X-ray Examination of the Gastrointestinal Tract BERTRAM R. GIRDANY, M.D. FRED A. LEE, M.D.
This article surveys and describes indications for radiographic studies of the alimentary tract in children. It discusses the lesions that can be satisfactorily demonstrated and the techniques that promote their demonstration. The radiographic findings are not described in detail except where they add to the discussion of the clinical problem. Roentgen examinations use ionizing radiation. Although no study has shown that roentgen rays are harmful at levels ordinarily used in these diagnostic procedures, it is prudent to minimize radiation exposure, particularly to small infants, in whom a moderate-sized field may represent an appreciable portion of the total patient area. Exposure to radiation is greatest in conventional fluoroscopy. Technical advances during the past decade, including image amplifiers, closed-circuit television systems and video tape recording, have significantly reduced the radiation required for satisfactory fluoroscopic viewing. Since gastrointestinal radiography is principally fluoroscopy, the new, less hazardous methods should be used in infants' and children's examinations,12, 13, 14 Moreover, these methods allow easier viewing, and children can be directly observed in non darkened rooms, where they are less likely to be frightened. Television and video tape recording allow prolonged observation at extremely low radiation levels. 12 For example, five minutes of fluoroscopy can be recorded with the same radiation exposure to the patient needed for a single conventional radiographic spot film. Infants and small children not only need more protection from radiation, but are also easier to examine by x-ray television methods. X-ray television is more difficult to apply to adults; the large size and thickness of many of their parts increase scatter radiation and diminish picture contrast. The radiologist must use special techniques to handle children. 9 The young patient must be immobilized so that he is not a moving target. From the Departments of Pediatrics and Radiology, University of Pittsburgh School of Medicine, and the Children's Hospital of Pittsburgh.
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The same methods of immobilization also protect the radiologist and the technician from exposure to primary and secondary radiation and enable them to control the examination directly. Pediatric radiography, particularly as applied to the alimentary tract, differs from adult work in that each examination is a directed exploration. The history and physical findings suggest and limit the diagnostic probabilities. The child with suspected megacolon has to have just enough of his colon filled with barium to identify or exclude transition from small- to large-calibered lumen. The child with recurrent abdominal pain has to have his terminal ileum filled to identify or exclude terminal ileitis. He does not need a time-consuming, radiationusing, methodical examination of the large bowel; his colon is not the site of unsuspected carcinoma. Neither does every study routinely require a whole series of overhead films with oblique, lateral and special "squatting" views. The radiologist should have a clear concept of the diagnostic probabilities before he begins the examination; he should expose only that part of the patient and only the necessary number of films that give reasonable promise of useful findings. In the following discussion the symptoms are related to lesions that can be readily identified by proper radiologic examination. When combinations of symptoms occur, the condition is discussed in association with the chief complaint. Constipation, megacolon, chronic abdominal pain, peptic ulcer and terminal ileitis are the subjects of separate papers in this symposium. When the term "cineHuoroscopy" is used, it refers to video tape recording or to cineradiographic recording on motion picture film.12
RESPIRATORY DISTRESS
Lesions of the proximal segment of the esophagus produce respiratory symptoms. 15
ASPIRATION
Aspiration occurs regularly in association with micrognathia and in infants and children with the Riley-Day syndrome. The infant with micrognathia has trouble in feeding, shows signs of aspiration pneumonia, and fails to thrive. The diagnosis of micrognathia is apparent on direct physical examination and can be confirmed by roentgenograms of the skull. Micrognathia is frequently associated with incoordination of swallowing and breathing, but there is poor correlation between the degree of micrognathia· and presence or absence of this
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X-RAY EXAMINATION OF THE GASTROINTESTINAL TRACT
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difficulty. A cinefluorographic study of swallowing made with the infant lying on his side shows opaque material flowing into the trachea and esophagus. Dysautonomia, the Riley-Day syndrome,26 is characterized by emotional lability, inconstant hypertension, defective lacrimation, and by widespread basilar bronchopneumonia. Unexpectedly widespread changes in the lungs of a child with mild to moderate scoliosis warrant consideration of this diagnosis. Cinefluorographic studies of swallowing show aspiration into the trachea. Aspiration is not associated with respiratory distress or coughing. The aspirated material is usually cleared from the lungs promptly and is not seen on chest radiographs 24 to 48 hours later. The radiographic study of swallowing of contrast material of varying viscosities determines the optimal thickness of the natural feedings for the particular dysautonomic child. Occasional infants with neurologic deficits of nonspecific nature who do not have micrognathia or dysautonomia may suffer from widespread bronchopneumonia and aspiration.
