Gastroesophageal Reflux Disease in Infants

GERD is a very common and usually benign physiological event in infants.

A diagnosis of GERD is considered when gastroesophageal reflux is associated with presentations such as excessive irritability and crying, failure to thrive, feed refusal, apnea, and aspiration pneumonia.

Many of these symptoms are not specific to GERD and can be due to other causes, such as feed intolerance, colic, constipation, or infection

Gastroesophageal reflux disease (GERD) can be defined as chronic symptoms or mucosal damage secondary to abnormal reflux of gastric contents into the esophagus.

Different methods have been introduced for diagnosis of the disease during childhood including barium meal, PH monitoring, manometry, and sonography.

Sonographic detection of GERD is mainly based on the detection of the returning gastric fluid to esophagus, so the Doppler study has increased the sensitivity of the mentioned method.

Although, the pH monitoring, manometry and gastroesophageal junction scintigraphy are more sensitive than sonography but could not provide morphologic data of the lower esophageal sphincter and esophagous .

Sonography as a non-invasive, cheap and readily available method could be described informative, accurate and sensitive technique in the diagnosis of GER in infants and children

that provides morphologic and functional information

, the patients were awake while they were relaxed in rest position. After using sufficient fluid according to patient’s age, such as milk or water, patients were studied in supine position using a color ultrasound machine with a 7.5 MHz linear array transducer with a color flow-mapping capability

.The stomach and lower segment of esophagus were studied.

Sonographic GERD diagnosis was made by backward movement of gastric content into the esophagus and the visualization of the clearance of refluxate material.

The GERD was divided into three groups based on the number of refluxes in 10 min time interval.

The groups include: (1) mild, less than three refluxes in 10 min; (2) moderate, four to six refluxes in 10 min; (3) severe, more than six refluxes in 10 min.

Other sonographic findings have been proposed for GERD diagnosis that includes measurement of abdominal esophagus length(subdiaphragmatic esophge) and assessment of GE junction . (It has been postulated that abdominal esophagus length is directly associated with the capacity for reflux prevention ).

some other anatomical assessments such as esophageal diameter;wall thikness; mucosal thikness; hiatal diameter;greater wall thikness,

In the sonographic evaluation, the mean esophageal diameter was 12±2.7 mm (6-17) in patients and 10.1±2.4 in controls (p<0.0001).

The mean sub diaphragmatic esophageal length was 15.9±6.3 mm in patients and 22.2±9.9 in controls (p<0.0001).

Other sonographic measurements of patients were statistically greater than controls

gastric wall thickness that was statistically equal in two groups

Esophageal length was measured carefully from the point at which it penetrated the diaphragm to the base of the triangular pad of gastric folds at the anterior surface of the fundus of the stomach.

Triangular pad, representing the radiation away from the cardiac orifice, was considered the point of entrance of esophagus into the stomach.

Measurement of the intra-abdominal portion of esophagus using left liver lobe as an ultrasonic window

Infantile Hypertrophic Pyloric Stenosis

The incidence of IHPS is approximately two to five per 1,000 births per year in most white populations,

IHPS is less common in India and among black and Asian populations, with a frequency that is one-third to one-fifth that in the white population .

The male-to-female ratio is approximately 4:1, with reported ratios ranging from 2.5:1 to 5.5:1 .

There is a familial link, . Male and female children of affected mothers carry a

20% and 7% risk of developing the condition, respectively, whereas male and female children of affected fathers carry a risk of 5% and 2.5%, respectively.

The incisura angularis divides the stomach into a body to the left and a pyloric portion to the right. The sulcus intermedius further divides the pyloric portion of the stomach:

the pyloric vestibule to the left, denoted by an outward convexity of the greater curvature, and the pyloric antrum or pyloric canal to the right .

The pyloric antrum is approximately 2.5 cm in length and terminates at the pyloric orifice and pyloric ring or sphincter.

The pyloric orifice marks the opening of the stomach into the duodenum .

ETIOLOGIC CONSIDERATIONS, Palmer suggested a link to thymic hyperplasia ,

which he subsequently recanted. the muscular layer is deficient in the quantity

of nerve terminals that leads to failure of relaxation of the pyloric muscle; increased synthesis of growth factors; and subsequent hypertrophy, hyperplasia, and obstruction .

