Pediatric Radiology
The Persistent Loop Sign in Neonatal Necrotizing Enterocolitis: A New Indication for Surgical Intervention? 1 Howard A. Wexler, M.D. A new radiographic sign in neonatal necrotizing enterocolitis is described. Five patients with necrotizing enterocolitis exhibited an unchanging dilated loop of small bowel, which was followed by perforation in 3 infants; the other 2 had surgical and/or autopsy corroboration of profound bowel-wall necrosis. It is suggested that infants with a "persistent loop" be considered candidates for laparotomy. INDEX TERMS: Colon, inflammation • (Gastrointestinal system, necrotizing enterocolitis, 7 [8] .267) • Intestines, diseases Radiology 126:201-204, January 1978
RADIOGRAPHIC findings in neonatal necrotizing enterocolitis have been extensively described (1-8); however, the etiology and treatment continue to generate much discussion (9-17) and the indications for operative intervention vary from center to center (7, 18-21). While most would agree that intestinal perforation leading to free air is a definite indication (19), there is no consensus about operating on patients with metabolic acidosis, shock, DIG, walled-off perforations, and peritoneal fluid (2, 6). Since perforation is associated with a poor prognosis, any signs of impending perforation would be helpful (2). I wish to describe a specific bowel pattern in patients with necrotizing enterocolitis that has been associated with a necrotic segment, often leading to perforation. Recognition of this "persistent loop" sign, i.e., a loop of bowel remaining relatively unchanged in position and configuration over a period of 24 to 36 hours, is increasingly regarded as an indication for surgery in this institution. Five cases with surgical and/or autopsy corroboration are described.
T
HE
CASE REPORTS CASE I: Gram-negative sepsis followed by abdominal distension developed in a 70o-g premature infant at two weeks of age. Prior to this the infant had been stable except for intermittent episodes of apnea and bradycardia requiring intubation and mechanical ventilation. An initial abdominal radiograph (Fig. 1) revealed moderate distension. Because necrotizing enterocolitis was suspected, follow-up films were obtained every 12 hours. Figure 2, obtained after 36 hours, shows diffuse abdominal distension with one dilated loop in the mid-abdomen appearing relatively unchanged in size and position (arrows). The significance of this "persistent loop" pattern was not appreciated at the time. Despite aggressive medical management, intestinal perforation occurred eight hours later. An emergency laparotomy confirmed peritonitis with necrosis of the distal ileum as well as a short portion of the jejunum. Postoperatively the patient did well but died three months later from respiratory failure and gram-negative sepsis.
Comment: Since this child was one of the first in which
a "persistent loop" was recognized, early intervention was not recommended and perforation did occur. If impending perforation had been anticipated, laparotomy could have been performed on an elective basis and gross spillage of fecal contents would have been avoided. CASE II: At one month of age this 925-g, 28-week-prernature infant exhibited abdominal distension with loose green stools. Abdominal radiographs revealed diffuse pneumatosis intestinalis with air in the portal veins (Fig. 3). She was started on a necrotizing enterocolitis regimen including nothing by mouth, nasogastric suction, and intravenous antibiotics. Serial films obtained during the next three days revealed clearing of the portal venous air, with continuing abdominal distension and a "persistent loop" in the right lower quadrant (Figs. 4 and 5). The importance of this radiographic finding was stressed; however, the infant was thought to be clinically improving, and surgery was withheld. Forty-eight hours later the patient again deteriorated with increasing abdominal distension and signs of disseminated intravascular coagulopathy. Exploratory laparotomy revealed diffuse necrosis of the terminal ileum without gross perforation. The postoperative course was complicated by bleeding, sepsis, and bronchopneumonia. The infant died eight days later.
