Overview
Definition:
Intussusception is a medical emergency where one segment of the intestine (intussusceptum) invaginates into an adjacent segment (intussuscipiens), leading to obstruction, ischemia, and potential perforation
It is the most common cause of intestinal obstruction in infants and young children.
Epidemiology:
It predominantly affects infants and toddlers, typically between 3 months and 3 years of age
The incidence is highest in infants aged 5-10 months
There is a slight male preponderance
Idiopathic intussusception is more common in this age group, while in older children, a specific lead point (e.g., Meckel's diverticulum, lymphoma, appendiceal stump) is often identified.
Clinical Significance:
Prompt diagnosis and treatment are crucial to prevent bowel ischemia, necrosis, perforation, and sepsis
Delayed management significantly increases morbidity and mortality
Understanding the ultrasound findings and the principles of non-operative reduction is vital for pediatric residents and DNB/NEET SS preparation.
Clinical Presentation
Symptoms:
Sudden onset of colicky abdominal pain, with episodes of severe crying followed by periods of lethargy or apparent well-being
Vomiting, often bilious, may occur once obstruction is established
Bloody, mucus-laden stools (currant jelly stools) are pathognomonic but often a late sign.
Signs:
A palpable, sausage-shaped abdominal mass, most commonly in the right upper quadrant or epigastrium
Signs of dehydration may be present
Rectal examination may reveal blood-stained mucus
Peritoneal signs suggest bowel compromise.
Diagnostic Criteria:
Diagnosis is primarily based on clinical suspicion combined with imaging
While there are no strict diagnostic criteria for intussusception itself, a high index of suspicion in an infant or toddler with characteristic abdominal pain is paramount
Ultrasound is the gold standard for diagnosis.
Diagnostic Approach
History Taking:
Detailed history of the onset, frequency, and severity of abdominal pain
Associated symptoms like vomiting, stool characteristics (presence of blood, mucus), and changes in child's behavior (lethargy, irritability)
Any recent viral illness or diarrheal episode
Red flags include persistent vomiting, bilious emesis, abdominal distension, and signs of shock.
Physical Examination:
Gentle abdominal palpation to identify any masses or tenderness
Auscultation for bowel sounds
Assess for hydration status and vital signs
Rectal examination for blood or mucus
Avoid excessive palpation, which can worsen pain or lead to further invagination.
Investigations:
Ultrasound: The investigation of choice, highly sensitive and specific
It shows a target sign (concentric rings of bowel wall) or pseudokidney sign
Air or saline enema: Can be diagnostic and therapeutic
presence of contrast/air in the intussusceptum confirms the diagnosis
Plain abdominal radiographs: May show signs of obstruction (dilated loops of bowel, air-fluid levels) but are often non-specific and can obscure ultrasound findings
Laboratory tests: Complete blood count (CBC) for leukocytosis, electrolytes, and renal function to assess hydration status.
Differential Diagnosis:
Gastroenteritis, viral illness, colic, appendicitis, volvulus, incarcerated hernia, Meckel's diverticulum, abdominal abscess, malrotation
The key distinguishing feature of intussusception is the characteristic ultrasound finding.
Management
Initial Management:
Fluid resuscitation to correct dehydration and electrolyte imbalances
Nasogastric tube insertion for gastric decompression if vomiting is persistent
Pain management
Consultation with pediatric surgery and radiology for planned reduction.
Medical Management:
NPO (nil per os)
IV fluids (e.g., Ringer's lactate or normal saline) with maintenance and deficit replacement
Antiemetics may be used cautiously
Antibiotics are generally not indicated unless perforation or sepsis is suspected.
Radiological Reduction:
Hydrostatic or pneumatic (air) enema reduction is the preferred initial treatment for uncomplicated intussusception if the patient is hemodynamically stable and has no signs of peritonitis
The procedure involves introducing contrast (barium or air) into the rectum under fluoroscopic or ultrasound guidance
The pressure is gradually increased to push the intussusceptum back into the intussuscipiens
Success rates are typically 70-90%
Recurrence is possible
If reduction fails or if there are signs of peritonitis, ischemia, or perforation, urgent surgical intervention is required.
Surgical Management:
Indications for surgery include failed non-operative reduction, signs of peritonitis, suspected bowel necrosis or perforation, or identification of a specific lead point that requires resection (e.g., Meckel's diverticulum, polyp, tumor)
Surgery may involve manual reduction or resection of the non-viable bowel segment with primary anastomosis or stoma formation
Laparoscopy is increasingly used for reduction, allowing for better visualization and less invasive management.
Complications
Early Complications:
Bowel perforation, intestinal necrosis, sepsis, recurrence after successful reduction
Perforation is a risk during reduction attempts and is more likely if bowel is already ischemic.
Late Complications:
Adhesions leading to bowel obstruction, short bowel syndrome if extensive resection is required, recurrent intussusception.
Prevention Strategies:
Early recognition and prompt intervention are key to preventing complications
Careful technique during radiological reduction to avoid excessive pressure or trauma to the bowel
Close monitoring of patients after reduction for signs of recurrence or complications.
Prognosis
Factors Affecting Prognosis:
The most critical factor is the time to diagnosis and treatment
Prompt reduction leads to an excellent prognosis
Delayed diagnosis and management, leading to bowel necrosis and perforation, are associated with significantly higher morbidity and mortality.
Outcomes:
With timely diagnosis and successful non-operative or operative reduction, most children recover fully with minimal long-term sequelae
Recurrence rates vary but are generally manageable
Patients undergoing bowel resection have a higher risk of complications.
Follow Up:
Follow-up typically involves monitoring for signs of recurrence, especially in the first 24-48 hours post-reduction
Education for parents on recognizing symptoms of recurrence is essential
Long-term follow-up is generally not required unless there were complications or a specific lead point was identified and managed.
Key Points
Exam Focus:
Ultrasound findings: target sign, pseudokidney sign
Indications for air/hydrostatic enema vs
surgery
Management of recurrent intussusception
Importance of hemodynamic stability for non-operative reduction
Common age group and lead points in older children.
Clinical Pearls:
Always consider intussusception in an infant or toddler with colicky abdominal pain, even without currant jelly stools
Ultrasound is your best friend for diagnosis
If reduction is attempted, ensure adequate sedation and analgesia, and stop if significant resistance or concerning signs appear.
Common Mistakes:
Delaying ultrasound in a child with suspicious symptoms
Attempting reduction in a hemodynamically unstable patient or one with signs of peritonitis
Inadequate fluid resuscitation prior to reduction
Over-reliance on plain X-rays for diagnosis.