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133-456: Spondyloarthritis is caused by a combination of genetic polymorphisms and environment, with the relative contributions of genes and environment varying across different types. It is associated with ileal inflammation, with an immunological connection between Crohn's disease and ankylosing spondylitis . Reactive arthritis is primarily caused by gastrointestinal pathogens, genitourinary and respiratory infections, and genetic variables. HLA-B27 ,

266-425: A bacterial episodic version of PSC. Upon physical exam, one may discern enlarged liver contours (hepatomegaly) or enlarged spleen (splenomegaly) as well as areas of excoriation. Yellow coloring of the skin, or jaundice, may also be present due to excess of bile byproduct buildup (bilirubin) from the biliary tract. In diagnosis, lab results often reveal a pattern indicative of biliary disease (cholestatic pattern). This

399-435: A balance or equilibrium between morphs. The mechanisms that conserve it are types of balancing selection . Most genes have more than one effect on the phenotype of an organism ( pleiotropism ). Some of these effects may be visible, and others cryptic, so it is often important to look beyond the most obvious effects of a gene to identify other effects. Cases occur where a gene affects an unimportant visible characteristic, yet

532-478: A cause for anemia, particularly microcytic anemia (small red blood cells), which can be evaluated with a serum ferritin , iron , total iron-binding capacity and transferrin saturation . Anemia may be due to a complication of treatment from azathioprine, which can cause low blood counts, or sulfasalazine, which can result in folate deficiency. Thiopurine metabolites (from azathioprine) and a folate level can help. UC may cause high levels of inflammation throughout

665-432: A change in fitness is recorded. In such cases, the gene's subsurface effects may be responsible for the change in fitness. Pleiotropism is posing continual challenges for many clinical dysmorphologists in their attempt to explain birth defects which affect one or more organ system, with only a single underlying causative agent. For many pleiotropic disorders, the connection between the genetic abnormality and its manifestations

798-436: A colonic perforation may ensue, which has a 50% mortality rate in people with UC. Other complications include hemorrhage , venous thromboembolism , and secondary infections of the colon including C. difficile or cytomegalovirus colitis. Ulcerative colitis may improve and enter remission. UC is characterized by immune dysregulation and systemic inflammation, which may result in symptoms and complications outside

931-452: A couple of decades the work of Fisher, Ford, Arthur Cain , Philip Sheppard and Cyril Clarke promoted natural selection as the primary explanation of variation in natural populations, instead of genetic drift. Evidence can be seen in Mayr's famous book Animal Species and Evolution , and Ford's Ecological Genetics . Similar shifts in emphasis can be seen in most of the other participants in

1064-418: A diagnosis of axial spondyloarthritis: they must be under 45 years old and have experienced back pain of any kind for at least three months. The second step comprises two sections that are assessed independently according to the existence of either sacroiliitis on imaging or human leukocyte antigen (HLA) B27 : Spondyloarthritis features: The initial requirement is that a person have at least one of

1197-401: A family history of inflammatory bowel disease. In addition, people with a first degree relative with UC have a four-fold increase in their risk of developing the disease. Twelve regions of the genome may be linked to UC, including, in the order of their discovery, chromosomes 16, 12, 6, 14, 5, 19, 1, and 3, but none of these loci has been consistently shown to be at fault, suggesting that

1330-477: A few days. Inflammatory back pain and dactylitis are also prevalent. Psoriatic arthritis is known to present in five distinct patterns: oligoarticular (affecting four or fewer joints); polyarticular (affecting five or more joints); prominent distal interphalangeal (DIP) joint involvement; arthritis mutilans ; and psoriatic spondylitis . More than 70% of cases follow the oligoarticular pattern. Distal joints are frequently impacted by psoriatic arthritis, which

1463-505: A founder of niche research, commented "It is very likely from an ecological point of view that all species, or at least all common species, consist of populations adapted to more than one niche". He gave as examples sexual size dimorphism and mimicry. In many cases where the male is short-lived and smaller than the female, he does not compete with her during her late pre-adult and adult life. Size difference may permit both sexes to exploit different niches. In elaborate cases of mimicry , such as

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1596-402: A high mortality rate as compared to milder forms of UC, with a 3-month and 12 month mortality rate of 0.84% and 1% respectively. People with fulminant UC may have inflammation extending beyond just the mucosal layer, causing impaired colonic motility and leading to toxic megacolon . Toxic megacolon represents a medical emergency, one often treated surgically. If the serous membrane is involved,

1729-463: A link between diet and the development of ulcerative colitis. Few studies have investigated such an association; one study showed no association of refined sugar on the number of people affected of ulcerative colitis. High intake of unsaturated fat and vitamin B6 may enhance the risk of developing ulcerative colitis. Other identified dietary factors that may influence the development and/or relapse of

1862-509: A migratory pattern. In those who do not fit the criteria for any of the well-established spondyloarthropathies, the term "undifferentiated spondyloarthropathy" is used to characterize the signs of spondyloarthritis. A tiny percentage of these eventually experience a characterized spondyloarthritis, but most experience more general symptoms such as dactylitis , enthesitis , unilateral or alternating buttock pain, inflammatory back pain , and occasionally extra-articular symptoms. Spondyloarthritis

1995-401: A more formal term is morphotype. Form and phase are sometimes used, but are easily confused in zoology with, respectively, "form" in a population of animals, and "phase" as a color or other change in an organism due to environmental conditions (temperature, humidity, etc.). Phenotypic traits and characteristics are also possible descriptions, though that would imply just a limited aspect of

2128-783: A normal CRP level. Serum albumin may also be low related to inflammation, in addition to loss of protein in the GI tract associated with bleeding and colitis. Low serum levels of vitamin D are associated with UC, although the significance of this finding is unclear. Specific antibody markers may be elevated in ulcerative colitis. Specifically, perinuclear antineutrophil cytoplasmic antibodies (pANCA) are found in 70 percent of cases of UC. Antibodies against Saccharomyces cerevisiae may be present, but are more often positive in Crohn's disease compared with ulcerative colitis. However, due to poor accuracy of these serolologic tests, they are not helpful in

2261-583: A number of studies examining the effects of TNF blockers on people with ankylosing spondylitis were published. These studies demonstrated that TNF-blocker therapy improves clinical symptoms, CRP levels, and MRI-detectable inflammation in the spine or sacroiliac joints. These improvements were noted with certolizumab pegol , etanercept , infliximab , adalimumab , and golimumab . The lives of people with ankylosing spondylitis are profoundly affected. According to recent statistics, people with ankylosing spondylitis , particularly those who are older and have had