Comment: The ominous finding of a persistent loop in this premature infant with necrotizing enterocolitis was recognized; however, her temporary clinical improvement delayed surgical intervention. By the time she was operated upon she had advanced bowel necrosis, peritonitis, and ascites. Her postoperative course was complicated by disseminated intravascular coagulopathy and bronchopneumonia. CASE III: A 900-g premature infant demonstrated gram-negative sepsis at one week of age. Two weeks later, necrotizing enterocolitis complicated by gross perforation occurred. At laparotomy there was extensive necrosis of a major portion of the jejunum and ileum. The most severely involved areas were resected; however, it was noted that several loops still appeared very dusky and cyanotic at closure. A serial postoperative abdominal radiograph (Fig. 6) revealed a "persistent loop" pattern in the middle abdomen. The patient died four days later with sepsis, acidosis, and scleredema.
1 From the Department of Radiology, University of Miami School of Medicine, Jackson Memorial Medical Center, Miami, Florida. Accepted for publication in August 1977. wjw
201
202
HOWARD
A.
WEXLER
January 1978
Fig. 1. CASE I. Supine view of the abdomen, revealing generalized nonspecific distension. Fig. 2. CASE I. The dilated loop in the mid-abdomen (apparent after 24 hours) is unchanged in position and configuration after 36 hours; most of the other loops have changed.
Comment: The "persistent loop" pattern in this postoperative infant was predictable, since it was not possible to resect all of the diseased bowel at laparotomy. The unchanging bowel pattern in the first three postoperative days suggested that the remaining necrotic intestine was irreparably damaged. Complications of necrotizing enterocolitis proved fatal in the immediate postoperative period.
vealed diffuse small bowel distension with multiple air-fluid levels and no free air. The infant was placed on a necrotizing enterocolitis protocol, which included abdominal radiographs every 12 hours. Follow-up films suggested a "persistent loop" in the right lower quadrant for 24 hours, immediately followed by loculated free air. Because of severe thrombocytopenia and a total-body bullous exfolliative dermatitis, laparotomy had to be deferred and the patient died ten days later. At postmortem, there were multiple fibrous adhesions in the peritoneum. Microscopic sections of small bowel were compatible with previous enterocolitis and peritonitis.
CASE IV: This 1-week old, 940-g premature infant was being treated for congestive heart failure secondary to a large patent ductus arteriosus when abdominal distension was noted. The child had received no oral feedings since birth. Initial abdominal radiographs revealed nonspecific mild abdominal distension. She was placed on a medical regimen for suspected necrotizing enterocolitis. Serial radiographs (Fig. 7) later revealed a persistent isolated loop. The importance Of this finding was recognized, but it was elected to continue medical therapy with careful observation. On the next radiograph a pneumoperitoneum was noted. At emergency laparotomy, a perforated necrotic segment of distal ileum was resected. Peritonitis with gross spillage of meconium and bile was present.
Comments: The morbid condition of this infant precluded surgical intervention at the time the "persistent loop" was identified. Loculated free air in the right lower quadrant was noted on the next film. At autopsy the perforation had closed over; however, as in the other cases, it was preceded by a "persistent loop."
Comment: Having now had previous experience with a "persistent loop," the significance of this radiographic finding was emphasized. Since the child's clinical condition did not warrant an emergency laparotomy, one more radiograph was obtained, by which time perforation had already occurred. Future attention to this finding will hopefully avoid this complication. CASE V: A 3-week old, 850-g premature infant exhibited abdominal distension with hematest-positive stools. Abdominal radiographs re-
DISCUSSION
Necrotizing enterocolitis is still being seen in epidemic proportions in many neonatal centers. Earlier recognition and treatment has lead to improved survival. Fewer patients with portal venous gas and free perforation are being seen at this institution than a few years ago. The real breakthrough awaits successful prevention in the high-risk premature infant (9-12, 14, 15). Although surgical resection is not the treatment of choice, many infants stil! come to laparotomy for perforation leading to free air. Many authors differ as to the indications for surgical exploration, although all would agree that operation is indicated in the infant with intestinal perforation and pneu-
Vol. 126
203
NEONATAL NECROTIZING ENTEROCOLITIS
Pediatric Radiology
Fig. 3. CASE II. Initial supine abdominal radiograph. revealing diffuse distension with linear and cystic pneumatosis intestinalis and air in the portal veins. Arrow indicates the position of the future persistent loop. Fig. 4. CASE II. Forty-eight-hour follow-up shows decreased distension. probable ascites. and a persistent right-Iowerquadrant loop. Fig. 5. CASE II. Seventy-two hours after onset, the ascites has increased and other loops have changed, with the exception of the one in the right lower quadrant (arrow).
