Skip to content

Alimentary Tract Conditions:

Esophageal Atresia and Tracheoesophageal Fistula (TEF)

Definition:

  • Esophageal atresia: A congenital condition causing esophageal discontinuity and proximal esophageal obstruction.
  • Tracheoesophageal fistula (TEF): An abnormal connection between the esophagus and trachea.
  • Can occur alone or in combination.

Incidence and Embryology:

  • Occurs in 1 in 1,500 to 3,000 live births, with a slight male predominance.
  • 60-70% of cases are associated with other anomalies (e.g., VATERL: vertebral, anorectal, tracheal, esophageal, renal, radial limb).
  • Caused by the failure of the esophagotracheal diverticulum to divide completely during the fourth week of gestation.

Anatomical Variants:

  • Five variants exist, the most common being Type C, where the proximal esophagus ends in a blind pouch, and there is a distal TEF near the carina.

image.png

Clinical Presentation:

  • Symptoms include:
    • Excessive salivation.
    • Coughing or choking during the first feeding.
    • Curling of the orogastric tube at the thoracic inlet is pathognomonic for esophageal atresia with/without TEF.
    • Polyhydramnios in maternal history, especially in isolated proximal atresia.
    • Acute gastric distention in proximal esophageal atresia with distal TEF due to air entering the distal esophagus.
    • Reflux of gastric contents into the trachea, leading to cough, tachypnea, apnea, or cyanosis.
  • In isolated TEF (without esophageal atresia), symptoms include choking and coughing associated with feedings, often presenting beyond the newborn period.

Diagnosis:

  • Inability to pass an orogastric tube into the stomach is a cardinal sign of esophageal atresia.
  • Chest radiograph:
    • Curled orogastric tube in the proximal esophagus confirms esophageal atresia.
    • Presence of gas below the diaphragm confirms an associated TEF.
    • Absence of air in the GI tract is diagnostic of isolated esophageal atresia.
  • Echocardiography and renal ultrasound are used to evaluate for associated cardiac and genitourinary anomalies.

Initial Management:

  • Decompression of the proximal esophageal pouch using a Replogle tube on continuous suction.
  • Positioning: Infant is placed upright prone to minimize gastroesophageal reflux (GER) and aspiration.
  • Antibiotics: Broad-spectrum IV antibiotics are initiated.
  • Avoid routine endotracheal intubation to prevent air entering the TEF, leading to gastric distention.
  • In severe cases, right mainstem intubation or placement of an occlusive balloon (Fogarty) catheter into the fistula can minimize air leak.
  • Thoracotomy with fistula ligation may be required in emergencies.

Surgical Repair:

  • Right thoracotomy is performed for infants with a left-sided aortic arch. For right-sided aortic arch, a left thoracotomy is preferred.
  • In proximal esophageal atresia with distal TEF, the extrapleural dissection approach is commonly used via open thoracotomy.
  • Bronchoscopy may be performed to rule out the presence of a second fistula.
  • Surgical steps:
    • Divide the azygos vein to expose the TEF.
    • The TEF is dissected, and its attachment to the trachea is divided.
    • A tension-free esophageal anastomosis is performed.
    • Thoracoscopic repair is gaining popularity but is used in selected patients.

Long Gap Esophageal Atresia:

  • Esophagomyotomy for lengthening has largely been abandoned due to esophageal dysmotility.
  • Staging techniques such as suturing the distal esophagus to the prevertebral fascia and allowing the proximal esophagus to lengthen over time are used.
  • In infants with pure esophageal atresia, initial gastrostomy is placed, and definitive repair occurs after esophageal lengthening.

Outcomes and Complications:

  • Mortality is related to associated anomalies, especially cardiac defects and chromosomal abnormalities.
  • Postoperative complications:
    • Esophageal motility disorders.
    • GER (25-50%).
    • Anastomotic stricture (15-30%).
    • Anastomotic leak (10-20%).
    • Tracheomalacia (8-15%).

This summary outlines the key features of esophageal atresia and tracheoesophageal fistula, including clinical presentation, diagnostic features, management, and surgical approaches.

Necrotizing Enterocolitis (NEC)

Overview:

  • NEC is the most common gastrointestinal surgical emergency in neonates, particularly affecting premature infants.
  • Prematurity is the single most important risk factor.
  • Other contributing factors: Ischemia, bacterial overgrowth, cytokines, and enteral feeding.
  • The incidence of NEC has decreased recently due to clinical feeding pathways and the increased use of breast milk.

