Inflammatory bowel disease
Encyclopedia
In medicine
, inflammatory bowel disease (IBD) is a group of inflammatory
conditions of the colon
and small intestine
. The major types of IBD are Crohn's disease
and ulcerative colitis
.
and ulcerative colitis
(UC).
Accounting for far fewer cases are other forms of IBD, which are not always classified as typical IBD:
The main difference between Crohn's disease and UC is the location and nature of the inflammatory changes. Crohn's can affect any part of the gastrointestinal tract
, from mouth
to anus
(skip lesions), although a majority of the cases start in the terminal ileum
. Ulcerative colitis, in contrast, is restricted to the colon
and the rectum.
Microscopically, ulcerative colitis is restricted to the mucosa (epithelial lining
of the gut), while Crohn's disease affects the whole bowel wall ("transmural lesions").
Finally, Crohn's disease and ulcerative colitis present with extra-intestinal manifestations (such as liver problems, arthritis, skin manifestations and eye problems) in different proportions.
Rarely, a definitive diagnosis of neither Crohn's disease nor ulcerative colitis can be made because of idiosyncrasies in the presentation. In this case, a diagnosis of indeterminate colitis may be made. Although a recognised definition, not all centres refer to this.
, diarrhea
, rectal bleeding
, severe internal cramps/muscle spasms in the region of the pelvis, weight loss
and various associated complaints or diseases like arthritis
, pyoderma gangrenosum
, and primary sclerosing cholangitis
. Diagnosis is generally by colonoscopy
with biopsy
of pathological lesions.
is more useful in ulcerative colitis
than in Crohn's disease
. Generally, depending on the level of severity, IBD may require immunosuppression
to control the symptom, such as prednisone
, TNF inhibition
, azathioprine
(Imuran), methotrexate
, or 6-mercaptopurine. More commonly, treatment of IBD requires a form of mesalazine
. Often, steroid
s are used to control disease flares and were once acceptable as a maintenance drug. In use for several years in Crohn's disease patients and recently in patients with ulcerative colitis, biologicals
have been used such as TNF inhibitors. Severe cases may require surgery
, such as bowel resection
, strictureplasty
or a temporary or permanent colostomy
or ileostomy
. Alternative medicine
treatments for bowel disease exist in various forms, however such methods concentrate on controlling underlying pathology in order to avoid prolonged steroidal exposure or surgical excisement.
Usually the treatment is started by administering drugs with high anti-inflammatory effects, such as prednisone. Once the inflammation is successfully controlled, the patient is usually switched to a lighter drug to keep the disease in remission, such as Asacol, a mesalazine
. If unsuccessful, a combination of the aforementioned immunosuppression drugs with a mesalazine
(which may also have an anti-inflammatory effect) may or may not be administered, depending on the patient.
Histoplasma produces toxins that cause intestinal disease called histoplasmosis that is a “serious consideration” in an immunocompromised patient with signs and symptoms of IBD. Antifungal drugs such as nystatin
(a broad spectrum gut antifungal) and either itraconazole (Sporanox) or fluconazole (Diflucan) have been suggested as a treatment for IBD disorders such as Crohn’s disease and ulcerative colitis
that all share the same symptoms such as diarrhea, weight loss, fever, and abdominal pain.
, bowel perforation and surgical complications are also rare.
While patients of IBD do have an increased risk of colorectal cancer
, this is usually caught much earlier than the general population in routine surveillance of the colon by colonoscopy, and therefore patients are much more likely to survive.
New evidence suggests that patients with IBD may have an elevated risk of endothelial dysfunction and coronary artery disease
The goal of treatment is toward achieving remission, after which the patient is usually switched to a lighter drug with fewer potential side effects. Every so often, an acute resurgence of the original symptoms may appear; this is known as a "flare-up". Depending on the circumstances, it may go away on its own or require medication. The time between flare-ups may be anywhere from weeks to years, and varies wildly between patients - a few have never experienced a flare-up.