moperitoneum. Earlier detection of advanced bowel necrosis, indicating imminent perforation, would be clinically helpful (2). The "persistent loop" sign may be helpful in evaluating prospective surgical candidates. A loop of bowel that is relatively unchanged in position and configuration over a 24- to 36-hour interval should raise the possibility of advanced bowel necrosis and impending perforation. The most likely explanation for the unchanging loop is that necrosis of the mucosa, submucosa, and serosa has taken place, rendering the segment aperistaftic and dead (22). Rigler et at. (23) described the roentgen signs of intestinal necrosis in adults but made no mention of infants with necrotizing enterocolitis. I submit that this "persistent
loop" pattern goes one step further, and identifies infants whose bowel injury is so profound that perforation is imminent. An awareness of this roentgenographic finding may help to avoid a middle-of-the-night emergency laparotomy for intestinal perforation in infants who are being followed for necrotizing enterocolitis. ACKNOWLEDGMENT: I wish to thank Miss La Donna Sherer for her assistance in preparing this manuscript.
REFERENCES 1.
Bell RS. Graham CB, Stevenson JK:
Roentgenologic and
204
HOWARD
A.
WEXLER
January 1978
Fig. 7. CASE IV. Serial abdominal radiograph, showing placement of a nasogastric tube with decreasing bowel gas. A persistent loop is identified in the mid-abdomen (arrows). Fig. 6. CASE III. Supine abdominal radiograph obtained on the third postoperative day, revealing a persistent loop pattern (arrows) in the mid-abdomen.
clinical manifestations of neonatal necrotizing enterocolitis. Am J RoentgenoI112:123-134, May 1971 2. Cohn R, Sunshine P, De Vries P: Necrotizing enterocolitis in the newborn infant. Am J Surg 124: 165-168, Aug 1972 3. Leonidas JC, Hall RT, Amoury RA: Critical evaluation of the roentgen signs of neonatal necrotizing enterocolitis. Ann Radiol 19: 123-132, Jan-Feb 1976 4. Mizrachi A, Barlow 0, Berdon WE, et al: Necrotizing enterocolitis in premature infants. J Pediatr 66:697-705, 1972 5. Pochaczevsky R, Kassner EG: Necrotizing enterocolitis of infancy. Am J RoentgenoI113:283-296, Oct 1971 6. Rabinowitz JG, Siegle RL: Changing clinical and roentgenographic patterns of necrotizing enterocolitis. Am J Roentgenol 126: 560-566, Mar 1976 7. Santulli TV, Schullinger IN, Heird WT, et al: Acute necrotizing enterocolitis in infancy: a review of 64 cases. Pediatrics 55:376-387, Mar 1975 8. Siegle RL, Rabinowitz JG, Korones SB, et al: Early diagnosis of necrotizing enterocolitis. Am J Roentgenol 127:629-632, Oct 1976 9. Barlow B, Santulli TV, Heird WC, et al: An experimental study of neonatal enterocolitis-the importance of breast milk. J Pediatr Surg 9:587 -595, Oct 1974 10. Bell MJ, Kosloske AM, Benton C, et al: Neonatal necrotizing enterocolitis: prevention of perforation. J Pediatr Surg 8:601-605, Oct 1973 11. Book LS, Herbst JJ, Atherton SO, et al: Necrotizing enterocolitis in low-birth-weight infants fed an elemental formula. J Pediatr 87:602-605, Oct 1975 12. Egan EA, Mantilla G, Nelson RM, et al: A prospective con-
