Skip to content

PAEDIATRIC SMALL BOWEL PATHOLOGY

Malrotation

  • 90% of cases manifest within the first year of life.
  • 50-75% manifest within the first month of life.

Developmental Stages

  • 5th week:
    • Midgut moves out of the umbilicus and rotates 90° anticlockwise around the SMA.
  • 10th week:
    • Midgut moves back into the umbilicus and rotates 180° anticlockwise around the SMA.
  • Final position:
    • DJ on the left and cecum on the right of the SMA/midline.

Types of Malrotation

  • Nonrotation: The most common (MC) form of malrotation.

    1. Complete Nonrotation: DJ on right, caecum on left of SMA, narrow mesentery, high risk of volvulus.
    2. Nonrotation of DJ with normal cecal rotation: Causes duodenal obstruction due to Ladd bands.
    3. Nonrotation of cecum with normal DJ: High risk of midgut volvulus.
    4. Reverse rotation: DJ anterior to SMA, cecum posterior to SMA, leading to transverse colon obstruction.

    image.png

Associated Congenital Anomalies (30% to 60% of cases)

  • Duodenal atresia, imperforate anus, Meckel diverticulum, annular pancreas, preduodenal portal vein, biliary atresia, cardiac anomalies, heterotaxia, trisomy 21, and 16q24 chromosomal deletion syndrome.

Hallmark Symptom

  • Bilious emesis in an infant is the hallmark of malrotation with midgut volvulus.

Diagnostic Tests

  • X-ray: Shows gasless abdomen, high-grade bowel obstruction, normal bowel gas pattern.
  • USG Abdomen: Shows reversal of the normal anatomic relationship between the SMA and SMV – Whirlpool sign.
  • UGI Barium Studies: Best test for diagnosis; shows Corkscrew appearance in midgut volvulus.

image.png

Surgical Management (Ladd Procedure)

  • First described by William Ladd in 1936.

  • Surgical approach:

    • Right upper transverse incision in infants and midline incision in adults.
    • If volvulus is present, derotate in an anticlockwise direction.
    • Ladd bands (peritoneal bands from the right paracolic gutter over the duodenum) are lysed.
    • The base of the mesentery is widened.
    • After surgery, the small bowel is placed on the right side and the cecum in the left upper abdomen.

    image.png

  • Complications:

    • Volvulus with vascular compromise occurs in 30% of cases.
    • Long-term complications in 10% of patients.

Intestinal Atresia

Duodenal Atresia

  • Cause: Due to a recanalization error during the 6th week of gestation when the gut tube fails to obliterate its lumen.
  • Location: 85% of cases are located at the junction of D1 and D2.
  • Prenatal Sign: Polyhydramnios occurs in 30-65% of cases.
  • Radiology: Double bubble sign is a key radiologic feature.

image.png

  • Associated Anomalies:
    • 28% associated with Down syndrome.
    • 23% associated with Annular pancreas.
    • 23% associated with Congenital heart disease.
    • 20% associated with Malrotation.
  • Surgical correction is the treatment of choice.

Skandalakis Classification of Duodenal Atresia

  • Type I: Mucosal web causing obstruction (most common, 92%).
  • Type II: Two blind ends of the duodenum connected by a fibrous cord (1%).
  • Type III: Two disconnected blind ends (7%).

image.png

Jejunoileal Atresia

  • More common than duodenal atresia.
  • Distribution: Equal distribution between jejunal and ileal involvement.
  • Cause: Due to an in utero vascular accident leading to necrosis and resorption of affected bowel segments.

Modified Louw Classification of Jejunoileal Atresia

  • Type I: Membranous atresia with intact bowel and mesentery.
  • Type II: Blind ends separated by a fibrous cord.
  • Type IIIa: Blind ends separated by a V-shaped mesenteric defect.
  • Type IIIb: Apple peel/Christmas tree deformity.
  • Type IV: Multiple atresias (string of sausages) – Worst prognosis.

image.png

Prognosis and Survival

  • Mortality depends on the length of the remaining small bowel.
    • If > 40 cm of bowel remains, survival is 95%.
    • For 14 to 40 cm, survival is 50%.
    • Type IIIb and IV often require extensive resection, leading to Short Bowel Syndrome and the need for Total Parenteral Nutrition (TPN).