Initial reports suggest that "helminthic therapy
" may not only prevent but even control IBD: a drink with roughly 2,500 ova of the Trichuris suis
helminth taken twice monthly decreased symptoms markedly in many patients. It is even speculated that an effective "immunization" procedure could be developed—by ingesting the cocktail at an early age.
Prebiotics and probiotics are showing increasing promise as treatments for IBD and in some studies have proven to be as effective as prescription drugs.
In 2005 New Scientist
published a joint study by Bristol University and the University of Bath
on the apparent healing power of cannabis
on IBD. Reports that cannabis eased IBD symptoms indicated the possible existence of cannabinoid receptors in the intestinal lining, which respond to molecules in the plant-derived chemicals. CB1 cannabinoid receptors – which are known to be present in the brain – exist in the endothelial cells which line the gut, it is thought that they are involved in repairing the lining of the gut when damaged. The team deliberately damaged the cells to cause inflammation of the gut lining and then added synthetically produced cannabinoids; the result was that gut started to heal: the broken cells were repaired and brought back closer together to mend the tears. It is believed that in a healthy gut, natural endogenous cannabinoids are released from endothelial cells when they are injured, which then bind to the CB1 receptors. The process appears to set off a wound-healing reaction, and when people use cannabis, the cannabinoids bind to these receptors in the same way. Previous studies have shown that CB1 receptors located on the nerve cells in the gut respond to cannabinoids by slowing gut motility, therefore reducing the painful muscle contractions associated with diarrhoea. The team also discovered another cannabinoid receptor, CB2, in the guts of IBD sufferers, which was not present in healthy guts. These receptors, which also respond to chemicals in cannabis, appear to be associated with apoptosis – programmed cell death – and may have a role in suppressing the overactive immune system and reducing inflammation by mopping up excess cells.
Medicine
Medicine is the science and art of healing. It encompasses a variety of health care practices evolved to maintain and restore health by the prevention and treatment of illness....
, inflammatory bowel disease (IBD) is a group of inflammatory
Inflammation
Inflammation is part of the complex biological response of vascular tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. Inflammation is a protective attempt by the organism to remove the injurious stimuli and to initiate the healing process...
conditions of the colon
Colon (anatomy)
The colon is the last part of the digestive system in most vertebrates; it extracts water and salt from solid wastes before they are eliminated from the body, and is the site in which flora-aided fermentation of unabsorbed material occurs. Unlike the small intestine, the colon does not play a...
and small intestine
Small intestine
The small intestine is the part of the gastrointestinal tract following the stomach and followed by the large intestine, and is where much of the digestion and absorption of food takes place. In invertebrates such as worms, the terms "gastrointestinal tract" and "large intestine" are often used to...
. The major types of IBD are Crohn's disease
Crohn's disease
Crohn's disease, also known as regional enteritis, is a type of inflammatory bowel disease that may affect any part of the gastrointestinal tract from mouth to anus, causing a wide variety of symptoms...
and ulcerative colitis
Ulcerative colitis
Ulcerative colitis is a form of inflammatory bowel disease . Ulcerative colitis is a form of colitis, a disease of the colon , that includes characteristic ulcers, or open sores. The main symptom of active disease is usually constant diarrhea mixed with blood, of gradual onset...
.
Classification
The main forms of IBD are Crohn's diseaseCrohn's disease
Crohn's disease, also known as regional enteritis, is a type of inflammatory bowel disease that may affect any part of the gastrointestinal tract from mouth to anus, causing a wide variety of symptoms...
and ulcerative colitis
Ulcerative colitis
Ulcerative colitis is a form of inflammatory bowel disease . Ulcerative colitis is a form of colitis, a disease of the colon , that includes characteristic ulcers, or open sores. The main symptom of active disease is usually constant diarrhea mixed with blood, of gradual onset...
(UC).
Accounting for far fewer cases are other forms of IBD, which are not always classified as typical IBD:
- Collagenous colitisCollagenous colitisCollagenous colitis is an inflammatory colonic disease with peak incidence in the 5th decade of life, affecting women more than men. Its clinical presentation involves watery diarrhea, usually in the absence of rectal bleeding...
