Neonatal GI Problems 1: The “Surgical Abdomen” Obstruction CHO NICU Lecture PJ, AD, DD Revised 06/29/11

Causes of GI Obstruction Upper Tract Esophageal atresia +/- tracheoesophageal atresia Gastric causes: antral web, bezoar Pyloric stenosis Duodenal atresia/stenosis, annular pancreas duodenal web Malrotation volvulus

Causes of GI Obstruction Mid-Gut Jejunal atresia Ileal atresia Meconium ileus (associated with cystic fibrosis) Small bowel perforation NEC Adhesions, strictures Intussusception Appendicitis Abdominal wall defects Omphalocele Gastroschisis

Causes of GI Obstruction Distal Gut Colonic atresia/stenosis Hirschsprung’s disease Meconium plug syndrome (associated with Hirschsprungs) Small left colon syndrome (IDM) Incarcerated inguinal hernia Imperforate anus

Non-Surgical Causes of Ileus Sepsis UTI Electrolyte abnormalities: Hypokalemia Hypermagnesemia Drugs: morphine

Intestinal Obstruction Symptoms and findings might include: Abdominal distention Emesis (bilious) Tenderness Visible loops of bowel, abdominal wall erythema Associated problems: Respiratory compromise, apnea Hypovolemia, hypotension Sepsis (NEC, perforation) Electrolyte imbalance Neutropenia (sepsis) Thrombocytopenia (sepsis, perforation, bowel necrosis) Check for incarcerated inguinal hernia, imperforate anus

Treatment of Intestinal Obstruction NG/OG to low intermittent suction Correct hypovolemia and hypotension Third spacing into the lumen of the distended bowel IV Fluids D5/D10 with 1/2 NS at 120-150 mL/kg/day Correct electrolyte abnormalities and acidosis Blood culture and Antibiotics Ampicillin, Gentamicin, Flagyl (sometimes) Respiratory support for abdominal distension or apnea

TEF/EA

Tracheo-esophageal fistula and esophageal atresia

Esophageal Atresia & Tracheo-esophageal Fistula Symptoms Respiratory distress from aspiration Poor handling of secretions: drooling, frequent suctioning, choking or other symptoms with feeding Inability to pass OG/NG to stomach Abdominal distention may occur with swallowing of air through TEF or due to associated anal atresia

Esophageal Atresia & Tracheoesophageal Fistula Associated Problems Prematurity RDS, pulmonary aspiration VACTERL (vertebral anomalies, anal atresia, cardiac anomalies, TEF, renal, limb) Abdominal distention due to air passed through TEF can cause gastric perforation

Esophageal Atresia & Tracheoesophageal Fistula: Management CXR with tube to the pharyngeal pouch LIS to the pharyngeal tube Blood culture, ampicillin and gentamicin Manage respiratory problems Examine for anomalies: VACTERL

Bilious Vomiting 40% of babies with bilious vomiting require surgical intervention Bilious vomiting in the neonate is due to mechanical obstruction until proven otherwise

Malrotation 1/5000 live births 80% occur during 1st month of life most during the 1st week of life Higher incidence in males (2:1) Normal exam early during course Sx of obstruction: Bilious vomiting Sx of bowel ischemia: Bloody stool, abdominal distension, tenderness, shock

Normal fixation of mesentary The Ligament of Treitz should normally be located over the left upper quadrant of the abdomen, left of the vertebral column and at the same level as the duodenal bulb and pyloris. The formation of normal bowel in the embryo involves a rotation of elongated intestine into the abdominal cavity.  The proximal small intestine develops a C-shaped contour, with the duodenum fixing to the left of the midline at the ligament of Treitz.  The caecum undergoes counter-clockwise rotation to end up in the right lower abdomen.  Incomplete rotation results in inadequate fixation of the intestinal mesentery.  Bands may be formed which cause incomplete intestinal obstruction.  If there is inadequate fixation of the small bowel, the intestine can twist on the axis of the superior mesenteric artery. Normal fixation of mesentary

Malrotation with Obstruction Failure of fixation and rotation of midgut, small bowel, right colon, and transverse colon Duodenal obstruction from Ladd’s bands