2394-412: A physicians assessment of severity, is often used clinically to classify UC as mild, moderate or severe. Acute-Severe Ulcerative Colitis (ASUC) is a severe form which presents acutely and with severe symptoms. This fulminant type is associated with severe symptoms (usually diarrhea, rectal bleeding and abdominal pain) and is usually associated with systemic symptoms including fever. It is associated with

2527-678: A polymorphic form of the HLA-B molecule, is found in up to 95% of those who are European and have spondylitis , 70% having reactive arthritis, 60% with psoriatic spondylitis, 25% with peripheral psoriatic arthritis, and 70% with spondylitis associated with inflammatory bowel disease. Spondyloarthritis is diagnosed based on clinical factors, including inflammatory back pain, limited spinal mobility, and radiological sacroiliitis , but many people do not have radiographic evidence of sacroiliitis for up to 10 years. Early diagnosis criteria consider HLA-B27 testing and MRI scanning advancements. Spondyloarthritis

2660-442: A progressive condition, and may result in cirrhosis of the liver. No specific therapy has been proven to affect the long-term course of PSC. Ulcerative colitis is an autoimmune disease characterized by T-cells infiltrating the colon. No direct causes for UC are known, but factors such as genetics, environment, and an overactive immune system play a role. UC is associated with comorbidities that produce symptoms in many areas of

2793-544: A recent Cochrane systematic review of published work, supervised group physiotherapy is superior to home exercises, individual home-based or supervised exercise programs are preferable to no intervention, and in-patient spondyloarthritis exercise therapy combined with follow-up group physiotherapy is superior to group physiotherapy alone. Recreational exercise, whether performed in a group setting or alone, helps people with ankylosing spondylitis feel less stiff and in pain. Back exercise also helps these people function better, but

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2926-589: A result, the unfolded protein response (UPR) modifies the immune cells ' cytokine output and reactivity to various innate immunological stimuli. Spondyloarthritis is primarily diagnosed, or at least first suspected, based on clinical factors. According to the current criteria for ankylosing spondylitis , a person must exhibit clinical symptoms of inflammatory back pain and limited spinal mobility together with radiological sacroiliitis . But many people with inflammatory back pain may have no radiographic evidence of sacroiliitis since up to 10 years might pass between

3059-402: A role in impairing this beta-oxidation pathway by interrupting the short chain acetyl-CoA dehydrogenase, an enzyme within the pathway. Furthermore, it has been suggested that the protective effect of smoking in ulcerative colitis is due to the hydrogen cyanide from cigarette smoke reacting with hydrogen sulfide to produce the non-toxic isothiocyanate, thereby inhibiting sulfides from interrupting

3192-590: A significant association with primary sclerosing cholangitis (PSC), a progressive inflammatory disorder of small and large bile ducts . Up to 70-90% of people with primary sclerosing cholangitis have ulcerative colitis. As many as 5% of people with UC may progress to develop primary sclerosing cholangitis. PSC is more common in men, and often begins between 30 and 40 years of age. It can present asymptomatically or exhibit symptoms of itchiness (pruritis) and fatigue. Other symptoms include systemic signs such as fever and night sweats. Such symptoms are often associated with

3325-413: A skin condition known as hidradenitis suppurativa (HS). This condition represents a chronic process in which follicles become occluded leading to recurring inflammation of nodules and abscesses and even fistulas tunnels in the skin that drain fluid. Ulcerative colitis may affect the circulatory and endocrine system. UC increases the risk of blood clots in both arteries and veins; painful swelling of

3458-491: A species from each other. Presently, geneticists use the term genetic polymorphism to describe the functionally silent differences in DNA sequence between individuals that make each human genome unique. Genetic polymorphism is actively and steadily maintained in populations by natural selection, in contrast to transient polymorphisms where a form is progressively replaced by another. By definition, genetic polymorphism relates to

3591-417: A subtype of juvenile idiopathic arthritis , and ankylosing spondylitis comprise the group of disorders currently referred to as spondyloarthritis. Polymorphism (biology) In biology , polymorphism is the occurrence of two or more clearly different morphs or forms , also referred to as alternative phenotypes , in the population of a species. To be classified as such, morphs must occupy

3724-431: A thrice higher rate of disability than the general population. Their overall frequency of disability and economic costs are comparable to those of rheumatoid arthritis . Furthermore, increasing evidence indicates that cardiovascular illness puts those with ankylosing spondylitis at risk for early death. Early research on the course of reactive arthritis indicated a poor prognosis. But more recent research has shown that

3857-423: Is sexual dimorphism , which occurs in many organisms. Other examples are mimetic forms of butterflies (see mimicry ), and human hemoglobin and blood types . According to the theory of evolution, polymorphism results from evolutionary processes, as does any aspect of a species. It is heritable and is modified by natural selection . In polyphenism, an individual's genetic makeup allows for different morphs, and

3990-424: Is a cost-effective, well-tolerated, non-invasive and readily available tool for the management of patients with inflammatory bowel disease (IBD), including UC, in clinical practice. Some studies demonstrated that bowel ultrasound is an accurate tool for assessing disease activity in people with ulcerative colitis. Imaging is otherwise of limited use in diagnosing ulcerative colitis. Magnetic resonance imaging (MRI)

4123-677: Is a long-standing debate as to how this situation could have arisen, and the question is not yet resolved. Whereas a gene family (several tightly linked genes performing similar or identical functions) arises by duplication of a single original gene, this is usually not the case with supergenes. In a supergene some of the constituent genes have quite distinct functions, so they must have come together under selection. This process might involve suppression of crossing-over, translocation of chromosome fragments and possibly occasional cistron duplication. That crossing-over can be suppressed by selection has been known for many years. Debate has centered round

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4256-426: Is associated with a generalized inflammatory process that can affect many parts of the body. Sometimes, these associated extra-intestinal symptoms are the initial signs of the disease. In contrast to Crohn's disease, which can affect areas of the gastrointestinal tract outside of the colon, ulcerative colitis is usually confined to the colon. Inflammation in ulcerative colitis is usually continuous, typically involving

4389-449: Is called the switch . This switch may be genetic, or it may be environmental. Taking sex determination as the example, in humans the determination is genetic, by the XY sex-determination system . In Hymenoptera ( ants , bees and wasps ), sex determination is by haplo-diploidy: the females are all diploid , the males are haploid . However, in some animals an environmental trigger determines

4522-677: Is categorized into two groups based on the Assessment of SpondyloArthritis International Society (ASAS) criteria: primarily axial involvement and predominantly peripheral manifestations. Non-steroidal anti-inflammatory drugs (NSAIDs) are administered first for active axial signs of spondyloarthritis. If NSAIDs are contraindicated or cause side effects, TNF blockers are used. Traditional disease-modifying antirheumatic drugs (DMARDs) are not used for people without peripheral disease signs. In all subtypes of spondyloarthritis, inflammatory back pain and/or asymmetrical arthritis , mainly affecting