- Lymphocytic colitisLymphocytic colitisLymphocytic colitis, a subtype of microscopic colitis, is a rare condition characterized by chronic non-bloody watery diarrhea. The colonoscopy is normal but the mucosal biopsy reveals an accumulation of lymphocytes in the colonic epithelium and connective tissue...
- Ischaemic colitis
- Diversion colitisDiversion colitisDiversion colitis is an inflammation of the colon which can occur as a complication of ileostomy or colostomy, often occurring within the year following the surgery. It can also occur in a neovagina created by colovaginoplasty, sometimes several years after the original procedure...
- Behçet's diseaseBehçet's diseaseBehçet's disease is a rare immune-mediated systemic vasculitis that often presents with mucous membrane ulceration and ocular involvements...
- Indeterminate colitis
The main difference between Crohn's disease and UC is the location and nature of the inflammatory changes. Crohn's can affect any part of the gastrointestinal tract
Gastrointestinal tract
The human gastrointestinal tract refers to the stomach and intestine, and sometimes to all the structures from the mouth to the anus. ....
, from mouth
Mouth
The mouth is the first portion of the alimentary canal that receives food andsaliva. The oral mucosa is the mucous membrane epithelium lining the inside of the mouth....
to anus
Anus
The anus is an opening at the opposite end of an animal's digestive tract from the mouth. Its function is to control the expulsion of feces, unwanted semi-solid matter produced during digestion, which, depending on the type of animal, may be one or more of: matter which the animal cannot digest,...
(skip lesions), although a majority of the cases start in the terminal ileum
Terminal ileum
The terminal ileum is the most distal part of the small intestine. It connects to the cecum, the pouch between the small and the large intestine, via the ileocecal valve.-Pathology of the terminal ileum:...
. Ulcerative colitis, in contrast, is restricted to the colon
Colon (anatomy)
The colon is the last part of the digestive system in most vertebrates; it extracts water and salt from solid wastes before they are eliminated from the body, and is the site in which flora-aided fermentation of unabsorbed material occurs. Unlike the small intestine, the colon does not play a...
and the rectum.
Microscopically, ulcerative colitis is restricted to the mucosa (epithelial lining
Epithelium
Epithelium is one of the four basic types of animal tissue, along with connective tissue, muscle tissue and nervous tissue. Epithelial tissues line the cavities and surfaces of structures throughout the body, and also form many glands. Functions of epithelial cells include secretion, selective...
of the gut), while Crohn's disease affects the whole bowel wall ("transmural lesions").
Finally, Crohn's disease and ulcerative colitis present with extra-intestinal manifestations (such as liver problems, arthritis, skin manifestations and eye problems) in different proportions.
Rarely, a definitive diagnosis of neither Crohn's disease nor ulcerative colitis can be made because of idiosyncrasies in the presentation. In this case, a diagnosis of indeterminate colitis may be made. Although a recognised definition, not all centres refer to this.
Signs and symptoms
Although very different diseases, both may present with any of the following symptoms: abdominal pain, vomitingVomiting
Vomiting is the forceful expulsion of the contents of one's stomach through the mouth and sometimes the nose...
, diarrhea
Diarrhea
Diarrhea , also spelled diarrhoea, is the condition of having three or more loose or liquid bowel movements per day. It is a common cause of death in developing countries and the second most common cause of infant deaths worldwide. The loss of fluids through diarrhea can cause dehydration and...
, rectal bleeding
Rectal bleeding
Rectal bleeding can refer to:* Lower gastrointestinal bleeding* Hematochezia* Fecal occult blood* Melena...
, severe internal cramps/muscle spasms in the region of the pelvis, weight loss
Weight loss
Weight loss, in the context of medicine, health or physical fitness, is a reduction of the total body mass, due to a mean loss of fluid, body fat or adipose tissue and/or lean mass, namely bone mineral deposits, muscle, tendon and other connective tissue...
and various associated complaints or diseases like arthritis
Arthritis
Arthritis is a form of joint disorder that involves inflammation of one or more joints....
