Inflammatory Bowel Disease

Healthful Vitality | 04/12/2019 | By Dr Subarna Ghosh | Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is an umbrella term that encompasses two diseases of the digestive system, namely ulcerative colitis and Crohn’s disease. The characteristic feature of these two conditions is the presence of chronic (long-term) inflammation of the gastro-intestinal (GI) tract. In IBD, persistent inflammation of the GI tract damages the tissues leading to a host of symptoms.

The worldwide prevalence of IBD is estimated to be about 396 cases per 100,000 persons/year. Individually, the global incidence of ulcerative colitis and Crohn’s disease is about 0.5-24.5 cases per 100,000 persons/year and 0.1-16 cases per 100,000 persons/year, respectively. The highest reported prevalence of IBD is found in Europe- 505 cases of ulcerative colitis per 100,000 persons in Norway and 322 cases of Crohn’s disease per 100,000 persons in Germany. In the United States, an estimated 1 to 1.3 million people currently suffer from IBD.

In most cases, the peak onset of inflammatory bowel diseases is seen during adolescence and early adulthood. Indeed, in approximately 25% IBD patients, the disease commences prior to 20 years of age. In children, the incidence of IBD is 4% in kids younger than 5 years and 18% in children aged 10 and younger. In all age-groups, while ulcerative colitis is more commonly seen in males, Crohn’s disease is more frequently observed in females.

Ulcerative Colitis and Crohn’s Disease: Differentiating Features

The table below enlists the differences between the two forms of IBD.

Ulcerative Colitis	Crohn’s Disease
The condition occurs in the large bowel (colon and rectum)	The condition can affect any region of the GI tract (mouth to anus). The most frequently affected part is the small bowel.
Damaged areas of the intestines form a continuous lesion.	Damaged areas of the GI tract form patchy areas which are interspersed with healthy bowel tissue.
Inflammation observed in ulcerative colitis is limited to the inner lining of the wall of the large bowel.	Inflammation in Crohn’s disease can extend from the inner layers of the wall of the GI tract to the outer layers.

IBD: Causes and Risk Factors

The underlying cause of IBD remains unknown. However, a defective immune system is believed to play a role in the development of IBD and facilitate its progression. Genetic, environmental, and microbial factors are thought to result in a dysregulated immune system, which predisposes an individual to IBD. Risk factors associated with the condition include the following:

• Age: Younger than 30 years
• Ethnicity: IBD is most commonly seen in Caucasian and Ashkenazic Jewish people
• Family history of IBD. The concordance rate of IBD in twins is about 50% (mainly in Crohn’s disease)
• Cigarette smoking
• Non-steroidal anti-inflammatory drugs such as, ibuprofen (Advil), diclofenac sodium (Voltaren), etc.
• Depression and impaired sleep
• Low vitamin D levels
• Imbalance in the gut microbes: Individuals with IBD are known to exhibit an imbalance in their intestinal micro-organisms. This imbalance is presented as a restriction in the overall intestinal bacterial species. While some bacterial species are present in excess, few others are observed in lower than normal numbers in the intestinal flora of IBD patients.

IBD: Signs and Symptoms

The clinical trajectory of inflammatory bowel disease can vary greatly from patient to patient. The most commonly seen signs and symptoms in IBD patients include the following:

• Chronic diarrhea with bloody diarrhea typically seen in ulcerative colitis
• Abdominal pain
• Weight loss
• Fatigue

IBD: Diagnostic Evaluation

The initial diagnosis of IBD is made based on the presenting signs and symptoms of the patient. This is followed by a spectrum of tests which are as follows:

• Laboratory tests:
• Complete blood count (CBC)- Presence of anemia (lower than normal numbers of red blood cells) and thrombocytosis (excess number of blood platelets) indicate persistent inflammation
• Renal (kidney) function tests
• Hepatic (liver) function tests
• Measurement of calprotectin in the stool. Calprotectin is a protein that is elevated in presence of gastrointestinal inflammation. Although elevated levels of calprotectin cannot help to make a definitive diagnosis of IBD, it is an important tool for non-invasive diagnostic evaluation of the condition.
• Testing for gastrointestinal infections (ex. Clostridium difficile). This is essential to exclude other co-existing GI problems.