An increased incidence of IHPS in neonates receiving erythromycin has been reported . The reason for this remains unclear

The mucosa filling the canal typically equals or exceeds the muscle thickness but at times may far exceed it . In histologic descriptions of the mucosa, submucosal edema and cellular infiltrates have been reported.

Foveolar hyperplasia after administration of prostaglandins has been implicated in the development of this condition .

The hypergastrinemia hypothesis proposes that an inherited increase in the number of parietal cells initiates a cycle of increased acid production, repeated pyloric contraction, and delayed gastric emptying .

Development of IHPS after initiation of feedings, increased postprandial gastrin levels, markedly increased gastric acid secretion in infants with IHPS,

CLINICAL PRESENTATION The clinical presentation varies with the length of symptoms. recent onset of forceful nonbilious vomiting, typically

described as “projectile.” the frequency of vomiting increases to follow all feeding.

Starvation can exacerbate diminished hepatic glucoronyl transferase activity, and indirect hyperbilirubinemia may be seen in 1%–2% of affected infants.

Vomiting of gastric contents leads to depletion of sodium, potassium, and hydrochloric acid, which results in hypochloremic alkalosis and sodium and potassium deficits. paradoxical aciduria.

Weight loss may be extensive, the distended stomach may be identifiable in the hypochondrium,

with active peristaltic activity visible through the thin abdominal wall

IHPS Anatomy . This channel is characterized by thickened muscle, which changes

rather abruptly from the normal 1-mm thickness in the distensible portion of the antrum to 3 mm or more in the hypertrophied canal

The muscle thickness may be greater than 6 mm, with larger usually being present in larger and older infants .

The diameter of the canal lumen is variable, ranging between 3 and 6 mm; the canal lumen is filled with compressed and redundant mucosa, presenting an obstructed passage to the gastric contents .

The rigid antropyloric canal is unable to accommodate the redundant mucosa, which protrudes into the gastric antrum. When viewed endoscopically, the mucosa protrudes as a nipplelike

Technique and Imaging Findings

UGI StudiesUGI is performed with the infant in the right

anterior oblique position, to facilitate gastric emptying.

The examination can be successfully accomplished with the child drinking from a bottle; these infants are usually very hungry and will drink with little effort. Insertion of a nasogastric tube is not necessary; however, emptying of an overdistended stomach may help to prevent vomiting, if needed.

Abnormal study:

Fluoroscopic observations include vigorous active peristalsis resembling a caterpillar and coming to an abrupt stop at the pyloric antrum, outlining the external thickened muscle as an extrinsic impression, termed the shoulder sign.

there is failure of relaxation of the prepyloric antrum, typically described as “elongation” of the pyloric canal. barium may be transiently trapped between the peristaltic wave and the muscle, and this is termed the tit sign. Eventual success of gastric peristaltic activity will propel contrast

material through the pyloric mucosal interstices, with the appearance as either the string sign or the double-track sign, although at times more than one layer of contrast material may be appreciated in the mucosal filling defect

Contrast material courses through the mucosal interstices of the canal, forming the double-track sign (large arrowheads), with an additional central channel along the distal portion (small arrowhead). Mass impression on the gastric antrum (arrow), best seen during peristaltic activity, is termed the shoulder sign.

. Top left: Image from upper gastrointestinal tract examination (UGI) shows a markedly widened pyloric channel with intervening mucosal filling defect (arrows). Top right: Sonogram in same patient shows hypertrophied mucosa (straight arrows) measuring approximately 8 mm protruding into the gastric antrum (curved arrow). Arrowheads = thickened pyloric muscle.

sonographyThe examination should be performed with high-

frequency transducers. We use a linear transducer

We begin by placing the transducer transversely below the xiphoid process, identifying the esophagus as it enters the abdomen anterior to the aorta at the diaphragmatic crus. Caudal movement of the transducer allows identification of the gastric fundus, and continued caudal motion subsequently allows definition of the gastric body, antrum, and duodenal cap, regardless of displacement or position and whether or not IHPS is present

Longitudinal sonogram of the normal stomach, pyloric ring (cursors), and duodenum outlining the open pyloric ring in

an infant without IHPS. distance between cursors is 3.1.

the normal pyloric ring (arrows) and the proximity of the duodenal cap (D) to the relaxed antropyloric portion of the stomach, bridged by the pyloric ring.

