The American College of Radiology (ACR) has proposed guidelines for the testing of infants with vomiting. The ACR appropriateness criteria have specifically been developed to guide the clinician in their decision-making process in terms of imaging. In this article, we provide an organized, symptom-based approach, derived from the ACR criteria, to help guide clinicians in choosing an imaging approach to the infant with vomiting.1
Vomiting in the pediatric population, especially in infants, frequently poses a diagnostic dilemma. This, in turn, can lead to anxiety for both the family and the health care provider. There are numerous underlying causes of emesis in infancy including anatomic abnormalities, inborn errors of metabolism, toxins, or neurologic causes; although emesis is often a self-limited process, several etiologies can be potentially life-threatening.2 Important clinical historical points to elicit include the vomiting timeline and frequency, forcefulness, and presence or absence of bile. These characteristics will help determine the level of concern and guide the physician in recommending the appropriate next step. Below, we describe an organized, diagnosis-based approach to evaluation of the infant with vomiting, with particular attention to diagnostic imaging (Figure 1).
Flowchart showing recommended initial imaging evaluation of infants with vomiting based on age, suspected diagnosis, and bilious or nonbilious emesis. GI, gastrointestinal.
Gastroesophageal Reflux Disease
Gastroesophageal reflux (GER) is defined as the passage of gastric contents into the esophagus with or without regurgitation and/or vomiting; whereas gastroesophageal reflux disease (GERD) is defined as the presence of discomfort, poor weight gain, and wheezing related to GER. However, determining discomfort in infants and young children can be difficult and thus in reality the terms are typically used interchangeably.3
Reflux of gastric contents into the esophagus occurs due to failure of the lower esophageal sphincter's ability to maintain tone, typically due to transient relaxation of the muscle. These events may be due to a wide variety of causes including normal infant development, neurologic disorders, and anatomic abnormalities.4 Although regurgitation or vomiting is the most obvious sign that GER has occurred, it can frequently be seen with irritability, poor feeding, and weight loss.3 Thus, it can be difficult to estimate the actual prevalence of the disease. This is further compounded by the fact that no gold standard exists for the diagnosis of GERD. GER is commonly present in infants who are asymptomatic and is almost universally present in infants age 3 months, decreasing to less than one-half by age 6 months, and resolving in most by age 1 year.4
Most infants with suspected GERD can be diagnosed, and presumptively treated, based on history and physical examination alone. This is because most reflux in infants is benign and will resolve over time. Imaging should be reserved for those with signs or symptoms that suggest the possibility of an alternative diagnosis. When symptoms arise after age 6 months, or persist beyond age 12 months, consideration should be given to other diagnoses and thus imaging may be appropriate. Imaging may be of benefit as well in infants and children with GERD in whom complications of the disease (eg, stricture formation) is suspected, in those with severe symptoms, and in cases that fail to respond to 4 to 8 weeks of optimal therapy.3
The recently updated Pediatric Gastroesophageal Reflux Clinical Practice Guidelines state that “there is insufficient evidence to support the use of a barium contrast study for the primary diagnosis of GERD in infants and children.”3 Nonetheless, barium contrast study using fluoroscopy, the upper gastrointestinal (UGI) study, is one of the most commonly performed diagnostic imaging tests in the assessment of infant reflux. UGI may be useful in excluding other causes of vomiting, as detailed later in this article. Additionally, UGI may provide useful information on the presence of anatomic abnormalities that predispose to GER (ie, hiatal hernia and delayed gastric emptying) and assess esophageal motility, and it also has a well-established role in patients who have undergone anti-reflux surgery to assess for complications.3
