THE MECONIUM PLUG SYNDROME* ROENTGEN EVALUATION AND DIFFERENTIATION FROM HIRSCHSPRUNG S DISEASE AND OTHER

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1 FEBRUARY, 1974 THE MECONIUM PLUG SYNDROME* ROENTGEN EVALUATION AND DIFFERENTIATION FROM HIRSCHSPRUNG S DISEASE AND OTHER PATHOLOGIC STATES By RUBEM POCHACZEVSKY, M.D., and JOHN C. LEONIDAS, M.D. Trn HE meconium plug syndrome is a relatively frequent cause of colonic mechanical obstruction in the newborn and is related to the failure to pass meconium in the first days of life. Many theories as to its etiology have been proposed including temporary inhibition of colonic peristalsis, alteration of the meconium composition, pancreatic enzyme de- 71 0, l.24,25,27 and neonatal hypermagnesemia. The retained meconium is hardened, with an increase in its surface tension and viscosity, causing it to become impacted i1:; the colon in the form ofa plug. The meconium plug syndrome usually follows a benign course and responds readily to conservative treatment. #{176} 24 Its recognition is, therefore, important in order that unnecessary operative treatment be avoided. The condition which most often mimics meconium plug syndrome is that of Hirschsprung s disease The latter s distinction is of equal importance since immediate surgical intervention is required. Other major pathologic conditions which may roentgenographically simulate the meconium plug syndrome are necrotizing enterocolitis of infancy, 9 20 meconium ileus, 8 ileal atresia, and, occasionally, midgut volvulus.2 In an attempt to evaluate criteria for their radiologic diagnoses and distinction, the authors reviewed the literature and their own case material of meconium plug syndrome, Hirschsprung s disease, necrotizing enterocoli tis of in fancy 9 2#{176} and meconium ileus. 8 NEW YORK, NEW YORK CASE MATERIAL MECONIUM PLUG SYNDROME Current case material consisted of 14 mi fants with meconium plug syndrome all o- whom were observed for periods of at least 2 years with no clinical evidence of Hirschsprung s disease or other gastrointestinal abnormality (Table I). All 14 cases of meconium plug syndrome had evidence of abdominal distention both clinically and roentgenographically (Fig. 1-4; and io). Accompanying mottled densities or bulky intraluminal colonic masses, which had the typical appearance of meconium (Fig. 1-4; and io), were noted on the plain film roentgenograms of the abdomen in 9 of these 14 cases. No meconium could be identified on the plain film roentgenograms of the other. Erect roentgeno- [ ABLE MECONIUM PLUG SYNDROME (14 Current Cases) Roentgen Abnormality Present Absent Total Plain Film Roentgenogram of the Abdomen Bowel distention Fluid levels (erect roentgenograms) Meconium identified Contrast Enema Roentgenogram Significant amounts of meconium Transition or collapsed colonic segment Stasis of contrast medium I * From the Department of Radiology, Mount Sinai Hospital Services, The City Hospital Center at Elmhurst and Mount Sinai School of Medicine, City University of New York, New York. 342

2 VOL. 120, No. 2 The Meconium Plug Syndrome 343 grams of the abdomen were obtained in 12 cases. No air-fluid levels were observed within the bowel in 7 of the 12 cases (Fig. 1-3), while air-fluid levels in the bowel were present in the remaining (Table i). Colonic contrast studies were performed on 8 patients. All showed an abnormally large amount of intraluminal meconium (Fig. 54; and 6-8) with a largely uninterrupted tape-like configuration threading through the major portion of the lumen of the colon (Fig. 54; 6-8; and iob). A collapsed or empty segment was noted distal to the meconium plug in 2 cases (Fig. 8). This pseudo transition simulated the appearance of Hirschsprung s disease. Delayed roentgenograms of the abdomen taken I day after the contrast study of the colon FIG. i. Case 1. Meconium plug syndrome. Erect roentgenogram of the abdomen. One day old female with a history of poor feedings and abdominal distention. Note retained colonic meconium giving the bowel a bubbly appearance. l ollowing this examination, a large meconium plug was passed. FIG. 2. Case II. Meconium plug syndrome. Twelve hour old male with abdominal distention and failure to pass meconium. Roentgenogram of the abdomen shows large meconium mass within cecum (arrows). Following this study a large meconium plug was passed. L 4! FIG.. Case iii. Meconium plug syndrome. One day old female. Erect roentgenogram of the abdomen. Note air-fluid level in the stomach, but no airfluid levels in the bowel. Note diffuse mottled densities due to meconium within the colon. A large meconium plug was subsequently passed. 1*

