowelobstruction, which can displace the normal DJJ because ofligamentous laxity and result in a false-positive UGI [21].We refer the reader to excellent reviews of this topic [22].

Corkscrew duodenum (Fig. 8)

This pattern (Fig. 10) is diagnostic of midgut volvulusand requires emergent surgery with detorsion and Laddprocedure [23].

Fig. 8 The five patterns on UGI. a Normal. A normal UGI demon-strates prompt gastric emptying, a normal-caliber duodenum, and anormally positioned DJJ. Normally, the duodenum crosses to the left ofthe left vertebral body pedicle and rises to the level of the duodenalbulb. On the lateral view, the duodenum remains retroperitonealthroughout its course. The radiologist should use the lateral view toensure the entire duodenum remains posterior. b Malposition of theDJJ. The duodenum fails to cross the midline and ascend to its normalposition in the left upper quadrant. There is no duodenal dilatation,

narrowing or spiraling. c Corkscrew duodenum. The duodenum spiralsinferiorly without crossing to the left of the bony spine. d Completeduodenal obstruction. Contrast material does not pass beyond the mid-duodenum. Air, however, is seen in more distal bowel loops, ruling outduodenal atresia. e Partial duodenal obstruction with normallypositioned DJJ. This pattern is assigned when a duodenal narrow-ing (and typically, dilation proximally) is seen, but sufficientcontrast material is able to traverse the narrowing to document anormally positioned DJJ

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Complete duodenal obstruction (Fig. 8)

Like the corkscrew duodenum, this pattern indicates theneed for emergent surgery. The appearance is strongly sug-gestive of midgut volvulus, perhaps resulting from a tightertwist than would produce the corkscrew pattern (Fig. 11).Duodenal atresia can be excluded on the basis of air distal tothe duodenum and by the fact that the proximal duodenum isnot markedly dilated.

This pattern requires patience by the radiologist. Time mustbe allowed for contrast agent to pass the mid-duodenum andreach the DJJ. It is only with the failure of contrast agent to passthat this pattern can be assigned. Recognition of this patternnecessitates emergent surgery with the presumptive diagnosisof midgut volvulus.

Partial duodenal obstruction with normally positioned DJJ(Fig. 8)

A persistent duodenal narrowing demonstrated on UGI istypically a surgical lesion in a vomiting infant. The narrow-ing can be extrinsic (Ladd band, annular pancreas) or

Fig. 9 Duodenojejunal malposition in a 3-day-old. UGI, performedafter a single episode of bilious vomiting, demonstrates an abnormalduodenum that fails to cross the midline or ascend to the level of theduodenal bulb. The infant was sent emergently to surgery, wheremalrotation was confirmed. There was no midgut volvulus at the timeof surgery

Fig. 10 Corkscrew duodenum in an infant girl who developed biliousvomiting at 2 days old. UGI demonstrates spiraling of the duodenumover the bony spine. Based on this finding, the girl was sent directly tosurgery, where midgut volvulus was confirmed

Fig. 11 Midgut volvulus in a 4-day-old girl. a Abdominal radiographdemonstrates a mildly distended stomach, with gas seen distally in non-dilated bowel (single bubble with distal gas). b Single image from UGIexamination demonstrates a complete obstruction to contrast agent at thelevel of the proximal duodenum (arrow). The stomach is distended withair. The girl was sent emergently to surgery with the presumptive diag-nosis of midgut volvulus, which was confirmed at surgery

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intrinsic (duodenal web, duodenal stenosis) to the duo-denum [24]. It is not always possible—or necessary—for the UGI to distinguish the cause of the partialobstruction. It is important only that the UGI distin-guish malrotation (with Ladd band or midgut volvulus)from the other causes of partial duodenal obstruction.This is best done by patiently waiting for contrast agentto pass through the stenotic area and document theposition of the DJJ.

If a normally positioned DJJ can be documented (Fig. 12),malrotation is excluded and surgery can be performed elec-tively rather than emergently, at a time when the child can beoptimally prepared for surgery. If a normal DJJ positioncannot be documented, then emergent surgery is indicated.