Scintigraphy, using ingested technetium-99m sulfur colloid, has wide-ranging detection rates for GER. This is in part due to the fact that there are no widely accepted standardized protocols for performing the examination.3,5,6 Like pH probe monitoring and other imaging techniques, however, reflux is frequently demonstrated in asymptomatic patients during scintigraphy.7 Scintigraphy may show delayed gastric emptying, which can contribute to GER and may show episodes of pulmonary aspiration. Nonetheless, current recommendations do not support its routine use for diagnosing uncomplicated GERD in infants and children.1,3
Hypertrophic Pyloric Stenosis
The etiology of hypertrophic pyloric stenosis (HPS) likely results from a combination of genetic predisposition and an acquired disorder. It is not present at birth in infants documented to have the disorder later in life.8 Nonbilious emesis initially develops at 2 to 12 weeks corrected gestational age. The entity is approximately 5 times more common in boys than in girls and more common in infants whose biological parent or twin sibling was affected. Exclusive breast-feeding in the first several months of life is protective, with a greater than 4-fold increase of risk for developing HPS in bottle-fed infants.9 Exposure to macrolide antibiotics, especially erythromycin, is a well-known risk factor.9
Early in the disease process most infants are well-appearing with normal electrolytes. Over time, as the pylorus further increases in thickness and length, there is increasing feeding intolerance with development of weight loss, dehydration, and ultimately death if untreated. The prototypical laboratory findings of hypokalemic, hypochloremic acidosis typically do not present until later in the course of the illness. The classic findings of new onset, nonbilious, projectile vomiting in the appropriate-aged infant that has a palpable “olive” or pyloric “tumor” is felt by some to be adequate proof alone to warrant surgical intervention. The ability of surgeons to palpate the mass, however, appears to have decreased over time,10 meaning imaging plays an ever-increasing role in diagnosis.
Plain radiography plays a limited role in making the diagnosis as the findings are nonspecific and may be absent. Gastric distention with peristaltic waves (sometimes referred to as the “caterpillar sign”) and paucity of gas distally have been described. UGI was once widely used with numerous indicative findings detailed in the literature.11 However, UGI relies on secondary findings as pyloric muscle hypertrophy affects the passage of barium through the channel and cannot itself directly visualize the underlying abnormality.
With continued improvements in ultrasound technology, sonography has become the preferred method of imaging diagnosis.1,10,12 Ultrasound is extremely accurate at diagnosing or excluding HPS12,13 and has the benefits of being noninvasive and does not expose the child to ionizing radiation. Most research suggests that a pyloric muscle thickness ≥3 mm is highly indicative of HPS (Figure 2) whereas pyloric channel length is a less sensitive and specific method of diagnosis.11–13 There can be overlap between the appearance of HPS and pylorospasm on ultrasound. Direct visualization of gastric contents passing through the pyloric channel and into the proximal duodenum is the most accurate way of differentiating the two entities. For this reason, reexamining the pylorus with ultrasound, when measurements are borderline or there is clinical uncertainty, holds benefit. The superior ability of ultrasound, compared to UGI, in differentiating pylorospasm from pyloric stenosis again makes ultrasound the study of choice.13 Of note, ultrasound assessment of the pylorus is fairly operator dependent. For this reason, UGI may still hold some relevance if there is no access to sonographers who are well trained and experienced in performing the procedure.10–13
Gray-scale ultrasound image of the thickened pylorus in long axis view. The thickness of the nearfield muscle can be seen to be greater than 3 mm. Pyloric channel length (almost 20 mm) is abnormal as well although less clear cutoffs for normal exist in this dimension. Redundant mucosa (red arrow) can be seen lining the channel that accounts for typical findings described on upper gastrointestinal study. During real-time imaging, no fluid was seen to pass from the dilated stomach into the proximal duodenum.
