For Patients & General Readers

Crohn's disease is a chronic inflammatory condition that can affect any part of the digestive tract, from the mouth to the anus. It often causes abdominal pain, diarrhea, and fatigue, and can significantly impact a person's quality of life. While the exact cause is unknown, it's thought to involve an abnormal immune response, and it typically affects young adults.

Clinical Overview

Crohn's disease is a chronic, transmural inflammatory disorder of the gastrointestinal tract, characterized by skip lesions and granulomatous inflammation. It can affect any segment from the oral cavity to the anus, with the terminal ileum and colon being most commonly involved. The etiology is multifactorial, involving genetic predisposition, environmental factors, gut microbiota dysbiosis, and dysregulated immune responses.

Clinical Presentation

Abdominal pain, often localized to the right lower quadrant, exacerbated by eating.
Chronic diarrhea, which can be watery or bloody.
Weight loss and malnutrition due to malabsorption.
Fatigue and malaise.
Perianal disease (fistulas, abscesses, skin tags).
Extraintestinal manifestations (arthritis, uveitis, skin lesions, liver disease).

Signs & Symptoms

Symptoms (Patient-Reported)

Persistent abdominal pain
Diarrhea, sometimes with blood or pus
Unexplained weight loss
Extreme tiredness (fatigue)
Fever
Mouth sores
Reduced appetite

Signs (Clinician-Observed)

Abdominal tenderness, particularly in the right lower quadrant
Palpable abdominal mass
Perianal fistulas or abscesses
Signs of malnutrition (e.g., pallor, muscle wasting)
Extra-intestinal manifestations (e.g., joint swelling, eye redness)

Differential Diagnoses

Condition	Distinguishing Feature
Ulcerative Colitis	Typically limited to the colon, continuous inflammation starting from the rectum, superficial mucosal involvement, absence of skip lesions and transmural inflammation.
Infectious Colitis (e.g., C. difficile, Salmonella)	Acute onset, often associated with recent antibiotic use or contaminated food/water, usually self-limiting or responsive to specific antimicrobial therapy.
Irritable Bowel Syndrome (IBS)	Absence of objective inflammatory markers, no weight loss or bleeding (typically), diagnosis of exclusion based on Rome criteria.
Appendicitis	Acute onset, localized right lower quadrant pain migrating from periumbilical area, fever, leukocytosis, usually resolves with appendectomy.
Malignancy (e.g., Colorectal Cancer)	Progressive symptoms, often in older individuals, presence of a mass on imaging, positive fecal occult blood test, biopsy confirmation.
Tuberculosis (Intestinal)	Can mimic Crohn's, especially in endemic areas; consider if travel history, weight loss, fever, and granulomas on biopsy.

Red Flags — Seek Immediate Care

Bowel obstruction (severe abdominal pain, vomiting, distension, obstipation)
Perforation (sudden severe abdominal pain, peritonitis)
Massive gastrointestinal bleeding
Toxic megacolon (rapid colonic dilation, systemic toxicity)

Key Investigations

Complete blood count (CBC) with differential to assess for anemia and leukocytosis.
Inflammatory markers (ESR, CRP) to assess disease activity.
Fecal calprotectin to assess for intestinal inflammation.
Endoscopy (colonoscopy with biopsies, upper endoscopy) to visualize the mucosa and obtain tissue samples.
Imaging studies (CT enterography, MR enterography) to assess the extent and severity of disease, and detect complications like strictures or fistulas.
Stool studies to rule out infectious causes.

Management Overview

Management is individualized and aims to induce and maintain remission, improve quality of life, and prevent complications. Treatment strategies include medical therapy (5-ASA agents, corticosteroids, immunomodulators, biologics) and nutritional support, with surgical intervention reserved for complications or refractory disease.

Disclaimer: This article is for educational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional for diagnosis and treatment. TruelyserMD does not replace clinical judgement.