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Localized lesions of the colon in infants and children
Localized
Lesions of the Colon in Infants Edward
B. Singleton,
M.D., and Fred Johnson,
T
HE APPEAL of pediatric radiology is not found in its limitations but in the knowledge that virtually all disorders that affect the adult may also affect children. The restriction imposed by the editor-to confine ourselves chiefly to conditions limited to the pediatric agegroup-puts us in the position of a radiologic schlepper.” Consequently, the subject content of this presentation will consist of congenital abnormalities (atresias, Hirschsprung disease,and imperforate anus), inflammatory lesions (localized ischemic colitis and typhlitis), and neoplasms (juvenile polyps, histiocytic fibroma, hemangioma, and adenocarcinoma). CONGENITAL
LESIONS
A tresia
Most intestinal atresiasoccur in the ileum (50%) and duodenum (25%). About 15% are multiple. Isolated colon atresia is rare, occurring about once per 40,000 live births.17 Although the theory of failure of recanalization of the solid cellular stage of colon development may account for somecasesof colon atresia,most are probably the result of intrauterine vascular insufficiency (intrauterine necrotizing enterocolitis). According to Sutton’s classification* there are three types: (1) complete obstruction of the intestinal lumen by a diaphragm; (2) an atretic cord joining proximal and distal segmentsof patent colon; and (3) complete separationof the proximal and distal segmentsof colon with a V-shaped mesenteric defect corresponding to the missing area. In our experience, the most common form is *Editor’s note: Yiddish expression. A bum is merely a worthless man. A schlepper is something less. A schlemiehl spills soup on a schlemazel; the schlepper rushes up and wipes it off (with his sleeve, no less). Edward B. Singleton, M.D.: Clinical Professor of Radiology, Baylor College of Medicine and the University of Texas Medical School at Houston, Houston, Texas. Fred Johnson, M.D.: Fellow in Pediatric Radiology, Baylor College of Medicine, Houston, Texas. Reprint requests should be addressed to Edward B. Singleton, M.D., Texas Childreni Hospital, 6621 Fannin, Houston, Texas 77025. 0 I9 76 by Grune & Stratton, Inc. Seminarsin
Roentgenology,
Vol.
Xl,
No.
2 (April),
1976
and Children M.D.
atresia just distal to the hepatic flexure with an atretic band extending to a patent lumen at the splenicflexure (Fig. 1). Clinically, thesenewborn infants quickly become distended, vomit, and fail to passmeconium. Plain films showan obstructive pattern that is frequently impossibleto differentiate from a wide variety of conditions, including meconium ileus, ileal astresia, meconium plug syndrome, small left colon syndrome,7 and Hirschsprungdisease. Barium enemais confirmatory. It showsa small unused colon with complete obstruction at the point of atresia (Fig. 1B). Inability to fill the proximal portion of the colon is diagnostic of atresia and excludes the other conditions mentioned in the differential considerations. With membranous atresia, the head of the contrast column has a distinctive “windsock” configuration.’ Rectal atresia may occur as an isolated lesion or may be associated with imperforate anus(Fig. 2). Hirschsprmg
Disease
Hirschsprung diseaseis caused by absence of myenteric and submucousneural plexuses,usually localized to the rectum or distal sigmoid and rectum. This denervation leadsto an obstruction that is paradoxically unrelated to the length of the involved segment.The condition usually is identified in the neonate or young infant and accounts for approximately 20% of the casesof neonatal bowel obstruction.‘7 The localized form of the diseaseis four times more common in males. Aganglionosis of the entire colon accounts for approximately 10% of patients, is equally common in girls and may be familial.3’5 Localized or skipped segmentsof aganglionosiswith normal distal myenteric plexusesare rare. Extremely low aganglionosisinvolving the anorectal junction is usually impossibleto diagnoseeither histologically or by radiographic studies and presentsthe same clinical features as habit or functional constipation. Clinically, there is failure to pass meconium during the first 24 hr of life and the gradual development of abdominal distension and vomiting. Alternating constipation and diarrhea may occur, 111
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Fig. 1. Colon atresia. (A) There is dilatation of the small bowel as well as marked distension of the hepatic flexure of the colon. (6) Barium enema shows distal microcolon with obstruction to the flow of barium at the splenic flexure. At operation a fibrous cord was identified extending between the patent splenic flexure and the distended hepatic flexure. This is the most common form of colon atresia.
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Fig. 2. Rectal into the cloaca1 of the I‘ectum. pouch is clearly
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atresia. Introduction of contrast media opening showed atresia of the midportion Gas within the proximal dilated rectal identified (arrow).
Fig. 3. Hirschsprung infant. The rectum at the rectosigmoid lateral view, made enema examination.