ATRESIA OF THE ESOPHAGUS
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Atresia is the most important congenital malformation of the esophagus. There are three basic structural variations of esophageal atresia. 1. Atresia of the esophagus is associated with tracheo-esophageal fistula in 95 per cent of the cases. The blind upper end of the esophagus is dilated, and the lower end communicates with the trachea at or near the carina. The stomach and intestines contain air. Rarely the upper end of the esophagus enters the trachea, or both segments of the esophagus communicate with the trachea. 2. Atresia of the esophagus without tracheo-esophageal fistula occurs in fewer than 5 per cent of cases. 3. Tracheo-esophageal fistula without esophageal atresia also occurs in fewer than 5 per cent of cases. The clinical signs of esophageal atresia begin during the first hours of life. The infant has large amounts of thick mucus in his nasopharynx and drools excessively. He regurgitates his first feedings, chokes, and becomes cyanotic. In frontal and lateral films, the dilated upper esophageal pouch impinges on his trachea. Atelectatic or pneumonic changes secondary to aspiration may be present in the right upper lobe. Overaeration of the lungs without pneumonia may reflect massive aspiration. Gaseous distention of the bowel indicates the presence of tracheo-esophageal fistula. A radiopaque catheter passed under fluoroscopic control impacts at the blind end of the esophagus. Opaque material is not necessary for
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diagnosis; it may be aspirated into the lungs. Identincation of the rare nstulous communication between the upper esophageal pouch and the trachea is not an indication for the use of contrast agents. The infant with direct communication between his upper esophageal segment and the trachea has extensive pneumonia and severe respiratory distress. Occasionally the catheter may be passed through the trachea and thence into the stomach by way of the tracheo-esophageal nstula. More often, a tube passed without radiographic control is reported to return gastric secretions. The dilated upper esophageal pouch allows the catheter to coil on itself. The large amount of accumulated secretions that can be removed from the pouch may suggest that the tube has been in the stomach. Under these circumstances the radiologist should instill a small amount of contrast material to identify the upper esophageal segment. He then should remove the opaque material by direct aspiration. The complications which follow successful repair include stenosis of the esophagus, respiratory distress with feeding, and recurrence of tracheo-esophageal nstula. In later infancy and childhood foreign bodies often impact in the esophagus, and esophageal motility is disturbed. The esophagus is functionally and structurally closed for about two to nve days after primary surgical anastomosis of the proximal and distal segments. During this period, air is absent from the gastrointestinal tract. Subsequently, opaque studies of the esophagus show the level of anastomosis and its functional patency. Incomplete and slow emptying of the upper pouch usually signines a suboptimal therapeutic result. Some infants become blue and cough during feeding. Opaque studies show that the dilated proximal segment of the esophagus impinges on, and narrows, the tracheal lumen. The infant's cough and other signs of respiratory distress disappear when his upper pouch empties. Recurrence of tracheo-esophageal nstula should be suspected when respiratory distress recurs with or without abdominal distention. An infant who has had successful repair of esophageal atresia and swallows fluid without difficulty may have obstruction from opaque or nonopaque foreign bodies, usually made up of solid food masses lodged in his esophagus at the level of anastomosis. The correlation between the incidence of impacted foreign bodies and the caliber of the esophagus at the site of anastomosis is not a close one. The infant with esophageal atresia without associated nstula cannot have immediate end-to-end repair of his esophagus because the distal segment is hypoplastic and the two ends of the esophagus cannot be successfully apposed. Altman2 examined the distal segment by reflux of opaque material after its introduction into the stomach through a gastrostomy tube. Repeated dilations of both upper and lower esophageal segments may ultimately allow a successful primary end-to-end anastomosis.