, pyoderma gangrenosum
Pyoderma gangrenosum
Pyoderma gangrenosum is a disease that causes tissue to become necrotic, causing deep ulcers that usually occur on the legs. When they occur, they can lead to chronic wounds. Ulcers usually initially look like small bug bites or papules, and they progress to larger ulcers. Though the wounds...
, and primary sclerosing cholangitis
Primary sclerosing cholangitis
Primary sclerosing cholangitis is a chronic liver disease caused by progressive inflammation and scarring of the bile ducts of the liver. The inflammation impedes the flow of bile to the gut, which can ultimately lead to liver cirrhosis, liver failure and liver cancer...
. Diagnosis is generally by colonoscopy
Colonoscopy
Colonoscopy is the endoscopic examination of the large bowel and the distal part of the small bowel with a CCD camera or a fiber optic camera on a flexible tube passed through the anus. It may provide a visual diagnosis and grants the opportunity for biopsy or removal of suspected...
with biopsy
Biopsy
A biopsy is a medical test involving sampling of cells or tissues for examination. It is the medical removal of tissue from a living subject to determine the presence or extent of a disease. The tissue is generally examined under a microscope by a pathologist, and can also be analyzed chemically...
of pathological lesions.
Treatment
Optimal treatment of inflammatory bowel disease depends on what form it consists of. For example, mesalazineMesalazine
Mesalazine , also known as Mesalamine or 5-aminosalicylic acid , is an anti-inflammatory drug used to treat inflammation of the digestive tract ulcerative colitis and mild-to-moderate Crohn's disease...
is more useful in ulcerative colitis
Ulcerative colitis
Ulcerative colitis is a form of inflammatory bowel disease . Ulcerative colitis is a form of colitis, a disease of the colon , that includes characteristic ulcers, or open sores. The main symptom of active disease is usually constant diarrhea mixed with blood, of gradual onset...
than in Crohn's disease
Crohn's disease
Crohn's disease, also known as regional enteritis, is a type of inflammatory bowel disease that may affect any part of the gastrointestinal tract from mouth to anus, causing a wide variety of symptoms...
. Generally, depending on the level of severity, IBD may require immunosuppression
Immunosuppression
Immunosuppression involves an act that reduces the activation or efficacy of the immune system. Some portions of the immune system itself have immuno-suppressive effects on other parts of the immune system, and immunosuppression may occur as an adverse reaction to treatment of other...
to control the symptom, such as prednisone
Prednisone
Prednisone is a synthetic corticosteroid drug that is particularly effective as an immunosuppressant drug. It is used to treat certain inflammatory diseases and some types of cancer, but has significant adverse effects...
, TNF inhibition
TNF inhibitor
Tumor necrosis factor promotes the inflammatory response, which in turn causes many of the clinical problems associated with autoimmune disorders such as rheumatoid arthritis, ankylosing spondylitis, Crohn's disease, psoriasis, hidradenitis suppurativa and refractory asthma. These disorders are...
, azathioprine
Azathioprine
Azathioprine is a purine analogue immunosuppressive drug. It is used to prevent organ rejection following organ transplantation and to treat a vast array of autoimmune diseases, including rheumatoid arthritis, pemphigus, inflammatory bowel disease , multiple sclerosis, autoimmune hepatitis, atopic...
(Imuran), methotrexate
Methotrexate
Methotrexate , abbreviated MTX and formerly known as amethopterin, is an antimetabolite and antifolate drug. It is used in treatment of cancer, autoimmune diseases, ectopic pregnancy, and for the induction of medical abortions. It acts by inhibiting the metabolism of folic acid. Methotrexate...
, or 6-mercaptopurine. More commonly, treatment of IBD requires a form of mesalazine
Mesalazine
Mesalazine , also known as Mesalamine or 5-aminosalicylic acid , is an anti-inflammatory drug used to treat inflammation of the digestive tract ulcerative colitis and mild-to-moderate Crohn's disease...