-old in a l-month. disease z one is small and I the transition is striking in the junction a limited bari following
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Fig. 4. lmperforate anus. Injection of contrast medium via the needle demonstrated the caudal extent of the dilated pouch. Note the small beak (arrow), which is the site of a rectal fistula. Clinical workup and subsequent surgery proved this to represent the origin of a fistula, whose distal aspect was an atretic cord. (Reproduced by permission of Pediatric Radiology. 25 )
the latter a result of periodic episodes of colitis. Occasionally, a compulsive mother can keep the colon decompressed by enemas so that the condition is not recognized until the first year or two of life, by which time the infant is usually undernourished, with a potbelly and wasted extremities. The radiographic findings are, in part, the result of the inability of the aganglionotic segment to partake in the peristaltic activity of fecal evacuation and, in part, attributable to the physiologic principle that denervated smooth muscle is abnormally sensitive to stimulation and tends to contract.24 Plain films usually show an absence of gas and feces in the rectum along with signs of bowel obstruction. Associated features, including calcified fecaloma,4 congenital heart disease, mongolism, pulmonary hypoplasia, and vertebral or rib abnormalities,21 may divert the radiologist’s attention from the diagnosis. The radiographic evaluation consists of plain films of the abdomen followed by a limited
barium enema. Preparation in the form of laxatives or enema is contraindicated, since it may decompress the colon above the aganglionotic segment, preventing accurate identification of the transition area. In the older patient with questionable Hirschsprung disease, the barium should be suspended in isotonic saline because of the danger of water intoxication. However, this danger is remote if the examination is properly performed by limiting the enema to the rectosigmoid region. In megacolon of any type, filling the colon completely with barium adds to the patient’s problem of constipation and impaction. A transition zone is the most specific finding in Hirschsprung disease (Fig. 3). Unfortunately, since the transition zone is a result of the accumulation of fecal material in the colon above the resistant aganglionotic segment, it may not be radiographitally obvious in the first 3-4 weeks of life. In these first weeks, failure of elimination of the injected barium within a 4%hr period is presumptive
LESIONS
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evidence of aganglionosis, and appropriate confirmation by rectal biopsy is indicated. Other signs of Hirschsprung disease, including sawtooth contractions of the aganglionotic segment, thickened nodular edematous mucosal folds in the proximal colon, and failure to expel barium after a 48-hr interval, help to differentiate Hirschsprung disease from the small left colon syndrome. In the latter condition, the infant generally weighs less than 1500 kg at birth and usually has a diabetic mother, and the transition zone is always at the splenic flexure .7,24 In the older baby, functional megacolon enters the differential diagnosis. The onset of constipation in these babies begins during the toilet training age and there is a history of fecal soiling and of passing stools so voluminous that the plumbing may be obstructed-features not encountered in Hirschsprung disease. If the clinical findings are equivocal, introduction of a small amount of barium in the patient with functional megacolon will show a patulous dilated rectum and redundant rectosigmoid. Since clinical history and rectal manometry do not distinguish the extent of the Hirschsprung disease and may not differentiate from small left colon syndrome, the radiographic examination should accomplish these objectives. Early diagnosis is important, since delay increases the possibility of mechanical obstruction and necrosis of bowel. Imperjbrate Anus Imperforate anus is part of a complex set of abnormal embryologic events that occur after the fifth week of gestation, resulting in arrest of descent of the urorectal septum and failure of development of the proctodeum. The imperforation is often associated with other urogenital anomalies, and sometimes with anomalies of other systems. In order to remember the other areas to be checked radiographically when imperforate anus is found, use the mnemonic VATER: Vvertebrae; A-anorectal region; T-trachea; Eesophagus (atresia); and R-renal area. Some patients also have polydactyly, anomalies of the iris, and congenital heart disease.’ 3 Clinically, the infant with imperforate anus presents early with signs of obstruction. If there is a perineal orifice, it may be presumed that there is a low distal rectal pouch. The absence of a perineal orifice suggests a high pouch. Occasionally an
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ectopic insertion may open very close to the normal anal region and appear normal. Under these circumstances, the radiologist can resolve his skepticism about the necessity of an extensive urologic workup by trying to elicit an anal wink. The normal anus will wink at you when the area around it is stimulated with a pin. The ectopic anus may smile wryly but never winks.” The immediate objective of the radiographic studies is to differentiate the high (supralevator) from the low (translevator) type of imperforate anus and to identify fistulas not apparent on the plain film. The inverted plain film is frequently uninformative in distinguishing high from low termination, since meconium may be packed into the distal rectal pouch, giving an erroneous impression of a high segment. The most reliable method in our experience is to inject the blind pouch (under fluoroscopic control) with a very small amount of water-soluble contrast material.” Following preliminary supine and inverted films, the anal dimple is perforated with a 16-gauge Rochester needle, which is advanced until air or meconium is identified in the syringe. Following aspiration of as much air and meconium as possible, 3-5 ml of 20% Hypaque is introduced. Higher volumes are hygroscopic and may deplete plasma volume. Sometimes a fistula opacifies completely with this technique. However, in most patients a beak-like deformity at the caudal end of the pouch identifies the site of the fistula (Fig. 4). In the absence of demonstrable fistula, the levator sling will occasionally be seen indenting the rectal pouch, confirming that it has the low type of termination and that a pull-through procedure can be performed. However, if the radiologist still does not have definitive criteria for determining if the fistula is high or low, colostomy should be performed. A mistaken diagnosis of low termination may result in a perineal exploration that destroys any hope of future urinary continence. At some point in the patient’s course, radiographic workup should always include cystourethrography and urography. Additional workup depends on whether there are other associated anomalies. Typhlitis Typhlitis is a complication of terminal leukemia or aplastic anemia in children who are agranulo-
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Localized Ischemic Lesions
Fig. 5. Typhlitis. This lo-year-old girl had monomyelogenous leukemia. Roentgenogram of the abdomen 1 day before death shows the changes of mechanical small bowel obstruction. Autopsy revealed considerable involvement of the colon by an agranulocytic inflammatory process. The ileocecal valve was so infiltrated that it had caused obstruction. The appendix was normal. (Reproduced by permission of the American Journal of Roentgenology.26)
cytic.26 Pathologically there is severe hemorrhagic necrosis of the cecum. The reason for the curious localization of the necrotic process in this portion of the bowel has not been explained. In all probability, the mucosal integrity of the gastrointestinal tract has been affected, either by the disease itself, the therapy utilized, or a combination of both. Clinically, the patient develops spiking fever, abdominal distension, and pain during the terminal period of his illness. Although a feeling of fullness involving the right lower quadrant may be detected, a palpable mass is usually not present. Radiographically, there is a lack of bowel gas in the right lower quadrant with progressive distension of the small bowel and diminution of colonic gas (Fig. 5). The radiographic features are similar to those of gangrenous appendicitis with pericecal abscess.
