Inflammatory Bowel Disease
By the end of this session the students will be able to
• Define inflammatory bowel disease
• Explain the etiology of inflammatory bowel disease
• Describe the pathophysiology of inflammatory bowel disease
Inflammatory bowel disease
Inflammatory bowel disease describes two major chronic nonspecific inflammatory disorders of the gastro intestinal tract
• They are:
• Crohn’s disease(CD)
• Ulcerative colitis(UC)
• Main difference between Crohn’s disease and UC is the location and nature of the inflammatory changes
• Crohn’s can affect any part of the gastrointestinal tract, from mouth to anus , although a majority of the cases start in the terminal ileum
• Ulcerative colitis, in contrast, is restricted to the colon and the rectum
Ulcerative colitis and Crohn’s
Etiology of Inflammatory bowel disease
Epidemology of Inflammatory bowel disease
|Ulcerative colitis||Crohn’s disease|
|Incidence (US)||11/100 000||7/100 000|
|Age of onset||15-30 & 60-80||15-30 & 60-80|
|Smoking||May prevent disease||May cause disease|
|Oral contraceptive||No increased risk||Relative risk 1,9|
|Monozygotic twins||8% concordance||67% concordance|
• Inflammatory response with IBD may indicate abnormal regulation of the normal immune response or an autoimmune reaction to self-antigens – microflora of the gastrointestinal tract may provide an environmental trigger to activate inflammation
• Crohn’s disease has been described as “a disorder mediated by T lymphocytes which arises in genetically susceptible individuals as a result of a breakdown in the regulatory constraints on mucosal immune responses to enteric bacteria”
• Microorganisms are a likely factor in the initiation of inflammation in IBD – Patients with inflammatory bowel diseases have increased numbers of surface-adherent and intracellular bacteria
• Suspect infectious agents include the measles virus, protozoans, mycobacteria, and other bacteria
• Bacteria elaborate peptides (e.g., formyl-methionylleucyl-phenylalanine) that have chemotactic properties – influx of inflammatory cells with subsequent release of inflammatory mediators and tissue destruction
• Genetic factors predispose patients to inflammatory bowel diseases, particularly Crohn’s disease – studies of monozygotic twins, there has been a high concordance rate, with both individuals of the pair having an IBD (particularly Crohn’s disease) – first-degree relatives of patients with IBD had a 13-fold increase in the risk of disease
• Other investigators – genetic markers – more frequent in those with IBD (particularly major histocompatability complex, HLA-DR2 for ulcerative colitis and HLA-A2 for Crohn’s disease)
• Inflammatory process is a component of wound healing, the inflamed mucosa activates the typical inflammation –associated genes and genes associated with wound healing
• Pro-inflammatory antigenic triggers in the intestinal lumen activate macrophages and t-helper lymphocytes to release inflammatory mediators
Pathophysiology of Inflammatory bowel disease
• UC is confined to be in rectum and colon and affects the mucosa and the sub mucosa – some instances, a short segment of terminal ileum may be inflamed
• Primary lesion of uc occurs in the crypts of the mucosa (crypts of liberkhun) in the form of crypt abscess
• Necrosis of the epithelium occurs and visible only in microscope
• Other typical ulceration patterns include a “collar button ulcer”, which results from extensive sub mucosal undermining at the ulcer edge which results in diarrhea and bleeding
• UC complications can be local (colon/rectum) or systemic
• Complications could be minor, serious or life threatening
• Minor complication occurs in the majority of ulcerative colitis patients. They include: hemorrhoids, anal fissures or perirectal abscesses
• Major complication is toxic megacolon (1-3%), massive colonic hemorrage
• Risk of colon cancer begins to increase after 10-15 years of uc diagnosis
Ulcerative colitis – microscopic features
• Process is limited to the mucosa and submucosa with deeper layer unaffected
