Clinical Scenario:
A 14-year-old boy presents with a 9-month history of intermittent abdominal pain, chronic diarrhea, poor appetite, and a 7-kg weight loss. He reports waking up at night to pass stools and has noticed increasing fatigue. Over the past 3 months, he has developed painful swelling around the anus with occasional purulent discharge.
On examination, his weight and height are both below the 5th percentile. He appears pale and has digital clubbing. Abdominal examination reveals mild right lower quadrant tenderness. Perianal examination demonstrates a skin tag and a draining fistula.
Investigations show:
Hemoglobin: 9.2 g/dL
ESR: 78 mm/hr
CRP: 62 mg/L
Serum albumin: 2.9 g/dL
Stool cultures: Negative
Fecal calprotectin: >1800 μg/g
Colonoscopy reveals patchy areas of inflammation with intervening normal mucosa. Multiple deep linear ulcers are seen in the terminal ileum and ascending colon.
Which of the following is the most likely diagnosis?
A. Abdominal tuberculosis
B. Crohn disease
C. Intestinal Behçet disease
D. Ulcerative colitis
E. Yersinia enterocolitica infection
Correct answer & Explanation:
Correct Answer: B. Crohn disease
Discussion: Crohn disease
This scenario contains several classic features of Crohn disease:
Chronic diarrhea with nocturnal symptoms
Weight loss and growth failure
Elevated inflammatory markers
Hypoalbuminemia
Perianal disease (skin tags and fistula)
Right lower quadrant pain
Patchy (“skip”) lesions on colonoscopy
Deep linear ulcers
Terminal ileal involvement
Among these findings, perianal fistulizing disease is particularly suggestive of Crohn disease and is uncommon in ulcerative colitis.
Why the Other Options Are Incorrect
A. Abdominal tuberculosis
May mimic Crohn disease but perianal fistulas are less common.
Usually associated with TB exposure, fever, and characteristic histological findings.
C. Intestinal Behçet disease
Can cause deep ulcers but is usually accompanied by recurrent oral and genital ulcers and other systemic manifestations.
D. Ulcerative colitis
Typically causes continuous colonic inflammation beginning in the rectum.
Perianal fistulas and terminal ileal deep ulceration strongly favor Crohn disease.
E. Yersinia enterocolitica infection
Usually presents as an acute or subacute illness rather than a 9-month progressive course with growth failure and fistulizing disease.
Key Learning Points
Growth failure may precede gastrointestinal symptoms in pediatric Crohn disease.
Perianal fistula, skin tags, and abscesses are hallmark features of Crohn disease.
Terminal ileal involvement and skip lesions differentiate Crohn disease from ulcerative colitis.
Chronic diarrhea, weight loss, anemia, and elevated fecal calprotectin should prompt evaluation for inflammatory bowel disease.
Examination Pearl
In a child with chronic diarrhea, growth failure, and perianal fistula, Crohn disease should be considered until proven otherwise. The presence of skip lesions and terminal ileal disease makes Crohn disease the most likely diagnosis.