Localized ischemic lesions of the colon may develop in babies who are under hypoxic conditions of stress and who develop reflex constriction of mesenteric arterial vessels as blood flow to the brain and heart is enhanced. This reflex mechanism as a cause for ischemic necrotizing enterocolitis has been well documented by experimental evidence.‘2~14~‘8~‘g~23 The recognizable radiographic bowel patterns of necrotizing enterocolitis and the complication of intramural gas will not be discussed here because the lesion is not localized. However, the complications during the reparative phase may result in localized stricture of the bowel, including the colon. Any infant who develops abdominal distension and vomiting 1 or more weeks after recovering from necrotizing enterocolitis should be suspected of having obstruction secondary to bowel stricture. This complication may be localized to the colon (Fig. 6). Rarely, stricture formation secondary to ischemic bowel disease will develop in an infant who has been under stress but who has not had the clinical or radiographic findings of necrotizing enterocolitis.
TUMORS
Juvenile Polyp A juvenile polyp is thought to begin as a retention cyst secondary to obstruction of the orifices of colonic mucous glands. A chronic irritation ensues, resulting in hyperplasia of the mucous glandswith superimposedinflammation. The condition is slightly more common in males,usually between 21 months and 11 years, with a peak at 3-4 years. The most common sign is nonpainful rectal bleeding appearingas drops of blood immediately after a normal bowel movement. However, the patient may manifest a wide variety of lessspecific findings, such as pain, constipation, diarrhea, and signsof intussusception. On rare occasionsthe polyp will prolapse.In this situation, the main purpose of the radiographic exam is to search for additional lesions, since as many as a third of these children have another polyp. Also, a variety of parasiteshave occasionally beendiscoveredin associationwith juvenile polyps,
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Fig. 6. Colon stricture following and colon. (6) Two months after stricture at the rectosigmoid level.
INFANTS
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necrotizing enterocolitis. recovery from the acute
Fig. 7. Solitary pedunculated polyp in the sigmoid 4-year -old child. The filling defect in the midsigmoid consta nt. Histologically, it was a juvenile polyp.
of a was
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(A) episode
At
2 weeks the colon
of age became
there is gas in the wall of the rectum obstructed. Barium enema shows a
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Fig. 8. Histiocytic fibroma in a l-month-old infant. The infant was obstructed. Barium enema disclosed an irreducible intussusception at the lower end of the descending colon.
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including oxyuris vernicularis, trichiuris trichiura, and giardiasis.” If a suggestive history is obtained, the optimal examination is an air-contrast enema after thoroughly cleansing the colon. The use of aerosol soap to inflate the rectum is an excellent way to visualize rectal polyps but is rarely necessary because of the accessibility of this area to the proctoscope. The polyp is usually encountered in the distal 20 cm of the colon, most commonly in the distal 5 cm. It is usually between 3 and 20 mm in diameter and may be pedunculated (Fig. 7). The histology is statistically predictable, since juvenile polyps account for over 75% of colon polyps in children.6 Management of the juvenile polyp depends on the severity of the bleeding. If symptoms are mild, the patient may be followed, since the polyp is usually spontaneously sloughed. With significant bleeding, the polyp can be removed surgically or via the colonoscope.
Histiocytic
Fibroma
Like the skin, the colon can manifest a wide variety of pathologic responses, some of which are unexpected. Also unexpected is the fact that lesions encountered in the skin may have a counterpart in the colon. One such lesion is the histiocytic fibroma. l6 This is a proliferation of fibrocytes and histiocytes that occurs most commonly on the skin but occasionally in the deeper tissues. Usually, this proliferation is a response to trauma, but occasionally it is neoplastic, with the power of repeated recurrence and metastatic spread. The lesion is less than 1 cm in diameter and may be pigmented with hemosiderin or lipid. Histologically, it must be differentiated from fibrosarcoma and xanthoma fibrosa. Intussusception may be the first manifestation (Fig. 8).
Hemangiti ma
Fig. 9. old child. identified
Hemangioma of the transverse colon in a 2-yearAn irregular-shaped sessile filling defect is on the superior wall. Proved at operation.
Another rare lesion that affects the colon as well as the skin and other organ systems is the hemangioma. It may present at any time in life with a wide variety of symptoms. There are a number of histologic types. A more complete discussion of the radiographic features is presented elsewhere in this issue (p. 131). Many authorities believe that isolated heman-
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F :ig. 10. Small hv. Confirmed
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art eriovenous at operation.
Fig.
INFANTS
malformation
11.