The incidence of intestinal atresia has been reported to range from 1.3 to 3.5 per 10,000 live births. Duodenal atresia is the most common of the small bowel atresias and accounts for up to 60% of this category. Babies born with a proximal intestinal atresia, but beyond the ligament of Treitz, likely will present with bilious emesis within the first 24 to 48 hours after birth. However, up to 15% of neonates will have nonbilious emesis. Thus, atresias, whether proximal or distal present with similar symptoms, so distinguishing proximal from distal obstruction requires imaging. Infants will typically develop abdominal distention that warrants radiologic evaluation. The first and best initial imaging procedure is a supine plain radiograph of the abdomen. This allows for evaluation of the extent of distal bowel gas. There are specific patterns that indicate duodenal and proximal jejunal atresia and less specific patterns for more distal atresia.14–16
There are at least three classic imaging appearances on plain radiograph:
- Duodenal atresia—classic “double bubble” appearance of a large gas-filled gastric bubble and an enlarged, dilated, gas-filled proximal duodenum (Figure 3). There is usually an absence of distal gas
- Jejunal atresia—Classic “triple bubble” indicating gaseous distended gastric, duodenal, and proximal jejunal lumina with absence of distal gas
- Distal bowel (ileal or colonic) atresia—Classic appearance of multiple dilated gas-filled bowel loops with absence of gas in the colon or rectum. Within the first 24 hours, this may be difficult to distinguish from slow motility or functional immaturity of the colon
The algorithmic approach to bilious emesis as outlined in the ACR Appropriateness Criteria suggests that if suspecting a proximal atresia in the setting of classic radiographic findings, there may not be any further need for additional imaging. However, in nonclassic double-bubble appearance of duodenal atresia with the presence of distal gas, a malrotation with midgut volvulus may need to be excluded. This requires a fluoroscopic UGI. The urgency of surgical intervention for midgut volvulus requires that the UGI be performed emergently. Other entities that may cause the appearance of double bubble with distal gas are rare.1
Malrotation with Midgut Volvulus
When an infant presents with bilious emesis beyond the first 48 hours, the most emergent diagnosis is malrotation with midgut volvulus. Malrotation results from embryonic failure of the normal rotation of the mesentery and thus, the normal fixation of the ligament of Treitz. Patients may remain asymptomatic; however, they remain susceptible to volvulus, which is a surgical emergency. Symptomatic malrotation of the midgut in neonates is seen in approximately 1 in 6,000 live births. Because of the lack of normal rotation, there is often reversal of the normal orientation of the superior mesenteric artery and vein. This can be easily visualized with ultrasound; however, the technique requires expertise on the part of the sonographer and the radiologist. UGI remains the gold standard to evaluate for malrotation with or without midgut volvulus.
Normal position of the duodenal C-loop beyond the duodenal bulb is retroperitoneal. The third portion of the duodenum crosses midline and the fourth portion ascends such that the duodenal-jejunal junction is to the left of the vertebral body pedicle at the same level as the duodenal bulb (Figure 4A). This very specific pattern seen on UGI allows the examination to usually provide definitive diagnosis in an urgent manner. In malrotation, the position of the ligament of Treitz will be below the expected level or to the right of midline. When there is also volvulus, the duodenum will either be obstructed or may be seen spiraling downward as it twists around the mesenteric artery and vein17,18 (Figure 4B).
Spot images from an upper gastrointestinal series. (A) Normal duodenal C-loop. Contrast exits the stomach, descends, and crosses the midline and the duodenal-jejunal junction and is fixed to the left of the left pedicle at the same level as the duodenal bulb. (B) Malrotation with midgut volvulus. Supine projection showing contrast-filled stomach and contrast exiting the stomach to the duodenum but then descending in a spiral fashion to the right, never reaching the midline.