Malrotation with Volvulus Small bowel twists around superior mesenteric artery, causing ischemia

Malrotation/Volvulus Abdominal XRay Normal film -20% Dilated duodenal bulb and paucity of distal bowel gas Double bubble sign Distal gas filled bowel loops; gas filled volvulus (obstructed mesenteric veins prevent absorption of gas

Plain films may be normal or may show evidence of duodenal obstruction with a paucity of bowel gas through the rest of the abdomen (see top image to left).  Air-fluid levels suggesting obstruction are not usual with malrotation.  An airless abdomen is a sign of severe problems and usually indicates intestinal infarction.  Upper intestinal contrast studies are reliable in localising the ligament of Treitz. There may be a typical corkscrew constriction of the third portion of the duodenum

Normal film can be found in 20% of cases Dilated stomach and duodenal bulb are suggestive of malrotation with volvulus Plain film findings o       Dilated, air-filled duodenal bulb and paucity of gas distally §         "Double bubble sign" = air-fluid levels in stomach and duodenum o       Isolated collection of gas-containing bowel loops distal to obstructed duodenum = gas-filled volvulus = closed-loop obstruction §         From nonresorption of intestinal gas secondary to obstruction of mesenteric veins

Duodenal Atresia Polyhydramnios Partial obstructions: duodenal web, duodenal stenosis, annular pancreas 40% of cases associated with trisomy 21 Most common gut atresia in neonates “Double bubble” Partial or complete duodenal obstruction may result from intrinsic causes or external compression.  Duodenal atresia results in complete obstruction. Radiographs show a characteristic picture of a "double bubble", with air filling a distended stomach and the blind-ended duodenum.  There is an association with Trisomy 21. Partial obstruction may be caused by an intraluminal web, duodenal stenosis, annular pancreas, or congenital bands. Duodenal obstruction may present in utero with polyhydramnios.  The antenatal ultrasound and plain radiograph images are of an infant with duodenal atresia who underwent a duodenoduodenostomy on the second day of life.  The karyotype was normal.

Double bubble-duodenal atresia Partial or complete duodenal obstruction may result from intrinsic causes or external compression.  Duodenal atresia results in complete obstruction. Radiographs show a characteristic picture of a "double bubble", with air filling a distended stomach and the blind-ended duodenum.  There is an association with Trisomy 21. Partial obstruction may be caused by an intraluminal web, duodenal stenosis, annular pancreas, or congenital bands. Duodenal obstruction may present in utero with polyhydramnios.  The antenatal ultrasound and plain radiograph images are of an infant with duodenal atresia who underwent a duodenoduodenostomy on the second day of life.  The karyotype was normal.

“triple bubble- jejunal atresia

Hirschsprung’s Disease Failure to pass meconium in 1st 24 hrs Absence of ganglion cells in mesenteric plexus Most commonly rectosigmoid junction 10% of cases involve entire colon 10% of cases associated with Trisomy 21

No gas in rectum- hirschsprungs

Clinical presentation is usually with abdominal distension and bilious vomiting.  There are often many gas-filled bowel loops, but without air-fluid levels.  Air-fluid levels are thought not to occur because the meconium does not provide a good air-fluid interface.  There may be a "soapy" mass in the right lower quadrant.  A contrast enema will show a microcolon secondary to distal ileal obstruction.  Calcification may be seen on a plain radiograph if there has been meconium peritonitis.

Hirschsprung’s Disease Contrast enema Suction biopsy Open biopsy Rectal irrigation Colostomy vs primary pull-through

In Utero Perforation Caused by obstruction: Meconium Ileus Hirschprungs Volvulus Early perforation leads to Ca++ deposits Later perforation may cause ascites, no Ca++ Adhesions lead to obstruction

Bowel obstruction with perforation occurring in utero can lead to leakage of meconium into the peritoneal cavity.  The subsequent chemical peritonitis can leave calcified areas that are visible on plain radiography.  Any cause of bowel obstruction (atresia, volvulus, meconium ileus, and Hirschsprung's disease) can lead to this appearance. If the peritonitis occurs close to delivery, there may not be sufficient time to develop calcification, although there may be a significant chemical peritonitis.  Ascites may also be present.  Some infants will require surgery for persistent bowel obstruction or for adhesions.