Adenocarcinoma
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in the
ascending
of the
lower
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colon
descending
(arrow)
demonstrated
colon
in a 15-year-old
by superia
boy.
mesentel
ric artel riog-
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gioma results from sequestrated mesenchyme that is embryologically activated.” An autosomal dominant hereditary factor is responsible when generalized vascular lesions are a part of the OslerWeber-Rendu syndrome. Genetic factors are also incriminated when the hemangiomas are associated with Turner or Peutz-Jegher syndromes.20 Multiple colonic lesions occasionally present in the neonate as a part of fatal diffuse neonatal hemangiomatosis.” The blue rubber bleb nevus syndrome may also be present in the newborn with compressible blue to purple rubbery cavernous hemangiomas 3-4 cm in diameter in the skin, small and large bowel, liver, spleen, and nervous system.g Older patients present with hemorrhage, obstruction, pain, intussusception, or occasionally palpable mass. Sometimes, because of an associated inflammatory component, the patient presents with symptoms suggesting an acute abdominal condition.” The radiographic presentation is variable. The hemangioma may appear as a diffuse infiltrating
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lesion involving a segment of the bowel with thickening of the wall and narrowing of the lumen, or it may be localized and project into the lumen (Fig. 9). It may resemble a duplication and in some parts of the world has been mistaken for a hydatid cyst.” Selective angiography is useful in the preoperative diagnosis (Fig. 10). Adenocarcinoma Another lesion that is unexpected in children is carcinoma of the colon. Less than 200 cases have been reported in the Western world since 1900. The colonic sites are the same as in adults.’ The most common symptom is abdominal discomfort, followed by rectal bleeding and change in bowel habits, usually constipation.3 Pathologically, there is a preponderance of colloid (mucinproducing) adenocarcinoma in childhood. The prognosis is usually poor, with most chiidren dying within a year.’ The radiographic findings are similar to those in the adult (Fig. 11).
REFERENCES 1. Blank E, Afshani E, Girdany BR, et al: “Windsock sign” of congenital membranous atresia of the colon. Am J Roentgen01 120:330-332, 1974 2. Bley WR, Franken EA Jr: Roentgenology of colon atresia. Pediatr Radio1 1: 105-108, 1973 3. Caffey JP: Pediatric X-Ray Diagnosis (ed 6). Chicago, Year Book Medical Publishers, 1972, pp 708-710 4. Campbell JB, Robinson AE: Hirschsprung’s disease presenting as calcified fecaloma. Pediatr Radio1 1:161163,1973 5. Cremin BJ: Functional intestinal obstruction in premature infants. Pediatr Radio1 1:109-112, 1973 6. Cremin BJ, Louw JH: Polyps in the large bowel in children. Clin Radio1 21:195-200, 1970 7. Davis WS, Allen RP, Favara BE, et al: small left colon syndrome. Am J Roentgen01 329,1974 8. Donaldson MH, Taylor P, Rawitscher R, et carcinoma in childhood. Pediatrics 48:307-312,
Neonatal 120:322al: Colon 1971
9. Esterly NB, Solomon LM: Neonatal dermatology. III. Pigmentary lesions and hemangiomas. J Pediatr 81: 1003-1013,1972 10. Fragoyannis SG, Anagnostopulos G: Hemangiolymphomatous hamartoma of the mesentery. Am J Dis Child 128:233-234, 1974 11. Holden KR, Alexander F: Diffuse neonatal hemangiomatosis. Pediatrics 46:411-421, 1970 12. Irving L, Scholander PF, Grinnell SW: The regula-
tion of arterial blood pressure in the seal during Am J Physiol 135:557-566, 1942
diving.
13. Kirkpatrick JA, Wagner ML, Pilling GP: A complex of anomalies associated with tracheoesophageal fistula and esophageal atresia. Am J Roentgen01 95:208-211, 1965 14. Louw JH: Congenital intestinal atresia and stenosis in the newborn. Observations on its pathogenesis and treatment. Ann R Co11 Surg Engl 25:209-234, 1959 15. McGovern B, Trump DS: Localization of the external sphincter during operation for imperforate anus. Surgery 66:1090-109!, 1969 16. MacKenzie DH: The Differential Diagnosis of Fibroblastic Disorders. Oxford, Blackwell Scientific Publications, 1970, pp 107-113 17. Nelson WE: Nelson Textbook of Pediatrics (ed 10). Philadelphia, Saunders, 1975, pp 827-829 18. Santulli TV, Blanc WA: Congenital atresia of the intestine: Pathogenesis and treatment. Ann Surg 154: 939-948, 1961 19. Singleton EB, Rosenberg HM, Samper L: Radiologic considerations of the perinatal distress syndrome. Radiology 76:200-212, 1961 20. Spiro HM: Clinical Gastroenterology. New York, Macmillan, 1970, p 894 21. Suzuki H, White JJ, el Shafie M, et al: Nonoperative diagnosis of Hirschsprung’s disease in neonates. Pediatrics 51:188-191, 1973
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22. Toccalino H, Guastavino Juvenile polyps of the rectum Stand 62:337-340,1973
IN
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E, De Pmni F, ct al: and colon. Acta Paediatr
23. Touloukian RJ, Berdon WE, Amoury RA, et al: Surgical experience with necrotizing enterocolitis in the infant. J Pediatr Surg 2~389-401, 1967 24. Vanhoutte
JJ, Katzman
D: Roentgenographic
man-
