Diagnosis of Crohn’s Disease
Diagnosis of Crohn’s disease involves a combination of clinical evaluation, laboratory testing, imaging studies, and endoscopic procedures. Since the symptoms of Crohn’s disease can resemble other gastrointestinal conditions such as ulcerative colitis, coeliac disease, or irritable bowel syndrome (IBS), a thorough and accurate diagnosis is essential.
Medical History and Physical Examination
Diagnosis begins with a comprehensive review of the patient’s:
Symptom history (e.g. duration, frequency, and triggers)
Bowel habits and abdominal pain
Weight fluctuations and dietary tolerance
Family history of inflammatory bowel disease (IBD)
During the physical exam, the doctor may check for:
Abdominal tenderness or masses
Signs of anaemia or weight loss
Perianal abnormalities such as skin tags or fistulas
Laboratory Tests | Diagnosis of Crohn’s Disease
Blood and stool tests help identify inflammation, infection, or nutritional deficiencies:
Full blood count (FBC) to detect anaemia or infection
C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) to assess inflammation
Stool calprotectin to measure intestinal inflammation and rule out infections
Vitamin B12, iron, and folate levels to assess malabsorption
Endoscopy and Biopsy
To directly examine the digestive tract, doctors may perform:
Colonoscopy: Doctors insert a camera through the rectum to examine the colon and terminal ileum. Biopsies are commonly collected and sent for lab analysis.
Upper endoscopy (EGD): Used if symptoms suggest upper gastrointestinal involvement.
Findings in Crohn’s often include patchy areas of inflammation, ulceration, or strictures, with “skip lesions” being a hallmark feature.
Imaging Studies
Non-invasive imaging is used to assess the extent and location of disease:
Magnetic resonance enterography (MRE) or CT enterography: Visualises inflammation, narrowing, or fistulas in the small intestine
Barium studies: Rarely used now but may show strictures or abnormal bowel movement
Distinguishing from Other Conditions
Crohn’s disease must be differentiated from:
Ulcerative colitis: Which affects only the colon and in a continuous pattern
Infections: Like salmonella or Clostridium difficile
Lactose intolerance or coeliac disease
In summary, diagnosis of Crohn’s disease involves a multi-step process combining symptom review, lab tests, imaging, and endoscopic biopsies. Early diagnosis is critical to minimise complications and guide effective treatment.
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