If the stomach is filled with gas: , placement of the patient in a right anterior oblique position

permits fluid to gravitate to the antrum for adequate evaluation.

In such cases, if the patient is slowly moved toward the

supine and even the left posterior oblique position, the pylorus will be able to rise anteriorly for optimal examination

Use of these simple gravity-aided maneuvers( eliminates the need for placement of nasogastric tubes to evacuate the stomach) thus markedly shortening the duration of the examination.

In patients with IHPS: the intervening mucosa is crowded, thickened to a variable degree,

and protrudes into the distended portion of the antrum (the nipple sign;) and can be seen filling the lumen on transverse sections .

The length of the hypertrophied canal is variable and may range

from as little as 14 mm to more than 20 mm.

The numeric value for the lower limit of muscle thickness has varied in reports in the literature, ranging between 3.0 and 4.5 mm.

the actual numeric value is less important than the overall morphology of the canal and the real-time observations.

The antropyloric canal, as part of the stomach, is a dynamic structure, and it is seen undergoing changes in both length and width during many examinations .

Longitudinal sonogram shows anterior thickened muscle (cursors). Double layer of crowded and redundant mucosa fills the channel and protrudes into fluid-filled antrum (arrow). D = fluid-filled duodenal

Cross-sectional sonogram shows circumferential muscular thickening (cursors) surrounding the central channel and filled with mucosa

. Note the shorter canal in image on left and subsequent elongation coincident with peristaltic activity in image on right. There is failure of relaxation of the pyloric channel, and persistent obliteration of the lumen. Also note that on the left image, the gastric contents and pyloric mucosa have similar echogenicity, falsely suggestive of unimpeded passage of gastric contents

. Left: On image obtained off center, the maximum width of the canal lumen and intervening mucosa (arrowheads) cannot be identified. Right: Image obtained through the central portion of the canal outlines full diameter of channel (arrowheads).

. Peristaltic changes in antropyloric anatomy on normal sonographic study. Left: Antropyloric channel is closed during peristaltic activity. Right: Distal antrum (A) is fully relaxed. Arrows = pyloric ring, D = duodenal cap.

Sonogram of normal pylorus before (left) and after (right) ingestion of a small amount of fluid

Patients in whom the muscle is 2–3 mm thick and does not relax throughout the examination warrant careful monitoring and follow-up examination, particularly if they are at the younger end of the age spectrum at the time of presentation .

UGI in these patients will not help clarify the diagnosis.

VOMITING INFANT: DIFFERENTIAL DIAGNOSIS AND IMAGING ALGORITHM

Patients with bilious vomiting do not have IHPS and are not directed to an initial sonographic evaluation. UGI is the study of choice in a child with bilious vomiting.

In patients with malrotation, inversion of the normal relationship of the superior mesenteric artery and vein may be observed at sonography. This finding is not constant, and, when encountered, UGI is necessary for confirmation of the diagnosis .

.

Patients with nonbilious vomiting typically have IHPS or reflux. Other conditions that can manifest with nonbilious vomiting include pylorospasm, hiatal hernia, and preampullary duodenal stenosis

IHPS can be diagnosed or excluded by using sonography. Pylorospasm is more easily demonstrated with sonography than with UGI because of the ability with the former to detect and measure the muscle thickness .

Hiatal hernia is uncommon in infants and can be detected easily at UGI . However, herniation of the gastric fundus can also be identified along the esophageal hiatus during sonography.

Preampullary duodenal stenosis is rare among the population of infants with nonbilious vomiting. At sonography, a normal pyloric ring bridges the distensible antrum to a dilated duodenal cap. In these patients, UGI may be performed for confirmation of this diagnosis

Preampullary duodenal stenosis. (a) Sonogram demonstrates a distensible antropyloric canal (A). However, there is a consistent gas shadow to the right of the pyloric ring, resembling a very dilated duodenal cap (D). This led to suspicion of preampullary duodenal stenosis and referral for UGI. (b) Initial UGI image of stomach shows gas-filled dilated duodenum (D).(c) UGI image obtained with patient prone shows normal pylorus (arrow) and dilated proximal duodenum (D).