4655-403: Is caused by a complicated combination of genetic polymorphisms and environment. The relative contributions of genes and environment may differ across different types of spondyloarthritis. Microscopically visible ileal inflammation is seen in about 50% of people with spondyloarthritis and ankylosing spondylitis during ileocolonoscopy. There seems to be an immunological connection between

4788-427: Is characterized by painful lesions or nodules that become ulcers which progressively grow. The ulcers are often filled with sterile pus-like material. In some cases, pyoderma gangrenosum may require injection with corticosteroids. Treatment may also involve inhibitors of tumor necrosis factor (TNF), a cytokine that promotes cell survival. Other associations determined between the skin and ulcerative colitis include

4921-477: Is feasible with traditional radiography. It has also allowed for accurate anatomical description of spinal components. The only imaging modality that can precisely identify and evaluate spinal inflammation at this time is magnetic resonance imaging (MRI) of the sacroiliac joints and spine. It is also being developed as a gauge of disease activity and response to treatment. When evaluating someone with reactive arthritis or psoriatic arthritis , plain radiographs of

5054-434: Is generally less common in those with ulcerative colitis (up to 10%) than in those with Crohn's disease (up to 20%), but it is more common in cases where a rheumatologist served as the assessor. Moll and associates first proposed the idea of a collection of similar conditions known as seronegative spondarthritides in 1974. Psoriatic arthritis , reactive arthritis , arthritis associated with inflammatory bowel disease ,

5187-426: Is insufficient evidence of treatment efficacy, those with axial spondyloarthritis who do not exhibit peripheral disease signs do not receive traditional disease-modifying antirheumatic drugs (DMARDs). But in the event that peripheral arthritis is present, those with spondyloarthritis should get treatment with conventional DMARDs before TNF-blocker medication and after the failure of NSAID therapy. According to

5320-470: Is insufficient evidence to support this theory in rheumatologic practice. The majority of those with established peptic ulcer disease should take selective COX-2 antagonists . When peripheral arthritis coexists with axial illness, conventional DMARDs such methotrexate , sulfasalazine , or leflunomide may be useful in treating peripheral spondyloarthritis. These drugs are typically ineffective in treating axial symptoms of spondyloarthritis. After 2000,

5453-471: Is most commonly associated with uveitis and episcleritis. UC may cause several joint manifestations, including a type of rheumatologic disease known as seronegative arthritis , which may affect few large joints (oligoarthritis), the vertebra ( ankylosing spondylitis ) or several small joints of the hands and feet (peripheral arthritis). Often the insertion site where muscle attaches to bone ( entheses ) becomes inflamed ( enthesitis ). Inflammation may affect

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5586-472: Is neither apparent nor understood. Epistasis occurs when the expression of one gene is modified by another gene. For example, gene A only shows its effect when allele B1 (at another locus ) is present, but not if it is absent. This is one of the ways in which two or more genes may combine to produce a coordinated change in more than one characteristic (for instance, in mimicry). Unlike the supergene, epistatic genes do not need to be closely linked or even on

5719-538: Is often displayed by markedly elevated alkaline phosphatase levels and milder or no elevation in liver enzyme levels. Results of endoscopic retrograde cholangiography (ERC) may show bile ducts with thicker walls, areas of dilation or narrowing. However, some patients with UC and PSC have inflammation that has significantly affected only ramified intrahepatic bile ducts of smaller diameter, also known as "small ducts", which are not visualized by ERC. In some cases, primary sclerosing cholangitis occurs several years before

5852-466: Is often unnecessary in diagnosis). In contrast to joint-related manifestations, erythema nodosum often occurs alongside intestinal disease. Thus, treatment of UC can often lead to resolution of skin nodules. Another skin condition associated with UC is pyoderma gangrenosum, which presents as deep skin ulcerations. Pyoderma gangrenosum is seen in about 1% of patients with UC and its formation is usually independent of bowel inflammation. Pyoderma gangrenosum

5985-413: Is required. But because structural change seen on radiographs can take months or years to emerge, normal radiographs or worrisome abnormalities only warrant additional diagnostic imaging in the context of suggestive clinical symptoms or findings. Furthermore, reading sacroiliac joint radiographs can be difficult and dependent on a number of variables, such as the image quality, the radiological technique,

6118-618: Is similar to that of HLA-B27 . The incidence of spondyloarthritis as a disease entity was recorded in only four investigations, and ranged from 0.48/100,000 in Japan to 62.5/100,000 in Spain . Data on the prevalence of spondyloarthritis were reported from 16 investigations; the results ranged from 0.01% in Japan to 2.5% in Alaska . Those with European heritage have a 0.2% to 0.7% prevalence of ankylosing spondylitis . Reactive arthritis prevalence

6251-448: Is strongly tied to the adaptation of a species to its environment, which may vary in colour, food supply, and predation and in many other ways including sexual harassment avoidance. Polymorphism is one good way the opportunities get to be used; it has survival value, and the selection of modifier genes may reinforce the polymorphism. In addition, polymorphism seems to be associated with a higher rate of speciation . G. Evelyn Hutchinson ,

6384-429: Is the sacroiliac (SI) joints ' erosion, ankylosis , and sclerosis . There must be clear evidence of sacroiliitis (at least grade 2 bilaterally or grade 3 unilaterally) on the radiographs in order to diagnose ankylosing spondylitis . When axial spondyloarthritis is suspected, sacroiliac joint radiographs are still the initial imaging approach. If radiographs clearly show sacroiliitis , then no more diagnostic imaging

6517-530: Is the classic pathophysiological paradigm for spondyloarthritis. It argues that HLA-B27 displays self-peptides that resemble pathogen-derived peptides to CD8 -restricted T cells . Two other theories have been proposed to explain HLA-B27's function. They suggest that HLA-B27's genesis may be autoinflammatory rather than autoimmune , as it plays a part in initiating innate immune responses instead of its traditional function of presenting antigens. According to

6650-405: Is typically asymmetrical. Up to 20% of people with inflammatory bowel disease (IBD) develop spondyloarthropathy. Those with Crohn's disease are more likely to have this association than those with ulcerative colitis . Arthritis may appear before clinical bowel disease. Usually, the lower extremities are asymmetrically affected by arthritis. The arthritis typically manifests abruptly and follows

