Crohn's disease
Crohn's disease is a type of inflammatory bowel disease (IBD) that may affect any segment of the gastrointestinal tract.[3] Symptoms often include abdominal pain, diarrhea, fever, abdominal distension, and weight loss.[1][3] Complications outside of the gastrointestinal tract may include anemia, skin rashes, arthritis, inflammation of the eye, and fatigue.[1] The skin rashes may be due to infections as well as pyoderma gangrenosum or erythema nodosum.[1] Bowel obstruction may occur as a complication of chronic inflammation, and those with the disease are at greater risk of colon cancer and small bowel cancer.[1]
Crohn's disease
Crohn disease, Crohn syndrome, granulomatous enteritis, regional enteritis, Leśniowski-Crohn disease
Abdominal pain, diarrhea (may be bloody), fever, weight loss,[1] fatigue, mouth sores, reduced appetite[2]
20–29 years[3]
Long term[1]
Uncertain
Genetic predisposition, living in a developed country,[4]
stress,[5] tobacco smoking,[6]
having undergone an appendectomy[7][8] or tonsillectomy[9]
Irritable bowel syndrome, celiac disease, Behçet's disease, nonsteroidal anti-inflammatory drug enteropathy, intestinal tuberculosis[1][10]
Slightly increased risk of death[11]
3.2 per 1,000 (developed world)[12]
Although the precise causes of Crohn's disease (CD) are unknown, it is believed to be caused by a combination of environmental, immune, and bacterial factors in genetically susceptible individuals.[3][13][14][15] It results in a chronic inflammatory disorder, in which the body's immune system defends the gastrointestinal tract, possibly targeting microbial antigens.[14][16] While Crohn's is an immune-related disease, it does not seem to be an autoimmune disease (the immune system is not triggered by the body itself).[17] The exact underlying immune problem is not clear; however, it may be an immunodeficiency state.[16][18][19]
About half of the overall risk is related to genetics, with more than 70 genes involved.[1][20] Tobacco smokers are three times as likely to develop Crohn's disease as non-smokers.[6] It often begins after gastroenteritis.[1] Other conditions with similar symptoms include irritable bowel syndrome and Behçet's disease.[1]
There is no known cure for Crohn's disease.[1][3] Treatment options are intended to help with symptoms, maintain remission, and prevent relapse.[1] In those newly diagnosed, a corticosteroid may be used for a brief period of time to improve symptoms rapidly, alongside another medication such as either methotrexate or a thiopurine used to prevent recurrence.[1] Cessation of smoking is recommended for people with Crohn's disease.[1] One in five people with the disease is admitted to the hospital each year, and half of those with the disease will require surgery at some time during a ten-year period.[1] While surgery should be used as little as possible, it is necessary to address some abscesses, certain bowel obstructions, and cancers.[1] Checking for bowel cancer via colonoscopy is recommended every few years, starting eight years after the disease has begun.[1]
Crohn's disease affects about 3.2 per 1,000 people in Europe and North America;[12] it is less common in Asia and Africa.[21][22] It has historically been more common in the developed world.[23] Rates have, however, been increasing, particularly in the developing world, since the 1970s.[22][23] Inflammatory bowel disease resulted in 47,400 deaths in 2015,[24] and those with Crohn's disease have a slightly reduced life expectancy.[1] It tends to start in adolescence and young adulthood, though it can occur at any age.[25][1][3][26] Males and females are equally affected.[3]
Name controversy[edit]
The disease was named after gastroenterologist Burrill Bernard Crohn, who in 1932, together with Leon Ginzburg (1898–1988) and Gordon D. Oppenheimer (1900–1974) at Mount Sinai Hospital in New York, described a series of patients with inflammation of the terminal ileum of the small intestine, the area most commonly affected by the illness.[27] Why the disease was named after Crohn has controversy around it.[28][29] While Crohn, in his memoir, describes his original investigation of the disease, Ginzburg provided strong evidence of how he and Oppenheimer were the first to study the disease.[30]
Prognosis[edit]
Crohn's disease is a chronic condition for which there is no known cure. It is characterised by periods of improvement followed by episodes when symptoms flare up. With treatment, most people achieve a healthy weight, and the mortality rate for the disease is relatively low. It can vary from being benign to very severe, and people with CD could experience just one episode or have continuous symptoms. It usually reoccurs, although some people can remain disease-free for years or decades. Up to 80% of people with Crohn's disease are hospitalized at some point during the course of their disease, with the highest rate occurring in the first year after diagnosis.[11] Most people with Crohn's live a normal lifespan.[237] However, Crohn's disease is associated with a small increase in risk of small bowel and colorectal carcinoma (bowel cancer).[238]
Epidemiology[edit]
The percentage of people with Crohn's disease has been determined in Norway and the United States and is similar at 6 to 7.1:100,000. The Crohn's & Colitis Foundation of America cites this number as approx 149:100,000; NIH cites 28 to 199 per 100,000.[239][240] Crohn's disease is more common in northern countries, and with higher rates still in the northern areas of these countries.[241] The incidence of Crohn's disease is thought to be similar in Europe but lower in Asia and Africa.[239] It also has a higher incidence in Ashkenazi Jews[1][242] and smokers.[243]
Crohn's disease begins most commonly in people in their teens and 20s, and people in their 50s through to their 70s.[1][37][26] It is rarely diagnosed in early childhood. It usually affects female children more severely than males.[244] However, only slightly more women than men have Crohn's disease.[245] Parents, siblings or children of people with Crohn's disease are 3 to 20 times more likely to develop the disease.[246] Twin studies find that if one has the disease there is a 55% chance the other will too.[247]
The incidence of Crohn's disease is increasing in Europe[248] and in newly industrialised countries.[249] For example, in Brazil, there has been an annual increase of 11% in the incidence of Crohn's disease since 1990.[249]