Clinical Presentation:

  • Hallmark Features:
    • Abdominal wall cellulitis.
    • Abdominal distention and tenderness.
    • Feeding intolerance.
    • Gross or occult blood in the stool.
  • Nonspecific signs:
    • Temperature instability.
    • Episodes of apnea or bradycardia.
  • Typically occurs within the first few days of life after initiating enteral feedings; 80% of cases occur in the first month.
  • Progression:
    • Can lead to sepsis, hemodynamic deterioration, and coagulopathy.

Radiographic Features:

  • Pneumatosis intestinalis: Pathognomonic sign, seen as gas within the bowel wall, caused by bacterial fermentation of luminal substrates.
  • Other findings:
    • Portal venous gas.
    • Ascites.
    • Fixed loops of small bowel.
    • Free air indicating perforation.
  • The distal ileum and ascending colon are most commonly affected, though NEC can involve the entire GI tract, known as NEC totalis.

Medical Management:

  • Orogastric tube decompression.
  • Fluid resuscitation.
  • Broad-spectrum antibiotics.
  • NEC can be successfully treated medically in more than 50% of cases.

Indications for Surgery:

  • Absolute indication: Presence of free air on abdominal radiographs.
  • Relative indications:
    • Clinical deterioration.
    • Abdominal wall cellulitis.
    • Palpable mass (matted ischemic bowel).
    • Persistent fixed bowel loop on radiograph.
    • Portal venous gas.

Surgical Management:

  • Resection of nonviable intestinal segments while preserving maximum intestinal length.
  • Ostomy diversion is often performed.
  • Second-look operation may be considered after 24-48 hours for ischemic but non-necrotic bowel.
  • Bowel resection with primary anastomosis is rarely considered, as it carries a high risk of anastomotic leak and stricture.

Peritoneal Drainage:

  • For extremely low birth weight infants (<1000 g) with perforated NEC, peritoneal drain placement may be used as a temporary measure.
  • Peritoneal drainage was found to be the definitive treatment in some cases, although outcomes are poor in infants with very low birth weight.
  • Multicenter randomized trial showed no significant differences in survival, need for parenteral nutrition, or length of hospital stay between infants treated with peritoneal drainage or laparotomy.

Complications:

  • Mortality rate: 10-50% for surgically managed NEC.
  • Short gut syndrome: NEC is the most common cause.
  • Intestinal strictures: Occur in about 10% of infants after medical or surgical treatment, particularly in the splenic flexure.
    • A contrast enema is routinely done before stoma reversal to assess for strictures.
  • Neurodevelopmental delay is a frequent long-term complication.

This summary outlines the key aspects of NEC, including its clinical presentation, management, surgical indications, and complications.

Meconium Ileus

Overview:

  • Meconium ileus is a neonatal intestinal obstruction that is closely associated with Cystic Fibrosis (CF).
  • CF is an autosomal recessive disorder resulting from mutations in the CF transmembrane regulator (CFTR) gene.
  • Affects multiple organs, including the intestine, pancreas, lungs, salivary glands, reproductive organs, and biliary tract.

Epidemiology:

  • Affects 10-15% of infants with CF.
  • CF incidence ranges from 1 in 1,000 to 2,000 live births.
  • Maternal polyhydramnios is present in approximately 20% of cases.

Pathophysiology:

  • Abnormal chloride transport leads to viscous secretions with high protein content (80-90%).
  • The terminal ileum becomes dilated and filled with thick, tar-like meconium, which obstructs the bowel.

Clinical Presentation:

  • Classic triad of symptoms within the first 24-48 hours of life:
    1. Generalized abdominal distention.
    2. Bilious emesis.
    3. Failure to pass meconium.
  • Simple meconium ileus:
    • Abdominal radiographs show dilated gas-filled bowel loops without air-fluid levels.
    • A mass of inspissated meconium creates a ground-glass or soap-bubble appearance in the right abdomen.

Diagnosis:

  • Contrast enema using gastrografin (water-soluble ionic solution) is both diagnostic and therapeutic:
    • Reveals a narrow-caliber colon with inspissated meconium in the terminal ileum.
    • Helps evacuate meconium by pulling water into the colon.
  • Pilocarpine iontophoresis sweat test:
    • Confirms CF with a chloride concentration >60 mEq/L.
  • Mutated CFTR gene detection is a more immediate test for CF.

