World Gastroenterology Organisation Global Guidelines Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a group of idiopathic chronic inflammatory intestinal conditions. The 2 main disease categories are Crohn’s disease (CD) and ulcerative colitis (UC), which have both overlapping and distinct clinical and pathologic features. The pathogenesis of IBD is incompletely understood. Genetic and environmental factors such as altered luminal bacteria and enhanced intestinal permeability play a role in the dysregulation of intestinal immunity, leading to gastrointestinal injury. GLOBAL INCIDENCE/PREVALENCE In developed countries, UC emerged first and then CD followed. In the past 20 years, CD has generally overtaken UC in incidence rates. In developing countries in which IBD is emerging, UC is typically more common than CD.1 The peak age of incidence of CD is in the third decade of life, with a decreasing incidence rate with age. The incidence rate in UC is quite stable between the third and seventh decades. Although more females than males have CD, the incidence rates among young children have been higher in males than in females during the past decade, and over time we may see an equalization of the sex distribution. There is already a male predominance for CD in studies from East Asia. The sex ratio is already equal in UC. The prevalence of CD seems to be higher in urban areas than in rural areas, and also higher in higher socioeconomic classes. Most studies show that when the incidence first starts to increase, it is mostly among those of higher social class, but that the disease becomes more ubiquitous with time. If individuals migrate to developed countries before adolescence, those initially belonging to low-incidence populations show a higher incidence of IBD. This is particularly true for the first generation of these families born in a country with a high incidence (Table 1).TABLE 1: Highest Annual Incidence Rates and Reported Prevalence Rates for Inflammatory Bowel DiseasePRESENTING FEATURES OF IBD: EAST-WEST DIFFERENCES The presentations of CD and UC are quite similar in such disparate areas of the world as North America, South America, Europe, Australia, and New Zealand: CD is distinguished from UC by disease proximal to the colon, perineal disease, fistulas, histologic granulomas, and full thickness as opposed to mucosa-limited disease. In CD, granulomas are evident in up to 50% of patients and fistulas in 25%. However, there are also differences in presentation between the East and the West. In East Asia, there is a higher prevalence of males with CD, ileocolonic CD, less familial clustering, lower rates of surgery, and fewer extraintestinal manifestations. Primary sclerosing cholangitis (PSC) associated with UC is less prevalent. Overall, the need for surgery is lower in Asian patients, at around 5% to 8%. However, there is a high rate of penetrating disease and perianal disease in Asia even at diagnosis, suggesting that complicated disease behavior is not uncommon in East Asia.2–12 Tuberculosis (TB) is an important differential-diagnostic issue in developing countries. CLINICAL FEATURES Symptoms IBD is a chronic, intermittent disease. The symptoms range from mild to severe during relapses, and they may disappear or decrease during remissions. In general, the symptoms depend on the segment of the intestinal tract involved. Symptoms Related to Inflammatory Damage in the Digestive Tract Diarrhea: Stool may contain mucus or blood. Nocturnal diarrhea. Incontinence. Constipation: May be the primary symptom in UC limited to the rectum (proctitis). Obstipation with no passage of flatus can be seen in cases of bowel obstruction. Pain or rectal bleeding with bowel movement. Bowel movement urgency. Tenesmus. Abdominal cramps and pain: In the right lower quadrant of the abdomen common in CD, or around the umbilicus, in the lower left quadrant in moderate to severe UC. Nausea and vomiting may occur, but more so in CD than UC. General Symptoms Associated With UC and CD in Some Cases Fever. Loss of appetite. Weight loss. Fatigue. Night sweats. Growth retardation. Primary amenorrhea. Extraintestinal Manifestations Extraintestinal manifestations include musculoskeletal conditions (peripheral or axial arthropathy), cutaneous conditions (erythema nodosum, pyoderma gangrenosum), ocular conditions (scleritis, episcleritis, uveitis), and hepatobiliary conditions (PSC). Complications Intestinal Complications Proximal gastrointestinal involvement is a complication, or a different disease presentation. It may occur more often in children and in some adult ethnic groups (African Americans, Ethiopians), but it is also sought more commonly in children, with whom gastroscopy is a routine early investigation, whereas in adults it is not.13 Hemorrhage: profuse bleeding from ulcers occurs in UC. Bleeding is less common in CD. Massive bleeding in CD is more often seen due to ileal ulceration than in colitis. About 5% to 10% of individuals with CD show ulceration in the stomach or duodenum. Bowel perforation is a concern in CD, and in both CD (if the colon is involved) and UC if megacolon ensues. Intra-abdominal abscesses in CD. Strictures and obstruction (narrowing of the bowel may be due to acute inflammation and edema, or due top chronic fibrosis): Strictures in CD are often inflammatory: Inflammatory strictures can resolve with medical treatment. Scarring (fixed or fibrotic) strictures may require endoscopic or surgical intervention to relieve the obstruction. 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