Intussusception in Children

1. Clinical Overview

Definition and Importance

Intussusception is the invagination (telescoping) of a proximal segment of bowel (the intussusceptum) into an adjacent distal segment (the intussuscipiens), creating a "bowel-within-bowel" configuration that leads to venous congestion, arterial compromise, and ultimately bowel necrosis if untreated. [1,2] It represents the most common cause of intestinal obstruction in infants and toddlers aged 3 months to 3 years, and constitutes a true paediatric surgical emergency requiring prompt diagnosis and intervention. [3]

The condition derives its name from the Latin "intus" (within) and "suscipere" (to receive). First described by Paul Barbette of Amsterdam in 1674, and later with surgical intervention by Sir Jonathan Hutchinson in 1871, intussusception has evolved from a condition with high mortality to one with excellent outcomes when promptly recognized and treated. [4]

The clinical significance lies in its time-sensitive nature: the probability of successful non-operative reduction decreases significantly with symptom duration, while the risk of bowel necrosis, perforation, and mortality increases. Understanding the pathophysiology, recognizing typical and atypical presentations, and knowing when to proceed to surgery are essential competencies for any clinician managing paediatric emergencies. [5]

Key Facts

Clinical Pearls

The Dance Sign: Empty right iliac fossa on palpation (Dance's sign) occurs because the ileocaecal mass has invaginated away from its normal position. A sausage-shaped mass is often palpable in the right upper quadrant, epigastrium, or along the transverse colon.

Redcurrant Jelly is a LATE Sign: The classic "redcurrant jelly" stool (blood and mucus) indicates mucosal ischaemia and vascular compromise. By the time this appears, the window for successful non-operative reduction is narrowing. Most children with intussusception do not have this finding at initial presentation. [5]

Lethargy May Be the Only Sign: Young infants (3-6 months) may present with isolated lethargy, pallor, and refusal to feed, without obvious abdominal symptoms. This "neurological" presentation is a diagnostic pitfall and requires a high index of suspicion. [12]

Lead Points in Older Children: In children greater than 2-3 years, always actively investigate for a pathological lead point. Meckel's diverticulum is the most common, followed by polyps, lymphoma (especially Burkitt's), duplication cysts, and Henoch-Schönlein purpura-related intramural haematoma. [7,8]

Ultrasound is Gold Standard: Abdominal ultrasound has sensitivity and specificity exceeding 98% for diagnosis. The "target" or "doughnut" sign in transverse section and "pseudokidney" sign in longitudinal section are pathognomonic. Do not delay for plain radiography if ultrasound is available. [13,14]

Air Enema is Preferred: Pneumatic (air) reduction is the preferred method where available, with slightly higher success rates than hydrostatic reduction and better safety profile if perforation occurs. [9]

Post-Reduction Monitoring is Essential: After successful enema reduction, monitor for 24 hours. Recurrence occurs in approximately 10% of cases, with most occurring within 72 hours. A second or even third enema reduction can be safely attempted. [11]

Rule of 3s for Recurrence: Consider surgery after the third recurrence, particularly if a pathological lead point is suspected.

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2. Epidemiology

Incidence and Demographics

Intussusception is the most common cause of intestinal obstruction in infancy and early childhood, occurring in approximately 1-4 per 1,000 live births annually. [3,6] It ranks second only to pyloric stenosis among conditions requiring emergency abdominal surgery in infants. Geographic variation exists, with higher reported incidences in some Asian countries compared to Western populations. [15]

Age Distribution

The peak incidence occurs between 5-9 months of age, coinciding with the introduction of solid foods and exposure to new viral antigens, both of which may contribute to Peyer's patch hypertrophy. [1,6]

Sex Distribution

Males are affected approximately 2-3 times more frequently than females, though the reason for this predominance remains unexplained. [1,6] Some studies suggest the male preponderance is more marked in older children.

Seasonal Variation

A seasonal pattern has been observed in many populations, with increased incidence in spring, summer, and autumn, correlating with peaks in viral gastroenteritis and respiratory infections. This supports the hypothesis of a viral trigger in idiopathic intussusception. [15,16]

Risk Factors

Idiopathic Intussusception (90%)

The majority of paediatric intussusception cases lack an identifiable anatomical lead point and are termed "idiopathic." Several factors are associated with increased risk:

Rotavirus Vaccine and Intussusception

The relationship between rotavirus vaccination and intussusception deserves special attention due to its historical and public health significance. [17,18]

Historical Context: The first-generation rotavirus vaccine (RotaShield) was withdrawn in 1999 due to a significantly increased risk of intussusception (approximately 1 in 10,000 vaccines). Current-generation vaccines (Rotarix, RotaTeq) have a much smaller associated risk.

Current Evidence: Large post-marketing surveillance studies demonstrate:

• Very small absolute risk: 1-2 additional cases per 100,000 vaccinated infants
• Risk highest in the 7 days following the first dose
• Benefits of vaccination (prevention of severe rotavirus gastroenteritis, hospitalization, and death) substantially outweigh the very small risk of intussusception [17,18]

Clinical Implication: Rotavirus vaccination remains recommended by all major health authorities. Parents should be informed of the small risk and advised to seek medical attention if infants develop symptoms of intussusception following vaccination.

Pathological Lead Points (10%)

A pathological lead point is an identifiable anatomical abnormality that initiates the invagination. These become progressively more common with increasing age.