Four patterns on contrast enema

The radiographic pattern of multiple, diffusely dilated bowelloops in the setting of a newborn who is vomiting and hasnot passed meconium suggests a low bowel obstruction andshould prompt a contrast enema.

The radiologist encounters one of four patterns in perfor-mance of a contrast enema in this setting. Each pattern offersa very limited differential diagnosis, which accounts forabout 98% of cases, and allows appropriate managementdecisions, which might be surgical or nonsurgical (Fig. 13).

Fig. 12 Partial duodenal obstruction with normal DJJ in a 3-week-oldgirl with congenital heart disease had persistent non-bilious vomiting.Single image from UGI, with contrast injected through an enteric tubeplaced in the proximal duodenum, demonstrates a focal narrowing ofthe descending duodenum (arrow). Contrast agent passes distally todocument normal position of the DJJ (arrowhead), allowing electivesurgery. At surgery, an annular pancreas narrowed the descendingduodenum

Fig. 13 The four patterns on contrast enema. a Microcolon. The entirecolon is small in luminal diameter (less than the height of an upper lumbarvertebral body) and nondistensible. b Short microcolon. The colon issmall or “micro” (as defined above) in caliber and its retrograde filling

terminates at some point short of the cecum. c Colonic caliber change.There is a demonstrable transition from small- or normal-caliber colondistally to more distended colon proximally. d Normal. The colon is ofnormal and uniform caliber throughout

Fig. 14 Meconium ileus in an infant with microcolon who presentedwith vomiting, abdominal distension and failure to pass meconium.Note caliber of colon is less than the height of an upper lumbarvertebral body. Contrast material is refluxed from a microcolon intoterminal ileal loops (arrows) outlining multiple filling defects indica-tive of meconium ileus. Obstruction was successfully relieved withcontrast enema. Note also reflux into the appendix (arrowhead)

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Significance of the four contrast enema patterns

Microcolon (Fig. 13)

Normally, the developing fetal colon is stimulated by dis-tension from meconium, sloughed cells and secreted fluid.A high-grade distal ileal obstruction prevents sufficient

bowel contents from reaching the colon, leaving it narrowand non-distensible, i.e. a microcolon [25].

The two most common causes of high-grade distal ilealobstruction leading to this pattern are meconium ileus andileal atresia. Meconium ileus is a bowel obstruction causedby the inspissation of abnormal meconium in the distalileum. Most children with meconium ileus have cystic fi-brosis [26]. Ileal atresia is caused by intrauterine vascularinsult with subsequent reabsorption [16].

Fig. 15 Ileal atresia in an infant with microcolon who, like the infantin Fig. 14, presented with vomiting, abdominal distension and failureto pass meconium. Contrast material is refluxed into decompressedterminal ileum (arrows), which is devoid of meconium filling defects.No contrast material could be refluxed into more proximal ileum. Mid-ileal atresia was confirmed at surgery

Fig. 16 Short microcolon, diagnostic of colonic atresia. Single frontalimage from contrast enema performed in a newborn with progressiveabdominal distension over the first 2 days after birth. Contrast agentopacifies a small-caliber colon but could be refluxed no further prox-imal than splenic flexure (arrow)

Fig. 17 Small left colon syndrome. Image shows colonic caliberchange at the splenic flexure (arrows) characteristic of small left colonsyndrome. Passage of plugs of meconium and abdominal decompres-sion followed within hours of this contrast enema

Fig. 18 Hirschsprung disease. Image shows colonic caliber change inthe proximal sigmoid colon (arrows) in a 5-day-old boy, demonstratedon a lateral view from a contrast enema. Rectal biopsy confirmedHirschsprung disease

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The two can usually be distinguished by the contrastenema. If refluxed contrast reaches ileal loops containingmultiple filling defects, a diagnosis of meconium ileus canbe made (Fig. 14). If no reflux can be achieved beyondsmall-caliber ileum devoid of filling defects, then ileal atre-sia is the presumptive diagnosis (Fig. 15). This distinction isimportant because uncomplicated meconium ileus can betreated with contrast enemas [27] whereas ileal atresiarequires surgery [4].