Bowel Lengthening Procedures

  • Bianchi (LILT procedure): Longitudinal intestinal lengthening and tailoring.
  • Serial transverse enteroplasty (STEP): Another bowel lengthening procedure.

image.png

Duplication Cysts

Ladd's Definition of Duplication Cysts

  1. Well-developed coat of smooth muscle.
  2. Epithelial lining representing gastrointestinal mucosa.
  3. Intimate anatomic association with a portion of the gastrointestinal tract.

Common Sites of Occurrence

  • Duplication cysts can occur anywhere in the gastrointestinal tract.
  • Most common (MC) sites in descending order:
    • Ileum
    • Esophagus
    • Jejunum
    • Colon
    • Stomach
    • Appendix
    • Rectum

Key Features

  • 10-20% of cases are multiple.
  • 25% of duplication cysts communicate with the lumen.
  • 25% contain gastric or pancreatic mucosa.
  • They can be cystic or tubular, with cystic being the most common.

image.png

Types of Duplication Cysts

  • Cystic Duplication:
    • Spherical structures located along the mesenteric border of the bowel.
    • Share a blood supply with the adjacent bowel.
    • Rarely have an intraluminal connection.
  • Tubular Duplication:
    • Located on the mesenteric side, sharing a common wall and blood supply with the normal bowel.
    • More frequently communicate with the lumen.
    • Have a high incidence of ectopic gastric mucosa.

Clinical Presentation

  • Majority of cases are symptomatic during infancy.
  • Symptoms are rarely seen after 12 years of age.

Diagnosis

  • Ultrasound is the most common imaging modality used for diagnosis.

Management

  • Surgical resection and anastomosis is the treatment of choice.

Meconium Disorders

Meconium Plug Syndrome

  • Associated with:
    • Hirschsprung disease in 3% - 38% of cases.
    • Cystic Fibrosis (CF) in 0% - 43% of cases.
  • Characterized by failure to pass meconium.
  • If the infant does not pass meconium, a rectal biopsy is necessary to exclude Hirschsprung disease.

image.png

Omphalomesenteric Remnants Overview

The Omphalomesenteric duct (also called the vitelline duct) is a temporary embryonic structure that connects the yolk sac to the developing midgut of the embryo. It typically obliterates during the 5th to 7th week of gestation. However, failure of this duct to regress can lead to various remnants and pathologies.

Types of Omphalomesenteric Remnants

  1. Meckel's Diverticulum (Image A):
    • Most common remnant of the omphalomesenteric duct.
    • Located on the antimesenteric border of the ileum, usually within 2 feet of the ileocecal valve.
    • Can contain ectopic tissue such as gastric or pancreatic tissue.
    • Associated with complications like bleeding, obstruction, and diverticulitis.
  2. Vitelline Cyst (Image B):
    • Forms when both ends of the duct close, but the middle portion remains patent, resulting in a cyst.
    • The cyst is usually connected to the ileum and the umbilicus by vitelline ligaments.
    • Generally asymptomatic, but can cause abdominal discomfort or become infected.
  3. Vitelline Fistula (Image C):
    • Occurs when the omphalomesenteric duct remains completely open, forming a connection between the ileum and the umbilicus.
    • This can lead to fecal discharge from the umbilicus.
    • Requires surgical correction due to the risk of infection and other complications.

Embryological Context

  • The vitelline duct is part of the midgut development, and its remnants can result in these anomalies if it fails to regress properly.
  • These remnants are often diagnosed in childhood due to symptoms like abdominal pain, distention, or intestinal obstruction.

Diagnosis and Management

  • Diagnosis of these conditions may involve imaging modalities like ultrasound, CT scans, or technetium-99m scans for cases like Meckel's diverticulum.
  • Surgical resection is the treatment of choice for symptomatic cases, especially with Meckel's diverticulum or vitelline fistula.

Necrotizing Enterocolitis (NEC)

  • Most common (MC) gastrointestinal emergency in neonates.
  • Perforation occurs in 1/3 of cases.
  • Most commonly involved areas:
    • Terminal ileum and colon.
    • The entire small bowel is involved in 10% of cases.
  • Primarily a disease of prematurity, but occurs in 10% of full-term infants.

Etiology

  • Multifactorial causes, including:

    • Prematurity.
    • Rapid advances in feeding of extremely low birth weight (ELBW) infants.
    • Asphyxia.
    • Patent ductus arteriosus (PDA).
    • Umbilical artery catheter with the tip at or above the mesenteric artery.
    • Medications such as Indomethacin/ibuprofen and Aminophylline.
    • Polycythemia.
    • Hypothermia.

    image.png

Surgical Treatment Options

  1. Laparotomy and peritoneal drainage (PD).
  2. Clip and drop back method.
  3. Patch, drain, and wait technique for cases with extensive necrosis.