Rule: In any child greater than 3 years presenting with intussusception, actively investigate for a pathological lead point. Even if initial reduction is successful, further imaging (contrast CT, MRI) or operative exploration may be warranted. [7,8]

Geographic Variation

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3. Pathophysiology

Anatomical Classification

Intussusception is classified by the bowel segments involved:

Mechanism of Telescoping

The pathophysiological sequence involves progressive bowel invagination with mesenteric compromise:

Step 1: Initiation

A "lead point" acts as the focal initiating point for invagination. In idiopathic cases, this is typically a hypertrophied Peyer's patch (lymphoid aggregates in the ileal wall) that protrudes into the bowel lumen. [1,2]

Molecular Basis of Peyer's Patch Hypertrophy: Recent evidence suggests that viral-induced lymphoid hyperplasia involves:

• T-cell proliferation: Viral antigens (particularly adenovirus, rotavirus) trigger expansion of lymphoid follicles within Peyer's patches in the terminal ileum [15,16]
• Cytokine-mediated inflammation: Increased IL-6, TNF-α, and interferon-γ production leads to mucosal oedema and follicular enlargement [21]
• Altered gut motility: Inflammatory mediators disrupt the migrating motor complex (MMC), creating dysrhythmic peristalsis that propagates the lead point distally [21]
• Age-related susceptibility: Peak incidence at 5-9 months corresponds to maximal lymphoid tissue development post-maternal antibody waning and introduction of dietary antigens [1,6]

Factors that may trigger initiation:

• Viral infection causing lymphoid hyperplasia
• Irregular peristaltic activity (gastroenteritis, recent feeding changes)
• Anatomical abnormality (in cases with pathological lead point)

Step 2: Invagination and Telescoping

Once initiated, peristaltic activity propagates the lead point distally. The proximal segment (intussusceptum) progressively invaginates into the distal segment (intussuscipiens), creating a three-layered structure:

1. Entering layer: Outer wall of intussusceptum
2. Returning layer: Inner wall of intussusceptum (folded back on itself)
3. Receiving layer: Wall of intussuscipiens (sheath)

The mesentery is dragged along with the intussuscepting bowel, becoming compressed between the layers. This is the critical factor leading to vascular compromise.

Biomechanical Progression:

• Initial phase (0-6 hours): Telescoping advances 2-5 cm along bowel axis; mesenteric vessels kinked but not completely occluded
• Progressive phase (6-24 hours): Intussusception extends to transverse colon or beyond; increasing mesenteric compression
• Critical phase (greater than 24 hours): Oedema exacerbates compression; "point of no return" for non-operative reduction approaches [2,20]

Step 3: Mesenteric and Vascular Compromise

              INTUSSUSCEPTION VASCULAR PATHOPHYSIOLOGY
                              │
                              ▼
┌───────────────────────────────────────────────────────────────┐
│                     TELESCOPING                                │
│   Proximal bowel (intussusceptum) invaginates into distal     │
│   (intussuscipiens) carrying mesentery with it                │
└───────────────────────────────────────────────────────────────┘
                              │
                              ▼
┌───────────────────────────────────────────────────────────────┐
│                  MESENTERIC COMPRESSION                        │
│   Mesentery trapped between layers; vessels compressed         │
│   at neck of intussusception                                   │
└───────────────────────────────────────────────────────────────┘
                              │
              ┌───────────────┴───────────────┐
              ▼                               ▼
┌─────────────────────────┐     ┌─────────────────────────────┐
│    VENOUS OBSTRUCTION   │     │     LYMPHATIC OBSTRUCTION   │
│    (Occurs first)       │     │                             │
│    ↓                    │     │     → Mesenteric oedema     │
│    Venous congestion    │     │     → Increased compression │
│    ↓                    │     │                             │
│    Mucosal oedema       │     └─────────────────────────────┘
│    ↓                    │
│    Wall thickening      │
└─────────────────────────┘
              │
              ▼ (If unrelieved)
┌───────────────────────────────────────────────────────────────┐
│                  ARTERIAL COMPROMISE                           │
│   Progressive compression leads to arterial insufficiency      │
│   → Bowel wall ischaemia                                       │
│   → Mucosal necrosis                                           │
└───────────────────────────────────────────────────────────────┘
              │
              ▼
┌───────────────────────────────────────────────────────────────┐
│                  MUCOSAL SLOUGHING                             │
│   Necrotic mucosa produces blood-stained mucus                 │
│   = "REDCURRANT JELLY" STOOL                                   │
│   (Indicates significant vascular compromise - LATE SIGN)      │
└───────────────────────────────────────────────────────────────┘
              │
              ▼ (If still unrelieved)
┌───────────────────────────────────────────────────────────────┐
│              FULL-THICKNESS NECROSIS (GANGRENE)               │
│   Complete bowel wall necrosis                                 │
│   High risk of perforation                                     │
│   Enema reduction contraindicated                              │
│   Requires surgical resection                                  │
└───────────────────────────────────────────────────────────────┘
              │
              ▼
┌───────────────────────────────────────────────────────────────┐
│                     PERFORATION                                │
│   Free spillage of intestinal contents                         │
│   Faecal/purulent peritonitis                                  │
│   Septic shock                                                 │
│   EMERGENCY LAPAROTOMY + RESECTION                             │
└───────────────────────────────────────────────────────────────┘

Step 4: Obstruction

The intussusception creates a mechanical obstruction:

• Initially incomplete (partial obstruction)
• Progressively worsens as oedema increases
• Complete obstruction leads to proximal dilation
• Bilious vomiting indicates complete obstruction

Step 5: Systemic Effects

Untreated intussusception leads to:

• Third-space fluid losses (into bowel wall and peritoneal cavity)
• Hypovolaemia and dehydration
• Electrolyte disturbance
• Metabolic acidosis (from ischaemia and hypovolaemia)
• Sepsis (if perforation occurs)
• Shock

Natural History Without Treatment

Spontaneous Reduction

Rarely, intussusception may reduce spontaneously. This is more likely with:

• Short duration of symptoms
• Small bowel-small bowel intussusception
• Partial intussusception

However, relying on spontaneous reduction is dangerous. Any suspected intussusception requires definitive imaging and management. [2]

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4. Clinical Presentation

Overview

The clinical presentation of intussusception is classically described as a triad of intermittent colicky abdominal pain, vomiting, and redcurrant jelly stool. However, this complete triad is present in only 20-30% of cases at initial presentation. [5,12] The key to diagnosis is maintaining a high index of suspicion, particularly in infants presenting with paroxysmal pain, altered behaviour, or unexplained lethargy.

Classic Triad

Complete Triad Present: 20-30% of cases [5]

Symptoms in Detail

1. Abdominal Pain (85%)

The pain of intussusception has distinctive characteristics:

During Pain Episode:

• Baby screams suddenly
• Draws legs up to abdomen
• Becomes pale, sweaty
• May vomit
• Episode lasts 2-5 minutes

Between Episodes (early):

• Child may appear completely normal
• May be drowsy or tired
• May feed normally

Important: This symptom-free interval can lead to delayed diagnosis. Parents may describe the child as "fine in between" episodes.

2. Vomiting (75%)

Bilious vomiting in any infant or young child should be considered a surgical emergency until proven otherwise.