6783-464: Is unknown and likely varies with time based on endemic rates of the enteric ( Shigella , Salmonella , Campylobacter ) and sexually acquired ( chlamydia ) infections that cause it. In the general community, 1–3% of people have psoriasis . It is less known how common psoriatic arthritis is, and it is more common in people with more severe disease; population studies in Caucasians suggest that

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6916-415: Is worse in the morning. Axial arthritis may begin in the sacroiliac joints and work its way up to the cervical spine over time. Spinal abnormalities such as flattening of the lumbar lordosis , exaggeration of the thoracic kyphosis , and hyperextension of the cervical spine lead to limited spinal motion. Hip and shoulder arthritis can occur in some people with ankylosing spondylitis , usually early in

7049-889: The ICN . Horticulturists sometimes confuse this usage of "variety" both with cultivar ("variety" in viticultural usage, rice agriculture jargon, and informal gardening lingo) and with the legal concept " plant variety " (protection of a cultivar as a form of intellectual property ). Three mechanisms may cause polymorphism: Endler's survey of natural selection gave an indication of the relative importance of polymorphisms among studies showing natural selection. The results, in summary: Number of species demonstrating natural selection: 141. Number showing quantitative traits: 56. Number showing polymorphic traits: 62. Number showing both Q and P traits: 23. This shows that polymorphisms are found to be at least as common as continuous variation in studies of natural selection, and hence just as likely to be part of

7182-647: The JAK-STAT intracellular T-cell signaling pathway, leading to the transcription , translation and release of inflammatory cytokines. This T-cell JAK-STAT signaling is inhibited by the medications tofacitinib , filgotinib and upadacitinib which are used in the treatment of ulcerative colitis. The initial diagnostic workup for ulcerative colitis consists of a complete history and physical examination, assessment of signs and symptoms, laboratory tests and endoscopy. Severe UC can exhibit high erythrocyte sedimentation rate (ESR), decreased albumin (a protein produced by

7315-522: The Mesolithic Holocene . Non-human apes have similar blood groups to humans; this strongly suggests that this kind of polymorphism is ancient, at least as far back as the last common ancestor of the apes and man, and possibly even further. The relative proportions of the morphs may vary; the actual values are determined by the effective fitness of the morphs at a particular time and place. The mechanism of heterozygote advantage assures

7448-508: The gastrozooids ; the individuals capable of asexual reproduction only, the gonozooids, blastostyles; and free-living or sexually reproducing individuals, the medusae . Balanced polymorphism refers to the maintenance of different phenotypes in population. Monomorphism means having only one form. Dimorphism means having two forms. Polymorphism crosses several discipline boundaries, including ecology, genetics, evolution theory, taxonomy, cytology, and biochemistry. Different disciplines may give

7581-425: The mesenteric lymph nodes where they present antigens to naive T-cells while also releasing the pro-inflammatory cytokines IL-12 and IL-23 which lead to T cell differentiation into Th1 and Th17 T-cells. IL-12 and IL-23 signaling is blocked by the biologic ustekinumab and IL-23 is blocked by guselkumab , mirikizumab and risankizumab , medications that are used in the treatment of ulcerative colitis. From

7714-572: The sacroiliac joint ( sacroiliitis ). It is estimated that around 50% of IBD patients suffer from migratory arthritis. Synovitis, or inflammation of the synovial fluid surrounding a joint, can occur for months and recur in later times but usually does not erode the joint. The symptoms of arthritis include joint pain , swelling, and effusion , and often leads to significant morbidity. Ankylosing spondylitis and sacroilitis usually occur independent of bowel disease activity in UC. Ulcerative colitis may affect

7847-455: The APCs release the cytokine TNFα which stimulates inflammatory signaling and recruits inflammatory cells to the intestines, leading to the inflammation that is characteristic of ulcerative colitis. The TNF inhibitors, including infliximab , adalimumab and golimumab , are used to inhibit this step during the treatment of ulcerative colitis. After phagocytosing the microbe, the APCs then enter

7980-722: The African butterfly Papilio dardanus , female morphs mimic a range of distasteful models called Batesian mimicry, often in the same region. The fitness of each type of mimic decreases as it becomes more common, so the polymorphism is maintained by frequency-dependent selection. Thus the efficiency of the mimicry is maintained in a much increased total population. However it can exist within one gender. Female-limited polymorphism and sexual assault avoidance Female-limited polymorphism in Papilio dardanus can be described as an outcome of sexual conflict. Cook et al. (1994) argued that

8113-481: The GI tract, chronic inflammation, and iron deficiency often leads to anemia , which can affect quality of life. The clinical presentation of ulcerative colitis depends on the extent of the disease process. Up to 15% of individuals may have severe disease upon initial onset of symptoms. A substantial proportion (up to 45%) of people with a history of UC without any ongoing symptoms (clinical remission) have objective evidence of ongoing inflammation. Ulcerative colitis

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8246-404: The activity of colitis. This so-called "backwash ileitis" can occur in 10–20% of people with pancolitis and is believed to be of little clinical significance. In addition to the extent of involvement, UC is also characterized by severity of disease. Severity of disease is defined by symptoms, objective markers of inflammation (endoscopic findings, blood tests), disease course, and the impact of

8379-409: The appendix at an early age may be protective. Diagnosis is typically by colonoscopy with tissue biopsies . Several medications are used to treat symptoms and bring about and maintain remission, including aminosalicylates such as mesalazine or sulfasalazine , steroids , immunosuppressants such as azathioprine , and biologic therapy . Removal of the colon by surgery may be necessary if

8512-407: The body outside the digestive system. A genetic component to the cause of UC can be hypothesized based on aggregation of UC in families, variation of prevalence between different ethnicities, genetic markers and linkages . In addition, the identical twin concordance rate is 10%, whereas the dizygotic twin concordance rate is only 3%. Between 8 and 14% of people with ulcerative colitis have

8645-416: The body, which may be quantified with serum inflammatory markers, such as CRP and ESR. However, elevated inflammatory markers are not specific for UC and elevations are commonly seen in other conditions, including infection. In addition, inflammatory markers are not uniformly elevated in people with ulcerative colitis. Twenty five percent of individuals with confirmed inflammation on endoscopic evaluation have

8778-521: The body. In the taxonomic nomenclature of zoology , the word "morpha" plus a Latin name for the morph can be added to a binomial or trinomial name. However, this invites confusion with geographically variant ring species or subspecies , especially if polytypic. Morphs have no formal standing in the ICZN . In botanical taxonomy , the concept of morphs is represented with the terms " variety ", " subvariety " and " form ", which are formally regulated by