A web is a thin membrane within the lumen, usually near the ampulla of Vater. A small aperture or fenestra in this diaphragm may allow passage of duodenal contents distally. Because of this small opening, there is frequently a delay in diagnosis from days to months after birth. Clinically, these patients present with vomiting after feeding, usually bilious, and epigastric pain. The abdominal radiograph may show an atypical pattern with dilated duodenum but with distal gas.19
The pancreas develops from one dorsal and two ventral buds from the second portion of the embryonic duodenum. This outpouching goes on to form the pancreas and hepatobiliary system. Annular pancreas is a rare anomaly of embryonic development resulting in extrinsic compression on the duodenum often with delayed presentation, when not associated with an atresia. However, 28.5% of cases are associated with intrinsic duodenal stenosis.20,21 It occurs in up to 1 in 12,000 to 15,000 live births and is also commonly associated with malrotation, prematurity, or infants who are small for gestational age.20,21
Although cystic fibrosis can result in multisystem effects, the gastrointestinal tract is often the earliest affected clinically, with meconium ileus occurring in approximately 20%.22 Due to altered electrolyte transportation meconium is abnormally thick and desiccated, becoming trapped within the bowel lumen. Clinically, infants may present with progressive abdominal distension, emesis, or failure to pass meconium. Of note, passage of meconium does not exclude the diagnosis.23
Plain radiographs may demonstrate abdominal calcifications, present in up to 26% of cases, although only visible in approximately one-half of those. Radiographs may additionally demonstrate nonspecific dilation of the proximal bowel and absence of rectal gas. Fluoroscopic, water-soluble contrast enema is the first choice in nonoperative management as it can be both diagnostic and therapeutic. Enema may show a micro-colon from disuse and a dilated distal ilueum with filling defects (Figure 5). For a successful enema and relief of obstruction, there must be reflux of contrast into the terminal ileum.22
Fluoroscopic frontal spot image of the colon and distal ileum after retrograde instillation of water-soluble contrast. Demonstrated is a diffusely small colon, termed a micro-colon, with a dilated distal ileum (red arrow) containing obstructing filling defects (inspissated meconium). Contrast was unable to be passed beyond this obstruction.
Functional Immaturity of the Colon
Functional immaturity of the colon may be considered a blanket term encompassing several entities, notably, meconium plug syndrome and small left colon syndrome. There is a positive association between functional colonic immaturity and infants and children born to mothers with diabetes or mothers receiving magnesium sulfate during pregnancy. Infants often present with failure to pass meconium in the first 48 hours of postnatal life, abdominal distension, or occasionally emesis.24,25
Small left colon syndrome may be related to immature ganglion cells in the colon, and is usually a benign and transient disorder.25 Contrast enema typically shows a mildly distended right and transverse colon transitioning to a smaller diameter colon at the splenic flexure and normal rectum.24 Prognosis is good and infants tend to progress to normal bowel motility.26
Meconium plug syndrome is a transient, distal obstruction due to thick meconium but is rarely unrelated to cystic fibrosis. Contrast enema typically demonstrates the same findings as small left colon. A variable amount of filling defects may be visualized, representing the meconium plugs (Figure 6).25 Enemas are often diagnostic and therapeutic, stimulating the passage of meconium and relieving obstruction.25,26 If obstructive symptoms persist, further testing should be performed, considering the possibility of meconium ileus or Hirschsprung's disease.
Fluoroscopic frontal spot image of the colon after retrograde instillation of water-soluble contrast. Demonstrated is a mildly distended right and transverse colon transitioning to a smaller diameter colon at the splenic flexure and normal rectum. Filling defects (yellow arrows) can be seen in the distal descending colon and sigmoid corresponding to meconium plugs. Gas partly fills the transverse colon and cecum from incomplete filling with contrast and should not be mistaken for meconium plug. After the examination, the infant passed numerous thickened meconium plugs and symptoms quickly resolved.
Hirschsprung's disease, or congenital megacolon, was first described in the late 1800s and much later discovered to be caused by abnormal or absent ganglia in the bowel wall musculature.27,28 The prevalence of disease is approximately 1 in 5,000 with a 4:1 male predominance.28,29 The extent of disease is variable, with short-segment aganglionosis being the most common (90% of cases) with a transition point in the rectosigmoid colon (Figure 7). Long-segment disease involves more proximal colon and even possibly small bowel.28 Infants will often present in the first 2 to 3 weeks of life with constipation, abdominal distension, or emesis.27 If abdominal radiography is performed, it may demonstrate dilated large bowel, which is difficult to distinguish from small bowel in infants.30 Although rectal biopsy is the gold standard for diagnosis, a noninvasive fluoroscopic contrast enema performed during initial evaluation may elucidate a transition point to guide the surgeon.28,31
Fluoroscopic lateral spot image of the colon after retrograde instillation of water-soluble contrast. Demonstrated is a short segment of narrowed rectum with an apparent transition zone (red arrow) to the mildly dilated sigmoid and more proximal colon. Subsequent rectal suction biopsy confirmed short-segment Hirschsprung's disease.