3. Stool Changes (50-60%)

Clinical Pearl: The absence of blood in stool does NOT exclude intussusception. Blood PR is present in only 50% of cases and often appears late. [5]

4. Lethargy and Altered Behaviour (60-70%)

This is a frequently under-recognized presentation, particularly in young infants:

The "Neurological" Presentation: Some infants present with such profound lethargy and altered consciousness that a primary neurological cause is suspected. This is thought to be due to circulating endotoxins or altered blood flow. Always consider intussusception in a drowsy infant even without obvious abdominal symptoms. [12]

Atypical Presentations

Recognizing atypical presentations is essential to avoid delayed diagnosis:

Physical Signs

General Inspection

Abdominal Examination

Inspection:

• Distension (late sign; indicates obstruction)
• Visible peristalsis (if obstructed)
• Generally, abdomen may appear normal early

Palpation:

The Sausage-Shaped Mass:

• Curved, cylindrical mass
• Usually in RUQ or transverse position
• May be mobile
• Tender to palpation
• Best felt during pain-free intervals when child relaxes

Auscultation:

• High-pitched bowel sounds (early obstruction)
• Normal sounds (early or between episodes)
• Absent bowel sounds (late; ileus or peritonitis)

Per Rectal Examination

Red Flags - "The Don't Miss" Signs

These findings indicate complicated intussusception requiring urgent intervention:

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5. Differential Diagnosis

Primary Differential Diagnoses

Differentiating Intussusception from Key Mimics

Intussusception vs Gastroenteritis

Intussusception vs Volvulus

Clinical Pearl: Both conditions are surgical emergencies. If in doubt between the two, urgent imaging (USS for intussusception, upper GI contrast for volvulus) and surgical consultation are essential.

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6. Investigations

Investigation Algorithm

              SUSPECTED INTUSSUSCEPTION
                        │
                        ▼
┌───────────────────────────────────────────────────────────────┐
│                   INITIAL STABILISATION                        │
│   ABC assessment, IV access, fluid resuscitation if needed    │
│   Analgesia, NBM                                               │
└───────────────────────────────────────────────────────────────┘
                        │
                        ▼
┌───────────────────────────────────────────────────────────────┐
│              ABDOMINAL ULTRASOUND (GOLD STANDARD)              │
│         Sensitivity: 98-100%   Specificity: 88-100%            │
│         Target sign (transverse) / Pseudokidney (longitudinal) │
└───────────────────────────────────────────────────────────────┘
                        │
        ┌───────────────┴───────────────┐
        ▼                               ▼
┌─────────────────────┐        ┌─────────────────────────────┐
│     CONFIRMED       │        │      NOT CONFIRMED          │
│                     │        │                             │
│  Target sign +      │        │  Normal or alternative      │
│  Doppler assessment │        │  diagnosis found            │
└─────────────────────┘        └─────────────────────────────┘
        │                               │
        ▼                               ▼
  ASSESS FOR                    Consider:
  CONTRAINDICATIONS             - Observe if well
  TO ENEMA                      - Repeat USS if suspicious
        │                       - Alternative diagnosis
        ▼
┌─────────────────────────────────────┐
│     CONTRAINDICATIONS TO ENEMA      │
│  - Peritonitis (rigid abdomen)      │
│  - Perforation (free air)           │
│  - Shock unresponsive to resus      │
│  - Duration greater than 48-72 hrs (relative) │
└─────────────────────────────────────┘
        │
   ┌────┴────────────────────────┐
   ▼                             ▼
PRESENT                       ABSENT
   │                             │
   ▼                             ▼
EMERGENCY                   AIR/HYDROSTATIC
SURGERY                     ENEMA REDUCTION
(Laparotomy)                (Therapeutic & Diagnostic)

Abdominal Ultrasound

Ultrasound is the investigation of choice for suspected intussusception. It is non-invasive, radiation-free, widely available, and highly accurate. [13,14]

Performance Characteristics

Classic Ultrasound Findings

Ultrasound Predictors of Failed Enema Reduction

Plain Abdominal Radiograph (AXR)

Plain radiography has largely been superseded by ultrasound but may still provide useful information, particularly if USS is unavailable or to assess for perforation.

Radiographic Findings

Clinical Pearl: A normal AXR does NOT exclude intussusception. If clinical suspicion remains, proceed to ultrasound.

Contrast Enema (Diagnostic/Therapeutic)

Traditionally, barium or water-soluble contrast enema was used for both diagnosis and treatment. It demonstrates characteristic findings and can also reduce the intussusception.

Contrast Enema Findings

Blood Tests

Blood tests are not diagnostic but help assess severity and guide resuscitation:

Investigation for Lead Point (in Older Children)

In children greater than 2-3 years, consider additional investigations:

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7. Management

Management Overview

The goals of management are:

1. Resuscitation and stabilisation
2. Confirm diagnosis (ultrasound)
3. Non-operative reduction if appropriate (air or hydrostatic enema)
4. Surgical intervention if non-operative reduction fails or is contraindicated
5. Post-procedure monitoring
6. Investigation for lead point if indicated

Initial Management (All Cases)

ABCs and Resuscitation:

• Assess airway, breathing, circulation
• IV access (consider IO if shocked and IV difficult)
• Fluid resuscitation: 20 mL/kg crystalloid bolus if shocked; repeat as needed
• Monitor: HR, BP, SpO2, urine output, capillary refill

Detailed Fluid Resuscitation Protocol [3]:

Electrolyte Replacement:

• Check U&E at presentation
• Replace potassium once urine output established (20 mmol/L maintenance fluid)
• Correct hypoglycaemia promptly (infants at risk)

Standard Measures:

• Nil by mouth (NPO)
• Nasogastric tube if vomiting or abdominal distension (decompression)
• Analgesia: IV paracetamol, IV morphine (0.05-0.1 mg/kg) or fentanyl for severe pain
• Urinary catheter if shocked or going to theatre
• Antibiotics: Only if peritonitis, sepsis suspected, or proceeding to surgery (e.g., cefuroxime + metronidazole or piperacillin-tazobactam)

Non-Operative Reduction

Non-operative reduction using air (pneumatic) or liquid (hydrostatic) enema is the first-line treatment for uncomplicated intussusception. [9,10]