It should be noted that total colonic Hirschsprungdisease can also produce a microcolon appearance[28]. This, however, is an uncommon presentation ofan uncommon entity.

Short microcolon (Fig. 13)

Recognition of a short or incomplete microcolon (Fig. 16)allows a diagnosis of colonic atresia. The challenge is to be

confident that sufficient back pressure was achieved withthe contrast enema such that the termination of the contrast-filled colon truly represents an atretic segment. Correlationwith the abdominal radiograph often shows a massivelydilated terminal loop just proximal to the atresia. Treatmentis surgical [29].

Colonic caliber change (Fig. 13)

A demonstrable transition from small- or normal-calibercolon distally to more dilated colon proximally narrowsthe differential diagnosis to two entities: Hirschsprung dis-ease and small left colon syndrome (SLCS). Both are func-tional obstructions. Hirschsprung disease results fromabsence of ganglion cells that innervate the colon, and thisdisease must be treated surgically [30]. SLCS is caused by afunctional immaturity of those ganglion cells, and it usuallyresolves after the contrast enema [31].

Fig. 19 The algorithm for the diagnostic imaging workup of the newborn with potential bowel obstruction

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Several imaging features distinguish these two entities.The location of the colonic caliber change is often helpful.SLCS is the presumptive diagnosis when the caliber transi-tion is at the splenic flexure (Fig. 17), assuming that meco-nium evacuation and decompression follow the contrastenema within 24–48 h. Hirschsprung disease is the likelydiagnosis if the transition is elsewhere in the colon (Fig. 18),especially at the classic rectosigmoid level but even at thesplenic flexure in a baby whose abdominal symptoms do notresolve after contrast enema.

Other discriminators have been described [32]. SLCSmight be favored over Hirschsprung disease when the rec-tum is more distensible or the caliber change more abrupt. Ahistory of maternal diabetes or maternal treatment withmagnesium sulfate for eclampsia might also suggest SLCS.Ultimately, questionable cases should undergo rectal biopsyto exclude Hirschsprung disease.

Normal (Fig. 13)

In the setting of a vomiting newborn with a distendedabdomen and an abdominal radiograph suggesting low ob-struction, a normal contrast enema should not necessarily bereassuring. The radiologist’s immediate concern should befor malrotation with midgut volvulus. It is very uncommonfor midgut volvulus to produce a radiographic pattern sug-gesting low obstruction, but it is well described [33] andshould be excluded with a UGI before the baby leaves thefluoroscopy suite.

If midgut volvulus is excluded with the UGI, thenHirschsprung disease should be reconsidered. The contrastenema is interpreted as normal in about half of cases of totalcolonic Hirschsprung disease [34], but this is a rare entity.More frequently, a subtle caliber change is not appreciatedin the case of classic low-segment Hirschsprung disease. Ithas been reported that Hirschsprung disease is missed on theinitial contrast enema in 25% of cases [35]. Considerationshould therefore be given to a rectal biopsy in this setting.

This differential diagnosis includes a functional obstruc-tion causing colonic dysmotility, often resulting from im-maturity of the neuronal apparatus. This is most often seenin extremely premature infants [36].

Conclusion

We have proposed a simplified, pattern-based approach toserve as a framework for the practicing radiologist in thecare and management of bowel obstruction in the neonate(Fig. 19). This is not presented as an all-inclusive review ofthe causes of newborn bowel obstruction, nor is it meant toimply that the recognition of patterns and assignment ofdiagnoses is always straightforward. But by becoming

familiar with the spectrum of imaging findings and commondiagnoses and by using a systematic approach to imagingstrategies, the radiologist can work with his or her surgicaland neonatology colleagues to provide the best care to theneonate with bowel obstruction.

Conflicts of interest None.

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