3 344 Rubem Pochaczevsky and John C. Leonidas FEBRUARY, 1974 FIG.. Case IV. Meconium plug syndrome. Four day old, premature, male twin with a history of sepsis and failure to pass meconium. Roentgenogram of the abdomen shows considerable amount of mewere available in 5 cases. Two of these showed no significant retention of contrast material after 24 hours, i had retention after 24 hours, while 2 demonstrated contrast material retention 72 hours post examination (Fig. 9) (Table i). Meconium plugs were passed by all 14 patients (Fig. 5B) with immediate clinical improvement in 13. The sole patient who did not improve (Case iv), was a premature twin who had associated sepsis, unrelated to the colon, and expired at 5 days of age. The other twin included among the 14 improved dramatically and continued to do well. HIRSCHSPRUNG S DISEASE Our case material consisted of 13 instances of biopsy proven Hirschsprung s disease diagnosed during Me first days of life (Table ii). All exhibited bowel distenconium in the region of the right colon (arrows). A cm. long meconium plug was passed after a rectal swab was inserted for stool culture. The infant had several subsequent apneic episodes, and died at days of age due to unrelated sepsis. FIG.. Case v. Meconium plug syndrome. Premature, i8 hour old male, with abdominal distention and failure to pziss meconium. (A) Barium enema examination shows large intracolonic meconium masses. (B) A large meconium plug was passed following completion of the barium enema study.

4 VOL. 120, No. 2 The Meconium Plug Syndrome 345 FIG. 6. Case VI. Meconium plug syndrome. Infant, 48 hours old, with a history of abdominal distention and vomiting. Barium enema examination accentuates long uninterrupted, intracolonic ribbon-like filling defects due to inspissated meconium. Following the barium enema studs a large oblong meconium plug was passed with immediate amelioration of the infant s symptoms. FIG.. Case VII. Meconium plug syndrome. One day old infant with abdominal distention and failure to pass meconium. Contrast enema examination shows undulating cylindrical meconium mass, extending from the rectum to the terminal ileum. lig. 8. Case VIII. Meconium plug syndrome. Newborn. Contrast enema examination shows an uninterrupted, snake-like mass of meconium occupying the entire transverse colon. Note collapsed colon distal to the splenic flexure. FIG. 9. Case ix. Meconium plug syndrome. Newborn. Previous contrast enema examination outlined considerable amounts of intraluminal meconium. Seventy-two hours following the enema study there is retained contrast medium within the colon. Retention of contrast medium is, therefore, not always a reliable point of differential distinction between the meconium plug syndrome and Hirschsprung s disease.

5 346 Rubem Pochaczevsky and John C. Leonidas FEBRUARY, 1974 TABLE II HIRSCHSPRUNG S DISEASE IN INFANTS FIG. io. Case xiv. Meconium plug syndrome. Newborn male with abdominal distention and mild respiratory distress. Roentgenogram of the abdomen shows marked bowel distention. Note sausage shaped oblong density within distal lumen of transverse colon (arrows). 4 DAYS OF AGE OR YOUNGER (13 Current Cases) Roentgen Abnormality Present Absent Total Plain Film Roentgenogram of the Abdomen Bowel distention,, Fluid levels (erect roentgenograms) 10 1 II Meconium identified 2 II 13 Contrast Enema Roentgenogram Excessive meconium identified Transition segment in rectosigmoid Stasis of contrast medium tion on the plain film roentgenograms of the abdomen. Ten of the 13 cases showed no mottled or bulky densities in the colon suggestive of meconium (Fig. i i4; 124; 134; and 14). Eleven of the 3 cases had ;.u. ; s disease. Two day old female with a history of L. to pass meconium and regurgitation of bile-stained material. (A) Abdominal roentgenogram shows marked bowel distention with no evidence of retained meconium. (B) Contrast enema roentgenogram demonstrates transitional segment in rectosigmoid. The lucency in the transverse colon is due to air. No significant amount of meconium is seen. A rectal biopsy confirmed the presence of Hirschsprung s disease.

