Atresia Fistulae and Duplications

Slide 1 · Atresia, Fistulae, and Duplications

Congenital structural abnormalities of the gastrointestinal tract

duplicated cavity

adjacent gut

Atresia

Fistula

Duplication

Dr Abu Suraih Sakhri

MBBS, MD (Pathology)

www.abusuraihsakhri.com

Slide 2 · Learning objectives

Distinguish atresia, stenosis, fistula, and duplication anatomically.

Explain neonatal symptoms from obstructed GI continuity or airway communication.

Recognize major esophageal and intestinal patterns and their complications.

Apply morphologic criteria and imaging logic to alimentary duplications.

Structure

Morphology

Clinical consequences

Clinicopathologic interpretation

Schematic

Slide 3 · Congenital GI defects: Three structural problems

Atresia: Segmental loss of a patent lumen.

Fistula: Abnormal connection between epithelial-lined structures.

Duplication: Extra alimentary segment, often a cyst sharing a gut wall.

ATRESIA

Discontinuity

FISTULA

Abnormal connection

DUPLICATION

Additional segment

Schematic

Slide 4 · Anatomic pattern predicts clinical consequences

Luminal interruption causes impaired transit and upstream distension.

Airway communication creates a route for aspiration or gas entry.

A duplicated segment may compress bowel or develop mucosal complications.

Lumen interrupted → retention

Airway connection → aspiration

Duplicated wall → mass or ulceration

Schematic

Slide 5 · Embryogenesis: One insult can affect several organs

Congenital anomalies vary with developmental process and timing.

Concurrent organ development explains associated abnormalities.

A GI birth defect should trigger a directed extraintestinal assessment.

Developmental disruption

Anatomic defect

Clinical phenotype

Schematic

Slide 6 · Atresia versus stenosis

Atresia is an interruption of normal lumen formation or continuity.

Stenosis retains a narrowed passage and may obstruct partially or completely.

Degree and location of blockage determine timing and severity.

Atresia: No patent continuity

Stenosis: Narrowed lumen

Schematic

Slide 7 · Complete versus partial obstruction

Complete obstruction stops passage across the affected level.

Partial obstruction permits some transit but causes retention and distension.

Clinical expression depends on site, residual caliber, and feeding.

Upstream

Downstream

Distension

Obstruction

Underused distal lumen

Schematic

Slide 8 · Esophageal atresia: Core morphology

A segment of the developing esophagus is absent or noncanalized.

A blind-ending proximal pouch prevents food reaching the stomach.

A thin noncanalized cord may connect the esophageal ends.

Trachea

Esophagus

No fistula • discontinuous esophagus

Schematic

Slide 9 · Agenesis, atresia, and stenosis are distinct

Agenesis: Extreme absence of esophageal formation; Very rare.

Atresia: Discontinuous lumen with blind pouch or pouches.

Stenosis: Residual lumen with reduced caliber.

Atresia: No patent continuity

Stenosis: Narrowed lumen

Schematic

Slide 10 · Robbins frequency estimate for esophageal atresia

Esophageal atresia is reported in 1–5 infants per 10,000 live births.

This frequency refers to atresia, not all congenital GI defects.

Anatomical subtype and associated anomalies shape clinical risk.

1–5

Per 10,000 live births

Schematic

Slide 11 · Relation to the tracheal bifurcation

The atretic segment most often occurs at or near the tracheal bifurcation.

Adjacent esophageal and respiratory structures permit fistulous connections.

The exact fistula arrangement changes both air and feeding pathways.

Trachea

Esophagus

Esophagus lies adjacent to airway

Schematic

Slide 12 · Normal esophagus–trachea relationship

Esophagus and trachea are separate adjacent conduits.

Food should pass toward the stomach without entering the airway.

The airway is not normally connected to the esophageal lumen.

Trachea

Esophagus

Two separate continuous conduits

Schematic

Slide 13 · Isolated atresia: No airway fistula

Upper and lower esophageal segments end blindly.

No communication with the trachea is depicted.

Obstructed saliva and feeds accumulate in the proximal pouch.

Trachea

Esophagus

No fistula • discontinuous esophagus

Schematic

Slide 14 · Distal fistula: Atresia with airway connection

The proximal esophagus ends blindly.

The distal esophageal segment communicates with the trachea.

This is the most common Robbins-depicted configuration.

Trachea

Esophagus

Blind proximal pouch • distal fistula

Schematic

Slide 15 · Isolated fistula: Esophagus remains continuous

The esophageal lumen remains continuous.