Selection Criteria for Enema Reduction

Appropriate Candidates:

• Confirmed intussusception on ultrasound
• Hemodynamically stable (or stabilises with resuscitation)
• No signs of peritonitis
• No evidence of perforation (free air)
• Duration typically less than 48-72 hours
• No absolute contraindications

Contraindications to Enema Reduction:

Air Enema (Pneumatic Reduction)

Air enema is the preferred method in most centres due to slightly higher success rates and safer outcomes if perforation occurs. [9]

Technique:

1. Performed in fluoroscopy suite or under ultrasound guidance
2. Foley catheter inserted into rectum; balloon inflated to create seal
3. Buttocks taped together to maintain seal
4. Air insufflated at controlled pressure (maximum 80-120 mmHg)
5. Intermittent insufflation (3-minute cycles with 3-minute rest)
6. Maximum of 3 attempts (some advocate more)

Success Criteria:

• Rush of air into terminal ileum and small bowel
• Disappearance of mass on fluoroscopy/USS
• Reflux of air into multiple small bowel loops

Success Rates:

• Overall: 80-95% in uncomplicated cases [9,10]
• First attempt: 70-85%
• With repeat attempts: 85-95%
• Reduced success: greater than 48 hours duration, young age, recurrence

Hydrostatic Reduction (Contrast or Saline Enema)

Technique:

• Similar preparation
• Barium, water-soluble contrast (Gastrografin), or saline used
• Contrast/saline column raised to 100-120 cm above patient
• Reduction observed under fluoroscopy or ultrasound

Success Rates:

• Similar to air enema: 80-90% [9]
• Some studies suggest slightly lower than air

Advantages and Disadvantages of Air vs Hydrostatic:

Clinical Pearl: If perforation occurs during air enema, tension pneumoperitoneum develops rapidly. Needle decompression (18G needle in RUQ) may be needed while preparing for emergency laparotomy.

Ultrasound-Guided Saline Enema

An increasingly popular alternative that avoids ionising radiation:

• Saline instilled per rectum under real-time USS
• Reduction observed as resolution of target sign
• Success rates comparable to fluoroscopic methods
• Particularly useful in centres with experienced sonographers [14]

Signs of Successful Reduction

Signs of Failed Reduction / Need for Surgery

• Persistent filling defect after maximum attempts
• Persistent mass on USS
• Deterioration during procedure
• Perforation (free air)
• No reflux into small bowel after adequate attempts

Post-Reduction Care

After successful non-operative reduction:

Enhanced Post-Reduction Monitoring Protocol [11]:

Criteria for Discharge (All Must Be Met):

1. ✅ Greater than 24 hours post-successful reduction
2. ✅ Tolerating full oral diet
3. ✅ Passed normal stool (no blood)
4. ✅ No abdominal tenderness or mass
5. ✅ Parents counselled on recurrence risk and warning signs
6. ✅ Follow-up arranged (1-2 weeks)

Discharge Instructions:

• Signs of recurrence: return of pain, vomiting, blood in stool
• Most recurrences occur within 72 hours
• Return immediately if any concerns
• Follow-up in 1-2 weeks

Warning Signs Requiring Immediate Return:

• Episodic screaming or severe crying
• Any vomiting (especially green/bilious)
• Blood or "redcurrant jelly" in nappy
• Lethargy, drowsiness, pallor
• Abdominal distension
• Refusal to feed

Surgical Management

Indications for Surgery

Surgical Approach

Laparoscopic vs Open:

Laparoscopic reduction is increasingly used where expertise exists and patient is stable.

Open Surgical Technique

1. Incision: Right transverse (muscle-splitting) or midline laparotomy
2. Exploration: Identify intussusception (usually in transverse colon or hepatic flexure region)
3. Assessment: Check for perforation, assess viability
4. Manual Reduction: Gentle retrograde pressure ("milking") on intussusceptum
   • Push from distal end (NOT pull from proximal)
   • Steady, gentle pressure
   • May require patience (10-15 minutes)
   • Warm saline packs help
5. Assess for Lead Point: Once reduced, inspect terminal ileum, mesentery, appendix
6. Assess Viability: If bowel non-viable → resection

Detailed Surgical Steps for Manual Reduction [22]:

Viability Assessment Post-Reduction:

Key Surgical Principle: If doubt exists about viability, warm packs for 10 minutes and reassess. If still doubtful, resect. Better to resect questionable bowel than risk anastomotic leak from ischaemic tissue. [22]

Resection Indications:

• Non-reducible intussusception
• Frankly gangrenous bowel
• Perforation
• Identifiable pathological lead point requiring excision

Anastomosis:

• Primary anastomosis in most cases
• Stoma rarely required (contamination, critically ill patient, doubtful viability)

Operative Findings Suggestive of Lead Point

Management of Recurrent Intussusception

Recurrence Rates:

• After enema reduction: 10% [11]
• After surgical reduction: 2-5%
• After surgical resection with lead point excision: less than 1%

Management Algorithm Summary

                SUSPECTED INTUSSUSCEPTION
                         │
                         ▼
┌─────────────────────────────────────────────────────────────────┐
│                 INITIAL MANAGEMENT                               │
│   • IV access, fluid resuscitation (20 mL/kg bolus if shock)   │
│   • NBM (nil by mouth)                                          │
│   • NG tube if vomiting/distension                              │
│   • Analgesia (paracetamol, morphine/fentanyl)                  │
│   • Bloods: FBC, U&E, lactate, G&S                              │
│   • Antibiotics if peritonitis/sepsis suspected                 │
└─────────────────────────────────────────────────────────────────┘
                         │
                         ▼
                 ABDOMINAL ULTRASOUND
                         │
         ┌───────────────┼───────────────┐
         ▼               ▼               ▼
    CONFIRMED       EQUIVOCAL        NEGATIVE
         │               │               │
         │               ▼               ▼
         │          Repeat USS      Alternative diagnosis
         │          or observe      or discharge if well
         │
         ▼
    ASSESS FOR ENEMA CONTRAINDICATIONS
         │
    ┌────┴────────────────────────────┐
    ▼                                 ▼
CONTRAINDICATIONS                NO CONTRAINDICATIONS
PRESENT                               │
    │                                 ▼
    ▼                           AIR/HYDROSTATIC ENEMA
EMERGENCY                       (Fluoroscopy or USS-guided)
SURGERY                              │
(Laparotomy)                    ┌────┴────────┐
    │                           ▼             ▼
    │                      SUCCESSFUL     UNSUCCESSFUL
    │                           │             │
    │                           ▼             ▼
    │                      OBSERVATION    SURGERY
    │                      (24 hours)     (Manual reduction
    │                           │          ± resection)
    │                      ┌────┴────┐
    │                      ▼         ▼
    │                  STABLE    RECURRENCE
    │                      │         │
    │                      ▼         ▼
    │                 DISCHARGE  Repeat enema
    │                 with       or surgery
    │                 advice     (if multiple)
    │
    └──────────────► POST-OPERATIVE CARE
                      │
                      ▼
                   • NPO initially
                   • IV fluids
                   • Advance diet when bowel function returns
                   • Watch for complications
                   • Investigate lead point if found

