Intestinal Obstruction in the Newborn Treatment & Management

Updated: Mar 17, 2016
  • Author: James G Glasser, MD, MA, FACS; Chief Editor: Ted Rosenkrantz, MD  more...
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Treatment

Approach Considerations

Intestinal obstruction generally causes fluid loss and an electrolyte imbalance, either from vomiting, in cases of proximal obstruction, or third-space sequestration of fluid within the intestine’s lumen, in more distal obstructions. To minimize mortality and morbidity, clinicians must treat these life-threatening consequences of the obstruction, while simultaneously identifying and treating the underlying cause.

Perform gastric intubation and decompression. Provide respiratory and cardiovascular support to maintain hemodynamic stability. Administer intravenous antibiotics, because as the bowel distends in response to increased intraluminal pressure, perfusion to the intestine diminishes (ie, Law of Laplace); consequently, its resistance to bacterial invasion diminishes. In addition, bacterial overgrowth occurs in association with intestinal obstruction.

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Enemas

A diatrizoate (Gastrografin) enema should be performed in cases of distal intestinal obstruction. Distal contrast radiography is diagnostic, and the diatrizoate enema has remarkable efficacy in loosening the sticky meconium and facilitating evacuation (>50% success rate).

Multiple enemas may be required in meconium plug syndrome. The enema fluid must be refluxed into the terminal ileum for successful relief of the obstruction. Diatrizoate and N-acetylcysteine may be administered antegrade by nasogastric tube to help loosen the impacted meconium. Hyperosmolar solutions (10% acetylcysteine) draw fluid into the lumen of the bowel and enhance their efficacy in evacuating thick meconium; however, this may also increase the risk of perforation, which reportedly occurs in 3-10% of cases.

In children with intussusception air enema may be superior relative to liquid enema for intussusception reduction. [23] In a meta-analysis of 102 articles comprising results for 32,451 children (age range, 1 day to 22 y), Sadigh et al found an 82.7% combined estimate of success rate for air enema in 44 studies (n = 16,187), whereas it was 69.6% for liquid enema in 52 studies (n = 15,752). [23] However, the combined estimates of perforation rate (0.39% vs 0.43%) and rate of first intussusception recurrence (6% vs 7.3%) were similar between air and liquid enema, respectively.

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Preparation for Operation

Duodenal atresia

Preoperative measures for duodenal atresia include fluid resuscitation and nasogastric decompression. The baby should be evaluated for trisomy 21.

Duodenal atresia is considered a “midline embryologic defect,” and evaluation for associated anomalies should include echocardiography, head and renal ultrasonography, and vertebral skeletal radiography.

Malrotation with volvulus

Preoperative treatment of malrotation and volvulus is focused on urgent relief of the intestinal obstruction. In addition to nasogastric decompression and fluid resuscitation, these infants may require intubation and mechanical ventilation as well as vasopressor agents for cardiovascular support. Broad-spectrum antibiotics should be administered because of the likelihood of ischemic or gangrenous bowel. A delay in diagnosis of malrotation/volvulus may lead to catastrophic loss of intestine.

Jejunal atresia

In patients with jejunal atresia, immediate preoperative nasogastric decompression limits distention of the proximal atretic bowel. Appropriate intravenous (IV) fluids should be started. A contrast enema corroborates the diagnosis and is useful in excluding a second, more distal obstruction. Postopoerative parenteral nutrition, as well as respiratory, cardiovascular, and hemodynamic support, may be necessary.

Meconium ileus

In cases of meconium ileus, nasogastric decompression and IV fluids and antibiotics are initially administered. A diatrizoate enema may be effective in loosening the meconium impaction, but the enema fluid must be refluxed into the terminal ileum. The volume of the instilled fluid must be carefully regulated in premature infants. [24] Diatrizoate diluted with N-acetylcysteine may be administered by nasogastric tube from above to further loosen the meconium. By drawing fluid into the lumen of the bowel, hyperosmolar solutions (10% acetylcysteine) have enhanced efficacy; however, this may cause electrolyte disturbances due to intracellular and extracellular fluid shifts, with the attendant risk of hypovolemic shock. Hyperosmolar enemas may increase the risk of perforation and sepsis with enteric bacteremia.

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Surgical Relief of Obstruction

Duodenal atresia

Correction of duodenal atresia requires identifying the cause of the obstruction (ie, atresia, annular pancreas, or web), locating the duodenum above and below the obstruction, and determining how best to bring the two lumens into continuity.

