IBD Diagnostic Differential Diagnosis

The following differential diagnosis is organized into categories to help guide the diagnostic process for Inflammatory Bowel Disease (IBD).

• Single Most Likely Diagnosis
  • Crohn's Disease: This is often considered the most likely diagnosis when presenting with symptoms such as chronic diarrhea, abdominal pain, weight loss, and fatigue, especially if there's a family history of IBD or if the patient has extraintestinal manifestations like joint pain or skin lesions.
• Other Likely Diagnoses
  • Ulcerative Colitis (UC): Similar to Crohn's, UC presents with chronic diarrhea, often bloody, and abdominal pain. The extent of colonic involvement can vary, and it typically starts in the rectum.
  • Microscopic Colitis: This condition causes chronic, watery diarrhea without visible inflammation on endoscopy but with microscopic evidence of colonic inflammation. It's more common in older adults and those with a history of smoking.
  • Irritable Bowel Syndrome (IBS): Although not an inflammatory condition, IBS can mimic IBD with symptoms like abdominal pain and changes in bowel habits. However, it lacks the inflammatory markers and structural changes seen in IBD.
• Do Not Miss Diagnoses
  • Infectious Colitis: Conditions like Clostridioides difficile infection, Salmonella, Shigella, or Campylobacter can cause severe diarrhea and abdominal pain, similar to IBD. Missing these diagnoses can lead to inappropriate treatment and severe consequences.
  • Ischemic Colitis: Reduced blood flow to the colon can cause sudden onset of abdominal pain and bloody diarrhea, which might be mistaken for IBD. This condition requires prompt diagnosis and treatment to prevent tissue death.
  • Diverticulitis: Inflammation of the diverticula in the colon can cause abdominal pain, changes in bowel habits, and potentially mimic IBD, especially if there's associated colitis.
• Rare Diagnoses
  • Eosinophilic Gastroenteritis: A rare condition characterized by eosinophilic infiltration of the gastrointestinal tract, leading to symptoms that can overlap with IBD, such as abdominal pain, diarrhea, and weight loss.
  • Behçet's Disease: A form of vasculitis that can affect the gastrointestinal tract, causing symptoms similar to IBD, including diarrhea, abdominal pain, and potentially life-threatening complications if not recognized.
  • Graft-Versus-Host Disease (GVHD): In patients with a history of bone marrow or stem cell transplant, GVHD can cause gastrointestinal symptoms that mimic IBD, including diarrhea and abdominal pain, and requires specific treatment to manage.