X-RAY EXAMINATION OF THE GASTROINTESTINAL TRACT
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TRACHEO-ESOPHAGEAL FISTULA
The presence of widespread bronchopneumonia in the lungs in infancy should raise the question of tracheo-esophageal fistula without atresia. This lesion occurs as an isolated congenital malformation or may be a postoperative complication of repaired esophageal atresia with tracheo-esophageal fistula. 30 The clinical features include recurring bouts of widespread bronchopneumonia and respiratory distress associated with abdominal distention. The fistula that allows food and gastric contents to flow from the esophagus into the trachea also allows air to flow freely from the trachea into the stomach. Radiographic examination is directed at identification of the fistula. The examiner must understand that the tracheo-esophageal fistula is inconstantly patent. Constant patency is incompatible with life. No method of examination that fails to take into account the intermittent patency of the fistula can be relied upon to identify the fistula. An opaque catheter is introduced through the infant's nose into the proximal esophagus with the tip of the catheter at the level of the clavicles. The infant is placed on his right side, and the introduction of the opaque material into the esophagus under the pressure of a hand syringe is recorded. The infant's nasopharynx must be included in the field of examination to allow differentiation between overflow aspiration of opaque material from the esophagus and its passage into the trachea through a tracheo-esophageal fistula. Repeated injections are made with the infant lying on each side, on his back and on his face. Cinefluorographic methods identify the fistula and avoid confusion with overflow aspiration, the main error in diagnosis. More than one examination may be needed to demonstrate a tracheo-esophageal fistula.
LARYNGOTRACHEO-ESOPHAGEAL CLEFTS
Such clefts are high fistulous communications between the hypopharynx and proximal respiratory tract. 6 , 31 They are best identified with cineradiographic studies of swallowing made while the infant feeds from a nipple. These defects are rare and are difficult to differentiate from overflow aspiration. The extent of the cleft varies from a small high communication between the larynx and the esophagus to complete absence of wall between trachea and esophagus, persistent esophagotrachea. 16
VASCULAR RING
Anomalies of the aortic arch that compress the esophagus and trachea are not intrinsic lesions of the esophagus. They should be sus-
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A. LEE
pected in the presence of stridor, difficulty in feeding, hoarseness, and cyanosis associated with feedings. Esophagograms demonstrate constant compression of the esophagus and confirm the diagnosis of vascular ring. Opaque studies of the trachea identify or exclude significant impingement on the tracheal lumen. VOMITING AND INTESTINAL OBSTRUCTION
The radiologist can obtain useful information by aspirating the gastric contents of the vomiting infant before he begins the fluoroscopic study. Bilious material indicates obstruction distal to the ampulla of Vater, and nonbilious liquid with milk curds usually means gastric outlet obstruction. A history of vomiting undigested food directs attention to the esophagus and cardio-esophageal junction. Although lesions of the proximal esophagus produce respiratory symptoms, disorders of the middle and distal portions cause vomiting, and occasionally aspiration pneumonia. Congenital stenosis of the esophagus, cardiospasm, chalasia and hiatus hernias can be identified by radiographic examinations of the esophagus with opaque agents.
CONGENITAL STENOSIS OF THE ESOPHAGUS
The cause and structure of congenital stenosis of the esophagus are obscure. Two main variations occur. The less common form consists of a long segment of narrowing originating at any level in the esophagus. It causes signs in newborns and simulates esophageal atresia. The infant has difficulty in swallowing, vomits, and aspirates. More commonly, congenital stenosis of the esophagus produces incomplete obstruction at the junction of the distal and middle thirds of the esophagus. Signs are not present during early infancy and do not appear until the infant is given a diet containing chopped or table foods. Congenital stenosis should be suspected in any child who has food or a foreign body impacted in the distal third of his esophagus. Cineesophagogram discloses a moderately dilated proximal esophageal segment with reverse peristaltic activity, which originates at the stenotic level. Conventional spot film observations may not show convincing discrepancy between lumens of the dilated proximal and stenotic distal esophageal segments.
CARDIOSPASM-ACHALASIA OF THE ESOPHAGUS
Cardiospasm in infants and children is rare. It produces vomiting, often projectile, and epigastric distress during feeding. Films of the
X-RAY EXAMINATION OF THE GASTROINTESTINAL TRACT
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thorax may show distention of the esophagus with air with or without air-fluid levels. Although the normal infant's esophagus is occasionally filled with air during routine radiography of his chest, dilatation of the esophagus with air on more than one film warrants suspicion of cardiospasm. In cardiospasm the esophagus is dilated and its distal end narrowed. Emptying is slow. Cardiospasm must be differentiated from hiatus hernia with secondary esophagitis.