Malrotation with volvulus

Malrotation with midgut volvulus is a true surgical emergency. Delay in diagnosis may result in catastrophic loss of the bowel and death. In patients with irreversible ischemia, the entire midgut is forfeit, and the child cannot survive without an intestinal transplant.

Surgery for malrotation/volvulus involves evisceration of the small intestine. The base of the mesentery is examined; and if volvulus is present, the colon will be wrapped around the mesentery. Volvulus is reduced by twisting the mesentery counterclockwise, thereby unraveling the colon. This maneuver restores blood flow to the midgut. The duodenum is then located and followed; bands attaching it to the colon are divided, and these two structures, duodenum and colon, are separated as widely as possible. The superior mesenteric vessels are seen as the leaves of the mesentery are separated like opening the pages of a book. The bowel is returned to the abdomen—duodenum to the right, colon to the left, midgut in the center—so as to spread out the small bowel mesentery. (See the images below.)

Midgut volvulus. The bowel is eviscerated and the Midgut volvulus. The bowel is eviscerated and the entire midgut is twisted counterclockwise, effecting reduction of the volvulus.
The midgut volvulus is reduced. The midgut volvulus is reduced.
The peritoneal bands (Ladd bands) tethering the du The peritoneal bands (Ladd bands) tethering the duodenum to the colon are divided, exposing the superior mesenteric vessels.

 

Whereas, before, the mesentery extended from the ligament of Treitz in the left upper quadrant to the cecum in the right lower quadrant, the ”Ladd procedure” reverses the position of the duodenojejunal junction to the right lower quadrant and the cecum to the left upper quadrant. The mesentery is draped over the retroperitoneum, where it becomes adherent, and this prevents recurrent volvulus. The appendix is removed, because its new location is the left upper quadrant, where a future diagnosis of appendicitis would be problematic.

Jejunoileal atresia

Surgical treatment of jejunoileal atresia involves resection and primary anastomosis of the proximal and distal segments of the intestine. A diverting enterostomy is avoided. As with surgery for duodenal atresia, resection or tapering of the proximal dilated segment is occasionally necessary to limit the dysmotility that occurs in grossly dilated bowel. The ileocecal valve is preserved if possible, because this prevents egress of bacteria from the colon into the small intestine and the resultant bacterial overgrowth and malabsorption.

Meconium ileus

Calcification on scout radiography indicates that an intestinal perforation occurred in utero and spontaneously sealed; if not, the extruded meconium is walled off by adjacent intestine to form a pseudocyst. Affected babies have meconium peritonitis and their appearance is unmistakable: The baby is born with a distended, erythematous abdomen. Laparotomy is undertaken with drainage of the meconium pseudocyst and identification of the site of the perforation, which is converted to an enterostomy. In uncomplicated meconium ileus, an enterotomy with irrigation and evacuation of the obstructing meconium may successfully relieve the intraluminal obstruction. In other patients, an ostomy for diversion and access for proximal and distal irrigation with N-acetylcysteine may be necessary.

Complicated meconium ileus. Volvulus of the dilate Complicated meconium ileus. Volvulus of the dilated, meconium-ladened loop of intestine.

Meconium plug syndrome

Operative intervention is indicated in infants with meconium plug syndrome only if diatrizoate enemas are unsuccessful in loosening the whitish meconium plug, thereby permitting the baby to evacuate the black and tarry meconium.

Hirschsprung disease

Treatment of Hirschsprung enterocolitis includes bowel irrigations and decompression, administration of antibiotics, and fluid resuscitation. Colostomies expeditiously decompress the bowel and allow affected babies to resume feedings with minimal delay. Pull-through procedures are usually performed at age 3-6 months.

If there is no history of enterocolitis, pull-through procedures are performed during the newborn period, with excellent results.

Innovations in the treatment of Hirschsprung disease include minimally invasive techniques, such as the transanal laparoscopic pull-through procedures.

Imperforate anus

If an imperforate anus is low, with a perianal or perineal fistula, it can be repaired primarily by means of a perineal anoplasty. If the distal rectum is high above the anus, or if a fistula runs from the rectum to the vagina or urethra, or to the urinary bladder, the imperforate anus is classified as high, and the infant should undergo a colostomy.

Definitive repair of the imperforate anus is accomplished by means of posterior sagittal anorectoplasty, in which the rectum is situated within the striated muscle complex (levator sling) and anal sphincter. This procedure allows the muscles of continence to function properly. [25] The ultimate outcome depends on the precision of the surgery, the presence or absence of normally innervated sacroperineal musculature, and the degree of colonic dysmotility.