A communication connects esophagus and trachea.

Feeding-associated airway symptoms may occur despite luminal continuity.

Trachea

Esophagus

Continuous esophagus • communicating fistula

Schematic

Slide 16 · Five Gross-classification anatomic types

Isolated atresia; Proximal fistula; Distal fistula; Double fistula.

Isolated fistula without atresia (often termed H-type).

Identify proximal and distal communications rather than memorizing letters alone.

A

Atresia only

B

Proximal fistula

C

Distal fistula

D

Two fistulae

E

Isolated fistula

Schematic

Slide 17 · Proximal versus distal fistula: Why it matters

A proximal fistula offers a direct route for pooled upper-pouch secretions.

A distal fistula can conduct tracheal gas toward stomach and bowel.

Both abnormal pathways create respiratory and nutritional hazards.

Trachea

Esophagus

Trachea

Esophagus

Proximal

Distal

Schematic

Slide 18 · Foregut separation and abnormal communications

Trachea and esophagus develop from the foregut.

Abnormal separation or development is implicated in EA–TEF.

The precise embryologic sequence varies across anomalies.

Developmental disruption

Anatomic defect

Clinical phenotype

Schematic

Slide 19 · Why newborns regurgitate during feeding

An atretic proximal pouch cannot deliver swallowed material distally.

Saliva or milk returns to the oropharynx.

Regurgitation shortly after birth is a classic Robbins clue.

Trachea

Esophagus

No fistula • discontinuous esophagus

Schematic

Slide 20 · Neonatal recognition: Saliva, choking, cyanosis

Excessive drooling indicates pooled secretions.

Coughing or choking during feeds suggests esophageal or airway pathology.

Failure to pass an orogastric tube raises suspicion for atresia.

Drooling / failed feeding

Tube stops in upper pouch

Confirm anatomy; Assess other organs

Schematic

Slide 21 · Aspiration and pneumonia: An anatomic mechanism

Pooled secretions may enter the upper airway.

A tracheoesophageal connection adds a second aspiration route.

Repeated aspiration can precipitate respiratory distress or pneumonia.

Pooled secretions / fistula

Material enters airway

Aspiration and lung injury

Schematic

Slide 22 · Respiratory deterioration may be rapid

Suffocation and aspiration as major hazards.

Milk, saliva, and gastric contents threaten the lungs through different routes.

An apparent feeding problem may therefore be an airway emergency.

Airway risk

Aspiration • choking

Pneumonia • suffocation

Slide 23 · Distal fistula and gastric air

Air can pass from the trachea through a distal fistula.

Gastric and bowel gas may persist despite proximal esophageal atresia.

This distinguishes many distal-fistula cases from isolated atresia.

Trachea

Esophagus

Blind proximal pouch • distal fistula

Schematic

Slide 24 · Isolated atresia and a gasless abdomen

Without a distal fistula, the airway cannot directly aerate the stomach.

Absent distal abdominal gas can support isolated esophageal atresia.

Interpret bowel gas with anatomy and clinical findings; Not alone.

Trachea

Esophagus

No fistula • discontinuous esophagus

Schematic

Slide 25 · Orogastric tube: What the image means

The tube fails to reach the stomach when the upper pouch ends blindly.

Radiography can show the tube coiled in the upper pouch.

Distal intestinal gas provides an additional anatomical clue.

Drooling / failed feeding

Tube stops in upper pouch

Confirm anatomy; Assess other organs

Schematic

Slide 26 · Prenatal clue: Polyhydramnios

Obstructed fetal swallowing may reduce normal fluid absorption.

Excess amniotic fluid is a prenatal clue, not a specific diagnosis.

Postnatal anatomic evaluation remains necessary.

Impaired fetal passage

Altered fluid handling

Prenatal imaging clue

Schematic

Slide 27 · VACTERL: Evaluate beyond the esophagus

Vertebral, Anal, Cardiac, Tracheoesophageal, Renal, Limb defects.

Esophageal anomalies with this multisystem pattern.

Associated structural disease may alter immediate surgical planning.

Vertebral

Anal

Cardiac

Tracheoesophageal

Renal

Limb

Schematic

Slide 28 · TACRD: Another associated malformation pattern

Tracheal agenesis/atresia and complex cardiac abnormalities.

Radial ray defects and duodenal atresia complete the acronym.

This association reinforces the need to survey multiple organs.

Vertebral

Anal

Cardiac

Tracheoesophageal

Renal

Limb

Schematic

Slide 29 · Additional anomalies

Heart, lungs, and great vessels may be affected.

