Approach to hematochezia (pediatrics) Quiz: Ace Your Exams

A 9-year-old boy is brought to the clinic for evaluation of three weeks of worsening bloody diarrhea. The caregiver reports 5–7 bowel movements per day, often with bright red blood in the stool. The child has abdominal pain, urgency to defecate, and fatigue, and has lost approximately 2 kg (4.4 lb.) in the past month due to decreased appetite. The family returned from a vacation to the Caribbean 3 weeks ago. There is no history of fever or vomiting. The child has no significant past medical history. Temperature is 37.8°C (100.0°F), blood pressure is 100/60 mmHg, heart rate is 102 beats per minute, respiratory rate is 20 breaths per minute, and oxygen saturation is 99% on room air. The child appears mildly uncomfortable. Abdominal examination reveals mild diffuse tenderness without guarding or rebound. A chaperoned rectal examination is unremarkable. Laboratory results are shown below. Which of the following is the best next step in confirming the most likely diagnosis?

Laboratory Value	Result	Reference Range
Hemoglobin	6.8 g/dL	11.5-15.5 g/dL
Hematocrit	23%	35-45%
Platelet count	310,000/µL	150,000-450,000/µL
White blood cell count	12,000/µL	4,300-11,000/µL
C-reactive protein	7 mg/dL	<1 mg/dL
Erythrocyte sedimentation rate (ESR)	0.6 mm/hr	1-20 mm/hr
Fecal calprotectin	150 µg/g	>100 µg/g