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ifcstations of immaturity of the intestinal neural plexus in premature infants. Radiology 106:363-367, 1973 25. Wagner ML, Harberg FJ, Kumar AP, et al: The evaluation of imperforate anus utilizing percutaneous injection of water-soluble iodide contrast material. Pediatr Radio1 1:34-40, 1973 26. Wagner ML, Rosenberg HS, Fernbach DJ, et al: Typhlitis: A complication of leukemia in childhood. Am J Roentgen01 109:341-350, 1970
Lesions of the Colon in Infants Edward
B. Singleton,
M.D., and Fred Johnson,
T
HE APPEAL of pediatric radiology is not found in its limitations but in the knowledge that virtually all disorders that affect the adult may also affect children. The restriction imposed by the editor-to confine ourselves chiefly to conditions limited to the pediatric agegroup-puts us in the position of a radiologic schlepper.” Consequently, the subject content of this presentation will consist of congenital abnormalities (atresias, Hirschsprung disease,and imperforate anus), inflammatory lesions (localized ischemic colitis and typhlitis), and neoplasms (juvenile polyps, histiocytic fibroma, hemangioma, and adenocarcinoma). CONGENITAL
LESIONS
A tresia
Most intestinal atresiasoccur in the ileum (50%) and duodenum (25%). About 15% are multiple. Isolated colon atresia is rare, occurring about once per 40,000 live births.17 Although the theory of failure of recanalization of the solid cellular stage of colon development may account for somecasesof colon atresia,most are probably the result of intrauterine vascular insufficiency (intrauterine necrotizing enterocolitis). According to Sutton’s classification* there are three types: (1) complete obstruction of the intestinal lumen by a diaphragm; (2) an atretic cord joining proximal and distal segmentsof patent colon; and (3) complete separationof the proximal and distal segmentsof colon with a V-shaped mesenteric defect corresponding to the missing area. In our experience, the most common form is *Editor’s note: Yiddish expression. A bum is merely a worthless man. A schlepper is something less. A schlemiehl spills soup on a schlemazel; the schlepper rushes up and wipes it off (with his sleeve, no less). Edward B. Singleton, M.D.: Clinical Professor of Radiology, Baylor College of Medicine and the University of Texas Medical School at Houston, Houston, Texas. Fred Johnson, M.D.: Fellow in Pediatric Radiology, Baylor College of Medicine, Houston, Texas. Reprint requests should be addressed to Edward B. Singleton, M.D., Texas Childreni Hospital, 6621 Fannin, Houston, Texas 77025. 0 I9 76 by Grune & Stratton, Inc. Seminarsin
Roentgenology,
Vol.
Xl,
No.
2 (April),
1976
and Children M.D.
atresia just distal to the hepatic flexure with an atretic band extending to a patent lumen at the splenicflexure (Fig. 1). Clinically, thesenewborn infants quickly become distended, vomit, and fail to passmeconium. Plain films showan obstructive pattern that is frequently impossibleto differentiate from a wide variety of conditions, including meconium ileus, ileal astresia, meconium plug syndrome, small left colon syndrome,7 and Hirschsprungdisease. Barium enemais confirmatory. It showsa small unused colon with complete obstruction at the point of atresia (Fig. 1B). Inability to fill the proximal portion of the colon is diagnostic of atresia and excludes the other conditions mentioned in the differential considerations. With membranous atresia, the head of the contrast column has a distinctive “windsock” configuration.’ Rectal atresia may occur as an isolated lesion or may be associated with imperforate anus(Fig. 2). Hirschsprmg
Disease
Hirschsprung diseaseis caused by absence of myenteric and submucousneural plexuses,usually localized to the rectum or distal sigmoid and rectum. This denervation leadsto an obstruction that is paradoxically unrelated to the length of the involved segment.The condition usually is identified in the neonate or young infant and accounts for approximately 20% of the casesof neonatal bowel obstruction.‘7 The localized form of the diseaseis four times more common in males. Aganglionosis of the entire colon accounts for approximately 10% of patients, is equally common in girls and may be familial.3’5 Localized or skipped segmentsof aganglionosiswith normal distal myenteric plexusesare rare. Extremely low aganglionosisinvolving the anorectal junction is usually impossibleto diagnoseeither histologically or by radiographic studies and presentsthe same clinical features as habit or functional constipation. Clinically, there is failure to pass meconium during the first 24 hr of life and the gradual development of abdominal distension and vomiting. Alternating constipation and diarrhea may occur, 111
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Fig. 1. Colon atresia. (A) There is dilatation of the small bowel as well as marked distension of the hepatic flexure of the colon. (6) Barium enema shows distal microcolon with obstruction to the flow of barium at the splenic flexure. At operation a fibrous cord was identified extending between the patent splenic flexure and the distended hepatic flexure. This is the most common form of colon atresia.
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Fig. 2. Rectal into the cloaca1 of the I‘ectum. pouch is clearly
THE
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atresia. Introduction of contrast media opening showed atresia of the midportion Gas within the proximal dilated rectal identified (arrow).
Fig. 3. Hirschsprung infant. The rectum at the rectosigmoid lateral view, made enema examination.