CHALASIA OF THE ESOPHAGUS
Berenberg and Neuhauser5 described 24 infants seen over a fiveyear period with prolonged, repeated emesis supposedly due to failure of sphincter action of the diaphragmatic crura contiguous to the lower esophagus. Nonprojectile vomiting began three to 10 days after birth and was most pronounced when the infants were recumbent. Roentgen examination showed that external pressure on the barium-filled stomach regularly produced regurgitation of the opaque material from the stomach into the esophagus and that the cardiac sphincter remained widely patent. Gravitational reflux of the barium mixture into the esophagus occurred when the infant was inverted. Maintenance of the infant in the erect position for half an hour after thickened feedings produced rapid reduction in reflux; within a few weeks the patients were well fluoroscopically and clinically. Conclusive chalasia of the esophagus is rare. Normal regurgitation and relaxation of the cardiac sphincter are often difficult to differentiate. The significance, diagnosis and incidence of varying degrees of chalasia are all uncertain.
CONGENITALLY SHORT ESOPHAGUS AND HIATUS HERNIA
The incidence and significance in children of hiatus hernia and related lesions are both under question. Some displacement or extrusion of the cardia of the stomach above the diaphragm is common in infancy, as it is in later life. Indeed, eructation in children in the prone position consistently produces small hiatus hernias. This temporary hiatus hernia results from, but is not the cause of, the vomiting. Hiatus hernia should be distinguished from thoracic stomach, in which a segment of stomach is almost constantly above the diaphragm, in which the distal esophagus is hyperirritable, with or without an actual ulcer, and in which endoscopic examination shows signs of esophagitis. Shortness of the esophagus is rarely a true prenatal malformation, and in most instances the shortness results from longitudinal contraction
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secondary to inflammatory esophagitis due to reflux of gastric hydrochloric acid and pepsin. The incidence of symptomatic hiatus hernias is unknown. In our opinion there are no basic differences in the pathogenesis and significance of hiatus hernias in infants and adults. Rupture or stretching of the cardiophrenic ligaments can occur after prolonged retching and cause reflux esophagitis, hiatus hernia and short esophagus. Surgical observations confirm this view. Prolonged vigorous efforts to induce transient hiatus hernias during fluoroscopic visualization of the esophagogastric junction may be successful. Such diaphragmatic hernias can be produced in normal infants.
COMPLETE INTESTINAL OBSTRUCTION
Intestinal obstruction can usually be recognized and its level assessed without the use of opaque agents. Radiographic examination of the abdomen and the pelvis in erect and recumbent positions and in frontal and lateral projections should precede the use of contrast material. The bowel proximal to the site of obstruction is distended with air and fluid, but air is not present in the distal portion of bowel. Barium studies of the alimentary tract are indicated when plain film diagnosis is uncertain. Small clusters of calcium density within the abdomen of the newborn infant indicate antenatal perforation with calcification of the extruded meconium or of the intestinal wall. Meconium peritonitis is not synonymous with meconium ileus. Although meconium peritonitis may be associated with meconium ileus, it occurs more frequently with other types of intestinal obstruction and atresia. It is usually possible to estimate the level of obstruction and to differentiate small from large bowel without an opaque agent, especially in newborns and very young infants. Introduction of a barium mixture into the rectum with the carefully controlled pressure of a hand syringe identifies the small caliber of the colon distal to the level of obstruction.
HYPERTROPHIC PYLORIC STENOSIS
Pyloric stenosis is the most frequent cause of organic obstruction of the intestinal tract in younger infants. Hypertrophy of its circular muscle narrows and elongates the pyloric channel. The clinical diagnosis is based on a history of vomiting and palpation of the pyloric tumor. A barium meal is essential when the clinical signs are uncertain. Radiographic examination with the infant lying prone with his right side down discloses an elongated, narrowed pyloric channel. When the channel cannot be visualized, Currarino8 uses the impingement of the pyloric tumor on the air-filled antrum as a radiographic sign of pyloric stenosis.