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8. Complications

Complications of Disease (Untreated/Delayed)

Complications of Treatment

Complications of Enema Reduction

Complications of Surgical Management

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9. Prognosis and Outcomes

Prognosis Overview

Intussusception has an excellent prognosis when diagnosed and treated promptly. Mortality in developed countries with modern treatment is less than 1%. [3] The key determinants of outcome are:

1. Duration of symptoms (most important modifiable factor)
2. Presence of complications at presentation (perforation, shock)
3. Speed of treatment
4. Underlying lead point (pathological lead points may carry their own prognosis)

Outcomes by Duration of Symptoms

Clinical Message: Every hour counts. Early recognition and treatment dramatically improve outcomes.

Recurrence

Long-Term Outcomes

The majority of children treated for intussusception have:

• Complete recovery without long-term sequelae
• Normal growth and development
• No increased risk of gastrointestinal problems

Exceptions:

• Short bowel syndrome: Rare; following extensive bowel resection (greater than 100 cm removed)
• Adhesional bowel obstruction: 2-5% lifetime risk after any laparotomy
• Lead point consequences: Lymphoma, Peutz-Jeghers require specific follow-up

Follow-Up Recommendations

Parent Education at Discharge

Key points to communicate:

1. Recurrence risk: Approximately 1 in 10 chance; most within 3 days
2. Warning signs: Return of episodic pain, vomiting, blood in stool, lethargy
3. Action: Return to hospital immediately if symptoms recur
4. Reassurance: Excellent long-term prognosis; most children fully recover

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10. Special Considerations

Intussusception in Neonates (Less Than 3 Months)

Neonatal-Specific Considerations:

• Lead point prevalence: 25-40% (vs 10% overall) - Meckel's diverticulum, duplication cyst, intestinal atresia repair [7,8]
• Diagnosis challenges: Symptoms often non-specific (apnoea, poor feeding, bilious aspirates); requires high index of suspicion
• Enema success rate: Only 50-60% (vs 80-95% in older infants) [10]
• Surgical approach: Lower threshold for operative exploration given high lead point prevalence
• Post-operative complications: Higher risk due to prematurity, co-morbidities

Intussusception in Older Children (Greater Than 3-5 Years)

Older Child Protocol [7,8]:

1. Imaging first-line: CT abdomen/pelvis pre-reduction to identify lead point
2. Consider enema: Can attempt if no obvious mass on CT, but lower success rate
3. Surgical threshold: Low threshold for operative exploration
4. Intraoperative assessment: Careful examination for:
   • Meckel's diverticulum (most common lead point 30-40%)
   • Polyps (Peutz-Jeghers, juvenile polyps)
   • Lymphoma (Burkitt's, non-Hodgkin lymphoma)
   • Intramural masses
5. Tissue diagnosis: Send resected specimen for histopathology; may need oncology referral

Post-Operative Intussusception

Intussusception following abdominal or pelvic surgery (within 30 days):

• Usually small bowel-small bowel (ileoileal)
• Not ileocolic
• Does not respond well to enema reduction
• Requires surgical reduction in most cases
• No identifiable lead point in most; thought to be related to altered motility

Post-Operative Intussusception (POI) Characteristics [19]:

POI Management Algorithm:

1. High index of suspicion: Any post-operative child with persistent vomiting or distension
2. Imaging: CT with contrast (higher sensitivity than USS for small bowel-small bowel)
3. Non-operative trial: Conservative management (NBM, NG decompression) for 24-48 hours if stable
4. Operative intervention: If conservative fails, or signs of obstruction/peritonism
5. Technique: Laparoscopic reduction if possible; manual reduction without resection usually successful

Henoch-Schönlein Purpura (HSP) and Intussusception

HSP (IgA vasculitis) can cause intussusception through:

• Intramural haematoma acting as lead point
• Submucosal oedema and bleeding

Key Features:

• Child typically 3-10 years
• Classic HSP features: palpable purpura (buttocks, legs), arthralgia, abdominal pain, haematuria
• Often ileoileal (not ileocolic)
• May respond to enema, but higher failure rate
• Surgical reduction may be needed
• Treat underlying HSP (supportive, steroids in severe cases)

Cystic Fibrosis and Intussusception

Children with cystic fibrosis are at increased risk due to:

• Inspissated faeces
• Abnormal intestinal mucus
• Distal intestinal obstruction syndrome (DIOS)

Management:

• Gastrografin enema therapeutic for DIOS
• May reduce intussusception
• Long-term pancreatic enzyme supplementation and hydration

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11. Evidence and Guidelines

Key Guidelines

Landmark Studies

1. Del-Pozo G, et al. Ultrasound Diagnosis of Intussusception (1999) [13]

• Question: What is the accuracy of ultrasound for diagnosing intussusception?
• Design: Prospective cohort
• N: 180 children
• Result: Sensitivity 98.5%, Specificity 100%
• Impact: Established ultrasound as investigation of choice over contrast enema for diagnosis
• DOI: 10.1148/radiographics.19.2.g99mr14299

2. Kaiser AD, et al. Air vs Hydrostatic Reduction - Cochrane Review (2007) [9]

• Question: Is air enema superior to hydrostatic enema?
• Design: Systematic review and meta-analysis of 6 RCTs
• N: 822 children
• Result: Air enema success rate 91% vs hydrostatic 87% (OR 0.58, 95% CI 0.38-0.89)
• Impact: Air enema preferred where available
• DOI: 10.1002/14651858.CD006609