Prognosis

  • Mortality rate for NEC is 20% to 35%.
  • 25% of infants who recover from NEC experience neurodevelopmental impairment.

Intussusception Overview

  • Definition: Invagination of a portion of the proximal intestine (intussusceptum) into the distal segment of the bowel (intussuscipiens).
  • Most common age group:
    • Occurs most frequently in the first year of life.
  • Etiology:
    • Most cases are idiopathic and lack a lead point.
    • Adenoviruses and rotavirus are responsible for 50% of idiopathic cases.
  • Pathology:
    • Hypertrophy of Peyer's patches is seen in all cases of intussusception.
  • Lead point:
    • The chances of a lead point (e.g., polyp, tumor) increase with age.

  • Clinical presentation:

    • Characterized by inconsolable pain that lasts for 5 to 15 minutes during episodes.

    image.png

Table 71.2: Types of Intussusception in Children

Type Percentage of Series (%)
Ileoleal 5
Ileocolic 77
Ileoileocolic 12
Colocolic 2
Multiple 1
Retrograde 0.2
Others 2.8

MCQ Discussion

Correct order of the most common types of intussusception in children is:

A) Ileocolic > Ileoileocolic > Colocolic > Ileoileal

B) Ileocolic > Colocolic > Ileoileocolic > Ileoileal

C) Ileoileocolic > Ileocolic > Colocolic > Ileoileal

D) Ileocolic > Ileoileocolic > Ileoileal > Colocolic

Correct Answer: D) Ileocolic > Ileoileocolic > Ileoileal > Colocolic

MCQs for Revision

1. High risk of midgut volvulus is seen in?

A) Complete nonrotation

B) Nonrotation of DJ with normal caecal rotation

C) Nonrotation of caecum with normal DJ

D) Reverse rotation

Correct Answer: C) Nonrotation of caecum with normal DJ

(Nonrotation of the caecum with normal DJ has a high risk of midgut volvulus)

2. Which of the following is considered a hallmark symptom of malrotation?

A) Pain abdomen

B) Bilious vomiting

C) Mass abdomen

D) Growth retardation

Correct Answer: B) Bilious vomiting

(Bilious vomiting is the hallmark symptom of malrotation)

3. All are true about duodenal atresia except?

A) A recanalization error

B) Gut tube fails to obliterate its lumen in the 6th week of gestation

C) Type 2 is the most common type

D) 85% are located at the junction of D1 & D2

Correct Answer: C) Type 2 is the most common type

(Type 1 is the most common type of duodenal atresia)

4. Hackam score is used in?

A) Intestinal atresia

B) Necrotizing enterocolitis

C) Duplication cyst

D) Meconium ileus

Correct Answer: B) Necrotizing enterocolitis

(Hackam score is used in the evaluation of necrotizing enterocolitis)

5. Skandalakis classification is used for?

A) Duodenal atresia

B) Jejunal atresia

C) Ileal atresia

D) Malrotation

Correct Answer: A) Duodenal atresia

(Skandalakis classification is used for duodenal atresia)

6. Modified Louw's classification is used in?

A) Duodenal atresia

B) Jejunal atresia

C) Ileal atresia

D) Malrotation

Correct Answer: B) Jejunal atresia

(Modified Louw's classification is used for jejunal atresia)

7. Whirlpool sign, a classical sign of malrotation, is found in?

A) USG abdomen

B) Barium meal follow through

C) CECT abdomen

D) Nuclear scan

Correct Answer: A) USG abdomen

(The whirlpool sign is seen on ultrasound in cases of malrotation)

8. All are true regarding Meckel's diverticulum except?

A) 90% of omphalomesenteric duct remnants

B) Most common congenital anomaly of the GI tract

C) H. pylori plays no pathogenic role in Meckel-related ulceration

D) Malignancies constitute around 8-10% of Meckel's complications

Correct Answer: D) Malignancies constitute around 8-10% of Meckel's complications

(Malignancies constitute about 0.5-3.2% of complications in Meckel's diverticulum)

9. The most common site of intestinal duplication cysts is?

A) Jejunum

B) Ileum

C) Appendix

D) Colon

Correct Answer: B) Ileum

(The ileum is the most common site for intestinal duplication cysts)