X-RAY EXAMINATION OF THE GASTROINTESTINAL TRACT
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This is a useful sign, but conclusive radiographic identification rests on visualization of the elongated pyloric channel. The infant's gastric contents should be aspirated before and after the radiographic examination. Retained food can mix with the barium meal and obscure radiographic detail; barium left in the obstructed stomach may be vomited and aspirated into the lungs. Elongation and relative narrowing of the pyloric channel without obstruction to the outflow of gastric contents normally persist for months after a successful Ramstedt procedure. Occasional infants continue to vomit after surgical treatment of pyloric stenosis. Radiographic examination may demonstrate inadequate pyloromyotomy as a segment of persistent narrowing and obstruction at either end of the elongated pyloric channel.
OBSTRUCTION ASSOCIATED WITH CONGENITAL ERRORS IN ROTATION (MALROTATION)
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Malrotation of the midgut is the second most common cause of organic obstruction of the alimentary tract in younger infants, and is an occasional cause of recurrent vomiting in children. In the normal embryologic development of the midgut, broad bands of mesentery attach the bowel to the posterior abdominal wall, and peritoneal folds fix the duodenum, cecum and ascending portions of the colon. Interference with orderly rotation of the midgut results in absence of the broad mesenteric attachment of the bowel, and in an abnormal disposition of peritoneal bands. The duodenum and the midtransverse colon remain the only portions of the midgut fixed to the posterior abdominal wall, so that twisting or volvulus of the entire midgut is possible on this narrow pedicle. Volvulus produces obstruction at the third portion of the duodenum, the proximal fixed portion of the pedicle of the midgut. Abnormal attachment of peritoneal folds across the duodenum and between the colon and the gallbladder or liver results from failure of the normal fixation of these folds during the last stage of rotation. Such bands constrict and obstruct the duodenal lumen. Volvulus and duodenal bands produce signs of ''high obstruction," which may be complete, or intermittent and incomplete, depending on the presence or absence and tightness of volvulus and the degree of constriction of the duodenum by peritoneal bands. Films of the abdomen usually show a normal gas pattern when obstruction is incomplete. Rarely, complete obstruction at the level of the first and second portions uf the duodenum cuts off the gas column at these levels and the remainder of the alimentary canal is gasless. Usually, barium meal demonstrates a dilated duodenum and shows the abnormal disposition of small-calibered loops of jejunum in the right half of the abdominal
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cavity. The normally disposed proximal jejunum lies in the left upper quadrant. The same peritoneal bands that obstruct the duodenum also keep the proximal portion of the transverse colon in the right upper quadrant of the abdomen. For this reason the disposition of the colon as demonstrated by barium enema approximates the normal, with the cecum on the right side of the abdomen. Upper gastrointestinal series identify the site and nature of obstruction. Houston and Wittenborg19 have suggested that a barium enema be used to show the high position of the cecum as a diagnostic criterion in obstructive malrotation of the midgut. It is not always easy to differentiate this from the normally high position of the cecum in infancy, and in any event, a barium enema does not denne the level of obstruction. Volvulus may severely compromise the blood supply of the midgut and produce gangrene. The portion of the intestines supplied by the superior mesenteric artery distends and nIls with blood. The clinical picture includes bilious vomiting, rectal bleeding and shock. Gangrene of the midgut due to volvulus is a dire surgical emergency and should be corrected immediately. Barium introduced per rectum meets obstruction to retrograde flow in the midportion of the transverse colon, where the distal segment of the midgut is anchored to the posterior abdominal wall. Obstruction to retrograde flow of barium at this level is presumptive evidence of gangrenous volvulus in a distended, vomiting infant suffering from shock and passing blood.
NONOBSTRUCTIVE MALROTATION OF THE MIDGUT
In this condition the jejunum is in the right upper quadrant, but the duodenum is not dilated. Constricting duodenal bands are not present, and the ascending colon is usually on the right side of the abdomen. Nonobstructive malrotation of the midgut is not a rare condition. No convincing evidence shows a causal relation between celiac disease and nonobstructive malrotation of the midgut.
