Malformations of the digestive organs and anterior abdominal wall

Embryonic duct pathologies

Normally, the vitelline duct and urachus undergo obliteration. Their failure to close leads to the formation of umbilical fistulas lined with epithelium.

Vitelline duct pathologies:

• Complete failure of obliteration leads to the formation of a small intestine fistula. Clinically, this manifests as a continuous discharge of intestinal contents directly from the umbilicus.
• Partial obliteration (incomplete closure) has no communication with the external environment. This results in the formation of Meckel's diverticulum—a blind-ending, cone- or cylinder-shaped pouch of the ileum. Its length is 3–8 cm, and its diameter equals the width of the intestine itself. The diverticulum is localized 30–80 cm from the ileocecal valve. Complications may include diverticulitis or acute intestinal obstruction.

Urachus pathologies:

• Complete failure of obliteration manifests as a patent vesicoumbilical fistula (urine discharges from the umbilicus).
• Incomplete closure leads to the formation of a urachal diverticulum of the bladder.

To diagnose umbilical fistulas, physical examination (assessing discharge upon straining or palpation) and fistulography (contrast medium injection) are used. To differentiate the origin of the fistula, a dye is injected into the urinary bladder. If it discharges from the umbilicus, it is a urachal anomaly. The presence of any umbilical fistula or complicated diverticulum is an absolute indication for surgical excision.

Omphalocele (exomphalos)

This pathology represents a pronounced defect of the abdominal wall in the umbilical region. The hernial protrusion has a rounded shape (diameter of 5–10 cm or more) and smoothly transitions into the umbilical cord.

Unlike conventional hernias, the contents (intestinal loops, liver) are covered not by skin, but by a thin, shiny, and transparent membrane consisting of the amnion and parietal peritoneum. The internal organs are clearly visible through this layer. When the child cries, the protrusion visibly increases in size.

Treatment of omphalocele is exclusively surgical and performed on an emergency basis—in the first hours after birth. Any delay is critically dangerous: the thin membranes quickly dry out and become infected, which inevitably leads to the development of severe peritonitis.

Malformations of the stomach and colon

Congenital pyloric stenosis (pylorostenosis congenita) occurs due to hypertrophy of the pyloric musculature and impaired innervation. This creates an insurmountable mechanical obstruction to the passage of food from the stomach into the duodenum. The onset of the disease most commonly occurs at the 3rd–4th week of life (less frequently at 4–5 months). Main symptoms: intense projectile vomiting; the vomitus has an unpleasant, stagnant odor. The infant rapidly loses weight (hypotrophy), and the stomach becomes distended. In emaciated children, the "hourglass" sign (enhanced visible peristalsis) is visualized in the left hypochondrium. Treatment consists of pyloromyotomy — longitudinal incision of the serosa and hypertrophied pyloric muscle fibers down to the submucosa, which remains intact.

Hirschsprung's disease is a congenital underdevelopment of nerve plexuses (agangliosis) in the rectosigmoid region of the colon. Due to the lack of innervation, the affected segment narrows, while the proximal segments of the colon pathologically dilate with thickening of the muscle layer (compensatory hypertrophy). Clinical presentation: severe, stubborn constipation (stools may be absent for several consecutive days) and marked abdominal distension due to flatulence, manifesting from the first years of life. In mild forms, patients may survive into adolescence or adulthood. The main diagnostic method is barium enema (irrigography), and treatment reduces to resection of the aganglionic zone of the colon.

Anomalies of the rectum and anal canal

Atresia of the anus and rectum is a rare malformation. It manifests as the complete absence of the anus and meconium passage. Acute intestinal obstruction rapidly develops in the infant, and their condition becomes extremely severe. Surgery to restore normal fecal passage is performed in the first hours after birth.

There are also fistulous forms, where the blind intestinal pouch communicates with other organs:

• In boys, fecal matter may be discharged with urine through a fistula connected to the urinary bladder.
• In girls, the intestine communicates with the vagina or the vaginal vestibule, causing feces to be discharged from the vaginal cleft.

In the presence of such fistulas, the disease proceeds somewhat more mildly due to partial decompression of the intestine.

Anal narrowing (anal stenosis), unlike atresia, usually manifests later—after the first year of life. The child suffers from difficult defecation, chronic constipation, and the formation of fecal impactions. The pathology also requires mandatory surgical correction.

Class and exam questions

What else to study on this topic

• Complications of Meckel's diverticulum (mechanisms of development of diverticulitis and intestinal obstruction)
• Fistulography and irrigography: performance technique and radiological presentation of malformations
• Surgical technique of pyloromyotomy and principles of postoperative management
• Surgical treatment methods for Hirschsprung's disease (types of resection)
• Staged surgical treatment of fistulous forms of rectal atresia

Other topics in "CHAPTER 16. CONGENITAL MALFORMATIONS"

Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.