Intestinal malrotation

Intestinal maltoration is a congenital anatomical anomaly which results from an

abnormal rotation of the gut as it returns to the abdominal cavity during embryogenesis. Although some individuals live their entire life with malrotated bowel without symptoms, the abnormality does predispose to midgut volvulus and internal hernias, with the potential for life threatening complications

Midgut malrotation has been estimated to occur in approximately one in 500 live births . However, it is difficult to ascertain the true incidence

It is also frequently (~ 50%) associated with other abdominal anomalies, some of which are causative and others merely associated:duodenal atresia / stenosis / web /congenital diaphragmatic herniation /gastroschisis /omphalocele heterotaxy : 70% of individuals will have a malrotation /choanal atresia

Clinical presentation correlates to the age of presentation 5. In the infant the most common presentation is with / 

midgut volvulus.In the older child or even adult presentation is more

frequently intermittent with episodes of spontaneously resolving duodenal obstruction. This is thought to be due to kinking of the duodenum by Ladd bands rather than a volvulus 5. Internal hernias are also encountered. 

In some individuals, presentation is very non-specific with episodes of abdominal pain, weight loss, melaena, or even chronic pancreatitis

PathologyDuring normal embryogenesis the bowel herniates into the base

of the umbilical cord and rapidly elongates. As it returns to the abdominal cavity it undergoes complex ~270 degree counter clockwise rotation resulting in the duodeno-jejunal (DJ) flexure normally located to the left of the midline, at the level of L1 verterbal body and the terminal ileum located in the right iliac fossa. This results in a broad mesentery running obliquely down from the DJ flexure to the caecum, and prevents rotation around the superior mesenteric artery (SMA) 1-6.

In malrotation this does not occur and as a result the mesentery has a short root, which allows it to act as a pedicle (through which the SMA and SMV pass) around which volvulus can occur. 

Radiographic features

Plain filmAbdominal radiographs, in the absence of

midgut volvulus, are neither specific nor sensitive 2. 

They may show: right sided jejunal markings

absence of stool filled colon in right lower quadrant

29-year-old woman with chronic intermittent abdominal pain. Supine frontal abdominal radiograph shows small bowel with jejunal markings on right (arrowheads) and colon predominately on left. Note absence of colon in right lower quadrant (arrow).

Ultrasound May show and inversion in the SMA /SMV

relationship with the SMA on the right and the SMV on the left.

Transverse sonogram obtained through upper abdomen in 11-year-old girl with malrotation shows vertical or slightly inverted orientation between superior mesenteric artery (arrowhead) and superior mesenteric vein (v

CTmay again show abnormal SMA (smaller and more

circular) / SMV relationshipvein (SMV) is a useful indicator of malrotation .

In most patients with quiescent malrotation, the SMA and SMV will assume a vertical relationship or show left—right inversion .

large bowel predominantly on left and small bowel predominantly on the right

 inspection of the pancreas in malrotation will reveal underdevelopment or absence of the uncinate process .

32-year-old man with left flank pain. Axial contrast-enhanced CT s shows inverted relationship between superior mesenteric artery (arrowhead) and superior mesenteric vein (v). Note absence of pancreatic uncinate process.

Axial contrast-enhanced CT scan obtained through mid abdomen shows characteristic appearance of small bowel on right and colon on left

—22-year-old man with episodic colicky abdominal pain. Axial contrast-enhanced CT scan shows vertical orientation of superior mesenteric artery (arrowhead) and superior mesenteric vein (v).

show bowel dilatation and mucosal hyperattenuation, findings indicative of global small-bowel ischemia. There is a twist at the root of the small-bowel mesentery, and an abnormal relationship between the superior mesenteric artery (long arrow) and the superior mesenteric vein (short arrow) is seen.

Appendicitis in patients with malrotation. Axial contrast-enhanced CT scans in 56-year-old woman with left lower quadrant abdominal pain, vomiting, and leukocytosis show abnormal dilated appendix with marked periappendiceal stranding extending from left-sided cecum. Note also superior mesenteric artery—superior mesenteric vein inversion

Appendicitis in patients with malrotation. Axial contrast-enhanced CT scan in 68-year-old woman with left-sided abdominal pain and clinical diagnosis of diverticulitis shows enlarged appendix (A) with periappendiceal inflammation on left. Note terminal ileum (asterisks) crossing to left-sided cecum.

