What is the approach to diagnosis and management of a pediatric patient presenting with hematochesia (passage of fresh blood per anus)?

Approach to Diagnosis and Management of Pediatric Hematochezia

Begin with immediate hemodynamic assessment, as approximately 15% of acute presentations of bright red rectal bleeding in children can involve hypovolemic shock requiring aggressive fluid resuscitation. 1

Initial Hemodynamic Stabilization

• Check vital signs immediately to assess for shock, including pulse rate, blood pressure, and signs of hypovolemia 2
• Calculate shock index (heart rate/systolic BP); a shock index >1 indicates hemodynamic instability requiring urgent intervention 2
• Initiate aggressive fluid resuscitation if signs of hypovolemic shock are present 1

Age-Specific Differential Diagnosis Framework

The most common causes vary dramatically by age group:

Infants (<1 year)

• Food protein-induced enterocolitis syndrome (FPIES) is the leading diagnosis, most commonly triggered by cow's milk or soy proteins passed through breast milk or formula 1, 3
• Anal fissures from constipation are also common in this age group 3

Young Children (1-5 years)

• Bacterial colitis is the most frequent cause, with infectious diseases accounting for 44% of all pediatric hematochezia cases 3
• Antibiotic-associated colitis occurs in approximately 5% of cases 3

Older Children and Adolescents (6-19 years)

• Inflammatory bowel disease becomes the predominant diagnosis in this age group 3
• Infectious colitis remains common 3

Critical History Elements

Obtain the following specific details:

• Feeding history: Exclusively breastfed infants may be sensitive to maternal dietary proteins, with symptoms appearing at average age of 7.4 weeks 4
• Systemic symptoms: Fever, abdominal pain, diarrhea (present in 71% of cases), weight loss, or failure to thrive suggest serious pathology requiring urgent gastroenterology referral 1, 4
• Medication exposure: Recent antibiotic use within the past 8 weeks raises concern for antibiotic-associated colitis 3
• Personal or family history: Easy bruising or excessive bleeding necessitates evaluation for bleeding disorders 1
• Trauma history: Always consider child abuse when bleeding presents with other concerning features 1

Physical Examination Priorities

• Digital rectal examination should be performed when appropriate to assess for masses, fissures, or stool consistency 1
• Examine for abdominal tenderness, distension, or peritoneal signs 2
• Assess for signs of chronic illness, including growth parameters and nutritional status 1

Laboratory Evaluation

Initial Testing

• Complete blood count (CBC) with hemoglobin and hematocrit to assess severity of bleeding; note that mild anemia is present in 60% of cases 2, 4
• Basic metabolic panel if dehydration or significant bleeding is present 1
• Routine stool test for red cells, white cells, and culture for bacterial pathogens 4

Important Caveat

• Do not rely on initial hemoglobin values alone, as they may appear falsely normal in the first 30-60 minutes after acute bleeding; serial measurements are essential 2

Bleeding Disorder Evaluation

• Consider coagulation studies (PT/INR, aPTT, platelet count) if there is personal or family history of easy bruising or excessive bleeding 1
• If blood product transfusions are given, delay screening for bleeding disorders until elimination of transfused clotting elements 5

Endoscopic Evaluation Strategy

Do not rely on sigmoidoscopy alone, as this misses more than one-fifth of polyps 1

When to Perform Colonoscopy

• Colonoscopy is indicated when systemic symptoms are present, when FPIES is suspected (showing red, fragile, hemorrhagic mucosa with increased eosinophils on biopsy), or when initial management fails 1
• Only 13.6% of pediatric patients with hematochezia require endoscopy in most series 3
• Urgent colonoscopy within 24 hours is indicated for high-risk features, evidence of ongoing bleeding, or hemodynamic instability 2

Upper GI Source Exclusion

• It is essential to exclude upper GI source, as 10-15% of patients with severe hematochezia have an upper GI bleeding source 1

Management Algorithm by Diagnosis

For Suspected FPIES (Infants)

• Maternal elimination diet: Remove all animal and plant proteins from the breastfeeding mother's diet for four weeks 4
• Gross hematochezia typically disappears within 72-96 hours after maternal protein-free diet 4
• If formula-fed, switch to extensively hydrolyzed or amino acid-based formula 1
• Do not use stool tests alone to diagnose FPIES, though they may show eosinophilic debris 1

For Infectious Colitis

• Supportive care with hydration and electrolyte management 3
• Stool culture for bacterial pathogens including Klebsiella oxytoca (present in 7.7% of cases) and Clostridium difficile 3
• Antibiotic-associated colitis may be caused by pathobionts other than C. difficile or K. oxytoca in many cases 3

For Suspected IBD

• Urgent gastroenterology referral for comprehensive evaluation and colonoscopy with biopsies 3

Critical Pitfalls to Avoid

• Never assume hemorrhoids without proper evaluation, as symptoms attributed to hemorrhoids frequently represent other pathology 1
• Always consider a broad differential, as many infantile gastrointestinal disorders cause overlapping symptoms 1
• Do not delay appropriate treatment for imaging in unstable patients; stabilization takes priority 2
• Laboratory testing suggestive of a bleeding disorder does not eliminate abuse from consideration 5

When to Consult Specialists

• Pediatric gastroenterology: For systemic symptoms, failure of initial management, suspected IBD, or need for endoscopy 1
• Pediatric hematology: If preliminary testing suggests bleeding disorder, if specific expanded testing is necessary, or if testing for rare conditions is needed 5