Overview
Definition:
Lower gastrointestinal bleeding (LGIB) in toddlers refers to bleeding originating from the gastrointestinal tract distal to the ligament of Treitz
It can range from occult blood loss detected on stool guaiac to frank hematochezia or melena.
Epidemiology:
LGIB is a common reason for pediatric hospital admissions
Meckel's diverticulum is the most common congenital anomaly of the gastrointestinal tract and a frequent cause of LGIB in children, particularly toddlers, accounting for approximately 20-25% of LGIB in this age group
Other causes include anal fissures, Meckel's diverticulitis, intussusception, inflammatory bowel disease, and polyps.
Clinical Significance:
Significant LGIB in toddlers can lead to hemodynamic instability, anemia, and require prompt diagnosis and management
Identifying the source of bleeding, especially Meckel's diverticulum, is crucial for preventing recurrent bleeding and potential complications, making knowledge of Meckel scan indications vital for pediatric residents preparing for DNB and NEET SS exams.
Clinical Presentation
Symptoms:
Painless rectal bleeding, often described as brick-red or maroon stools
Occasional bright red blood per rectum
Melena (black, tarry stools) is less common but can occur if bleeding is slow and blood is digested
Symptoms of anemia: pallor, fatigue, irritability, poor feeding
Abdominal pain, vomiting, or fever may suggest complications like intussusception or diverticulitis.
Signs:
Vital signs may be normal or show signs of hypovolemia (tachycardia, hypotension) in severe bleeding
Abdominal examination may reveal tenderness, distension, or a palpable mass in cases of intussusception
Rectal examination can identify anal fissures or, rarely, the bleeding source directly.
Diagnostic Criteria:
No specific diagnostic criteria for LGIB itself
Diagnosis is based on clinical suspicion, confirmed by presence of blood in stool or rectum
The decision for further investigation, including a Meckel scan, is guided by the severity, frequency, and suspected etiology of the bleeding.
Diagnostic Approach
History Taking:
Detailed history of bleeding: frequency, quantity, color of stool
association with bowel movements
Presence of pain, vomiting, fever, or diarrhea
Previous episodes of bleeding
Family history of GI disorders
Diet and recent antibiotic use
Medications (NSAIDs)
Red flags: hemodynamic instability, severe anemia, recurrent significant bleeding.
Physical Examination:
Complete physical examination focusing on vital signs, assessment for pallor, abdominal palpation for masses or tenderness, and a digital rectal examination to assess for anal fissures or external bleeding sources.
Investigations:
Complete blood count (CBC) to assess for anemia (hemoglobin and hematocrit) and leukocytosis
Coagulation profile if coagulopathy is suspected
Stool studies: guaiac test for occult blood
Imaging: Technetium-99m pertechnetate (99mTc-pertechnetate) scintigraphy (Meckel scan) is the gold standard for diagnosing a Meckel's diverticulum with ectopic gastric mucosa
Other imaging like abdominal ultrasound or CT scan may be used to evaluate for intussusception or other structural abnormalities.
Differential Diagnosis:
Anal fissure: often associated with pain during defecation
Intussusception: typically presents with colicky abdominal pain, vomiting, and currant jelly stools
often a palpable mass
Inflammatory bowel disease (e.g., Crohn's disease, ulcerative colitis): usually associated with diarrhea, abdominal pain, and sometimes fever
Juvenile polyps: usually painless bleeding, polyps may be visible on sigmoidoscopy
Malignancy: rare in toddlers but should be considered in persistent bleeding.
Meckel Scan Indications
Primary Indication:
Painless rectal bleeding in a toddler where other common causes have been excluded, and a Meckel's diverticulum is suspected
This is particularly true for significant or recurrent bleeding episodes.
Secondary Indications:
Bleeding with equivocal findings on other investigations
Suspected Meckel's diverticulum with complications such as intussusception or volvulus, even without overt bleeding
Pre-operative evaluation for suspected Meckel's diverticulum before definitive surgery.
Contraindications:
Active massive hemorrhage which requires immediate resuscitation and surgical intervention
Known allergy to radiopharmaceuticals
Pregnancy.
Interpretation:
A positive Meckel scan shows an area of increased activity corresponding to the expected location of the diverticulum, typically in the mid-abdomen
Ectopic gastric mucosa is crucial for radionuclide uptake
False positives can occur due to intestinal duplication cysts, or malrotation
False negatives are rare but can occur if the Meckel's diverticulum does not contain ectopic gastric mucosa or if it is very small.
Management
Initial Management:
For hemodynamically unstable patients: immediate fluid resuscitation with intravenous crystalloids, blood transfusion if necessary
For stable patients: diagnostic workup to identify the source of bleeding
Maintain adequate hydration and monitor vital signs
NPO (nil per os) if active bleeding or vomiting.
Medical Management:
Treatment of anemia with iron supplementation if indicated
Management of associated conditions like inflammatory bowel disease
Antibiotics if infection is suspected (e.g., diverticulitis).
Surgical Management:
Surgical excision of Meckel's diverticulum is indicated if diagnosed and symptomatic with bleeding, intussusception, or volvulus
Laparoscopic or open diverticulectomy
If ectopic gastric mucosa is confirmed, its excision along with the diverticulum is recommended.
Supportive Care:
Close monitoring of vital signs, urine output, and stool output
Regular complete blood count monitoring
Nutritional support as needed.
Complications
Early Complications:
Hemorrhagic shock and hypovolemia
Anemia
Rebleeding
Perforation or obstruction secondary to Meckel's diverticulitis or intussusception.
Late Complications:
Adhesions leading to bowel obstruction
Recurrent bleeding if incomplete excision or if bleeding originates from elsewhere
Fistula formation.
Prevention Strategies:
Prompt diagnosis and appropriate management of Meckel's diverticulum
Early surgical intervention for symptomatic lesions
Careful surgical technique during diverticulectomy to ensure complete excision and minimize risks of complications.
Prognosis
Factors Affecting Prognosis:
Severity of bleeding, degree of anemia, presence of hemodynamic instability, promptness of diagnosis and treatment
Presence of associated complications like intussusception or obstruction.
Outcomes:
With timely diagnosis and surgical management, the prognosis for toddlers with Meckel's diverticulum-related bleeding is generally excellent
Recurrence of bleeding is uncommon after appropriate surgical resection.
Follow Up:
Follow-up typically includes monitoring for resolution of anemia and general well-being
Long-term follow-up is usually not required unless complications arise or there is suspicion of recurrent bleeding.
Key Points
Exam Focus:
Meckel's diverticulum is the most common congenital anomaly and a frequent cause of painless LGIB in toddlers
Technetium-99m pertechnetate scintigraphy (Meckel scan) is the investigation of choice for suspected Meckel's diverticulum causing bleeding
Indications for Meckel scan are primarily painless, significant, or recurrent LGIB in toddlers after other causes are excluded.
Clinical Pearls:
Always consider Meckel's diverticulum in a toddler with unexplained rectal bleeding
While Meckel's diverticulum is classically associated with painless bleeding, pain can occur if it becomes inflamed or causes intussusception
A negative Meckel scan does not definitively rule out Meckel's diverticulum if it lacks ectopic gastric mucosa
surgical exploration may be warranted in select cases with strong suspicion.
Common Mistakes:
Delaying investigation in cases of significant LGIB
Over-reliance on less sensitive imaging modalities for suspected Meckel's diverticulum
Failing to consider Meckel's diverticulum in the differential diagnosis of LGIB in this age group
Not performing adequate resuscitation in hemodynamically compromised infants.