• Two major histologic features:
– the crypt architecture of the colon is distorted
– some patients have basal plasma cells and multiple basal lymphoid aggregates
• 40-50% of patients have disease limited to the rectum and rectosigmoid
• 30-40% of patients have disease extending beyond the sigmoid
• 20% of patients have a total colitis
• Proximal spread occurs in continuity without areas of uninvolved mucosa
Symptoms of Ulcerative colitis
• Target point for CD- terminal ileum
• About two-thirds of patients have some colonic involvement, and 15% to 25% of patients have only colonic disease
• Bowel wall injury is extensive and the intestinal lumen is often narrowed
• Mesentery first becomes thickened and edematous and then fibrotic
• Ulcers tend to be deep and elongated and extend along the longitudinal axis of the bowel, atleast into the submucosa
• “Cobblestone” appearance of the bowel wall results from deep mucosal ulceration intermingled with nodular submucosal thickening
• Fistula formation is common and occurs much more frequently than with ulcerative colitis
• Fistulae often occur in the areas of worst inflammation, where loops of bowel have become matted together by fibrous adhesions
• Nutritional deficiencies are common with Crohn’s disease
• Weight loss, growth failure in children, iron deficiency anemia, vitamin B12 deficiency, folate deficiency, hypoalbuminemia, hypokalemia, and osteomalacia
Sign & Symptoms of Crohn’s disease
Dignosis of Crohn’s disease
• The first clue in the diagnosis of IBD are the symptoms:
• Unrelenting diarrhea
• Blood or mucus in the stool (more common with ulcerative colitis than Crohn’s disease)
• Abdominal pain
• Complete blood cell (CBC) count,
• Electrolyte panel, and
• Liver function tests (LFT)
• Fecal occult blood test (also called stool gaiac or hemoccult test)
ü BARIUM ENEMA
Comparision of Ulcerative colitis & Crohn’s disease
|Depth of inflammation||Mucosal||Transmural|
|Fistula and sinus tracts||Rare||Common|
|Distribution||Diffuse, contiguous spread; always involves rectum; spares
proximal gastrointestinal tract
|Segmental, noncontiguous spread (“skip lesions”); less
common rectal involvement; occurs in entire GIT
Clinical Features of Ulcerative colitis & Crohn’s disease
|Blood in stool||Yes||Occasionally|
• Inflammatory bowel disease describes two major chronic nonspecific inflammatory disorders of the gastro intestinal tract ulcerative colitis and crohns disease
• Major causes of inflammatory bowel disease are infectious agents, environmental factors, genetics, diet
• UC is confined to be in rectum and colon and affects the mucosa and the sub mucosa by release of inflammatory cells
• Ulcers in crohn’s tend to be deep and elongated and extend along the longitudinal axis of the bowel, into the submucosa
Frequently Asked Questions (FAQ) about Inflammatory Bowel Disease:
Q1: What is Inflammatory Bowel Disease (IBD)? Inflammatory Bowel Disease (IBD) refers to a group of chronic inflammatory conditions that affect the digestive tract. It includes Crohn’s disease and ulcerative colitis. IBD is characterized by inflammation and damage to the gastrointestinal lining.
Q2: What is the difference between Crohn’s disease and ulcerative colitis? Crohn’s disease can affect any part of the digestive tract, from the mouth to the anus, and often involves deeper layers of the bowel wall. Ulcerative colitis primarily affects the colon and rectum, and the inflammation is typically limited to the inner lining of the colon.
Q3: What causes IBD? The exact cause of IBD is not fully understood, but it is believed to involve a combination of genetic, environmental, and immune system factors. Potential triggers include genetics, infections, diet, and an abnormal immune response.
Q4: What are the common symptoms of IBD? Common symptoms of IBD include abdominal pain, diarrhea, weight loss, fatigue, and blood in the stool. The severity and specific symptoms can vary between individuals and may fluctuate over time.