-old in a l-month. disease z one is small and I the transition is striking in the junction a limited bari following
SINGLETON
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Fig. 4. lmperforate anus. Injection of contrast medium via the needle demonstrated the caudal extent of the dilated pouch. Note the small beak (arrow), which is the site of a rectal fistula. Clinical workup and subsequent surgery proved this to represent the origin of a fistula, whose distal aspect was an atretic cord. (Reproduced by permission of Pediatric Radiology. 25 )
the latter a result of periodic episodes of colitis. Occasionally, a compulsive mother can keep the colon decompressed by enemas so that the condition is not recognized until the first year or two of life, by which time the infant is usually undernourished, with a potbelly and wasted extremities. The radiographic findings are, in part, the result of the inability of the aganglionotic segment to partake in the peristaltic activity of fecal evacuation and, in part, attributable to the physiologic principle that denervated smooth muscle is abnormally sensitive to stimulation and tends to contract.24 Plain films usually show an absence of gas and feces in the rectum along with signs of bowel obstruction. Associated features, including calcified fecaloma,4 congenital heart disease, mongolism, pulmonary hypoplasia, and vertebral or rib abnormalities,21 may divert the radiologist’s attention from the diagnosis. The radiographic evaluation consists of plain films of the abdomen followed by a limited
barium enema. Preparation in the form of laxatives or enema is contraindicated, since it may decompress the colon above the aganglionotic segment, preventing accurate identification of the transition area. In the older patient with questionable Hirschsprung disease, the barium should be suspended in isotonic saline because of the danger of water intoxication. However, this danger is remote if the examination is properly performed by limiting the enema to the rectosigmoid region. In megacolon of any type, filling the colon completely with barium adds to the patient’s problem of constipation and impaction. A transition zone is the most specific finding in Hirschsprung disease (Fig. 3). Unfortunately, since the transition zone is a result of the accumulation of fecal material in the colon above the resistant aganglionotic segment, it may not be radiographitally obvious in the first 3-4 weeks of life. In these first weeks, failure of elimination of the injected barium within a 4%hr period is presumptive
LESIONS
OF
THE
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IN
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AND
CHILDREN
evidence of aganglionosis, and appropriate confirmation by rectal biopsy is indicated. Other signs of Hirschsprung disease, including sawtooth contractions of the aganglionotic segment, thickened nodular edematous mucosal folds in the proximal colon, and failure to expel barium after a 48-hr interval, help to differentiate Hirschsprung disease from the small left colon syndrome. In the latter condition, the infant generally weighs less than 1500 kg at birth and usually has a diabetic mother, and the transition zone is always at the splenic flexure .7,24 In the older baby, functional megacolon enters the differential diagnosis. The onset of constipation in these babies begins during the toilet training age and there is a history of fecal soiling and of passing stools so voluminous that the plumbing may be obstructed-features not encountered in Hirschsprung disease. If the clinical findings are equivocal, introduction of a small amount of barium in the patient with functional megacolon will show a patulous dilated rectum and redundant rectosigmoid. Since clinical history and rectal manometry do not distinguish the extent of the Hirschsprung disease and may not differentiate from small left colon syndrome, the radiographic examination should accomplish these objectives. Early diagnosis is important, since delay increases the possibility of mechanical obstruction and necrosis of bowel. Imperjbrate Anus Imperforate anus is part of a complex set of abnormal embryologic events that occur after the fifth week of gestation, resulting in arrest of descent of the urorectal septum and failure of development of the proctodeum. The imperforation is often associated with other urogenital anomalies, and sometimes with anomalies of other systems. In order to remember the other areas to be checked radiographically when imperforate anus is found, use the mnemonic VATER: Vvertebrae; A-anorectal region; T-trachea; Eesophagus (atresia); and R-renal area. Some patients also have polydactyly, anomalies of the iris, and congenital heart disease.’ 3 Clinically, the infant with imperforate anus presents early with signs of obstruction. If there is a perineal orifice, it may be presumed that there is a low distal rectal pouch. The absence of a perineal orifice suggests a high pouch. Occasionally an
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ectopic insertion may open very close to the normal anal region and appear normal. Under these circumstances, the radiologist can resolve his skepticism about the necessity of an extensive urologic workup by trying to elicit an anal wink. The normal anus will wink at you when the area around it is stimulated with a pin. The ectopic anus may smile wryly but never winks.” The immediate objective of the radiographic studies is to differentiate the high (supralevator) from the low (translevator) type of imperforate anus and to identify fistulas not apparent on the plain film. The inverted plain film is frequently uninformative in distinguishing high from low termination, since meconium may be packed into the distal rectal pouch, giving an erroneous impression of a high segment. The most reliable method in our experience is to inject the blind pouch (under fluoroscopic control) with a very small amount of water-soluble contrast material.” Following preliminary supine and inverted films, the anal dimple is perforated with a 16-gauge Rochester needle, which is advanced until air or meconium is identified in the syringe. Following aspiration of as much air and meconium as possible, 3-5 ml of 20% Hypaque is introduced. Higher volumes are hygroscopic and may deplete plasma volume. Sometimes a fistula opacifies completely with this technique. However, in most patients a beak-like deformity at the caudal end of the pouch identifies the site of the fistula (Fig. 4). In the absence of demonstrable fistula, the levator sling will occasionally be seen indenting the rectal pouch, confirming that it has the low type of termination and that a pull-through procedure can be performed. However, if the radiologist still does not have definitive criteria for determining if the fistula is high or low, colostomy should be performed. A mistaken diagnosis of low termination may result in a perineal exploration that destroys any hope of future urinary continence. At some point in the patient’s course, radiographic workup should always include cystourethrography and urography. Additional workup depends on whether there are other associated anomalies. Typhlitis Typhlitis is a complication of terminal leukemia or aplastic anemia in children who are agranulo-
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Localized Ischemic Lesions
Fig. 5. Typhlitis. This lo-year-old girl had monomyelogenous leukemia. Roentgenogram of the abdomen 1 day before death shows the changes of mechanical small bowel obstruction. Autopsy revealed considerable involvement of the colon by an agranulocytic inflammatory process. The ileocecal valve was so infiltrated that it had caused obstruction. The appendix was normal. (Reproduced by permission of the American Journal of Roentgenology.26)
cytic.26 Pathologically there is severe hemorrhagic necrosis of the cecum. The reason for the curious localization of the necrotic process in this portion of the bowel has not been explained. In all probability, the mucosal integrity of the gastrointestinal tract has been affected, either by the disease itself, the therapy utilized, or a combination of both. Clinically, the patient develops spiking fever, abdominal distension, and pain during the terminal period of his illness. Although a feeling of fullness involving the right lower quadrant may be detected, a palpable mass is usually not present. Radiographically, there is a lack of bowel gas in the right lower quadrant with progressive distension of the small bowel and diminution of colonic gas (Fig. 5). The radiographic features are similar to those of gangrenous appendicitis with pericecal abscess.