ATRESIAS AND STENOSES
These occur at all levels. Atresias cause complete obstruction and can usually be recognized on plain RIms in which the intraluminal gas furnishes a natural diagnostic contrast agent. If there has been prolonged vomiting or constant medical aspiration of intestinal contents, the abdomen may be gasless. Intestinal stenosis is easily demonstrated with barium meal at its most common site, the duodenum. It is often associated with malrotation. Duodenal stenosis and atresia are common causes of intestinal obstruction in mongoloids. Annular pancreas pro-
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X-RAY EXAMINATION OF THE GASTROINTESTINAL TRACT
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duces complete or incomplete obstructions in the descending second portion of the duodenum. Radiographic examination localizes the level, but not the cause, of duodenal obstruction. Stenosis is more difficult to identify in the distal portions of the small intestine.
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MECONIUM ILEUS
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Meconium ileus is a low ileal obstruction which occurs in newly born infants with cystic fibrosis. Their inspissated meconium cannot pass through the terminal ileum and ileocecal valve. The bowel proximal to the inspissated meconium is dilated and elongated. Strong peristaltic waves may produce localized volvulus of these loops. Intestinal atresia may result from fetal volvulus. No single pathognomonic roentgen sign differentiates meconium ileus from other forms of distal ileal obstruction. It should be suspected in any newly born infant with a family history of cystic fibrosis and signs of low intestinal obstruction. Admixture of gas and meconium in the distally dilated ileal loops occurs frequently in meconium ileus, but is not peculiar to it. The absence of air-fluid levels on the erect film is an inconstant finding. Measurements of salivary and sweat chlorides in the newly born infant are valuable confirmatory findings. Inspissation of intestinal contents in the distal ileum may occur in infants and children with cystic fibrosis who receive inadequate dietary supplements of pancreatic enzymes. The inspissations can serve as lead points of intussusceptions.17
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INCARCERATED AND STRANGULATED INGUINAL HERNIAS
These are a cause of incomplete low ileal obstruction. The radiologic examination which discloses this obstruction is a valuable confirmatory adjunct to careful physical examination. Films may show a gas-containing soft tissue mass in the inguinal region which directs the clinician's attention to this lesion.
!
!i NEUROGENIC MEGACOLON
Megacolon is an important cause of low intestinal obstruction in young infants.29 Plain film examination with frontal and lateral projections of the abdomen is often useful in suggesting the diagnosis. A small-calibered, gas-containing rectum associated with generalized dilatation of gas-containing loops of bowel warrants consideration of neurogenic megacolon. Careful introduction of barium mixture through a soft rubber catheter into the rectum with controlled pressure of a hand
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LEE
syringe shows a zone of transition from small-calibered aganglionic rectum and colon distally, to dilated and normally innervated colon proximally. The radiologist cannot always wait for a 24-hour postevacuation study to complete his evaluation. Symptomatic neurogenic megacolon in infancy demands prompt identification and relief of obstruction if the high mortality rate associated with it is to be eliminated. Aganglionic megacolon is rare in prematurely born and in small full-term infants. Sieber et aps described unexplained "functional" intestinal obstruction simulating aganglionosis coli in prematurely born infants with anatomically normal colons. Berdon et aU reported necrotizing enterocolitis in prematurely born infants weighing less than 1500 gm. Some of these infants had air in the subserosal and submucosal layers of the intestines and in the portal veins.
ATRESIA OR ECTOPIA OF THE ANUS
This condition is usually obvious on direct physical inspection. Too much attention has been directed to attempts to identify the level of obstruction. At most, the Wangensteen technique of exposing lateral and frontal projections of the inverted infant with an opaque marker over his anal dimple shows the distance between the distal-most loop of aircontaining bowel and the opaque marker. Berdon3 and others have re-emphasized the uncertainty of this identification and the lack of anatomic correlation with the x-ray examination.
OTHER
LESIONS
Vomiting and abdominal distention in children who have had previous complicated abdominal surgery or perforation are always suggestive of complete or incomplete intestinal obstruction due to adhesions. Films of the abdomen show generalized distention of bowel, but do not show the cause or site of obstruction. Serial films help the surgeon in his evaluation of the progress of the obstruction. Bilious vomiting and abdominal distention may accompany sepsis. Films of the abdomen show moderate to more severe generalized dilatation of the bowel. Barium studies of the colon show its lumen dilated and suggest that the ileus is functional and not organic. Newly born infants who fail to pass adequate amounts of meconium may become distended and vomit bile. Barium studies of their colons which show large luminal filling defects may be therapeutic by causing passage of the meconium plugs and relieving the signs of obstruction. The incidence of the "meconium plug" syndrome is uncertain. N eurogenic megacolon should be suspected in the long-term follow-up care of every infant in whom this diagnosis is made.