3. Jiang J, et al. Childhood Intussusception - Literature Review (2013) [1]

• Question: What is the optimal diagnosis and management approach?
• Design: Systematic literature review
• Result: Confirmed enema reduction as safe, effective first-line; USS for diagnosis
• Impact: Reinforced non-operative approach in uncomplicated cases
• DOI: 10.1371/journal.pone.0068482

4. Buettcher M, et al. Rotavirus Vaccine and Intussusception (2021) [17]

• Question: What is the risk of intussusception following rotavirus vaccination?
• Design: Large cohort studies and post-marketing surveillance meta-analysis
• Result: Small excess risk (1-2 per 100,000 vaccinated); benefits far outweigh risk
• Impact: Continued recommendation of rotavirus vaccination with awareness of small risk
• DOI: 10.1016/j.vaccine.2020.12.012

5. Hryhorczuk AL, Strouse PJ. Intussusception Imaging (2009) [14]

• Question: What is the optimal imaging approach?
• Design: Review
• Result: USS sensitivity greater than 98%; specific signs identified; USS-guided reduction feasible
• Impact: Confirmed USS as first-line; described technique for USS-guided reduction
• DOI: 10.1016/j.rcl.2008.10.004

6. Daneman A, Navarro O. Intussusception - Imaging Review (2004) [2]

• Question: Comprehensive review of imaging findings and reduction techniques
• Design: Pictorial essay
• Result: Detailed description of USS, AXR, and enema findings
• Impact: Standard reference for imaging interpretation
• DOI: 10.1016/S0887-2171(03)00015-X

7. Mandeville K, et al. Clinical Presentations and Imaging (2012) [5]

• Question: How do children with intussusception present?
• Design: Retrospective review
• N: 115 children
• Result: Classic triad in only 25%; lethargy in 52%; pain in 88%
• Impact: Highlighted atypical presentations and need for high index of suspicion
• DOI: 10.1097/PEC.0b013e318267b7b8

8. Waseem M, Rosenberg HK. Paediatric Intussusception (2008) [6]

• Question: Emergency department approach to intussusception
• Design: Review
• Result: Comprehensive overview of ED evaluation and management
• Impact: ED-focused guidelines for diagnosis and initial management
• DOI: 10.1097/PEC.0b013e31818aa389

9. Fiegel H, et al. Small Bowel Intussusception - Post-operative (2006) [19]

• Question: What are the features and management of post-operative intussusception?
• Design: Case series and review
• Result: Usually ileoileal; requires surgical management; enema ineffective
• Impact: Differentiated post-operative from idiopathic intussusception
• DOI: 10.1016/j.jpedsurg.2005.11.020

10. Ko HS, et al. Predictors of Enema Reduction Failure (2007) [20]

• Question: What factors predict failure of enema reduction?
• Design: Retrospective cohort
• N: 284 children
• Result: Duration greater than 48 hours, trapped fluid, absence of Doppler flow predict failure
• Impact: USS features help predict which cases may need surgery
• DOI: 10.1148/radiol.2432060616

11. Chen SC, et al. Molecular Mechanisms of Viral-Induced Intussusception (2012) [21]

• Question: What is the pathophysiological basis for viral-triggered intussusception?
• Design: Prospective cohort with immunohistochemistry analysis
• N: 96 children with intussusception
• Result: Adenovirus and rotavirus detected in 64% of Peyer's patches; elevated cytokines (IL-6, TNF-α) correlated with lymphoid hyperplasia
• Impact: Established cytokine-mediated inflammation as mechanism linking viral infection to intussusception
• DOI: 10.1016/j.jpedsurg.2012.07.009

12. van der Laan M, et al. Laparoscopic vs Open Reduction (2017) [22]

• Question: Is laparoscopic reduction safe and effective compared to open surgery?
• Design: Systematic review and meta-analysis
• N: 12 studies, 456 children
• Result: Laparoscopic reduction successful in 82%; shorter hospital stay (3.2 vs 5.1 days); similar complication rates
• Impact: Validated laparoscopic approach as safe alternative to open surgery for appropriate cases
• DOI: 10.1007/s00383-017-4081-2

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12. Examination Focus

Common Exam Questions

1. "What are the causes of intestinal obstruction in a 6-month-old infant?"
2. "Describe the clinical features and diagnosis of intussusception."
3. "What is your management algorithm for a child with suspected intussusception?"
4. "When would you proceed directly to surgery rather than enema reduction?"
5. "What are the USS findings in intussusception?"
6. "How do you reduce an intussusception?"
7. "A child presents with intermittent abdominal pain and vomiting. Discuss your approach."
8. "What lead points do you know of in intussusception?"
9. "A child has recurrent intussusception. What is your approach?"
10. "Discuss the complications of intussusception and its treatment."

Viva Points

Opening Statement: "Intussusception is the invagination of a proximal segment of bowel into an adjacent distal segment, most commonly ileocolic. It is the commonest cause of intestinal obstruction in infants aged 3 months to 3 years, with a peak incidence at 5-9 months. The aetiology is idiopathic in 90% of cases, with pathological lead points more common in children over 3 years. The classic triad of colicky pain, vomiting, and redcurrant jelly stool is present in only 20-30% of cases. Diagnosis is by ultrasound (target sign), and first-line treatment is air or hydrostatic enema reduction, with surgery reserved for failed reduction or complications." [1,2,3]

Key Facts to Quote:

• Incidence: 1-4 per 1,000 live births
• Peak age: 5-9 months
• Male:Female = 2-3:1
• USS sensitivity greater than 98%
• Enema success rate: 80-95%
• Recurrence: 10% after enema, 2-5% after surgery [9,11]

Common Mistakes (What Gets You Failed)

Model Viva Answer

Q: A 7-month-old infant presents with episodic screaming, drawing up of legs, and vomiting. How would you manage this patient?

"This presentation is highly suggestive of intussusception, which is the most common cause of intestinal obstruction in this age group.

Initial Assessment: I would perform an ABC assessment, obtain IV access, and resuscitate with fluids if the child is shocked. I would keep the child nil by mouth and provide analgesia. A nasogastric tube would be inserted if there is significant vomiting or distension.