8911-401: The bowel symptoms of ulcerative colitis develop. PSC does not parallel the onset, extent, duration, or activity of the colonic inflammation in ulcerative colitis. In addition, colectomy does not have an impact on the course of primary sclerosing cholangitis in individuals with UC. PSC is associated with an increased risk of colorectal cancer and cholangiocarcinoma (bile duct cancer). PSC is

9044-434: The colon ( megacolon ), inflammation of the eye, joints, or liver, and colon cancer . The cause of UC is unknown. Theories involve immune system dysfunction , genetics , changes in the normal gut bacteria , and environmental factors. Rates tend to be higher in the developed world with some proposing this to be the result of less exposure to intestinal infections , or to a Western diet and lifestyle. The removal of

9177-402: The colon. Commonly affected organs include: eyes, joints, skin, and liver. The frequency of such extraintestinal manifestations has been reported as between 6 and 47%. UC may affect the mouth. About 8% of individuals with UC develop oral manifestations. The two most common oral manifestations are aphthous stomatitis and angular cheilitis . Aphthous stomatitis is characterized by ulcers in

9310-453: The condition longer, may be more likely than population controls to be work handicapped or not engage in the labor market. Additionally, those with ankylosing spondylitis were more likely to have never married or been divorced. Compared to expectations, women with ankylosing spondylitis were less likely to have had children. People with ankylosing spondylitis experience up to 50% more sick leave episodes, an overall 8% loss of productivity, and

9443-483: The course of the illness. Usually, the other peripheral joints start to be affected later. Most frequently, there is an asymmetrical involvement of the lower extremities. Reactive arthritis is an aseptic arthritis caused by an infectious pathogen found outside the joint. Particularly affecting the joints in the lower limbs, the arthritis is usually oligoarticular. In most cases, the condition develops quickly; two to four joints may swell and hurt in an uneven manner within

9576-473: The descending colon). Proctosigmoiditis describes inflammation of the rectum and sigmoid colon. Pancolitis describes involvement of the entire colon, extending from the rectum to the cecum. While usually associated with Crohn's disease, ileitis (inflammation of the ileum) also occurs in UC. About 17% of individuals with UC have ileitis. Ileitis more commonly occurs in the setting of pancolitis (occurring in 20% of cases of pancolitis), and tends to correlate with

9709-406: The diagnosis of ulcerative colitis. If the fecal calprotectin is low, the likelihood of inflammatory bowel disease are less than 1 percent. Lactoferrin is an additional nonspecific marker of intestinal inflammation. Overall, imaging tests, such as x-ray or CT scan, may be helpful in assessing for complications of ulcerative colitis, such as perforation or toxic megacolon. Bowel ultrasound (US)

9842-426: The diagnostic evaluation of possible inflammatory bowel disease. Several stool tests may help quantify the extent of inflammation present in the colon and rectum. Fecal calprotectin is elevated in inflammatory conditions affecting the colon, and is useful in distinguishing irritable bowel syndrome (noninflammatory) from a flare in inflammatory bowel disease. Fecal calprotectin is 88% sensitive and 79% specific for

9975-553: The diet. As a result of a class-action lawsuit and community settlement with DuPont , three epidemiologists conducted studies on the population surrounding a chemical plant that was exposed to PFOA at levels greater than in the general population. The studies concluded that there was an association between PFOA exposure and six health outcomes, one of which being ulcerative colitis. Levels of sulfate-reducing bacteria tend to be higher in persons with ulcerative colitis, which could indicate higher levels of hydrogen sulfide in

10108-416: The disease include meat protein and alcoholic beverages. Specifically, sulfur has been investigated as being involved in the cause of ulcerative colitis, but this is controversial. Sulfur restricted diets have been investigated in people with UC and animal models of the disease. The theory of sulfur as an etiological factor is related to the gut microbiota and mucosal sulfide detoxification in addition to

10241-681: The disease is severe, does not respond to treatment, or if complications such as colon cancer develop. Removal of the colon and rectum generally cures the condition. People with ulcerative colitis usually present with diarrhea mixed with blood , of gradual onset that persists for an extended period of time (weeks). It is estimated that 90% of people experience rectal bleeding (of varying severity), 90% experience watery or loose stools with increased stool frequency (diarrhea), and 75-90% of people experience bowel urgency. Additional symptoms may include fecal incontinence, mucous rectal discharge, and nocturnal defecations. With proctitis (inflammation of

10374-773: The disease on day-to-day life. Most patients are categorized through endoscopy and fecal calprotectin levels. Indicators of low risk for future complications in mild and moderate UC include the following parameters: exhibiting less than 6 stools daily and lack of fever/weight loss. Other indicators include lack of extraintestinal symptoms, low levels of the inflammatory markers C-reactive protein (CRP), and erythrocyte sedimentation rate (ESR), and fecal calprotectin , and later age of diagnosis (over 40 years). Mild disease correlates with fewer than four stools daily; in addition, mild urgency and rectal bleeding may occur intermittently. Mild disease lacks systemic signs of toxicity (e.g. fever, chills, weight changes) and exhibits normal levels of

10507-400: The disease. The simple clinical colitis activity index was created in 1998 and is used to assess the severity of symptoms. The best test for diagnosis of ulcerative colitis remains endoscopy , which is examination of the internal surface of the bowel using a flexible camera. Initially, a flexible sigmoidoscopy may be completed to establish the diagnosis. The physician may elect to limit

10640-479: The disorder is influenced by multiple genes. For example, chromosome band 1p36 is one such region thought to be linked to inflammatory bowel disease. Some of the putative regions encode transporter proteins such as OCTN1 and OCTN2 . Other potential regions involve cell scaffolding proteins such as the MAGUK family . Human leukocyte antigen associations may even be at work. In fact, this linkage on chromosome 6 may be

10773-492: The effects vary depending on how long the disease has been present. People's health improves when they engage in back exercises five days a week and recreational activity for at least half an hour each day. NSAIDs continue to be the first line of treatment for spondylitis , and many people will get adequate symptom relief on their own with just these medications. The best NSAID for treating those with ankylosing spondylitis appears to be tolmetin or indomethacin , although there

10906-404: The evolutionary process. Since all polymorphism has a genetic basis, genetic polymorphism has a particular meaning: The definition has three parts: a) sympatry : one interbreeding population; b) discrete forms; and c) not maintained just by mutation. In simple words, the term polymorphism was originally used to describe variations in shape and form that distinguish normal individuals within

11039-443: The evolutionary synthesis, such as Stebbins and Dobzhansky , though the latter was slow to change. Kimura drew a distinction between molecular evolution , which he saw as dominated by selectively neutral mutations, and phenotypic characters, probably dominated by natural selection rather than drift. Ulcerative colitis Ulcerative colitis ( UC ) is one of the two types of inflammatory bowel disease (IBD), with