trolled trial of oral kanamycin in the prevention of neonatal necrotizing enterocolitis. J Pediatr 89:467-470, Sep 1976 13. Frantz 10 3d, L'heureux PL, Engel RR, et al: Necrotizing enterocolitis. J Pediatr 86:259-263, Feb 1975 14. Hakanson DO, Oh W: Necrotizing enterocolitis and hyperviscosity in the newborn infant. J Pediatr 90:458-461, Mar 1977 15. Leake RD, Thanopoulos B, Nieberg R: Hyperviscosity syndrome associated with necrotizing enterocolitis. Am J Dis Child 129: 1192-1194, Oct 1975 16. Robinson AE, Grossman H, Brumley, GW: Pneumatosis intestinalis in the neonate. Am J RoentgenoI120:333-341, Feb 1974 17. Wilson SE, Woolley, MM: Primary necrotizing enterocolitis in infancy. Arch Surg 99:563-566, Nov 1969 18. Arnon RG, Fishbein JF: Portal venous gas in the pediatric age group. Review of the literature and report of twelve new cases. J Pediatr 79:255-259, Aug 1971 19. Stevenson JK, Oliver TK, Graham CB, et al: Aggressive treatment of neonatal necrotizing enterocolitis: 38 patients with 25 survivors. J Pediatr Surg 6:28-35, Feb 1971 20. Stevenson JK, Graham CB, Oliver TK, et al: Neonatal necrotizing enterocolitis. Am J Surg 118:260-272, Aug 1969 21. Touloukian RJ, Berdon WE, Amoury RA, et al: Surgical experience with necrotizing enterocolitis in the infant. J Pediatr Surg 2: 389-401, Oct 1967 22. Tomchik FS, Wittenberg J, Ottinger LW: The roentgenographic spectrum of bowel infarction. Radiology 96:249-260, Aug 1970 23. Rigler LG, Pogue WL: Roentgen signs of intestinal necrosis. Am J Roentgenol 94:402-409, Jun 1965
Howard A. Wexler, M.D. 2485 N.E. 202nd St. N. Miami Beach, Fla. 33180
The Persistent Loop Sign in Neonatal Necrotizing Enterocolitis: A New Indication for Surgical Intervention? 1 Howard A. Wexler, M.D. A new radiographic sign in neonatal necrotizing enterocolitis is described. Five patients with necrotizing enterocolitis exhibited an unchanging dilated loop of small bowel, which was followed by perforation in 3 infants; the other 2 had surgical and/or autopsy corroboration of profound bowel-wall necrosis. It is suggested that infants with a "persistent loop" be considered candidates for laparotomy. INDEX TERMS: Colon, inflammation • (Gastrointestinal system, necrotizing enterocolitis, 7 [8] .267) • Intestines, diseases Radiology 126:201-204, January 1978
RADIOGRAPHIC findings in neonatal necrotizing enterocolitis have been extensively described (1-8); however, the etiology and treatment continue to generate much discussion (9-17) and the indications for operative intervention vary from center to center (7, 18-21). While most would agree that intestinal perforation leading to free air is a definite indication (19), there is no consensus about operating on patients with metabolic acidosis, shock, DIG, walled-off perforations, and peritoneal fluid (2, 6). Since perforation is associated with a poor prognosis, any signs of impending perforation would be helpful (2). I wish to describe a specific bowel pattern in patients with necrotizing enterocolitis that has been associated with a necrotic segment, often leading to perforation. Recognition of this "persistent loop" sign, i.e., a loop of bowel remaining relatively unchanged in position and configuration over a period of 24 to 36 hours, is increasingly regarded as an indication for surgery in this institution. Five cases with surgical and/or autopsy corroboration are described.