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Postoperative Care

In the postoperative period, derangements in fluid balance, glucose metabolism, and respiratory status may occur. Many infants following laparotomy have third-space fluid sequestration, and their intravenous (IV) fluid requirements are increased 1.5 to 2 times normal.

By checking the patient’s heart rate and blood pressure, peripheral perfusion (capillary refill), and urine output, the adequacy of fluid resuscitation can be determined. Serum electrolyte levels should be closely monitored, because fluid shifts between the intravascular and extravascular spaces are common and require prompt responses. Replacement of fluid lost through third-space fluid sequestration should consist of 0.5% to normal (0.9%) saline.

Gastric decompression “puts the injured part at rest” and facilitates healing of an intestinal anastomosis. The duration and depth of anesthesia reflect the length and complexity of the surgical procedure, which relates to the analgesic requirement and resultant respiratory depression as well as the duration of postoperative ileus, which impairs normal movement of the diaphragm and increases the requirement for respiratory support. 

The duration of antibiotic therapy depends on whether there was contamination of the peritoneal cavity. Total parental nutrition (TPN) is indicated until return of bowel function permits delivery of adequate enteral nutrition. Even when peristalsis has resumed, these infants may not tolerate enteral feedings, because their intestinal mucosa must regenerate before it is able to absorb nutrients. A period of trophic feeding may stimulate mucosal regeneration, and a predigested or elemental formula may be better tolerated. If the terminal ileum is resected, derangements in folate metabolism and in the enterohepatic circulation may occur.

Cardiovascular and coagulation complications, such as shock and disseminated intravascular coagulation, may occur with intestinal ischemia or necrosis. Management of these issues may also challenge the clinician during the postoperative period.

Wound care is usually straightforward; antibiotics are not generally required beyond the immediate preoperative period.

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Complications

General complications

General complications include postoperative strictures and adhesions, prolonged ileus because of impaired gut motility, and malabsorption, usually related to inadequate gut length or intestinal injury from ischemia or infection; there are also complications related to prolonged use of total parenteral nutrition (TPN), including problems in obtaining central venous access and catheter complications, such as sepsis.

Percutaneously inserted catheters (PIC) are utilized successfully in this population, but the caliber of these catheters is small and infusion of blood products may require alternative routes. Problems caused by the TPN solution include cholestasis, liver damage, and nutritional deficiencies. Meticulous attention to the composition of TPN solutions may minimize these long-term complications.

A fish-oil lipid emulsion appears to minimize the liver toxicity that is seen with traditional soybean oil lipid formulations. [26]

Normal oropharyngeal activities (eg, sucking) should be encouraged or oral aversion may develop.

Postoperative adhesions may occur between loops of intestine or between the intestine and the peritoneum. Anastomotic strictures may develop. In a study of 1541 children who had intestinal surgery, approximately 10% had adhesions at the operative site, and 5% occurred in areas that were away from the site of surgery. [27] Gentle manipulation of the bowel, limiting contamination of the peritoneal cavity, and meticulous anastomotic technique may limit postoperative strictures and adhesions.

Decreased gut motility is often observed after bowel resection for intestinal obstruction. Chronic dilatation of the intestine proximal to the obstruction may alter normal peristalsis across that segment of bowel, even after the obstruction has been relieved. Interruption of vagal neuroenteric pathways by an atresia or a surgical anastomosis may also contribute to abnormal intestinal motility.

Two promotility pharmacologic agents are used in this age group: metoclopramide and erythromycin. Randomized controlled trials of these agents have produced variable results compared with placebo; and each drug has side effects that may be unacceptable. Utilization is frequently based upon anecdotal reports or personal experience, rather than” evidence-based medicine”.

The normal length of the small bowel in a term infant is approximately 250 cm; in adults, it is 600-800 cm. The estimated minimum length for adequate intestinal function in a term infant is 75 cm. Resection of more than 60% of the small bowel or resection that removes crucial anatomic segments (eg, the ileocecal valve) predisposes the infant to malabsorption, which may cause failure to thrive, in which the infants do not grow and develop normally. Bacterial overgrowth also contributes to malabsorption. Accordingly, every effort to preserve bowel length is imperative.