• Endoscopy: It is the gold standard for diagnosis of IBD. For ulcerative colitis, colonoscopy is used for diagnostic evaluation. For Crohn’s disease, esophagogastroduodenoscopy is used which examines the esophagus, stomach, and the initial part of the small intestine. Histologic examination of tissue sample obtained during endoscopy can further assist in making a definitive diagnosis of the condition.

• Imaging tests:

• Ultrasonography
• Magnetic resonance imaging (MRI)
• Computed tomography (CT) scan in emergency cases

IBD: Treatment

IBD is managed using various medications. The main classes of drugs used in the treatment of IBD include the following:

• Corticosteroids (Budesonide, prednisolone)
• Aminosalicylates (Sulfasalazine)
• Immune suppressants (azathioprine, methotrexate)
• Monoclonal antibody biologic drug (infliximab, vedolizumab)

The above drugs are used for the treatment of mild to severe forms of IBD. Currently, surgery is indicated only in severe cases of IBD which cannot be effectively managed using pharmacologic therapy. Other indications for surgical management include the following:

• Crohn’s disease complications:
• Complex inflammatory alterations seen along the length of the small and large bowel
• Formation of abscesses (pus-filled regions)
• Formation of fistula (an abnormal passage connecting one organ to another) to the bladder, stomach, etc.
• Ulcerative colitis complications:
• Bowel perforation
• Severe bleeding
• Toxic megacolon (a rare, fatal condition where the colon is totally or partially obstructed with no passage of gas or feces that can lead to colonic rupture)
• Intractable disease course

At present, laparoscopic procedures are more commonly used for the surgical management of IBD. These procedures are minimally invasive and provide a safe and effective alternative to conventional open surgery. For Crohn’s disease, depending on the site of the disease, surgical techniques used for treatment include small-bowel segmental resection, ileocecal resection, and stricturoplasty (alleviates narrowing of the bowel). For active ulcerative colitis, the surgical method of choice is subtotal colectomy with transient ileostoma and proctectomy (the procedure involves partial removal of the colon with complete removal of the rectum).

IBD: Long-term Complications

The complications associated with IBD include the following:

• Increased risk of colon cancer: Individuals with IBD have a higher risk of developing colon cancer.
• Adverse effects of medications: High blood pressure and osteoporosis are associated with long-term corticosteroid use.
• Primary sclerosing cholangitis: IBD patients are at increased risk of this condition where there is scar formation in the bile ducts.

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References:

1. Rosen MJ, Dhawan A, Saeed SA. Inflammatory Bowel Disease in Children and Adolescents. JAMA Pediatr. 2015;169(11):1053-60. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4702263/
2. Wehkamp J, Götz M, Herrlinger K, Steurer W, Stange EF. Inflammatory Bowel Disease. Dtsch Arztebl Int. 2016;113(5):72-82. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4782273/
3. Chang S, Malter L, Hudesman D. Disease monitoring in inflammatory bowel disease. World J Gastroenterol. 2015;21(40):11246-59. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4616202/
4. Centers for Disease Control: Inflammatory Bowel Disease. https://www.cdc.gov/ibd/what-is-IBD.htm
5. Centers for Disease Control: Prevalence of Inflammatory Bowel Disease Among Medicare Fee-For-Service Beneficiaries — United States, 2001−2018 https://www.cdc.gov/mmwr/volumes/70/wr/mm7019a2.htm
6. https://www.medscape.com/answers/179037-54870/what-is-the-global-prevalence-of-inflammatory-bowel-disease-ibd
7. https://www.nature.com/articles/nrgastro.2015.34