X-RAY EXAMINATION OF THE GASTROINTESTINAL TRACT
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Direct injury to the abdomen may cause intramural, submucosal hemorrhages resulting in partial or complete intestinal obstruction. The descending and transverse portions of the duodenum are the most common sites of such lesions. 24 Hematomas associated with purpura and hemophilia may also be identified in radiographic examinations. IS They may serve as lead points of intussusceptions and result in intestinal obstruction.
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BLEEDING
Esophageal and gastric varices in infants and children with congestive splenomegaly can be identified by barium studies of the esophagus. The dilated vessels cause characteristic serpiginous filling defects in the barium column. The child with hiatus hernia may have peptic esophagitis or ulceration of his esophagus. Peptic ulcers of the stomach and duodenum occasionally cause gastrointestinal bleeding. The roentgen identification of esophageal varices, significant hiatus hernias and peptic ulcers requires careful application of the same methods used for their demonstration in adults. Duplications of the alimentary tract occur at all levels. Esophageal duplications present as masses of water density in the posterior portions of the thorax, often associated with malformations of thoracic vertebrae. Although they rarely produce bleeding or obstructive symptoms, they may be associated with intra-abdominal duplications. Indeed, the identification of an intrathoracic mass in a child bleeding per rectum is suggestive evidence of a bleeding duplication within his abdomen. Duplications that communicate with the lumen of the intestinal tract bleed from mural ulcerations. Blind duplications do not bleed into the main intestinal lumen, but may produce obstruction by extrinsic pressure on the lumen of adjacent bowel. Moderate to massive rectal bleeding warrants consideration of intestinal duplication and of Meckel's diverticulum. The identification of either of these lesions by roentgen examination is fortuitous, rare and unpredictable. Radiographic examination cannot, and should not, be expected to demonstrate or exclude their presence. Small amounts of bright red bleeding are usually due to anal fissures or polyps. Solitary polyps of the colon proximal to the splenic flexure rarely occur. The roentgen search for polyps is directed to the mucosa of the descending colon and sigmoid. The examination need not include the portions of the sigmoid and rectum that are accessible to direct endoscopic inspection. Barium enema with 0.5 per cent concentration of tannic acid added is probably the most efficacious way of demonstrating polyps. The barium-tannic acid mixture is allowed to run from the rectum up to the splenic flexure. A radiograph is made before the patient is allowed to evacuate on the commode. An overhead
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film exposed after evacuation shows excellent mucosal detail in the descending and sigmoid portions of the colon. The tannic acid serves as both a colonic evacuant and mucosal astringent. Tannic acid should not be used to examine the colons of children suspected of having ulcerative colitis. Their denuded mucosal surfaces may allow excessive absorption of tannic acid and increase the hazards of damage to the liver. Currently, the Food and Drug Administration forbids the use of tannic acid in barium studies of the colon. Prospective controlled studies and retrospective observations show the usefulness and safety of tannic acid when it is used at recommended concentrations;7, 20,32 it is likely that the ban on its use will be removed.