Genitourinary structures and anus may also be abnormal.

An isolated-looking foregut lesion does not exclude major coexisting defects.

Heart

Lungs

Great vessels

Kidneys

Anus

Limbs

Schematic

Slide 30 · Imperforate anus: Related developmental context

Robbins relates imperforate anus to failure of the cloacal diaphragm to involute.

Anorectal outlet obstruction is anatomically separate from esophageal atresia.

Perineal inspection forms part of congenital anomaly assessment.

Upstream

Downstream

Distension

Obstruction

Underused distal lumen

Schematic

Slide 31 · Fluid and electrolyte disturbances

Ineffective feeding threatens intake and hydration.

Regurgitation and vomiting increase gastrointestinal losses.

Severe fluid and electrolyte imbalance as a risk.

Developmental disruption

Anatomic defect

Clinical phenotype

Schematic

Slide 32 · Immediate care logic: Protect the airway

Suspected EA–TEF requires urgent neonatal surgical assessment.

Avoid oral feeding while airway and anatomy are evaluated.

Protect the lungs and stabilize hydration before definitive repair.

Protect airway / stabilize

Define associated anatomy

Surgical correction or repair

Schematic

Slide 33 · Surgical correction: The anatomic objectives

Re-establish a usable esophageal passage when feasible.

Divide and close the abnormal communication with the airway.

Identify and address concurrent major malformations.

Protect airway / stabilize

Define associated anatomy

Surgical correction or repair

Schematic

Slide 34 · Repair does not end gastrointestinal surveillance

Esophageal dysmotility and feeding difficulties may persist.

Gastroesophageal reflux and anastomotic narrowing are recognized sequelae.

Long-term follow-up is relevant beyond the neonatal period.

Esophageal reconstruction

Functional sequelae

Long-term symptom surveillance

Schematic

Slide 35 · Postrepair stricture: Clinicopathologic relevance

Anastomotic narrowing may produce dysphagia or food retention.

Long-gap repair, leaks, and reflux can contribute.

Distinguish postoperative stricture from congenital stenosis.

Atresia: No patent continuity

Stenosis: Narrowed lumen

Schematic

Slide 36 · Congenital stenosis: Wall narrowing

A markedly reduced lumen with fibrous wall thickening.

Luminal compromise can be incomplete or severe.

Unlike atresia, some passage may remain.

Atresia: No patent continuity

Stenosis: Narrowed lumen

Schematic

Slide 37 · Acquired stenosis: Four etiologic pathways

Chronic gastroesophageal reflux can produce inflammatory scarring.

Irradiation and caustic injury can lead to fibrosis.

Systemic sclerosis is another described setting.

Chronic reflux

Caustic injury

Irradiation

Systemic sclerosis

Schematic

Slide 38 · Why esophagus and small intestine are vulnerable

Stenosis may occur anywhere in the GI tract.

Clinically significant narrowing in narrower lumens.

Even modest wall thickening may compromise transit.

Upstream

Downstream

Distension

Obstruction

Underused distal lumen

Schematic

Slide 39 · Intestinal atresia: A second obstructive phenotype

Congenital intestinal lumen is interrupted at an intestinal level.

Symptoms usually relate to retained content proximal to the block.

Duodenal and jejunoileal atresias have different common developmental explanations.

Upstream

Downstream

Distension

Obstruction

Underused distal lumen

Schematic

Slide 40 · Duodenal atresia: Failure of canalization

Normal embryonic duodenal lumen formation requires recanalization.

Failure can result in a complete luminal block.

The obstruction often presents early with vomiting.

Proximal duodenum

Distal duodenum

Lumen interrupted in the duodenal segment

Schematic

Slide 41 · Duodenal obstruction: The double-bubble pattern

Two dilated gas-filled compartments represent stomach and proximal duodenum.

Little or no distal bowel gas favors complete obstruction.

The sign describes anatomy, not a pathognomonic cause.

Stomach

Proximal duodenum

Two gas-filled proximal compartments

Schematic

Slide 42 · Double bubble: Important differential diagnoses

Duodenal atresia and duodenal web or stenosis.

Annular pancreas or extrinsic bands with duodenal obstruction.

Malrotation-associated obstruction must remain in the differential.

Duodenal atresia

Duodenal web

Annular pancreas

Malrotation / bands

Schematic

Slide 43 · Duodenal atresia and other congenital anomalies

Down syndrome is a recognized association.

Cardiac and additional intestinal or rotational defects may coexist.

An associated anomaly survey is clinically relevant.