T
HE
CASE REPORTS CASE I: Gram-negative sepsis followed by abdominal distension developed in a 70o-g premature infant at two weeks of age. Prior to this the infant had been stable except for intermittent episodes of apnea and bradycardia requiring intubation and mechanical ventilation. An initial abdominal radiograph (Fig. 1) revealed moderate distension. Because necrotizing enterocolitis was suspected, follow-up films were obtained every 12 hours. Figure 2, obtained after 36 hours, shows diffuse abdominal distension with one dilated loop in the mid-abdomen appearing relatively unchanged in size and position (arrows). The significance of this "persistent loop" pattern was not appreciated at the time. Despite aggressive medical management, intestinal perforation occurred eight hours later. An emergency laparotomy confirmed peritonitis with necrosis of the distal ileum as well as a short portion of the jejunum. Postoperatively the patient did well but died three months later from respiratory failure and gram-negative sepsis.
Comment: Since this child was one of the first in which
a "persistent loop" was recognized, early intervention was not recommended and perforation did occur. If impending perforation had been anticipated, laparotomy could have been performed on an elective basis and gross spillage of fecal contents would have been avoided. CASE II: At one month of age this 925-g, 28-week-prernature infant exhibited abdominal distension with loose green stools. Abdominal radiographs revealed diffuse pneumatosis intestinalis with air in the portal veins (Fig. 3). She was started on a necrotizing enterocolitis regimen including nothing by mouth, nasogastric suction, and intravenous antibiotics. Serial films obtained during the next three days revealed clearing of the portal venous air, with continuing abdominal distension and a "persistent loop" in the right lower quadrant (Figs. 4 and 5). The importance of this radiographic finding was stressed; however, the infant was thought to be clinically improving, and surgery was withheld. Forty-eight hours later the patient again deteriorated with increasing abdominal distension and signs of disseminated intravascular coagulopathy. Exploratory laparotomy revealed diffuse necrosis of the terminal ileum without gross perforation. The postoperative course was complicated by bleeding, sepsis, and bronchopneumonia. The infant died eight days later.
Comment: The ominous finding of a persistent loop in this premature infant with necrotizing enterocolitis was recognized; however, her temporary clinical improvement delayed surgical intervention. By the time she was operated upon she had advanced bowel necrosis, peritonitis, and ascites. Her postoperative course was complicated by disseminated intravascular coagulopathy and bronchopneumonia. CASE III: A 900-g premature infant demonstrated gram-negative sepsis at one week of age. Two weeks later, necrotizing enterocolitis complicated by gross perforation occurred. At laparotomy there was extensive necrosis of a major portion of the jejunum and ileum. The most severely involved areas were resected; however, it was noted that several loops still appeared very dusky and cyanotic at closure. A serial postoperative abdominal radiograph (Fig. 6) revealed a "persistent loop" pattern in the middle abdomen. The patient died four days later with sepsis, acidosis, and scleredema.
1 From the Department of Radiology, University of Miami School of Medicine, Jackson Memorial Medical Center, Miami, Florida. Accepted for publication in August 1977. wjw
201
202
HOWARD
A.
WEXLER
January 1978
Fig. 1. CASE I. Supine view of the abdomen, revealing generalized nonspecific distension. Fig. 2. CASE I. The dilated loop in the mid-abdomen (apparent after 24 hours) is unchanged in position and configuration after 36 hours; most of the other loops have changed.
Comment: The "persistent loop" pattern in this postoperative infant was predictable, since it was not possible to resect all of the diseased bowel at laparotomy. The unchanging bowel pattern in the first three postoperative days suggested that the remaining necrotic intestine was irreparably damaged. Complications of necrotizing enterocolitis proved fatal in the immediate postoperative period.
vealed diffuse small bowel distension with multiple air-fluid levels and no free air. The infant was placed on a necrotizing enterocolitis protocol, which included abdominal radiographs every 12 hours. Follow-up films suggested a "persistent loop" in the right lower quadrant for 24 hours, immediately followed by loculated free air. Because of severe thrombocytopenia and a total-body bullous exfolliative dermatitis, laparotomy had to be deferred and the patient died ten days later. At postmortem, there were multiple fibrous adhesions in the peritoneum. Microscopic sections of small bowel were compatible with previous enterocolitis and peritonitis.