Short-gut syndrome results when the remaining intestine cannot sustain normal absorption of nutrients. Children with short-gut syndrome may survive with parenteral nutrition supplementation, predigested formulas, and pharmacologic agents used to slow motility. Probiotics have been shown to normalize bowel flora and improve absorption of nutrients.

Bowel-lengthening procedures abetted by the creation of intraluminal valves, and pharmacologic manipulation of bowel recovery with nutritional and hormonal treatments assist in weaning children with short-gut syndrome from dependence on parenteral nutrition. Newer techniques, such as the serial transverse enteroplasty (STEP) procedure, may offer improved bowel function and length in some patients.

Patients with volvulus and infarction of the entire midgut or who have multiple intestinal atresias may not have enough intestine to survive. A difficult ethical decision is whether to proceed with intestinal resection and whether to continue life support. Small-bowel transplantation, with or without other viscera such as the liver and pancreas, is being performed in select centers in the United States, with varying results.

Complications associated with specific conditions

Complications may also be particularly associated with one or another of the various conditions that cause bowel obstruction in the newborn.

Malrotation

With malrotation, complications depend on the condition of the bowel at the time of presentation and surgical treatment. The most feared complication is necrosis of the entire midgut.

Reduction of the volvulus, performing a Ladd procedure, and planning a second-look procedure 24 hours later may allow salvage of intestine that initially appeared nonviable. If a massive small bowel resection is performed, a high jejunostomy is created, which results in the loss of large volumes of fluid and electrolytes and makes formulation of TPN solutions more complex.

In time, the ostomy can be closed. The remaining colon absorbs fluid and electrolytes and may simplify the baby’s management; however, severe diarrhea and the attendant complications may occur.

Duodenal atresia

The most frequent complication of a duodenal anastomosis is delayed emptying. Patience is required, because the anastomosis will usually function by the third postoperative week. Revising an anastomosis is rarely necessary.

Jejunoileal atresia

In uncomplicated cases of intestinal atresia, complications are very uncommon. The obstruction resulted from an in utero event leading to ischemia or necrosis of a segment of intestine. If the bowel is in good condition at birth, a primary repair is possible. Small bowel atresia may occur in conjunction with gastroschisis, however, and the exposed bowel may be inflamed, thickened, and matted together. In such cases, it may take time to differentiate the mechanical obstruction, the atresia, from the dysfunction associated with injury from exposure to the amniotic fluid. The atresia may not be diagnosed for several weeks after surgical repair of the abdominal wall defect.

Failure of normal bowel motility and function 4 weeks following repair should prompt a contrast medium study to look for evidence of mechanical obstruction, such as extrinsic compression (associated Ladd bands), atresia, or postinflammatory adhesions.

Meconium ileus and plug syndrome

Complications in treating babies with meconium plug syndrome are extremely rare. Babies with meconium ileus and cystic fibrosis may require enzyme replacement, although predigested or elemental formulas may be sufficient during the neonatal period.

Hirschsprung disease

Infants with Hirschsprung disease may present with enterocolitis, which is suggested by abdominal distention and explosive diarrhea, especially following a rectal examination and dilation of the anal sphincter. Sepsis (enteric organisms) may result from compromise of the integrity of the massively dilated proximal bowel, which allows bacterial mucosal translocation and invasion into the intestinal vascular supply.

Management includes intravenous (IV) fluids and antibiotics, along with irrigation of the distal colon using a rectal tube inserted through the anus. Stool studies may be positive for the Clostridium difficile toxin, mandating the use of oral vancomycin or metronidazole. A diverting colostomy may be necessary, if rectal irrigations fail to control recurrent episodes.

Imperforate anus

Babies who have low imperforate anus typically suffer from constipation, although the anus is widely patent. The major complication in babies with high imperforate anus is incontinence, which occurs either because the rectum is improperly situated within the striated muscle complex or because the muscle complex is defective. Constipation or diarrhea may occur, depending on the motility of the colon.

Other minor complications, such as prolapse of rectal mucosa through the neoanus, are easily repaired surgically. Pena has devised a bowel-training program that is extremely helpful in the management of these patients. [25]

 

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Consultations

In all of these conditions in volving bowel obstruction in the newborn, the neonatologist and pediatric surgeon work together, so that the diagnosis can be quickly established and appropriate therapy rapidly implemented. In conditions that are associated with systemic disease, such as duodenal atresia (trisomy 21) and meconium ileus (cystic fibrosis), appropriate consultation should be obtained early, and with the continued involvement of appropriate specialists long after the baby has recovered from the initial hospitalization.

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