Heart

Lungs

Great vessels

Kidneys

Anus

Limbs

Schematic

Slide 44 · Jejunoileal atresia: Vascular disruption model

Intrauterine mesenteric vascular compromise is a major explanation.

Ischemic loss may interrupt a previously formed intestinal segment.

The model does not necessarily explain every familial or complex case.

Mesenteric flow disruption

Segmental ischemic injury

Atresia / mesenteric defect

Schematic

Slide 45 · Proximal and distal bowel changes

Proximal bowel becomes distended by retained contents.

Distal bowel may remain narrow or underused.

Difference in caliber matters for surgical reconstruction.

Upstream

Downstream

Distension

Obstruction

Underused distal lumen

Schematic

Slide 46 · Jejunoileal atresia Type I

An internal mucosal or membranous obstruction blocks the lumen.

External intestinal serosal continuity is maintained.

There is no associated mesenteric defect in the classical description.

Intact outer bowel wall

Obstructing intraluminal membrane

Schematic

Slide 47 · Types II and IIIa: Interruptions and mesentery

Type II: Blind ends joined by a fibrous cord.

Type IIIa: Discontinuity with a V-shaped mesenteric defect.

The mesenteric anatomy helps distinguish these forms.

Type II: Fibrous cord

Type IIIa adds a mesenteric gap

Schematic

Slide 48 · Types IIIb and IV: Complex small-bowel atresia

Type IIIb: “apple-peel” configuration with an abnormal remaining mesentery.

Type IV: Multiple atretic segments.

Bowel-length implications are important in these forms.

IIIb: Abnormal coiled residual bowel

IV: Multiple interrupted segments

Schematic

Slide 49 · Neonatal intestinal obstruction: Clinical clues

Bilious vomiting may signal obstruction beyond entry of bile into duodenum.

Abdominal distension and delayed passage of stool may be present.

The anatomical level influences clinical timing and distension.

Upstream

Downstream

Distension

Obstruction

Underused distal lumen

Schematic

Slide 50 · Initial evaluation of suspected intestinal atresia

Stabilize the infant and limit enteral accumulation.

Use imaging to identify level and likely mechanism of obstruction.

Pediatric surgery evaluates definitive anatomic correction.

Protect airway / stabilize

Define associated anatomy

Surgical correction or repair

Schematic

Slide 51 · Other causes of neonatal obstruction

Malrotation with volvulus may mimic a congenital obstructive lesion.

Meconium ileus and meconium plug syndrome have distinct mechanisms.

Colonic atresia and anal atresia are more distal possibilities.

Atresia

Malrotation / volvulus

Meconium obstruction

Anal outlet defect

Schematic

Slide 52 · Alimentary duplication: Definition

A congenital extra segment lies in close association with gut.

It commonly shares a smooth-muscle wall with the native segment.

The lesion may be cystic or tubular.

Duplicated cavity

Adjacent gut

Schematic

Slide 53 · The histologic triad of duplication

Epithelial lining of alimentary-type mucosa.

A defined smooth-muscle component in its wall.

Intimate relation to adjacent gastrointestinal tract.

Lumen

Mucosal lining

Muscle wall

Schematic

Slide 54 · Cystic and tubular duplications

Cystic lesions commonly do not communicate with bowel lumen.

Tubular duplications may connect to the parent bowel.

Communication alters filling, symptoms, and surgical anatomy.

Cystic

Tubular

Configuration governs luminal communication

Schematic

Slide 55 · Where duplications arise

Alimentary duplication can occur along the gastrointestinal tract.

The ileum and esophagus are commonly described sites.

Symptoms depend more on location and relationships than on name alone.

Foregut: Esophagus

Midgut: Small intestine (ileum)

Hindgut: Distal bowel

Schematic

Slide 56 · Embryogenesis of duplication: Multiple theories

Proposed mechanisms include abnormal recanalization and abortive twinning.

Persistent embryonic diverticula and other theories have been described.

No single hypothesis explains every duplication phenotype.

Developmental disturbance

Proposed alternative mechanisms

Congenital duplicate segment

Schematic

Slide 57 · Duplication histology: Layers have meaning

Enteric-type epithelium lines the cyst or duplicated lumen.

Smooth-muscle layers support an alimentary duplication diagnosis.

Mucosal type may differ from the adjacent bowel segment.

Lumen

Mucosal lining

Muscle wall

Schematic

Slide 58 · Ectopic gastric mucosa: Why bleeding occurs

Gastric-type mucosa may occur within an intestinal duplication.