Q5: How is IBD diagnosed? Diagnosis of IBD involves a combination of medical history, physical examination, blood tests, imaging (such as colonoscopy or endoscopy), and biopsy of affected tissue. These tests help confirm the diagnosis and determine the type and severity of IBD.
Q6: Is there a cure for IBD? Currently, there is no cure for IBD, but there are various treatment options available to manage symptoms and control inflammation. Medications, dietary changes, lifestyle modifications, and, in some cases, surgery may be used.
Q7: What are the potential complications of IBD? Complications of IBD may include strictures (narrowing of the intestine), fistulas (abnormal connections between organs), abscesses, malnutrition, and an increased risk of colorectal cancer. Regular monitoring and management are essential to reduce complications.
Q8: Can IBD be managed through dietary changes? Dietary modifications can play a significant role in managing IBD. Some individuals find relief from specific diets, such as the low-FODMAP diet, while others may need nutritional support to address malabsorption and deficiencies.
Q9: How does IBD affect daily life and quality of life? IBD can significantly impact daily life due to unpredictable symptoms, fatigue, and potential limitations on activities. Managing the condition with healthcare providers and support networks is important to improve quality of life.
Q10: Is IBD the same as irritable bowel syndrome (IBS)? No, IBD and IBS are different conditions. IBD involves chronic inflammation of the digestive tract, while IBS is a functional disorder characterized by abdominal pain, bloating, and changes in bowel habits. The two should not be confused.
Q11: What is Crohn’s disease? Crohn’s disease is a chronic inflammatory condition that primarily affects the gastrointestinal tract. It can lead to a range of digestive symptoms and complications, including abdominal pain, diarrhea, weight loss, and fatigue.
Q12: What are the common symptoms of Crohn’s disease? Common symptoms of Crohn’s disease include abdominal pain, diarrhea, weight loss, fatigue, and sometimes blood in the stool. Symptoms can vary in intensity and may come and go over time.
Q13: What causes Crohn’s disease? The exact cause of Crohn’s disease is not fully understood, but it is believed to result from a combination of genetic, environmental, and immune system factors. Potential triggers may include genetics, infections, diet, and an abnormal immune response.
Q14: How is Crohn’s disease diagnosed? Diagnosis of Crohn’s disease typically involves a combination of medical history, physical examination, blood tests, imaging studies (such as colonoscopy or endoscopy), and biopsy of affected tissue. These tests help confirm the diagnosis and assess the extent of the disease.
Q15: Is there a cure for Crohn’s disease? There is currently no cure for Crohn’s disease, but various treatment options are available to manage symptoms, control inflammation, and improve the patient’s quality of life. These may include medications, dietary changes, and, in some cases, surgery.
Q16: What are the potential complications of Crohn’s disease? Crohn’s disease can lead to complications such as strictures (narrowing of the intestine), fistulas (abnormal connections between organs), abscesses, malnutrition, and an increased risk of colorectal cancer. Regular monitoring is important to detect and manage these complications.
Q17: How can Crohn’s disease be managed in daily life? Managing Crohn’s disease involves working closely with healthcare providers to develop a treatment plan that may include medications, dietary adjustments, and lifestyle modifications. Patients may also need to monitor their symptoms and seek regular check-ups.
Q18: Can Crohn’s disease affect a person’s quality of life? Crohn’s disease can significantly impact a person’s quality of life due to chronic symptoms and the potential for complications. However, with proper management, many individuals with Crohn’s disease can lead fulfilling lives.
Q19: Can diet make a difference in managing Crohn’s disease? Dietary modifications can play a role in managing Crohn’s disease. Some individuals may find relief from specific diets, but dietary approaches can vary from person to person. It’s important to work with a healthcare provider or dietitian to determine the most suitable diet.
Q20: Can Crohn’s disease be passed down through families? There is a genetic component to Crohn’s disease, and it can run in families. Having a family history of the condition may increase the risk, but it does not guarantee that an individual will develop Crohn’s disease.