Localized ischemic lesions of the colon may develop in babies who are under hypoxic conditions of stress and who develop reflex constriction of mesenteric arterial vessels as blood flow to the brain and heart is enhanced. This reflex mechanism as a cause for ischemic necrotizing enterocolitis has been well documented by experimental evidence.‘2~14~‘8~‘g~23 The recognizable radiographic bowel patterns of necrotizing enterocolitis and the complication of intramural gas will not be discussed here because the lesion is not localized. However, the complications during the reparative phase may result in localized stricture of the bowel, including the colon. Any infant who develops abdominal distension and vomiting 1 or more weeks after recovering from necrotizing enterocolitis should be suspected of having obstruction secondary to bowel stricture. This complication may be localized to the colon (Fig. 6). Rarely, stricture formation secondary to ischemic bowel disease will develop in an infant who has been under stress but who has not had the clinical or radiographic findings of necrotizing enterocolitis.
TUMORS
Juvenile Polyp A juvenile polyp is thought to begin as a retention cyst secondary to obstruction of the orifices of colonic mucous glands. A chronic irritation ensues, resulting in hyperplasia of the mucous glandswith superimposedinflammation. The condition is slightly more common in males,usually between 21 months and 11 years, with a peak at 3-4 years. The most common sign is nonpainful rectal bleeding appearingas drops of blood immediately after a normal bowel movement. However, the patient may manifest a wide variety of lessspecific findings, such as pain, constipation, diarrhea, and signsof intussusception. On rare occasionsthe polyp will prolapse.In this situation, the main purpose of the radiographic exam is to search for additional lesions, since as many as a third of these children have another polyp. Also, a variety of parasiteshave occasionally beendiscoveredin associationwith juvenile polyps,
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Fig. 6. Colon stricture following and colon. (6) Two months after stricture at the rectosigmoid level.
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necrotizing enterocolitis. recovery from the acute
Fig. 7. Solitary pedunculated polyp in the sigmoid 4-year -old child. The filling defect in the midsigmoid consta nt. Histologically, it was a juvenile polyp.
of a was
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(A) episode
At
2 weeks the colon
of age became
there is gas in the wall of the rectum obstructed. Barium enema shows a
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Fig. 8. Histiocytic fibroma in a l-month-old infant. The infant was obstructed. Barium enema disclosed an irreducible intussusception at the lower end of the descending colon.
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including oxyuris vernicularis, trichiuris trichiura, and giardiasis.” If a suggestive history is obtained, the optimal examination is an air-contrast enema after thoroughly cleansing the colon. The use of aerosol soap to inflate the rectum is an excellent way to visualize rectal polyps but is rarely necessary because of the accessibility of this area to the proctoscope. The polyp is usually encountered in the distal 20 cm of the colon, most commonly in the distal 5 cm. It is usually between 3 and 20 mm in diameter and may be pedunculated (Fig. 7). The histology is statistically predictable, since juvenile polyps account for over 75% of colon polyps in children.6 Management of the juvenile polyp depends on the severity of the bleeding. If symptoms are mild, the patient may be followed, since the polyp is usually spontaneously sloughed. With significant bleeding, the polyp can be removed surgically or via the colonoscope.
Histiocytic
Fibroma
Like the skin, the colon can manifest a wide variety of pathologic responses, some of which are unexpected. Also unexpected is the fact that lesions encountered in the skin may have a counterpart in the colon. One such lesion is the histiocytic fibroma. l6 This is a proliferation of fibrocytes and histiocytes that occurs most commonly on the skin but occasionally in the deeper tissues. Usually, this proliferation is a response to trauma, but occasionally it is neoplastic, with the power of repeated recurrence and metastatic spread. The lesion is less than 1 cm in diameter and may be pigmented with hemosiderin or lipid. Histologically, it must be differentiated from fibrosarcoma and xanthoma fibrosa. Intussusception may be the first manifestation (Fig. 8).
Hemangiti ma
Fig. 9. old child. identified
Hemangioma of the transverse colon in a 2-yearAn irregular-shaped sessile filling defect is on the superior wall. Proved at operation.
Another rare lesion that affects the colon as well as the skin and other organ systems is the hemangioma. It may present at any time in life with a wide variety of symptoms. There are a number of histologic types. A more complete discussion of the radiographic features is presented elsewhere in this issue (p. 131). Many authorities believe that isolated heman-
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F :ig. 10. Small hv. Confirmed
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art eriovenous at operation.
Fig.
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11.