CASE IV: This 1-week old, 940-g premature infant was being treated for congestive heart failure secondary to a large patent ductus arteriosus when abdominal distension was noted. The child had received no oral feedings since birth. Initial abdominal radiographs revealed nonspecific mild abdominal distension. She was placed on a medical regimen for suspected necrotizing enterocolitis. Serial radiographs (Fig. 7) later revealed a persistent isolated loop. The importance Of this finding was recognized, but it was elected to continue medical therapy with careful observation. On the next radiograph a pneumoperitoneum was noted. At emergency laparotomy, a perforated necrotic segment of distal ileum was resected. Peritonitis with gross spillage of meconium and bile was present.
Comments: The morbid condition of this infant precluded surgical intervention at the time the "persistent loop" was identified. Loculated free air in the right lower quadrant was noted on the next film. At autopsy the perforation had closed over; however, as in the other cases, it was preceded by a "persistent loop."
Comment: Having now had previous experience with a "persistent loop," the significance of this radiographic finding was emphasized. Since the child's clinical condition did not warrant an emergency laparotomy, one more radiograph was obtained, by which time perforation had already occurred. Future attention to this finding will hopefully avoid this complication. CASE V: A 3-week old, 850-g premature infant exhibited abdominal distension with hematest-positive stools. Abdominal radiographs re-
DISCUSSION
Necrotizing enterocolitis is still being seen in epidemic proportions in many neonatal centers. Earlier recognition and treatment has lead to improved survival. Fewer patients with portal venous gas and free perforation are being seen at this institution than a few years ago. The real breakthrough awaits successful prevention in the high-risk premature infant (9-12, 14, 15). Although surgical resection is not the treatment of choice, many infants stil! come to laparotomy for perforation leading to free air. Many authors differ as to the indications for surgical exploration, although all would agree that operation is indicated in the infant with intestinal perforation and pneu-
Vol. 126
203
NEONATAL NECROTIZING ENTEROCOLITIS
Pediatric Radiology
Fig. 3. CASE II. Initial supine abdominal radiograph. revealing diffuse distension with linear and cystic pneumatosis intestinalis and air in the portal veins. Arrow indicates the position of the future persistent loop. Fig. 4. CASE II. Forty-eight-hour follow-up shows decreased distension. probable ascites. and a persistent right-Iowerquadrant loop. Fig. 5. CASE II. Seventy-two hours after onset, the ascites has increased and other loops have changed, with the exception of the one in the right lower quadrant (arrow).
moperitoneum. Earlier detection of advanced bowel necrosis, indicating imminent perforation, would be clinically helpful (2). The "persistent loop" sign may be helpful in evaluating prospective surgical candidates. A loop of bowel that is relatively unchanged in position and configuration over a 24- to 36-hour interval should raise the possibility of advanced bowel necrosis and impending perforation. The most likely explanation for the unchanging loop is that necrosis of the mucosa, submucosa, and serosa has taken place, rendering the segment aperistaftic and dead (22). Rigler et at. (23) described the roentgen signs of intestinal necrosis in adults but made no mention of infants with necrotizing enterocolitis. I submit that this "persistent
loop" pattern goes one step further, and identifies infants whose bowel injury is so profound that perforation is imminent. An awareness of this roentgenographic finding may help to avoid a middle-of-the-night emergency laparotomy for intestinal perforation in infants who are being followed for necrotizing enterocolitis. ACKNOWLEDGMENT: I wish to thank Miss La Donna Sherer for her assistance in preparing this manuscript.
REFERENCES 1.
Bell RS. Graham CB, Stevenson JK:
Roentgenologic and
204
HOWARD
A.