Management:

  • Non-surgical (successful in 75% of cases):
    • Contrast enema is first-line for simple meconium ileus.
    • Hydration and close monitoring are essential.
  • Surgical Intervention:
    • Indicated if obstruction persists despite enema.
    • N-acetylcysteine (Mucomyst) administered via nasogastric tube to break down meconium.
    • Historical approach involved resection of dilated terminal ileum and creating stomas.
    • Current practice favors enterotomy with saline/N-acetylcysteine irrigation to evacuate meconium without creating stomas.
    • If evacuation is incomplete, a T-tube may be left in place for postoperative irrigation.

Complicated Meconium Ileus:

  • Complicated when there is in utero or early neonatal perforation leading to meconium peritonitis.
  • Clinical presentations:
    • Meconium pseudocyst.
    • Adhesive peritonitis.
    • Ascites with or without secondary bacterial infection.
  • Abdominal radiographs may show:
    • Calcifications.
    • Bowel dilation.
    • Mass effect and ascites.
  • Treatment for distal ileal obstructive syndrome (formerly meconium ileus equivalent):
    • Often nonoperative with enemas or oral polyethylene glycol purging solutions.

Complications:

  • Distal ileal obstructive syndrome: May occur due to noncompliance with oral enzyme replacement or dehydration.
  • Fibrosing cholangiopathy: Rare, but related to enteric-coated, high-strength pancreatic enzyme replacement therapy.
  • Surgical treatment of inflammatory colon strictures may be required in some cases.

Meconium Plug Syndrome

Overview:

  • Different from meconium ileus, it is not associated with CF in most cases.
  • Common cause of neonatal intestinal obstruction.

Associated Conditions:

  • Hirschsprung disease.
  • Maternal diabetes.
  • Hypothyroidism.

Clinical Presentation:

  • Abdominal distention.
  • Failure to pass meconium within the first 24 hours of life.

Diagnosis and Treatment:

  • Contrast enema shows a microcolon with dilated segments filled with thick meconium plug.
  • Therapeutic contrast enema often relieves the obstruction, and surgical intervention is usually not needed.

This summary provides a detailed understanding of meconium ileus and meconium plug syndrome, including their pathophysiology, diagnosis, and management.

Hirschsprung Disease

Pathogenesis:

  • Hirschsprung disease is characterized by aganglionated distal colon/rectum, caused by the absence of ganglion cells in the myenteric (Auerbach) and submucosal (Meissner) plexuses.
  • Results in muscular spasm of the distal colon and internal anal sphincter, leading to functional obstruction.
  • The abnormal bowel is the contracted distal segment, and the normal bowel is the dilated proximal segment.
  • The area between the dilated and contracted segments is known as the transition zone.

Epidemiology:

  • Occurs in 1 in 5000 live births.
  • Male predominance (4:1).
  • 3-5% of patients have Down syndrome.
  • Family history increases risk; associated with the RET oncogene on chromosome 10.

Clinical Presentation:

  • >90% of infants present with:
    • Abdominal distention.
    • Bilious emesis.
    • Failure to pass meconium within the first 24 hours of life.
  • Missed diagnoses may present later with chronic constipation and abdominal distention.
  • Enterocolitis is a common cause of death, characterized by diarrhea, fever, abdominal distention, and hematochezia.

Diagnosis:

  • Contrast enema is the imaging study of choice, showing:
    • Narrow distal rectum with dilated proximal sigmoid colon.
    • Failure to evacuate contrast after 24 hours is a strong indicator of Hirschsprung disease.
  • Rectal biopsy is the gold standard:
    • Suction biopsy in newborns, performed 2 cm above the dentate line.
    • Full-thickness biopsy in older children, requiring general anesthesia.
    • Histopathologic findings: Absence of ganglia, hypertrophied nerve trunks, and acetylcholinesterase immunostaining.
    • Calretinin immunostaining is an adjunct for diagnosis.

Surgical Management:

  • Soave Procedure (Laparoscopy-Assisted):
    • The most common definitive surgical approach.
    • Steps:
      1. Seromuscular biopsies to identify the ganglionated segment.
      2. Endorectal mucosal dissection via transanal approach.
      3. Coloanal anastomosis after pulling through the ganglionated colon.
    • Can be done completely through a transanal approach.
  • Swenson Procedure:
    • Removal of the aganglionic bowel down to the internal sphincters with coloanal anastomosis.
  • Duhamel Procedure:
    • The aganglionic rectal stump is left in place, and the ganglionated colon is pulled behind it.
    • A stapler is used to form a neorectum that empties normally through the ganglionated bowel patch.
  • Historical Approach:
    • Two- or three-stage procedures involving open leveling colostomy followed by a pull-through surgery (Soave or Duhamel) are rarely used, except in cases with delayed diagnosis and massively dilated colon.