11172-428: The extent of the initial exam if severe colitis is encountered to minimize the risk of perforation of the colon. However, a complete colonoscopy with entry into the terminal ileum should be performed to rule out Crohn's disease, and assess extent and severity of disease. Endoscopic findings in ulcerative colitis include: erythema (redness of the mucosa ), friability of the mucosa, superficial ulceration, and loss of

11305-433: The field: And in the laboratory: Without proper field-work, the significance of the polymorphism to the species is uncertain and without laboratory breeding the genetic basis is obscure. Even with insects, the work may take many years; examples of Batesian mimicry noted in the nineteenth century are still being researched. Polymorphism was crucial to research in ecological genetics by E. B. Ford and his co-workers from

11438-487: The first hypothesis, HLA-B27 heavy chains devoid of β2 microglobulin can form disulphide -linked homodimers that are produced at the cell surface and can be recognized directly by KIR3DL2 killer immunoglobulin -like receptors, regardless of the associated peptide . According to the second hypothesis, the B pocket's Cys 67 residue causes HLA-B27 heavy-chain misfolding in the endoplasmic reticulum before assembling into complexes with peptide and β2 microglobulin . As

11571-401: The following three findings: If the person meets the previous requirements, they must exhibit at least one of Group A's spondyloarthritis features or two of Group B's spondyloarthritis features. Group A spondyloarthritis features: Group B spondyloarthritis features: Improving the persons's state (pain, functional impairment, etc.) and preventing further clinical deterioration are

11704-567: The general population will develop ankylosing spondylitis , the correlation between HLA-B27 and the prevalence of spondyloarthritis is weak. Therefore, the illness prevalence in a particular population must be taken into account when interpreting results from HLA-B27 testing. Spondyloarthritis is classified into two categories based on the Assessment of SpondyloArthritis International Society (ASAS) classification criteria: primarily axial involvement and predominantly peripheral manifestations. A person must meet two requirements to be considered for

11837-724: The genes start on the same chromosome. They argue that supergenes arose in situ . This is known as Turner's sieve hypothesis. John Maynard Smith agreed with this view in his authoritative textbook, but the question is still not definitively settled. Selection, whether natural or artificial, changes the frequency of morphs within a population; this occurs when morphs reproduce with different degrees of success. A genetic (or balanced) polymorphism usually persists over many generations, maintained by two or more opposed and powerful selection pressures. Diver (1929) found banding morphs in Cepaea nemoralis could be seen in prefossil shells going back to

11970-413: The genotype, such as single nucleotide polymorphisms that may not always correspond to a phenotype, but always corresponds to a branch in the genetic tree. See below . Polymorphism is common in nature; it is related to biodiversity , genetic variation , and adaptation . Polymorphism usually functions to retain a variety of forms in a population living in a varied environment. The most common example

12103-479: The goals of spondyloarthritis treatment. The ASAS has issued guidelines regarding the use of TNF blockers specifically as well as the general care of spondyloarthritis. Non-steroidal anti-inflammatory drugs (NSAIDs) should be administered first to those with active, primarily axial signs of spondyloarthritis. If NSAID medication is contraindicated, does not work, or causes side effects, people are then treated with tumor necrosis factor (TNF) blockers . Because there

12236-741: The gut inflammation observed in Crohn's disease and ankylosing spondylitis . It is known that, in comparison to healthy controls, people with ankylosing spondylitis and those related to them have higher intestinal permeability. The majority of organisms responsible for reactive arthritis are gastrointestinal pathogens, such as Shigella flexneri , Clostridioides difficile , Yersinia enterocolitica and Yersinia pseudotuberculosis , Campylobacter jejuni and Campylobacter coli , and Salmonella spp . Genitourinary and respiratory infections, such as Chlamydia trachomatis and Chlamydia pneumoniae , have also been linked to reactive arthritis. Given

12369-411: The hands and feet are very beneficial. Seventy-five percent of those with psoriatic arthritis have radiographic abnormalities of the peripheral joints, such as soft tissue swelling, erosions, periarticular osteopenia , periostitis , and narrowing of the joint space. Aggressive psoriatic arthritis erosions can result in the articular surface of the proximal bone of the joint being destroyed and taking on

12502-484: The inflammation of ulcerative colitis is limited to the mucosa. Blood and stool tests serve primarily to assess disease severity, level of inflammation and rule out causes of infectious colitis. All individuals with suspected ulcerative colitis should have stool testing to rule out infection. A complete blood count may demonstrate anemia, leukocytosis, or thrombocytosis. Anemia may be caused by inflammation or bleeding. Chronic blood loss may lead to iron deficiency as

12635-415: The interior portion of the eye, leading to uveitis and iritis . Uveitis can cause blurred vision and eye pain, especially when exposed to light ( photophobia ). Untreated, uveitis can lead to permanent vision loss. Inflammation may also involve the white part of the eye ( sclera ) or the overlying connective tissue ( episclera ), causing conditions called scleritis and episcleritis . Ulcerative colitis

12768-468: The intestinal epithelium and phagocytose (engulf and destroy) pathogenic microorganisms and present parts of the microorganism as antigens to T-cells to stimulate differentiation and activation of the T-cells. However, in ulcerative colitis, aberrant activity of dendritic cells and macrophages results in them phagocytosing bacteria of the normal gut microbiome. After ingesting the microbiome bacterium,

12901-486: The intestine. An alternative theory suggests that the symptoms of the disease may be caused by toxic effects of the hydrogen sulfide on the cells lining the intestine. Infection by Mycobacterium avium , subspecies paratuberculosis , has been proposed as the ultimate cause of both ulcerative colitis and Crohn's disease. An increased amount of colonic sulfate-reducing bacteria has been observed in some people with ulcerative colitis, resulting in higher concentrations of

13034-444: The jaguar has only one possible trait for that gene, it would be termed "monomorphic". For example, if there was only one possible skin colour that a jaguar could have, it would be termed monomorphic. The term polyphenism can be used to clarify that the different forms arise from the same genotype . Genetic polymorphism is a term used somewhat differently by geneticists and molecular biologists to describe certain mutations in

13167-448: The last quarter of the 20th century when ideas such as Kimura 's neutral theory of molecular evolution was given much attention. The significance of the work on ecological genetics is that it has shown how important selection is in the evolution of natural populations, and that selection is a much stronger force than was envisaged even by those population geneticists who believed in its importance, such as Haldane and Fisher . In just