WEXLER
January 1978
Fig. 7. CASE IV. Serial abdominal radiograph, showing placement of a nasogastric tube with decreasing bowel gas. A persistent loop is identified in the mid-abdomen (arrows). Fig. 6. CASE III. Supine abdominal radiograph obtained on the third postoperative day, revealing a persistent loop pattern (arrows) in the mid-abdomen.
clinical manifestations of neonatal necrotizing enterocolitis. Am J RoentgenoI112:123-134, May 1971 2. Cohn R, Sunshine P, De Vries P: Necrotizing enterocolitis in the newborn infant. Am J Surg 124: 165-168, Aug 1972 3. Leonidas JC, Hall RT, Amoury RA: Critical evaluation of the roentgen signs of neonatal necrotizing enterocolitis. Ann Radiol 19: 123-132, Jan-Feb 1976 4. Mizrachi A, Barlow 0, Berdon WE, et al: Necrotizing enterocolitis in premature infants. J Pediatr 66:697-705, 1972 5. Pochaczevsky R, Kassner EG: Necrotizing enterocolitis of infancy. Am J RoentgenoI113:283-296, Oct 1971 6. Rabinowitz JG, Siegle RL: Changing clinical and roentgenographic patterns of necrotizing enterocolitis. Am J Roentgenol 126: 560-566, Mar 1976 7. Santulli TV, Schullinger IN, Heird WT, et al: Acute necrotizing enterocolitis in infancy: a review of 64 cases. Pediatrics 55:376-387, Mar 1975 8. Siegle RL, Rabinowitz JG, Korones SB, et al: Early diagnosis of necrotizing enterocolitis. Am J Roentgenol 127:629-632, Oct 1976 9. Barlow B, Santulli TV, Heird WC, et al: An experimental study of neonatal enterocolitis-the importance of breast milk. J Pediatr Surg 9:587 -595, Oct 1974 10. Bell MJ, Kosloske AM, Benton C, et al: Neonatal necrotizing enterocolitis: prevention of perforation. J Pediatr Surg 8:601-605, Oct 1973 11. Book LS, Herbst JJ, Atherton SO, et al: Necrotizing enterocolitis in low-birth-weight infants fed an elemental formula. J Pediatr 87:602-605, Oct 1975 12. Egan EA, Mantilla G, Nelson RM, et al: A prospective con-
trolled trial of oral kanamycin in the prevention of neonatal necrotizing enterocolitis. J Pediatr 89:467-470, Sep 1976 13. Frantz 10 3d, L'heureux PL, Engel RR, et al: Necrotizing enterocolitis. J Pediatr 86:259-263, Feb 1975 14. Hakanson DO, Oh W: Necrotizing enterocolitis and hyperviscosity in the newborn infant. J Pediatr 90:458-461, Mar 1977 15. Leake RD, Thanopoulos B, Nieberg R: Hyperviscosity syndrome associated with necrotizing enterocolitis. Am J Dis Child 129: 1192-1194, Oct 1975 16. Robinson AE, Grossman H, Brumley, GW: Pneumatosis intestinalis in the neonate. Am J RoentgenoI120:333-341, Feb 1974 17. Wilson SE, Woolley, MM: Primary necrotizing enterocolitis in infancy. Arch Surg 99:563-566, Nov 1969 18. Arnon RG, Fishbein JF: Portal venous gas in the pediatric age group. Review of the literature and report of twelve new cases. J Pediatr 79:255-259, Aug 1971 19. Stevenson JK, Oliver TK, Graham CB, et al: Aggressive treatment of neonatal necrotizing enterocolitis: 38 patients with 25 survivors. J Pediatr Surg 6:28-35, Feb 1971 20. Stevenson JK, Graham CB, Oliver TK, et al: Neonatal necrotizing enterocolitis. Am J Surg 118:260-272, Aug 1969 21. Touloukian RJ, Berdon WE, Amoury RA, et al: Surgical experience with necrotizing enterocolitis in the infant. J Pediatr Surg 2: 389-401, Oct 1967 22. Tomchik FS, Wittenberg J, Ottinger LW: The roentgenographic spectrum of bowel infarction. Radiology 96:249-260, Aug 1970 23. Rigler LG, Pogue WL: Roentgen signs of intestinal necrosis. Am J Roentgenol 94:402-409, Jun 1965
Howard A. Wexler, M.D. 2485 N.E. 202nd St. N. Miami Beach, Fla. 33180