Complications:

  • Postoperative complications include:
    • Constipation.
    • Soiling.
    • Incontinence.
    • Postoperative enterocolitis.
  • Persistent stool dysfunction may require histologic reevaluation to ensure that adequate ganglionated bowel was pulled through.
  • Strictures at the coloanal anastomosis may also occur.

This summary highlights the essential aspects of Hirschsprung disease, including its pathogenesis, clinical presentation, diagnostic criteria, and surgical management.

Anorectal Malformations (ARM)

Overview:

  • Incidence: Occurs in 1 in 5000 live births with a male predominance of 58%.
  • Spectrum of defects: Ranges from simple anal stenosis to cloacal persistence.
  • The most common defect is imperforate anus with a fistula connecting the distal colon to the urethra in boys or vaginal vestibule in girls.

Embryology:

  • By the 6th week of gestation, the urorectal septum divides the cloaca into the anterior urogenital sinus and posterior anorectal canal.
  • Failure of this septum to form results in rectourethral fistula (in boys) or rectovaginal fistula (in girls).
  • The anal membrane may fail to resorb, leading to anal stenosis or imperforate anus.

Anatomic Classification:

  • Classified based on the level of the rectal pouch in relation to the levator ani musculature:
    • Low lesions: Rectal pouch closer to the perineum.
    • Intermediate lesions: Rectal pouch in the middle zone.
    • High lesions: Rectal pouch located higher up.

Clinical Presentation:

  • Boys: Perineal fistula or rectourethral fistula (bulbar, prostatic, or bladder neck).
  • Girls: Perineal fistula or vestibular fistula. A persistent cloaca is indicated by a single orifice in the perineum where the rectum, vagina, and urethra merge.
  • Symptoms: Failure to pass meconium, abdominal distention, and signs of obstruction.

Associated Conditions:

  • VACTERL association (Vertebral, Anorectal, Cardiac, Tracheoesophageal, Renal, and Limb anomalies) should be considered.
  • Bone abnormalities of the sacrum and spine occur in one-third of patients.
  • Genitourinary abnormalities (e.g., vesicoureteral reflux, hydronephrosis, horseshoe kidney, hypospadias) are more common in higher anorectal malformations.

Diagnosis:

  • Physical examination: Careful inspection of the perineum to identify the presence of a fistula.
  • Invertogram: Previously used radiograph technique to assess the rectal pouch location.
  • Imaging: Renal ultrasound, voiding cystourethrogram, and echocardiogram if cardiac defects are suspected.

Surgical Management:

image.png

image.png

  1. Low lesions:
    • Perineal or vestibular fistula: Primary single-stage repair without colostomy.
    • Anal stenosis: Managed with serial dilations.
  2. Anteriorly displaced anus:
    • Requires transposition anoplasty or miniposterior sagittal anorectoplasty to restore normal anal position.
  3. High lesions:
    • Initial diverting colostomy followed by three-stage reconstruction:
      1. Colostomy with mucous fistula to prevent fecal contamination.
      2. Posterior sagittal anorectoplasty (PSARP): Pull-through procedure involving dissection and placement of the rectum in the sphincter muscles.
      3. Colostomy reversal after 3-6 months.
  4. Laparoscopic approach:
    • Laparoscopic-assisted PSARP: Minimally invasive alternative with potential advantages, but long-term outcomes are still under study.

Prognosis and Complications:

  • Fecal continence is the primary goal of surgical correction.
    • 75% of patients achieve voluntary bowel movements, but 50% may still have occasional soiling.
  • Constipation is a common postoperative issue.
  • Bowel management programs with daily enemas are essential to reduce soiling and improve the quality of life.

Classification of Anorectal Malformations (Box 67.1):

Female:

  • Cutaneous (perineal fistula).
  • Vestibular fistula.
  • Imperforate anus without fistula.
  • Rectal atresia.
  • Cloaca.
  • Complex malformation.

Male:

  • Cutaneous (perineal fistula).
  • Rectourethral fistula (bulbar, prostatic).
  • Recto-bladder neck fistula.
  • Imperforate anus without fistula.
  • Rectal atresia.

This summary covers the key aspects of anorectal malformations, including pathogenesis, diagnosis, surgical management, and associated conditions.