13300-411: The liver), and various changes in electrolytes. As discussed previously, UC patients often also display elevated alkaline phosphatase. Inflammation in the intestine may also cause higher levels of fecal calprotectin or lactoferrin. Specific testing may include the following: Although ulcerative colitis is a disease of unknown causation, inquiry should be made as to unusual factors believed to trigger

13433-469: The look of a "pencil in cup." Laboratory abnormalities in spondyloarthritis are nonspecific and less effective for diagnosing a specific disease than clinical presentation. Normochromic normocytic anemia , increased C reactive protein , and erythrocyte sedimentation rate are frequently present nonspecific indicators. Testing for the human leukocyte antigen (HLA) can be the most beneficial laboratory investigation. Since only 5% of those with HLA-B27 in

13566-457: The lower legs can be a sign of deep venous thrombosis , while difficulty breathing may be a result of pulmonary embolism (blood clots in the lungs). The risk of blood clots is about threefold higher in individuals with IBD. The risk of venous thromboembolism is high in ulcerative colitis due to hypercoagulability from inflammation, especially with active or extensive disease. Additional risk factors may include surgery, hospitalization, pregnancy,

13699-424: The lower limbs, are the most common symptoms. Another distinguishing characteristic is enthesitis , which is inflammation at the locations where ligaments , tendons , or joint capsules adhere to bone. Inflammatory back pain associated with ankylosing spondylitis usually starts slowly, has a dull feel to it, and spreads into the gluteal areas. Back pain has a nocturnal component, gets better with movement, and

13832-415: The lymphatic venules by blocking binding to MAdCAM-1. While the medications ozanimod and etrasimod inhibit the sphingosine-1-phosphate receptor to prevent T-cell migration into the efferent lymphatic venules. Once the mature Th1 and Th17 T-cells exit the efferent lymphatic venule, they travel to the intestinal mucosa and cause further inflammation. T-cell mediated inflammation is thought to be driven by

13965-574: The male-like phenotype in some females in P. dardanus population on Pemba Island, Tanzania functions to avoid detection from a mate-searching male. The researchers found that male mate preference is controlled by frequency-dependent selection, which means that the rare morph suffers less from mating attempt than the common morph. The reasons why females try to avoid male sexual harassment are that male mating attempt can reduce female fitness in many ways such as fecundity and longevity. The mechanism which decides which of several morphs an individual displays

14098-430: The mesenteric lymph node, the T-cells then enter the intestinal lymphatic venule which provides transport to the intestinal epithelium where they mediate further inflammation characteristic of ulcerative colitis. The T-cells exit the lymphatic venule via the adhesion protein mucosal vascular addressin cell adhesion molecule 1 MAdCAM-1 , the ulcerative colitis biologic treatment vedolizumab inhibits T-cell migration out of

14231-416: The mid-1920s to the 1970s (similar work continues today, especially on mimicry ). The results had a considerable effect on the mid-century evolutionary synthesis , and on present evolutionary theory . The work started at a time when natural selection was largely discounted as the leading mechanism for evolution, continued through the middle period when Sewall Wright 's ideas on drift were prominent, to

14364-413: The most convincing and consistent of the genetic candidates. Multiple autoimmune disorders are associated with ulcerative colitis, including celiac disease , psoriasis , lupus erythematosus , rheumatoid arthritis , episcleritis , and scleritis . Ulcerative colitis is also associated with acute intermittent porphyria . Many hypotheses have been raised for environmental factors contributing to

14497-458: The mouth, which are benign, noncontagious and often recurrent. Angular chelitis is characterized by redness at the corners of the mouth, which may include painful sores or breaks in the skin. Very rarely, benign pustules may occur in the mouth (pyostomatitis vegetans). UC may affect the eyes manifesting in scleritis, iritis, and conjunctivitis. Patients may be asymptomatic or experience redness, burning, or itching in eyes. Inflammation may occur in

14630-402: The mucosa are taken during endoscopy to confirm the diagnosis of UC and differentiate it from Crohn's disease, which is managed differently clinically. Histologic findings in ulcerative colitis includes: distortion of crypt architecture, crypt abscesses, and inflammatory cells in the mucosa (lymphocytes, plasma cells, and granulocytes). Unlike the transmural inflammation seen in Crohn's disease,

14763-493: The onset of inflammatory back pain and the development of radiographic sacroiliitis. Criteria for the early diagnosis of axial spondyloarthritis have been developed in light of the emergence of effective treatments. These criteria consider the added value of HLA-B27 testing, as well as current advancements in MRI scanning. Imaging is crucial to the spondyloarthritis diagnosis process. The most distinctive radiographic observation

14896-511: The other type being Crohn's disease . It is a long-term condition that results in inflammation and ulcers of the colon and rectum . The primary symptoms of active disease are abdominal pain and diarrhea mixed with blood ( hematochezia ). Weight loss , fever , and anemia may also occur. Often, symptoms come on slowly and can range from mild to severe. Symptoms typically occur intermittently with periods of no symptoms between flares. Complications may include abnormal dilation of

15029-493: The pathogenesis of ulcerative colitis, including diet , breastfeeding and medications. Breastfeeding may have a protective effect in the development of ulcerative colitis. One study of isotretinoin found a small increase in the rate of UC. As the colon is exposed to many dietary substances which may encourage inflammation , dietary factors have been hypothesized to play a role in the pathogenesis of both ulcerative colitis and Crohn's disease. However, research does not show

15162-471: The pathway. An unrelated study suggested that the sulfur contained in red meats and alcohol may lead to an increased risk of relapse for people in remission. Other proposed mechanisms driving the pathophysiology of ulcerative colitis involve an abnormal immune response to the normal gut microbiota . This involves abnormal activity of antigen presenting cells (APCs) including dendritic cells and macrophages . Normally, dendritic cells and macrophages patrol

15295-427: The population of some alternative alleles at the locus or loci involved. Only if competing selection disappears will an allele disappear. However, heterozygote advantage is not the only way a polymorphism can be maintained. Apostatic selection , whereby a predator consumes a common morph whilst overlooking rarer morphs is possible and does occur. This would tend to preserve rarer morphs from extinction. Polymorphism

15428-417: The prevalence is about 0.1%. Inflammatory bowel disease about 400 Caucasians per 100,000 people, with a male–to–female ratio of 1:1. People of Asian and African ancestry rarely experience it. Varying reports have varying risks for spondylitis and peripheral arthritis, which may be related to the observer's specialty. 15% to 20% of people with inflammatory bowel disease have spondylitis. Peripheral arthritis

15561-504: The prognosis for juvenile spondyloarthritisis is unknown. According to the data available, children who have had a condition for longer than five years are more likely to be impaired. After five years of the illness, the chance of remission was only 17 percent. After ten years of the condition, moderate to severe restriction affects around 60% of children with juvenile spondyloarthritis. The prevalence of ankylosing spondylitis and spondyloarthritis in particular varies across populations and