Meconium Ileus Usually a manifestation of cystic fibrosis 20% of infants with CF present with mec ileus Obstruction of proximal ileum by thick, sticky round meconium pellets Absence of air fluid levels “soap bubbles” Complications: perforation, peritonitis, pseudocyst, ileal atresia/stenosis Intestinal obstruction in infants with meconium ileus is generally evident within 24 to 48 hours following birth. Although a family history of cystic fibrosis is certainly helpful, it is only present in only a few percent of patients (no more than 1 in 4). In approximately 20% of patients, particularly those with complicated meconium ileus, there is a history of maternal polyhydramnios. Although meconium ileus is uncommon in premature infants, many are dysmature or small-for-dates. Associated congenital malformations are uncommon. With meconium ileus, three cardinal signs of intestinal obstruction are generally evident including generalized abdominal distention, bilious vomiting, and failure to pass meconium within 48 hours. At times it is possible to feel a dilated intestinal loop filled with obstructing meconium. With complicated meconium ileus, patients generally present either at or shortly following birth because of severe abdominal distention that is often associated with respiratory distress. At times the abdominal wall is red and inflamed. Progressive hypovolemia may lead to cardiovascular instability, and such infants appear extremely ill. Plain radiographs of the abdomen may be extremely helpful. In patients with simple obturation obstruction, the characteristic radiologic features include varying-sized loops of distended intestine, a relative absence of air-fluid levels, and a "soap bubble" appearance of portions of the abdomen (Neuhauser's sign), particularly the right lower quadrant (Figure 2A). Other disorders that may share some of these radiologic findings include Hirschsprung's disease, ileal atresia, and meconium plug syndrome.

Meconium Ileus Contrast enema: Small colon Filled with pellet-like meconium when contrast extends to IC valve Contrast can wash out the obstructing plugs and meconium plugs The diagnosis of CF should be ruled-out

When meconium ileus is suspected, a contrast enema study should be performed. The classic finding is a small colon filled with pellet-like meconium when contrast material goes back into last part of the small intestine. The xray dye may be used to wash out the obstructing plugs and dried out meconium. In patients with complicated meconium ileus, a contrast enema study is not required before laparotomy because xrays are often diagnostic. After relief of intestinal obstruction, the diagnosis of CF should be verified.

Meconium Plug Syndrome Diagnosis of exclusion Probably same as "small left colon" syndrome Transient disorder due to functional immaturity of colon Common in IDM, premies, PIH, Mg Rx Infants with CF may present with mec plugs, although mec ileus most common 10-30% may have Hirschsprungs also

Meconium Plug Syndrome Present within the first 24 to 36 hours of age: Abdominal distention Vomiting (bilious) Failure to pass meconium Plain films show distal intestinal obstruction Contrast enema usually shows: distention of the right and transverse colon transition near the splenic flexure to a narrow descending colon and rectosigmoid region Meconium within the colon Main differential diagnosis is Hirschsprung's disease: In Hirschsprung's disease, aganglionic colon is usually normal caliber In Meconium Plug Syndrome, colon is usually small

Meconium plug syndrome is a common cause of neonatal obstruction Meconium plug syndrome is a common cause of neonatal obstruction. It is felt to most likely be synonymous with "small left colon" syndrome and functional immaturity of the colon. These neonates generally present within the first 24 to 36 hours of age with abdominal distention, vomiting (bilious), and failure to pass meconium. Infants of diabetic mothers, as well as premature infants, are particularly predisposed to the entity. Plain films characteristically demonstrate findings consistent with a low intestinal obstruction. A contrast enema most commonly demonstrates distention of the right and transverse colon and a transition near the splenic flexure to a narrow descending colon and rectosigmoid region. In addition, meconium will be demonstrated within the colon. The major differential diagnostic consideration is Hirschsprung's disease. The roentgenographic findings may be similar, but in Hirschsprung's disease the aganglionic colon is usually of normal caliber, while it is usually small with meconium plug syndrome. In addition, the transition zone of meconium plug syndrome is usually abrupt whereas the transition zone in Hirschsprung's disease is more gradual.