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Inflammatory bowel disease (Crohn disease and ulcerative colitis): Difference between revisions
Inflammatory bowel disease (Crohn disease and ulcerative colitis) (view source)
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'''Inflammatory bowel disease''' (IBD) is an umbrella term for two idiopathic conditions; '''Crohn disease''' (CD) and '''ulcerative colitis''' (UC). Both are chronic diseases of the gastrointestinal tract that involve some inappropriate immune activation of the mucosa. Luckily for medical students the two diseases have different features that can be used to differentiate them. | <section begin="clinical biochemistry" />'''Inflammatory bowel disease''' (IBD) is an umbrella term for two idiopathic conditions; '''Crohn disease''' (CD) and '''ulcerative colitis''' (UC). Both are chronic diseases of the gastrointestinal tract that involve some inappropriate immune activation of the mucosa. Luckily for medical students the two diseases have different features that can be used to differentiate them. | ||
IBD is a chronic disease, but it isn’t always active. There are usually periods of active disease with weeks or months of asymptomatic periods between them. The asymptomatic periods are called ''remission'' while the symptomatic periods are called ''flares''. Several factors may provoke a flare-up, like stress, specific types of food, or cigarette smoking. However, most flares occur without an apparent trigger. | IBD is a chronic disease, but it isn’t always active. There are usually periods of active disease with weeks or months of asymptomatic periods between them. The asymptomatic periods are called ''remission'' while the symptomatic periods are called ''flares''. Several factors may provoke a flare-up, like stress, specific types of food, or cigarette smoking. However, most flares occur without an apparent trigger.<section end="clinical biochemistry" /> | ||
The disease usually presents during adolescence or in young adults, although there is a second peak of incidence around the age of 50s. It’s most prevalent in Western countries like North America, northern Europe and Australia, and more common in the Northern parts of these regions compared to the Southern parts. | The disease usually presents during adolescence or in young adults, although there is a second peak of incidence around the age of 50s. It’s most prevalent in Western countries like North America, northern Europe and Australia, and more common in the Northern parts of these regions compared to the Southern parts. | ||
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* [[Ankylosing spondylitis]] | * [[Ankylosing spondylitis]] | ||
* Aphthous stomatitis | * Aphthous stomatitis | ||
<section begin="clinical biochemistry" /> | |||
= Crohn disease = | = Crohn disease = | ||
Crohn disease may affect the entire GI tract, from the rectum to the oral cavity. It most frequently affects the terminal ileum and coecum. | Crohn disease may affect the entire GI tract, from the rectum to the oral cavity. It most frequently affects the terminal ileum and coecum. | ||
<section end="clinical biochemistry" /> | |||
In homozygotic twins where one twin has CD the other twin has 50% risk for developing CD as well. This shows that genetics are highly involved in the development of the disease but not the only important factor. The gene ''NOD2'' is especially implicated in CD. | In homozygotic twins where one twin has CD the other twin has 50% risk for developing CD as well. This shows that genetics are highly involved in the development of the disease but not the only important factor. The gene ''NOD2'' is especially implicated in CD. | ||
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Crohn disease is associated with certain extraintestinal manifestations, although it’s rare that a patient presents with these. These include arthritis, uveitis, ankylosing spondylitis, erythema nodosum, and pyoderma gangrenosum. | Crohn disease is associated with certain extraintestinal manifestations, although it’s rare that a patient presents with these. These include arthritis, uveitis, ankylosing spondylitis, erythema nodosum, and pyoderma gangrenosum. | ||
<section begin="clinical biochemistry" /> | |||
== Diagnosis and evaluation == | == Diagnosis and evaluation == | ||
Diagnosis of CD is histological, requiring biopsy. The workup of CD involves [[MR enterography]] (to visualise the small bowels) and [[colonoscopy]]. Biopsies should be taken from any lesions visible, as well as the terminal ileum. If there are oesophageal or gastric symptoms, [[upper endoscopy]] should be performed as well. Laboratory tests should check for [[anaemia]] and vitamin deficiencies. | Diagnosis of CD is histological, requiring biopsy. The workup of CD involves [[MR enterography]] (to visualise the small bowels) and [[colonoscopy]]. Biopsies should be taken from any lesions visible, as well as the terminal ileum. If there are oesophageal or gastric symptoms, [[upper endoscopy]] should be performed as well. Laboratory tests should check for [[anaemia]] and vitamin deficiencies. | ||
Non-infectious intestinal inflammation correlates directly with the amount of | Non-infectious intestinal inflammation correlates directly with the amount of calprotectin in the faeces. Measurement of this protein is useful both for excluding the diagnosis (if negative) and for follow-up (to detect flares). CRP and ESR may be elevated in severe cases. Anti-saccharomyces cerevisiae antibodies (ASCA) is specific for Crohn disease and can be used to distinguish it from UC in uncertain cases.<section end="clinical biochemistry" /> | ||
== Treatment == | == Treatment == | ||
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After some weeks/months, the seton may be removed and the fistula allowed to close, if deemed peaceful. If not, fistulotomy may be necessary. | After some weeks/months, the seton may be removed and the fistula allowed to close, if deemed peaceful. If not, fistulotomy may be necessary. | ||
<section begin="clinical biochemistry" /> | |||
= Ulcerative colitis = | = Ulcerative colitis = | ||
UC is similar to Crohn disease in some ways but different in many other. The biggest difference perhaps is that UC can only affect the colon, and that the inflammation is never deeper than the submucosa. Because ulcerative colitis only affects the colon, it can be cured by total colectomy. | UC is similar to Crohn disease in some ways but different in many other. The biggest difference perhaps is that UC can only affect the colon, and that the inflammation is never deeper than the submucosa. Because ulcerative colitis only affects the colon, it can be cured by total colectomy. | ||
<section end="clinical biochemistry" /> | |||
== Pathology == | == Pathology == | ||
UC always starts in the rectum and may spread proximally. If UC only affects the rectum is the condition called ''ulcerative proctitis'', if it affects the whole colon is it called ''ulcerative pancolitis.'' If there is pancolitis there may be a small “spill-over” of inflammation into the terminal ileum, a condition called ''backwash ileitis''. | UC always starts in the rectum and may spread proximally. If UC only affects the rectum is the condition called ''ulcerative proctitis'', if it affects the whole colon is it called ''ulcerative pancolitis.'' If there is pancolitis there may be a small “spill-over” of inflammation into the terminal ileum, a condition called ''backwash ileitis''. | ||
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Like CD, UC may cause extraintestinal manifestations. | Like CD, UC may cause extraintestinal manifestations. | ||
<section begin="clinical biochemistry" /> | |||
== Diagnosis and evaluation == | |||
[[Colonoscopy]] with biopsy is essential. The diagnosis of UC is made in the patient with chronic diarrhoea, colitis on biopsy, and when other causes of diarrhoea have been ruled out. | |||
Stool should be tested for bacterial causes of diarrhoea. P-ANCA is positive in UC and negative in CD and so can be used to distinguish the two. Faecal calprotectin is elevated in UC as well. <section end="clinical biochemistry" /> | |||
== Treatment == | == Treatment == | ||
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Total colectomy with end ileostomy is a possible alternative. | Total colectomy with end ileostomy is a possible alternative. | ||
<noinclude>[[Category:Gastroenterology]] | <noinclude> | ||
[[Category:Gastroenterology]] | |||
[[Category:Gastrointestinal surgery]] | [[Category:Gastrointestinal surgery]] | ||
</noinclude> | </noinclude> | ||
[[Category:Internal Medicine (POTE course)]] | [[Category:Internal Medicine (POTE course)]] | ||