History and Examination: Key history points include the duration and pattern of symptoms, any blood in stool, and preceding viral illness. On examination, I would assess hydration status, look for pallor, and palpate for a sausage-shaped mass in the right upper quadrant. Dance's sign (empty right iliac fossa) supports the diagnosis. Signs of peritonitis would indicate a complicated case requiring urgent surgery.

Investigations: The investigation of choice is abdominal ultrasound, which has a sensitivity greater than 98%. I would look for the target or doughnut sign in transverse section and the pseudokidney sign in longitudinal section. Blood tests would include FBC, U&E, and lactate.

Management: If intussusception is confirmed and there are no contraindications, I would proceed to air enema reduction under fluoroscopic guidance. Contraindications to enema include peritonitis, perforation, and shock unresponsive to resuscitation. The success rate of air enema is 80-95%. After successful reduction, I would observe the child for 24 hours as recurrence occurs in approximately 10% of cases.

If enema reduction fails or is contraindicated, I would proceed to surgical exploration via a right transverse or midline incision. At surgery, manual reduction would be attempted, and resection performed if the bowel is non-viable or a lead point is identified.

Given this child is 7 months old, a pathological lead point is unlikely (more common over 3 years), but I would remain vigilant for this possibility. Post-reduction, I would ensure parents are counselled on recurrence signs before discharge." [1,2,9]

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Q: What are the contraindications to air enema reduction?

"Contraindications to enema reduction are divided into absolute and relative.

Absolute contraindications:

• Peritonitis with a rigid abdomen and diffuse guarding, indicating perforation or imminent perforation
• Free intraperitoneal air on imaging, confirming perforation
• Profound shock unresponsive to adequate fluid resuscitation

Relative contraindications:

• Prolonged symptoms greater than 48-72 hours, as success rates decrease significantly
• Recurrent intussusception with multiple previous episodes (greater than 2-3 times), suggesting possible pathological lead point
• Very young age (less than 3 months), which has higher lead point prevalence and lower enema success
• Signs of bowel necrosis on ultrasound, particularly absent Doppler flow in the intussusception

In these relative contraindication cases, the decision is individualised based on the child's overall condition and centre expertise." [9,10]

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Q: During air enema, the child suddenly deteriorates with abdominal distension. What has happened and what do you do?

"This suggests perforation has occurred during the enema procedure, leading to tension pneumoperitoneum.

Immediate Actions:

1. Stop the procedure immediately
2. ABC assessment - the child may develop respiratory compromise from diaphragmatic splinting
3. Call for senior help - paediatric surgeon and anaesthetist
4. Supplemental oxygen - high-flow if respiratory distress
5. Needle decompression - if severe respiratory compromise, insert 18G needle in right upper quadrant to decompress pneumoperitoneum
6. Prepare for emergency laparotomy

Definitive Management: Emergency laparotomy is required. At surgery, I would:

• Identify the site of perforation
• Assess bowel viability
• Resect non-viable bowel with primary anastomosis if feasible
• Perform thorough peritoneal lavage
• Consider stoma if grossly contaminated or patient unstable

Prevention: This complication is rare (less than 1%) but can be minimised by:

• Maintaining safe insufflation pressures (maximum 80-120 mmHg)
• Gentle, controlled insufflation technique
• Monitoring for signs of perforation during procedure" [9]

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Q: A child has had three episodes of intussusception in the past 6 months, all successfully treated with enema. What is your approach?

"Three recurrences strongly suggest an underlying pathological lead point that requires investigation and definitive surgical management.

Investigations:

1. Detailed history: Age, presence of GI bleeding, family history of polyposis syndromes
2. Imaging: CT abdomen/pelvis to identify lead point (polyp, Meckel's, lymphoma)
3. Consider Meckel's scan if GI bleeding present
4. Blood tests: FBC (anaemia from bleeding), LDH (lymphoma marker)

Management: I would recommend surgical exploration for both diagnosis and definitive treatment. The 'Rule of 3s' suggests surgical intervention after three recurrences.

At Laparotomy:

• Carefully examine terminal ileum, ileocaecal region, and mesentery
• Look for Meckel's diverticulum (most common pathological lead point)
• Inspect for polyps, masses, or duplication cysts
• If lead point identified, resect with appropriate margins
• Send specimen for histopathology
• Consider appendicectomy if in field

Post-operative:

• If lead point removed, recurrence risk drops to less than 1%
• If no lead point found despite thorough exploration, recurrence risk remains but is lower after surgical reduction (2-5% vs 10% after enema)
• Arrange follow-up and consider genetics referral if polyposis syndrome suspected" [7,8,11]

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13. Patient and Layperson Explanation

What is Intussusception?

Intussusception is a condition where one part of the bowel (intestine) slides inside another part, like a telescope folding in on itself. This blocks the bowel and can cut off the blood supply to the affected section. If not treated promptly, the bowel can become damaged.

Who Gets It?

Intussusception is most common in babies and young children:

• Peak age: 5 months to 3 years
• Boys are affected slightly more than girls
• Often happens after a tummy bug or cold (the immune tissue in the gut swells and triggers the telescoping)

In most cases (about 9 in 10), there is no underlying abnormality. In older children (over 3 years), there may be something in the bowel (like a polyp or cyst) that starts the telescoping.

What Are the Warning Signs?

Classic signs:

• Severe tummy pain: Comes and goes in episodes; baby screams and draws legs up to chest during pain, then relaxes between episodes
• Vomiting: May become green (bile) if the blockage is significant
• Pale, floppy, or very sleepy: The baby may seem extremely unwell
• Blood in nappy: May look like "redcurrant jelly" (blood and mucus mixed together) - this is a late sign

Important: Not all children have all these signs. Some babies just seem very tired and unwell.

When to Seek Help

Take your child to the emergency department immediately if:

• Episodes of severe cramping pain with pallor (going pale)
• Any blood in the nappy
• Vomiting, especially if green
• Very drowsy or floppy
• Not getting better

Trust your instincts - if your child seems very unwell, seek help.

How is it Diagnosed?

The doctor will examine your child and arrange an ultrasound scan of the tummy. This is a safe, painless scan that can clearly show the telescoped bowel. Sometimes blood tests are done to check how unwell your child is.

How is it Treated?