6 VOL. 120, No. 2 The Meconium Plug Syndrome 347 FIG. 12. Hirschsprung s disease. Two day old infant with a history of abdominil distention. (A) Erect roentgenogram of the abdomen shows distention of bowel with air-fluid levels, but no evidence of meconium. (B) Contrast enema study shows no evidence of transitional segments and no significant meconium. G.I3.Lirschsprung s disease. One day old male with a history of vomiting and abdominal stention. (, Erect roentgenogram of the abdomen shows marked colonic distention with air-fluid levels (arrows). (B) Barium enema study demonstrates transitional segment in rectosigmoid. No significant meconium was noted. A rectal biopsy confirmed the roentgen diagnosis of aganglionosis.

7 348 Rubem Pochaczevsky and John C. Leonidas FEBRUARY, 1974 FIG. 14. Hirschsprung s disease. One day old male with a history of vomiting bile-stained material and feeding poorly. He had not passed any meconium since birth. Erect roentgenogram of the abdomen shows distention of bowel with air-fluid levels and no evidence of meconium. A barium enema study revealed a relative decrease in the caliber of the left colon. A diagnosis of Hirschsprung s disease was confirmed by rectal biopsy. erect roentgenograms of the abdomen and io exhibited air-fluid levels within the bowel (Fig. 124; 134; and (Table ii). Contrast studies of the colon were performed on 10 patients during the first days of life. Insignificant or only minimal amounts of colonic meconium were detected in 8 (Fig. IiB; I2B; and 13B) with significant amounts of meconium present in the remaining 2 cases. A transition segment in the rectosigmoid was seen in of the 10 cases (Fig. i ib; and i3b) and not seen in the others (Fig. i 2B). Delayed roentgenograms of the abdomen were obtained in 6 cases with significant contrast material retention seen in. The remaining case showed no significant contrast material retention on a 24 hour roentgenogram of the abdomen. DISCUSSION AND DIFFERENTIAL DIAGNOSIS Analysis of our 14 cases of meconium plug syndrome (Table i) and review of the Ii ,27 showed that several pertinent roentgen findings were almost always present. The meconium plug syndrome usually presents with a picture of mechanical obstruction due to the presence of inspissated intraluminal meconium. The latter is often identifiable on the plain film roentgenograms of the abdomen by telltale mottled densities or bulky intraluminal colonic masses (Fig. -4; and io). If not readily recognizable on the plain film roentgenograms, contrast colonic enema examinations may demonstrate the typical tape or ribbon-like or sausage shaped defects occupying most of the colonic lumen (Fig. 4; and 6-8). Large amounts of meconium may, however, occasionally be appreciated as incidental findings on roentgenograms of newborns without clinical evidence of intestinal obstruction. In the meconium plug syndrome, a long con tracted pseudo transi tion segment may be present extending from the splenic flexure down to the rectum (Fig. 8). This is due to collapse of the colon distal to the plug and should not be confused with the true transition segment of Hirschsprung s disease which is most commonly located in the rectosigmoid (Fig. i ib; and i3b). A transition segment in the vicinity of the splenic tlexure was not seen in any of our patients with Hirschsprung s disease and appeared to be extremely rare in our review of published cases Roentgenographically, Hi rschsprung s disease is the entity which may most closely mimic the meconium plug syndrome (Tables II and iii). Hirschsprung s disease frequently presents with signs of mechanical large bowel obstruction in the immediate neonatal period with the plain film roentgenogram of the abdomen showing marked bowel distention (Fig. ii 4; 124; 134; and i). The diagnosis is usually confir#{241}ied with the demonstration of a transi-