Adenocarcinoma
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in the
ascending
of the
lower
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colon
descending
(arrow)
demonstrated
colon
in a 15-year-old
by superia
boy.
mesentel
ric artel riog-
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gioma results from sequestrated mesenchyme that is embryologically activated.” An autosomal dominant hereditary factor is responsible when generalized vascular lesions are a part of the OslerWeber-Rendu syndrome. Genetic factors are also incriminated when the hemangiomas are associated with Turner or Peutz-Jegher syndromes.20 Multiple colonic lesions occasionally present in the neonate as a part of fatal diffuse neonatal hemangiomatosis.” The blue rubber bleb nevus syndrome may also be present in the newborn with compressible blue to purple rubbery cavernous hemangiomas 3-4 cm in diameter in the skin, small and large bowel, liver, spleen, and nervous system.g Older patients present with hemorrhage, obstruction, pain, intussusception, or occasionally palpable mass. Sometimes, because of an associated inflammatory component, the patient presents with symptoms suggesting an acute abdominal condition.” The radiographic presentation is variable. The hemangioma may appear as a diffuse infiltrating
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lesion involving a segment of the bowel with thickening of the wall and narrowing of the lumen, or it may be localized and project into the lumen (Fig. 9). It may resemble a duplication and in some parts of the world has been mistaken for a hydatid cyst.” Selective angiography is useful in the preoperative diagnosis (Fig. 10). Adenocarcinoma Another lesion that is unexpected in children is carcinoma of the colon. Less than 200 cases have been reported in the Western world since 1900. The colonic sites are the same as in adults.’ The most common symptom is abdominal discomfort, followed by rectal bleeding and change in bowel habits, usually constipation.3 Pathologically, there is a preponderance of colloid (mucinproducing) adenocarcinoma in childhood. The prognosis is usually poor, with most chiidren dying within a year.’ The radiographic findings are similar to those in the adult (Fig. 11).
REFERENCES 1. Blank E, Afshani E, Girdany BR, et al: “Windsock sign” of congenital membranous atresia of the colon. Am J Roentgen01 120:330-332, 1974 2. Bley WR, Franken EA Jr: Roentgenology of colon atresia. Pediatr Radio1 1: 105-108, 1973 3. Caffey JP: Pediatric X-Ray Diagnosis (ed 6). Chicago, Year Book Medical Publishers, 1972, pp 708-710 4. Campbell JB, Robinson AE: Hirschsprung’s disease presenting as calcified fecaloma. Pediatr Radio1 1:161163,1973 5. Cremin BJ: Functional intestinal obstruction in premature infants. Pediatr Radio1 1:109-112, 1973 6. Cremin BJ, Louw JH: Polyps in the large bowel in children. Clin Radio1 21:195-200, 1970 7. Davis WS, Allen RP, Favara BE, et al: small left colon syndrome. Am J Roentgen01 329,1974 8. Donaldson MH, Taylor P, Rawitscher R, et carcinoma in childhood. Pediatrics 48:307-312,
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9. Esterly NB, Solomon LM: Neonatal dermatology. III. Pigmentary lesions and hemangiomas. J Pediatr 81: 1003-1013,1972 10. Fragoyannis SG, Anagnostopulos G: Hemangiolymphomatous hamartoma of the mesentery. Am J Dis Child 128:233-234, 1974 11. Holden KR, Alexander F: Diffuse neonatal hemangiomatosis. Pediatrics 46:411-421, 1970 12. Irving L, Scholander PF, Grinnell SW: The regula-
tion of arterial blood pressure in the seal during Am J Physiol 135:557-566, 1942
diving.
13. Kirkpatrick JA, Wagner ML, Pilling GP: A complex of anomalies associated with tracheoesophageal fistula and esophageal atresia. Am J Roentgen01 95:208-211, 1965 14. Louw JH: Congenital intestinal atresia and stenosis in the newborn. Observations on its pathogenesis and treatment. Ann R Co11 Surg Engl 25:209-234, 1959 15. McGovern B, Trump DS: Localization of the external sphincter during operation for imperforate anus. Surgery 66:1090-109!, 1969 16. MacKenzie DH: The Differential Diagnosis of Fibroblastic Disorders. Oxford, Blackwell Scientific Publications, 1970, pp 107-113 17. Nelson WE: Nelson Textbook of Pediatrics (ed 10). Philadelphia, Saunders, 1975, pp 827-829 18. Santulli TV, Blanc WA: Congenital atresia of the intestine: Pathogenesis and treatment. Ann Surg 154: 939-948, 1961 19. Singleton EB, Rosenberg HM, Samper L: Radiologic considerations of the perinatal distress syndrome. Radiology 76:200-212, 1961 20. Spiro HM: Clinical Gastroenterology. New York, Macmillan, 1970, p 894 21. Suzuki H, White JJ, el Shafie M, et al: Nonoperative diagnosis of Hirschsprung’s disease in neonates. Pediatrics 51:188-191, 1973
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22. Toccalino H, Guastavino Juvenile polyps of the rectum Stand 62:337-340,1973
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E, De Pmni F, ct al: and colon. Acta Paediatr
23. Touloukian RJ, Berdon WE, Amoury RA, et al: Surgical experience with necrotizing enterocolitis in the infant. J Pediatr Surg 2~389-401, 1967 24. Vanhoutte
JJ, Katzman
D: Roentgenographic
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ifcstations of immaturity of the intestinal neural plexus in premature infants. Radiology 106:363-367, 1973 25. Wagner ML, Harberg FJ, Kumar AP, et al: The evaluation of imperforate anus utilizing percutaneous injection of water-soluble iodide contrast material. Pediatr Radio1 1:34-40, 1973 26. Wagner ML, Rosenberg HS, Fernbach DJ, et al: Typhlitis: A complication of leukemia in childhood. Am J Roentgen01 109:341-350, 1970