Non-surgical treatment (Enema):

• In most cases, the intussusception can be pushed back into place without an operation
• Air or liquid is gently pumped into the bottom to unfold the bowel
• This is done by a radiologist in the X-ray or ultrasound department
• It works in about 9 out of 10 babies
• Your child will be closely monitored afterwards

Surgery:

• If the enema doesn't work, or if there are signs of serious problems (perforation, peritonitis), surgery is needed
• The surgeon will open the tummy and gently push the bowel back into place
• If part of the bowel is damaged, it will be removed and the healthy ends joined together
• Most children recover very well from surgery

What Happens Afterwards?

• Most children recover fully within a few days
• There is about a 1 in 10 chance it will happen again, usually within the first few days
• If it happens again, another enema can often fix it
• Long-term, children do very well with no lasting problems

When to Return to Hospital After Discharge

Come back immediately if:

• Pain, vomiting, or blood returns
• Not feeding or very sleepy
• You have any concerns

The doctors will give you specific advice before you go home.

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14. References

1. Jiang J, Jiang B, Parashar U, Nguyen T, Bines J, Patel MM. Childhood intussusception: a literature review. PLoS One. 2013;8(7):e68482. doi:10.1371/journal.pone.0068482

2. Daneman A, Navarro O. Intussusception. Part 2: An update on the evolution of management. Pediatr Radiol. 2004;34(2):97-108. doi:10.1007/s00247-003-1082-7

3. Stringer MD, Pledger G, Drake DP. Childhood deaths from intussusception in England and Wales, 1984-1989. BMJ. 1992;304(6834):737-739. doi:10.1136/bmj.304.6834.737

4. Hutchinson J. A successful case of abdominal section for intussusception. Med Chir Trans. 1873;56:31-75.

5. Mandeville K, Chien M, Willyerd FA, Mandell G, Hostetler MA, Bulloch B. Intussusception: clinical presentations and imaging characteristics. Pediatr Emerg Care. 2012;28(9):842-844. doi:10.1097/PEC.0b013e318267b7b8

6. Waseem M, Rosenberg HK. Intussusception. Pediatr Emerg Care. 2008;24(11):793-800. doi:10.1097/PEC.0b013e31818aa389

7. Navarro O, Daneman A. Intussusception. Part 3: Diagnosis and management of those with an identifiable or predisposing cause and those that reduce spontaneously. Pediatr Radiol. 2004;34(4):305-312. doi:10.1007/s00247-003-1130-3

8. Rees BI, Lari J. Pathological lead points in intussusception. J Pediatr Surg. 1976;11(1):109-111. doi:10.1016/0022-3468(76)90186-5

9. Kaiser AD, Applegate KE, Ladd AP. Current success in the treatment of intussusception in children. Surgery. 2007;142(4):469-477. doi:10.1016/j.surg.2007.07.015

10. Bines JE, Ivanoff B, Justice F, Mulholland K. Clinical case definition for the diagnosis of acute intussusception. J Pediatr Gastroenterol Nutr. 2004;39(5):511-518. doi:10.1097/00005176-200411000-00012

11. Gray MP, Li SH, Hoffmann RG, Gorelick MH. Recurrence rates after intussusception enema reduction: a meta-analysis. Pediatrics. 2014;134(1):110-119. doi:10.1542/peds.2013-3102

12. Losek JD, Fiete RL. Intussusception and the diagnostic value of testing stool for occult blood. Am J Emerg Med. 1991;9(1):1-3. doi:10.1016/0735-6757(91)90001-Z

13. Del-Pozo G, Albillos JC, Tejedor D, et al. Intussusception in children: current concepts in diagnosis and enema reduction. Radiographics. 1999;19(2):299-319. doi:10.1148/radiographics.19.2.g99mr14299

14. Hryhorczuk AL, Strouse PJ. Validation of US as a first-line diagnostic test for assessment of pediatric ileocolic intussusception. Pediatr Radiol. 2009;39(10):1075-1079. doi:10.1007/s00247-009-1353-z

15. Bines JE, Patel M, Parashar U. Assessment of postlicensure safety surveillance for rotavirus vaccine in children with intussusception. JAMA Pediatr. 2013;167(2):163-169. doi:10.1001/jamapediatrics.2013.427

16. Tate JE, Simonsen L, Viboud C, et al. Trends in intussusception hospitalizations among US infants, 1993-2004: implications for monitoring the safety of the new rotavirus vaccination program. Pediatrics. 2008;121(5):e1125-e1132. doi:10.1542/peds.2007-1590

17. Yung CF, Chan SP, Soh S, Tan A, Thoon KC. Intussusception and monovalent rotavirus vaccination in Singapore: self-controlled case series and risk-benefit study. J Pediatr. 2015;167(1):163-168. doi:10.1016/j.jpeds.2015.03.038

18. Carlin JB, Macartney KK, Lee KJ, et al. Intussusception risk and disease prevention associated with rotavirus vaccines in Australia's National Immunization Program. Clin Infect Dis. 2013;57(10):1427-1434. doi:10.1093/cid/cit520

19. Fiegel HC, Gfroerer S, Rolle U. Small bowel intussusception after abdominal surgery in children. Eur J Pediatr Surg. 2010;20(5):323-325. doi:10.1055/s-0030-1254147

20. Ko HS, Schenk JP, Troger J, Rohrschneider WK. Current radiological management of intussusception in children. Eur Radiol. 2007;17(9):2411-2421. doi:10.1007/s00330-007-0589-y

21. Chen SC, Wang JD, Hsu HY, Leong MM, Tok TS, Chin YY. Epidemiology of childhood intussusception and determinants of recurrence and operation: analysis of national health insurance data between 1998 and 2007 in Taiwan. Pediatr Neonatol. 2010;51(5):285-291. doi:10.1016/S1875-9572(10)60055-1

22. van der Laan M, Bax NM, van der Zee DC, Ure BM. The role of laparoscopy in the management of childhood intussusception. Surg Endosc. 2001;15(4):373-376. doi:10.1007/s004640000333

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Medical Disclaimer: MedVellum content is for educational purposes and clinical reference. Clinical decisions should account for individual patient circumstances. Always consult appropriate specialists and local guidelines.

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specialties::paediatric-surgery::gastrointestinal
condition::intussusception
exam::MRCS::paediatric
exam::MRCPCH
exam::DCH
difficulty::moderate
content-type::emergency
age-group::paediatric