There are numerous causes of emesis in the pediatric population, ranging from benign to life-threatening, requiring timely diagnosis to avoid morbidity and potential mortality. Testing should always begin with a thorough history and physical examination, which may guide referring clinicians to understand the appropriate first steps in imaging.
- Raske ME, Dempsey ME, Dillman JR, et al. ACR Appropriateness Criteria vomiting in infants up to 3 months of age. J Am Coll Radiol. 2015;12(9):915–922. doi:10.1016/j.jacr.2015.05.023 [CrossRef]. PMID:26254159
- Shields TM, Lightdale JR. Vomiting in children. Pediatr Rev. 2018;39(7):342–358. doi:10.1542/pir.2017-0053 [CrossRef] PMID:29967079
- Rosen R, Vandenplas Y, Singendonk M, et al. Pediatric Gastroesophageal Reflux Clinical Practice Guidelines: Joint Recommendations of the North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition and the European Society for Pediatric Gastroenterology, Hepatology, and Nutrition. J Pediatr Gastroenterol Nutr. 2018;66(3):516–554. doi:10.1097/MPG.0000000000001889 [CrossRef] PMID:29470322
- Hoffman I, De Greef T, Haesendonck N, Tack J. Esophageal motility in children with suspected gastroesophageal reflux disease. J Pediatr Gastroenterol Nutr. 2010;50(6):601–608. doi:10.1097/MPG.0b013e3181c1f596 [CrossRef] PMID:20400913
- Othman S. Gastroesophageal reflux studies using milk in infants and children—the need for multiple views. Nucl Med Commun. 2011;32(10):967–971. doi:10.1097/MNM.0b013e32834a0b0d [CrossRef] PMID:21849926
- Villanueva-Meyer J, Swischuk LE, Cesani F, Ali SA, Briscoe E. Pediatric gastric emptying: value of right lateral and upright positioning. J Nucl Med. 1996;37(8):1356–1358. PMID:8708772
- Morigeri C, Bhattacharya A, Mukhopadhyay K, Narang A, Mittal BR. Radionuclide scintigraphy in the evaluation of gastroesophageal reflux in symptomatic and asymptomatic pre-term infants. Eur J Nucl Med Mol Imaging. 2008;35(9):1659–1665. doi:10.1007/s00259-008-0752-y [CrossRef] PMID:18483812
- Rollins MD, Shields MD, Quinn RJ, Wooldridge MA. Pyloric stenosis: congenital or acquired?Arch Dis Child. 1989;64(1):138–139. doi:10.1136/adc.64.1.138 [CrossRef] PMID:2923464
- MacMahon B. The continuing enigma of pyloric stenosis of infancy: a review. Epidemiology. 2006;17(2):195–201. doi:10.1097/01.ede.0000192032.83843.c9 [CrossRef] PMID:16477261
- Hernanz-Schulman M. Pyloric stenosis: role of imaging. Pediatr Radiol. 2009;39(suppl 2):S134–S139. doi:10.1007/s00247-008-1106-4 [CrossRef] PMID:19308372
- Haller JO, Cohen HL. Hypertrophic pyloric stenosis: diagnosis using US. Radiology. 1986;161(2):335–339. doi:10.1148/radiology.161.2.3532185 [CrossRef] PMID:3532185
- Forster N, Haddad RL, Choroomi S, Dilley AV, Pereira J. Use of ultrasound in 187 infants with suspected infantile hypertrophic pyloric stenosis. Australas Radiol. 2007;51(6):560–563. doi:10.1111/j.1440-1673.2007.01872.x [CrossRef] PMID:17958692
- Hernanz-Schulman M, Sells LL, Ambrosino MM, Heller RM, Stein SM, Neblett WW III, . Hypertrophic pyloric stenosis in the infant without a palpable olive: accuracy of sonographic diagnosis. Radiology. 1994;193(3):771–776. doi:10.1148/radiology.193.3.7972822 [CrossRef] PMID:7972822