Acid secretion can ulcerate susceptible nearby mucosa.

Hemorrhage is a consequence of mucosal biology, not simply mass effect.

Lumen

Mucosal lining

Muscle wall

Schematic

Slide 59 · Clinical consequences of duplication

Mass effect can narrow or obstruct adjacent bowel.

Intussusception, volvulus, and bleeding are recognized complications.

Presentation ranges from infancy to incidental later detection.

Duplicated cavity

Adjacent gut

Schematic

Slide 60 · Imaging clue: The gut-signature wall

Ultrasonography may show inner echogenic mucosa and outer hypoechoic muscle.

Layered architecture is suggestive of a duplication cyst.

The sign has mimics; Pathology and anatomic context remain important.

Echogenic inner layer

Hypoechoic outer layer

Simplified ultrasound wall schematic

Slide 61 · Duplication differential: Do not overcall cysts

Mesenteric or other abdominal cysts can resemble a duplication.

Meckel diverticulum is a true bowel-wall diverticulum, not a closed duplication cyst.

Location, communication, and wall histology separate diagnoses.

Duplication cyst

Meckel diverticulum

Mesenteric cyst

Other cystic lesions

Schematic

Slide 62 · Comparative pathology: Three structural phenotypes

Atresia primarily obstructs luminal continuity.

Fistula creates abnormal inter-compartment communication.

Duplication adds a second tissue-lined structure near native bowel.

ATRESIA

Discontinuity

FISTULA

Abnormal connection

DUPLICATION

Additional segment

Schematic

Slide 63 · Case 1: Newborn with repeated choking during feeds

Excessive saliva and inability to advance an orogastric tube.

A radiograph depicts the tube coiled above the stomach.

Question: Which congenital lesion explains the findings?

Trachea

Esophagus

Where would a feeding tube stop?

Schematic

Slide 64 · Case 1: Anatomic answer

Esophageal atresia explains the blind-ending pouch.

Inspect abdominal gas for a possible distal airway communication.

Assess cardiac, vertebral, renal, anorectal, and limb anatomy.

Trachea

Esophagus

Blind proximal pouch • distal fistula

Schematic

Slide 65 · Case 2: Neonate with bilious emesis

Radiography shows a dilated stomach and proximal duodenum.

Little or no distal intestinal gas is identified.

Question: What does the two-compartment pattern localize?

Stomach

Proximal duodenum

Two gas-filled proximal compartments

Schematic

Slide 66 · Case 2: Level first, cause second

The double bubble localizes proximal duodenal obstruction.

Duodenal atresia is important but not the only possible cause.

Correlate anatomy and evaluate associated anomalies.

Proximal duodenum

Distal duodenum

Lumen interrupted in the duodenal segment

Schematic

Slide 67 · Case 3: Enteric-lined cyst in a child

A cystic lesion is closely attached to the small-intestinal wall.

Histology shows mucosa and a distinct smooth-muscle coat.

Question: Which developmental lesion is most likely?

Lumen

Mucosal lining

Muscle wall

Schematic

Slide 68 · Case 3: Integrated answer

An alimentary duplication cyst explains the anatomical and histologic triad.

Check for heterotopic mucosa and ulceration.

Clinical concern includes obstruction, bleeding, and other complications.

Duplicated cavity

Adjacent gut

Schematic

Slide 69 · Synthesis: Structure predicts symptoms

Esophageal obstruction: Drooling, regurgitation, failed tube passage.

Airway fistula: Aspiration risk and possible gastric aeration.

Intestinal obstruction: Vomiting and characteristic bowel-gas patterns.

Duplication: Cystic mass effect or heterotopic mucosal disease.

Lumen interrupted → retention

Airway connection → aspiration

Duplicated wall → mass or ulceration

Schematic

Slide 70 · References — primary text and clinical context

Robbins, Cotran & Kumar. Pathologic Basis of Disease. 11th ed. Chapter 17, p. 685.

Baldwin & Yadav. Esophageal Atresia. StatPearls, updated 2023.

Osuchukwu & Rentea. Ileal Atresia. StatPearls, updated 2023.

Anand & Aleem. Duplication Cyst. StatPearls, updated 2022.

Slide 71 · References — additional verification

Merck Manual Professional. Duodenal Obstruction, updated 2025.

Merck Manual Professional. Congenital Gastrointestinal Anomalies, updated 2026.

Krishnan et al. ESPGHAN–NASPGHAN EA–TEF GI follow-up guideline. 2016.

Enteric duplication cysts in children: imaging findings. Insights Imaging. 2018.