8 VOL. 120, No. 2 The Meconium Plug Syndrome 349 TABLE III ROENTGEN COMPARISONS IN MECONIUM PLUG AND HIRSCHSPRUNG S DISEASE Meconium Syndrome Plug Hirschsprung s Disease in 4 day old or younger infant Bowel Distention Plain Film Roentgenogram of the Abdomen Fluid Levels. Meconium. Meconium Frequent Uncommon Frequent Large amount prior to the passage of plug tional segment in the colon (Fig. i ib; and I 3B). Untreated Hirschsprung s disease, particularly in older infants, is further characterized by considerable retention of fecal material. However, in a majority of our cases (Table II) of Hirschsprung s disease studied in the first days of life, as well as in a majority of those abdominal film roentgenograms and barium enema studies reviewed from the literature including total aganglionosis of the colon and terminal 4522 no roentgen evidence of excessive meconium retention was observed in the first days of life. It is during this period, however, that the meconium plug syndrome is evident. To date, no abnormal composition of the meconium has been described in Hirschsprung s disease with the basic abnormality related to an aganglionic bowel segment. Additionally, air-fluid levels were absent in more than half of the meconium plug syndrome cases (Fig. 1-3) (Table I), while they were almost always present in the large and small bowel on erect roentgenograms of the abdomen obtained in cases of Hirschsprung s disease (Fig. 114; 124; 134; and 14) (Tables i and III). This may be related to the fact that meconium dry and harden in the meconium plug syndrome with an associated paucity of fluid in the bowel possibly precluding the formation of air-fluid levels. Contrast Enema Roentgenogram Transition Segment Long contracted segment may occur distal to the plug Frequent Frequent Uncommon Absent or modcrate amount only Frequent; usually located in rectosigmoid May. Stasis Frequent occur Hirschsprung s disease, however, may simulate the meconium plug syndrome in several respects (Table III). Furthermore, the typical transitional segments or prolonged retention of contrast medium may not be apparent in the first days oflife in many cases of Hirschsprung s disease3 5 8 (Fig. I2B). It is, therefore, essential that these difficulties in differential diagnosis be kept in mind in the individual case and that all infants in whom a diagnosis of meconium plug syndrome has been made be followed for an adequate period of time to ensure the absence of recurrent intestinal obstruction. If any gastrointestinal signs or symptoms recur, a repeat contrast enema examination should be performed for possible detection of a transition zone which may have become more apparent in the interim. Rectal biopsy may be necessary in doubtful cases. Necrotizing enterocolitis of infancy may also present with abdominal distention in the newborn and may, occasionally, resemble the meconium plug syndrome. A recent review of our experience with 20 cases of necrotizing enterocolitis of infancy as well as an extensive review of the literature revealed that the most commonly associated major roentgen findings consisted of pneumoperi toneum, pneumatosis intestinalis, portal venous gas and small bowel distention. 9 2#{176}

9 350 Rubem Pochaczevsky and John C. Leonidas FEBRUARY, 1974 FIG. 15. Necrotizing enterocolitis of infancy. Erect abdominal roentgenogram, first day of life. History of bile emesis, rectal bleeding and respiratory distress. Note frothy appearance in distal transverse and descending colon, as well as curvilinear stripes of gas at the splenic flexure indicative of pneumatosis intestinalis. Note similarity to Case (Fig. ) and Case III (Fig. 3). Pneumatosis intestinalis may lend a frothy appearance to the colon (Fig. ii), simulating retained meconium (Fig. 1-3). However, the diagnosis is aided by the identification of su bserosal extralum inal bowel gas (gas stripes in the bowel) in necrotizing enterocolitis. Gas in the portal hepatic venous system and pneumoperitoneum are usually absent in meconium plug syndrome. Actually, the clinical presentation of the 2 entities is different in the overwhelming majority of cases.2#{176} Meconium ileus may also be associated with a bubbly appearance of retained meconium. However, this is usually limited to the distal small bowel,5 since the colon rarely contains appreciable amounts of meconium. 4 If a colonic contrast study is performed, it will frequently reveal an unused type of colon or microcolon. The obstruction is caused by tenacious, viscous meconium in the small bowel producing great variation in the size of the bowel loops and few or no air-fluid levels.6 25 Meconium ileus is associated with pancreatic cystic fibrosis and with an abnormal chloride sweat test Infants with meconium plug syndrome only rarely show evidence of cystic fibrosis of the pancreas,24 but because of this possibility careful follow-up of all patients with a history of meconium plug, including a sweat test is advisable. A bubbly appearance within distended loops may also be seen in cases of intestinal atresia unassociated with meconium ileus 8 22 (Fig. 16). Barium enema examination shows a microcolon as in meconium ileus and the differential diagnosis between the 2 may be impossible without appropriate laboratory studies, such as the sweat test. SUMMARY The authors experience with 14 cases of the meconium plug syndrome and 13 cases l IG. i6. Lower jejunal atresia. Note markedly distended small bowel loops in right upper quadrant containing large amounts of meconium. A colon study demonstrated a microcolon.