Fluoroscopy  paediatric upper gastrointestinal contrast study is the

examination of choice when the diagnosis is suspected. The key findings of malrotation are:

abnormal duodeno-jejunal (DJ) junction location duodenum fails to cross the midline DJ flexure lies inferior to the duodenal bulb

Contrast enema has historically also been used, the theory being that in malrotation the large bowel will also be malrotated. Unfortunately in 20 - 30% of cases with malrotation the caecum is normally located. The converse is also true, with position of the caecum in normal individuals being variable 4.

Malrotation Presenting with Acute SymptomsMidgut volvulus is a complication of malrotation in

which clockwise twisting of the bowel around the SMA axis occurs because of the narrowed mesenteric attachment .

The clinical diagnosis of midgut volvulus in adolescents and adults is difficult because the presentation is usually nonspecific and malrotation is rarely considered. Recurrent episodes of colicky abdominal pain with vomiting over a period of months or years are typical and may eventually lead to imaging .

Diarrhea and malabsorption from chronic venous and lymphatic obstruction may also occur .

Findings on abdominal radiographs in midgut volvulus are usually abnormal

but non-specific . Upper gastrointestinal examination (the study of choice in

neonates) shows the typical corkscrew appearance of the proximal small bowel.

However, in older patients with acute symptoms, CT is generally performed instead of a barium examination. . The CT whirl or whirlpool sign describes the swirling appearance of bowel and mesentery twisted around the SMA axis. A similar appearance can be seen on sonography.

Additional CT findings include duodenal obstruction, congestion of the mesenteric vasculature, and evidence of underlying malrotation .

The presence of intestinal ischemia or necrosis is an ominous sign

6-day-old girl with malrotation and midgut volvulus

Midgut volvulus in an infantLateral upper GI image obtained in a different patient also shows the classic corkscrew-like

29-year-old man with acute abdominal pain and vomiting His history was significant for similar prior episodes without diagnosis. Axial contrast-enhanced CT scans show characteristic whirllike appearance of bowel and mesentery wrapping around superior mesenteric artery (arrowheads, B). Note dilated duodenum (D, B), engorged mesenteric vessels (arrows, C), and underlying malposition of bowel.

12-year-old girl with acute abdominal pain from malrotation with midgut volvulus. Axial contrast-enhanced CT scans show characteristic clockwise twisting of bowel, mesentery, and superior mesenteric vein (arrowheads) around axis of superior mesenteric artery.

Internal hernia caused by abnormal peritoneal bands is an

underrecognized complication of malrotation after childhood . This condition may also be life-threatening because of the risk of bowel obstruction and strangulation.

CT findings of malrotation and small-bowel obstruction (without volvulus) may be seen in patients having this complication .

Evidence of ischemic bowel again portends a poor prognosis .

Some patients may present with a combination of midgut volvulus and internal hernia .

Axial unenhanced CT scan shows dilated bowel loops on right with pneumatosis (arrowheads) and gas (arrow) in superior mesenteric vein, strongly suggesting ischemic or necrotic bowel

Fig. 12C. —23-year-old man with acute abdominal pain from malrotation with internal hernia and partial midgut volvulus. Axial contrast-enhanced CT scans show dilated duodenum (D, A), small whirl sign involving more distal superior mesenteric artery (arrowheads, B), and malpositioning of bowel. Localized cluster of unopacified bowel or fluid is present inferiorly (arrows, C). Internal hernia with encapsulated appearance was found at surgery

Malrotation Associated with HeterotaxyRotational abnormalities are seen in

approximately 70% of patients with situs ambiguous (heterotaxy), including both asplenia and polysplenia syndromes. Most patients with heterotaxy syndromes die in childhood because of their complex congenital heart disease.

Approximately 10% of patients with polysplenia (left-sided isomerism) may reach adulthood without any complication .

Axial contrast-enhanced CT scan shows 16-year-old girl with reversed (mirror image) malrotation related to polysplenia syndrome. Note right-sided stomach (St), multiple spleens (arrowheads), and interruption of inferior vena cava with azygos continuation (arrow)

27-year-old woman with unsuspected polysplenia variant and malrotation who presented with abdominal pain, fever, and leukocytosis. Axial contrast-enhanced CT scans show multiple spleens in left upper quadrant (arrows, A), superior mesenteric artery—superior mesenteric vein inversion (arrowhead, B), and intestinal malpositioning.