ABDOMINAL PAIN
Acute abdominal pain may be an indication for plain film examination of the abdomen, and for films of the thorax made with the child erect. Lobar pneumonia, silent on physical examination, is readily identified on radiographic study of the chest. Perforation of a hollow viscus due to ulceration or trauma introduces air under the diaphragm which can be seen on the chest film. Calcifying fecalith in the region of the appendix lends strong support to a diagnosis of acute appendicitis, and there may be dilated loops of air-containing small bowel in this area with or without a fecalith to reHect localized ileus secondary to the inHammation. Recurrent cramping abdominal pain in a child three months to three years of age suggests intussusception. Vomiting, a palpable abdominal mass and passage of blood in the stool are the other classic clinical signs, but they may be absent in individual cases. In the infant with suspected intussusception film examination without contrast agent is not diagnostic, but may be suggestive. Occasionally there is a visible soft tissue mass, and air-containing bowel may be absent from the right lower abdominal quadrant. A normal plain film study neither excludes nor identifies intussusception. Barium study of the colon identifies ileocolic intussusception with certainty. Currently hydrostatic reduction of intussusception with barium enema is the accepted treatment of choice of uncomplicated ileocolic intussusception. Reduction is a surgical procedure done by an experienced radiologist in cooperation with an attending surgeon. The radiologist adheres to well established criteria and techniques in administration of the enema and evaluating its success. lO , 11,23,25 Frank intestinal obstruction, shock, high fever and dehydration are contraindications to attempts at hydrostatic reduction. Intestinal obstruction suggests the strong probability of gangrenous bowel needing resection, or of ileoileal intussusception. 11 Allen et al. l have directed attention to acute left lower quadrant
X-RAY EXAMINATION OF THE GASTROINTESTINAL TRACT
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abdominal pain associated with volvulus of the sigmoid in children. Film examination of the abdomen without contrast agent may be normal, but barium enema shows obstruction to retrograde flow at the proximal limb of the sigmoid. This is distinct from the distal limb obstruction seen in the adult. The enema may be therapeutic, but some children have required surgical reduction of the volvulus. 21 ,
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MISCELLANEOUS CONDITIONS
It "
Radiographic examination of the gastrointestinal tract may be helpful in the evaluation of constipation, in the identification of abdominal masses, in the investigation of diarrhea, steatorrhea and hypoproteinemia, and to explain fever and failure to thrive. Barium meal may be useful in the identification of intra-abdominal masses, but is rarely diagnostic. It serves only to show the displacement of bowel away from the mass. Barium in the gastrointestinal lumen may obscure important details in the abdomen. Barium studies should be deferred until urography and angiography as indicated have been completed. Infants and children with celiac disease and steatorrhea show radiographic evidence of disturbance in small bowel motility. The barium mixture is in an uneven distribution and is fragmented in the lumen of the small bowel. The caliber of the bowel shows much variation, and in particular the duodenal lumen is large. Cineradiographic studies show churning of the barium mixture back and forth in the first and second portions of the duodenum, as well as similar vigorous to-and-fro peristaltic activity in dilated loops of jejunum and ileum. The correlation of these findings with mucosal biopsy in celiac disease is so high that the absence of disturbed motility renders a diagnosis of celiac disease unlikely. Disturbance in intestinal motility is not limited to one disease and is not a specific finding. It occurs with food allergies, exudative en· teropathy, hepatic insufficiency, and in some otherwise normal children. It is most conspicuous in children with regional ileitis, in which it is associated with slow passage of the barium meal. We have observed severe disturbances in intestinal motility, "disturbed motor function," in 12 children with surgically and histologically proved terminal ileitis. Terminal ileitis may be the cause of growth failure and of unexplained fever. It should be suspected in children with vague abdominal pains, weight loss, nausea and intermittent diarrhea. Since regional ileitis almost always involves the terminal ileum before more proximal segments of small bowel are affected, gastrointestinal series in children should include observation of the motility of the small bowel and clear visualization of the terminal ileum. Multiple films are not necessary to follow the progress of the barium meal.
18
BERTRAM
R.
GIRDANY, FRED
A.
LEE
Ulcerative colitis is suspected in children with chronic bloody diarrhea. Such children have not had striking changes in small intestinal motility. Barium studies of the colon early in the course of this disease may be normal, and normal findings do not exclude the disease. The barium study in the child with suspected ulcerative colitis should include examination of his cecum and terminal ileum. Classic ulcerative colitis begins in the rectum, the disease progressing proximally. Involvement of the ascending colon and ileum indicates extensive disease. Granulomatous colitis results from antegrade involvement of the colon in terminal ileitis. 22 • 27 It is difficult to differentiate the granulomatous colitis associated with terminal ileitis from the pseudopolypoid changes that can accompany idiopathic ulcerative colitis.
SUMMARY AND CONCLUSIONS
1. Radiographic examination of the gastrointestinal tract is a useful means of investigating a wide variety of respiratory and abdominal complaints. 2. It should be conducted according to a specific plan that allows identification or exclusion of the conditions suggested by the history and physical findings in each case. 3. The most important indications for roentgen examination of the alimentary canal in children have been discussed. The radiographic findings have not been described in detail.
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X-RAY EXAMINATION OF THE GASTROINTESTINAL TRACT
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