10 VOL. 120, No. 2 The Meconium Plug Syndrome 35 of Hirschsprung s disease is presented and the roentgenographic findings reviewed. Criteria for differentiation of meconium plug syndrome from Hirschsprung s disease as well as from other pathologic processes, such as necrotizing enterocolitis of infancy and meconium ileus, are formulated and illustrated. The following roentgen findings were almost always present in the meconium plug syndrome: small and large bowel distention, mottled or bulky intraluminal colonic masses reflecting excessive meconium retention and producing ribbon-like or sausage shaped defects on contrast enema roentgenograms. Air-fluid levels in the bowel were uncommon. Long contracted colonic segments simulating the transition segments of Hirschsprung s disease, and due to collapse of the colon distal to the plug, may be seen involving the descending colon down to the sigmoid and/or rectum. In distinction, excessive meconium was infrequently seen on plain film roentgenograms or contrast enema studies in 13 current cases of Hirschsprung s disease in infants days of age or younger. Additionally, air-fluid levels in the bowel were almost always present. If transition segments were identified in these young patients, they were localized to the rectosigmoid in most cases. Hirschsprung s disease remains, however, the most difficult problem in the differential diagnosis since it may occasionally present with clinical and roentgen findings almost identical with the meconium plug syndrome. Follow-up of all cases with the diagnosis of meconium plug syndrome is, therefore, recommended to exclude recurrence of symptoms in which event careful re-evaluation should be undertaken. Rubem Pochaczevsky, M.D. Department of Radiology City Hospital Center at Elmhurst Broadway Elmhurst, New York The authors wish to express their appreciation to Drs. David Bryk and E. George Kassner for case material contribution from The Jewish Hospital and Medical Center of Brooklyn. REFERENCES I. ASCH, M. J., WEITZMAN, J. J., HAYS, D. M., and BRENNAN, P. I otal colon aganglionoses. A.M.A. Arch. Surg., 1972, 105, BENSON, C. D., and LLOYD, J. R. Meconium plug syndrome. In: Pediatric Surgery. Edited by Orwar Seenson. Year Book Medical Publishers, Inc., Chicago, 1969, 2, BERDON, W. E., and BAKER, D. H. Roentgenographic diagnosis of Hirschsprung s disease in infancy. AM. J. ROENTGENOL., RAD. THERAPY & NUCLEAR MED., 1965, 93, BERDON, W. E., KOONTZ, P., and BAKER, D. H. Diagnosis ofcolonic and terminal ileal aganglionosis. AM. J. ROENTGENOL., RAD. THERAPY & NUCLEAR MED., 1964, 9!, BERMAN, C. Z. Roentgenographic manifestations of congenital megacolon (Hirschsprung s disease) in early infancy. Pediatrics, 1965, i8, BRYK, D. Meconium ileus: demonstration of meconium mass on barium enema study. AM. J. ROENTGENOL., RAD. THERAPY & NUCLEAR MED., 1965, 95, CLATWORTHY, H. W., JR., HOWARD, W. H. R., and LLOYD, J. Meconium plug syndrome. Surgery, 1956,39, DAVIs, W. S., and PARKER, A. Conditioning value of plain film examination in diagnosis of neonatal Hi rschsprung s disease. Radiology, 1969, 93, EHRENPREIS, T. H. Megacolon in the newborn: clinical and roentgenological study with special regard to pathogenesis. Acta paediat., 1945, 32, ELLIS, D. G., and CLATWORTHY, H. W., JR. Meconium plug syndrome revisited. 7. Pediat. Surg., 1966, 1, u. EMERY, J. L. Abnormalities in meconium of foetus and newborn. Arch. Dis. Childhood, 1957,32, EVANS, W. A., and WILLIS, R. Hirschsprung s disease: roentgen diagnosis in infants. AM. J. ROENTGENOL., RAD. THERAPY & NUCLEAR MED., 1957, 78, GILLI5, D. A., and GRANTYMYRE, E. B. Meconium plug syndrome and Hirschsprung s disease. Canad. M.A.7., 1965, 92, GROSSMAN, H., BERDON, W. E., and BAKER, D. H. Gastrointestinal findings in cystic fibrosis. AM. J. ROENTGENOL., RAD. THERAPY & NUCLEAR MED., 1966, 97, i. HILLER, H. G., and MCDONALD, P. Neonatal Hirschsprung s disease. Prog. Pediat. Radiol., 1969, 2,