15694-479: The prognosis for reactive arthritis is generally favourable. Within six months of onset, the majority of cases seem to resolve. The prognosis for psoriatic arthritis is worse than previously thought, according to recent research. It has also been demonstrated that those with psoriatic arthritis have a higher mortality rate, which is linked to high erythrocyte sedimentation rate , high usage of medications, and early radiographic damage. While not well researched,

15827-439: The question of whether the component genes in a super-gene could have started off on separate chromosomes, with subsequent reorganization, or if it is necessary for them to start on the same chromosome. Originally, it was held that chromosome rearrangement would play an important role. This explanation was accepted by E. B. Ford and incorporated into his accounts of ecological genetics. However, many believe it more likely that

15960-437: The reader's background, and variations in sacroiliac anatomy. A challenge associated with radiographic imaging is the typical ten-year lag between the beginning of inflammatory back pain and the development of radiographic sacroiliitis . MRI imaging of the spine and entheses has made it possible to distinguish between inflammatory spinal lesions associated with ankylosing spondylitis and those unrelated to it earlier than

16093-624: The rectum), people with UC may experience urgency or rectal tenesmus , which is the urgent desire to evacuate the bowels but with the passage of little stool. Tenesmus may be misinterpreted as constipation , due to the urge to defecate despite small volume of stool passage. Bloody diarrhea and abdominal pain may be more prominent features in severe disease. The severity of abdominal pain with UC varies from mild discomfort to very painful bowel movements and abdominal cramping. High frequency of bowel movements, weight loss, nausea, fatigue, and fever are also common during disease flares. Chronic bleeding from

16226-481: The rectum, with involvement extending proximally (to sigmoid colon , ascending colon, etc.). In contrast, inflammation with Crohn's disease is often patchy, with so-called "skip lesions" (intermittent regions of inflamed bowel). The disease is classified by the extent of involvement, depending on how far the disease extends: proctitis (rectal inflammation), left sided colitis (inflammation extending to descending colon), and extensive colitis (inflammation proximal to

16359-476: The same chromosome . Both pleiotropism and epistasis show that a gene need not relate to a character in the simple manner that was once supposed. Although a polymorphism can be controlled by alleles at a single locus (e.g. human ABO blood groups), the more complex forms are controlled by supergenes consisting of several tightly linked genes on a single chromosome . Batesian mimicry in butterflies and heterostyly in angiosperms are good examples. There

16492-458: The same concept different names, and different concepts may be given the same name. For example, there are the terms established in ecological genetics by E.B. Ford (1975), and for classical genetics by John Maynard Smith (1998). The shorter term morphism was preferred by the evolutionary biologist Julian Huxley (1955). Various synonymous terms exist for the various polymorphic forms of an organism. The most common are morph and morpha, while

16625-424: The same habitat at the same time and belong to a panmictic population (one with random mating). Put simply, polymorphism is when there are two or more possibilities of a trait on a gene. For example, there is more than one possible trait in terms of a jaguar's skin colouring; they can be light morph or dark morph. Due to having more than one possible variation for this gene, it is termed 'polymorphism'. However, if

16758-446: The serum inflammatory markers ESR and CRP. Moderate to severe disease correlates with more than six stools daily, frequent bloody stools and urgency. Moderate abdominal pain, low-grade fever , 38 to 39 °C (100 to 102 °F), and anemia may develop. ESR and CRP are usually elevated. The Mayo Score, which incorporates a combination of clinical symptoms (stool frequency and amount of rectal bleeding) with endoscopic findings and

16891-494: The sex: alligators are a famous case in point. In ants the distinction between workers and guards is environmental, by the feeding of the grubs. Polymorphism with an environmental trigger is called polyphenism . The polyphenic system does have a degree of environmental flexibility not present in the genetic polymorphism. However, such environmental triggers are the less common of the two methods. Investigation of polymorphism requires use of both field and laboratory techniques. In

17024-475: The skin. The most common type of skin manifestation, erythema nodosum , presents in up to 3% of UC patients. It develops as raised, tender red nodules usually appearing on the outer areas of the arms or legs, especially in the anterior tibial area (shins). The nodules have diameters that measure approximately 1–5 cm. Erythema nodosum is due to inflammation of the underlying subcutaneous tissue ( panniculitis ), and biopsy will display focal panniculitis (although

17157-416: The switch mechanism that determines which morph is shown is environmental. In genetic polymorphism, the genetic makeup determines the morph. The term polymorphism also refers to the occurrence of structurally and functionally more than two different types of individuals, called zooids , within the same organism. It is a characteristic feature of cnidarians . For example, Obelia has feeding individuals,

17290-444: The toxic gas hydrogen sulfide. Human colonic mucosa is maintained by the colonic epithelial barrier and immune cells in the lamina propria (see intestinal mucosal barrier ). The short-chain fatty acid n -butyrate gets oxidized through the beta oxidation pathway into carbon dioxide and ketone bodies. It has been shown that n -butyrate helps supply nutrients to this epithelial barrier. Studies have proposed that hydrogen sulfide plays

17423-480: The use of corticosteroids and tofacitinib, a JAK inhibitor. Osteoporosis may occur related to systemic inflammation or prolonged steroid use in the treatment of UC, which increases the risk of bone fractures. Clubbing , a deformity of the ends of the fingers, may occur. Amyloidosis may occur, especially with severe and poorly controlled disease, which usually presents with protein in the urine ( proteinuria ) and nephritic syndrome . Ulcerative colitis (UC) has

17556-469: The vascular appearance of the colon. When present, ulcerations may be confluent. Pseudopolyps may be observed. Ulcerative colitis is usually continuous from the rectum, with the rectum almost universally being involved. Perianal disease is rare. The degree of involvement endoscopically ranges from proctitis (rectal inflammation) to left sided colitis (extending to descending colon), to extensive colitis (extending proximal to descending colon). Biopsies of

17689-681: The well-established familial aggregation and the concordance rate of up to 63% in identical twins (vs 23% in nonidentical twins), it is evident that genetic variables play a role in the susceptibility to ankylosing spondylitis . There is limited research on familial aggregation in other forms of spondyloarthritis. HLA-B27 is a polymorphic form of the HLA-B molecule found in up to 95% of people with ankylosing spondylitis of European ancestry, 70% with reactive arthritis , 60% with psoriatic spondylitis , 25% with peripheral psoriatic arthritis , and 70% with spondylitis associated with inflammatory bowel disease . The arthritogenic-peptide theory

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