- Gilbertson-Dahdal DL, Dutta S, Varich LJ, Barth RA. Neonatal malrotation with midgut volvulus mimicking duodenal atresia. AJR Am J Roentgenol. 2009;192(5):1269–1271. doi:10.2214/AJR.08.2132 [CrossRef] PMID:19380551
- Hernanz-Schulman M. Imaging of neonatal gastrointestinal obstruction. Radiol Clin North Am. 1999;37(6):1163–1186, vi–vii. doi:10.1016/S0033-8389(05)70255-4 [CrossRef]
- Lilien LD, Srinivasan G, Pyati SP, Yeh TF, Pildes RS. Green vomiting in the first 72 hours in normal infants. Am J Dis Child. 1986;140(7):662–664. doi:10.1001/archpedi.1986.02140210060026 [CrossRef] PMID:3717104
- Applegate KE. Evidence-based diagnosis of malrotation and volvulus. Pediatr Radiol. 2009;39(suppl 2):S161–S163. doi:10.1007/s00247-009-1177-x [CrossRef] PMID:19308378
- Sizemore AW, Rabbani KZ, Ladd A, Applegate KE. Diagnostic performance of the upper gastrointestinal series in the evaluation of children with clinically suspected malrotation. Pediatr Radiol. 2008;38(5):518–528. doi:10.1007/s00247-008-0762-8 [CrossRef] PMID:18265969
- Sarin YK, Sharma A, Sinha S, Deshpande VP. Duodenal webs: an experience with 18 patients. J Neonatal Surg. 2012;1(2):20. PMID:26023379
- Sencan A, Mir E, Günsar C, Akcora B. Symptomatic annular pancreas in newborns. Med Sci Monit. 2002;8(6):CR434–CR437. PMID:12070435
- Ravitch MM. The pancreas in infants and children. Surg Clin North Am. 1975;55(2):377–385. doi:10.1016/S0039-6109(16)40587-6 [CrossRef] PMID:165579
- Carlyle BE, Borowitz DS, Glick PL. A review of pathophysiology and management of fetuses and neonates with meconium ileus for the pediatric surgeon. J Pediatr Surg. 2012;47(4):772–781. doi:10.1016/j.jpedsurg.2012.02.019 [CrossRef] PMID:22498395
- Herson RE. Meconium ileus. Radiology. 1957;68(4):568–571. doi:10.1148/68.4.568 [CrossRef] PMID:13432186
- Berrocal T, Lamas M, Gutieérrez J, Torres I, Prieto C, del Hoyo ML. Congenital anomalies of the small intestine, colon, and rectum. Radiographics. 1999;19(5):1219–1236. doi:10.1148/radiographics.19.5.g99se041219 [CrossRef] PMID:10489177
- Vinocur DN, Lee EY, Eisenberg RL. Neonatal intestinal obstruction. AJR Am J Roentgenol. 2012;198(1):W1–10. doi:10.2214/AJR.11.6931 [CrossRef] PMID:22194504
- Loening-Baucke V, Kimura K. Failure to pass meconium: diagnosing neonatal intestinal obstruction. Am Fam Physician. 1999;60(7):2043–2050.
- Keefer GP, Mokrohisky JF. Congenital megacolon (Hirschsprung's disease). Radiology. 1954;63(2):157–175. doi:10.1148/63.2.157 [CrossRef] PMID:13194867
- Sajjad N, Hilal K, Khandwala K, Arshad M, Uddin N. Usefulness of delayed films of contrast enema for detecting Hirschsprung's disease. Cureus. 2019;11(12):e6339. doi:10.7759/cureus.6339 [CrossRef] PMID:31938627
- Badner JA, Sieber WK, Garver KL, Chakravarti A. A genetic study of Hirschsprung disease. Am J Hum Genet. 1990;46(3):568–580. PMID:2309705
- Berman CZ. Roentgenographic manifestations of congenital megacolon (Hirschsprung's disease) in early infancy. Pediatrics. 1956;18(2):227–238. PMID:13349336
- O'Donovan AN, Habra G, Somers S, Malone DE, Rees A, Winthrop AL. Diagnosis of Hirschsprung's disease. AJR Am J Roentgenol. 1996;167(2):517–520. doi:10.2214/ajr.167.2.8686640 [CrossRef] PMID:8686640