11 352 Rubem Pochaczevsky and John C. Leonidas FEBRUARY, 1974 i6. HOPE, J. W., BORNS, P. F., and BERG, P. K. Roentgenologic manifestations of Hirschsprung s disease in infancy. AM. J. ROENT- GENOL., RAD. THERAPY & NUCLEAR MED., 1965, 95, KOTTMEIER, P. K., and CLATWORTHY, H. W., JR. Aganglionic and functional megacolori in children: diagnostic dilemma. Pediatrics, 1965, 36, i8. LEONIDAS, J. C., BERDON, W. E., BAKER, D. H., and SANTULLI, T. V. Meconium ileus and its complications: reappraisal of plain film roentgen diagnostic criteria. AM. J. ROENTGENOL., RAD. THERAPY & NUCLEAR MED., 1970, io8, POCHACZEVSKY, R., and BRYK, D. New roentgenographic signs of neonatal gastric perforation. Radiology, 1972, 102, POCHACZEVSKY, R., and KA55NER, G. E. Necrotizing enterocolitis of infancy. AM. J. ROENT- GENOL., RAD. THERAPY & NUCLEAR MED., 1971, 113, POCHACZEVSKY, R., RATNER, H., LEONIDAS, J. C., NAYSAN, P., and FERARU, F. Unusual forms of volvulus after neonatal period. AM. J. ROENTOENOL., RD. THERAPY & NUCLEAR MED., 1972, 114, SINGLETON, E. R. Radiologic evaluation of intestinal obstruction in newborn. Radiol. Clin. North America, 1963, 1, i. 23. SOKAL, M. M., KOENIGSBERGER, M. R., RosE, J. S., BERDON, W. E., and SANTULLI, T. V. Neonatal hypermagnesemia and meconium plug syndrome. New England 7. Med., 1972, 286, SWISCHUK, L. E. Meconium plug syndrome: cause of neonatal intestinal obstruction. AM. J. ROENTGENOL., RAD. THERAPY & NUCLEAR MED., 1968, 103, TUCKER, A. S., and IZANAT, R. J., JR. Problems with meconium. AM. J. ROENTGENOL., RAD. 1HERAPY & NUCLEAR MED., 1971, 112, VAN LEEUWEN, G., GLENN, L., and WOODRUFF, C. Meconium plug syndrome with aganglionosis. Pediatrics, 1967, 40, ZACHARY, R. B. Meconium and faecal plugs in newborn. Arch. Dis. Childhood, 1957, 32,

12 This article has been cited by: 1. Lakshmana Das Narla, Elizabeth A. Hingsbergen Case 22: Total Colonic Aganglionosis Long-Segment Hirschsprung Disease. Radiology 215:2, [CrossRef] 2. S. M. Hussain, M. Meradji, S. G. F. Robben, W. C. J. Hop Plain film diagnosis in meconium plug syndrome, meconium ileus and neonatal Hirschsprung's disease. Pediatric Radiology 21:8, [CrossRef] 3. Catherine A. Poole, Marc I. Rowe Distal neonatal intestinal obstruction: The choice of contrast material. Journal of Pediatric Surgery 11:6, [CrossRef] 4. Paul R. White An Approach to Pediatric Gastrointestinal Radiology. Pediatric Clinics of North America 22:4, [CrossRef]