. Often, steroid
Steroid
A steroid is a type of organic compound that contains a characteristic arrangement of four cycloalkane rings that are joined to each other. Examples of steroids include the dietary fat cholesterol, the sex hormones estradiol and testosterone, and the anti-inflammatory drug dexamethasone.The core...
s are used to control disease flares and were once acceptable as a maintenance drug. In use for several years in Crohn's disease patients and recently in patients with ulcerative colitis, biologicals
Biological therapy for inflammatory bowel disease
Biological therapy refers to the use of medication that is tailored to specifically target an immune or genetic mediator of disease. Even for diseases of unknown cause, molecules that are involved in the disease process have been identified, and can be targeted for biological therapy; many of...
have been used such as TNF inhibitors. Severe cases may require surgery
Surgery
Surgery is an ancient medical specialty that uses operative manual and instrumental techniques on a patient to investigate and/or treat a pathological condition such as disease or injury, or to help improve bodily function or appearance.An act of performing surgery may be called a surgical...
, such as bowel resection
Bowel resection
A bowel resection is a surgical procedure in which a part of the large or small intestine is removed. It may be performed due to cancer, necrosis, enteritis, diverticular disease, or a block in the intestine due to scar tissue...
, strictureplasty
Strictureplasty
Strictureplasty is a surgical procedure performed in response to scar tissue that has built up in the intestinal wall from inflammatory bowel conditions such as Crohn's disease. The scar tissue accumulates as a result of repeated damage and healing, with the scarring causing a stricture...
or a temporary or permanent colostomy
Colostomy
A colostomy is a surgical procedure in which a stoma is formed by drawing the healthy end of the large intestine or colon through an incision in the anterior abdominal wall and suturing it into place. This opening, in conjunction with the attached stoma appliance, provides an alternative channel...
or ileostomy
Ileostomy
An ileostomy is a surgical opening constructed by bringing the end or loop of small intestine out onto the surface of the skin. Intestinal waste passes out of the ileostomy and is collected in an external pouching system stuck to the skin...
. Alternative medicine
Alternative medicine
Alternative medicine is any healing practice, "that does not fall within the realm of conventional medicine." It is based on historical or cultural traditions, rather than on scientific evidence....
treatments for bowel disease exist in various forms, however such methods concentrate on controlling underlying pathology in order to avoid prolonged steroidal exposure or surgical excisement.
Usually the treatment is started by administering drugs with high anti-inflammatory effects, such as prednisone. Once the inflammation is successfully controlled, the patient is usually switched to a lighter drug to keep the disease in remission, such as Asacol, a mesalazine
Mesalazine
Mesalazine , also known as Mesalamine or 5-aminosalicylic acid , is an anti-inflammatory drug used to treat inflammation of the digestive tract ulcerative colitis and mild-to-moderate Crohn's disease...
. If unsuccessful, a combination of the aforementioned immunosuppression drugs with a mesalazine
Mesalazine
Mesalazine , also known as Mesalamine or 5-aminosalicylic acid , is an anti-inflammatory drug used to treat inflammation of the digestive tract ulcerative colitis and mild-to-moderate Crohn's disease...
(which may also have an anti-inflammatory effect) may or may not be administered, depending on the patient.
Histoplasma produces toxins that cause intestinal disease called histoplasmosis that is a “serious consideration” in an immunocompromised patient with signs and symptoms of IBD. Antifungal drugs such as nystatin
Nystatin
Nystatin is a polyene antifungal medication to which many molds and yeast infections are sensitive, including Candida. Due to its toxicity profile, there are currently no injectable formulations of this drug on the US market...
(a broad spectrum gut antifungal) and either itraconazole (Sporanox) or fluconazole (Diflucan) have been suggested as a treatment for IBD disorders such as Crohn’s disease and ulcerative colitis
Ulcerative colitis
Ulcerative colitis is a form of inflammatory bowel disease . Ulcerative colitis is a form of colitis, a disease of the colon , that includes characteristic ulcers, or open sores. The main symptom of active disease is usually constant diarrhea mixed with blood, of gradual onset...
that all share the same symptoms such as diarrhea, weight loss, fever, and abdominal pain.
Prognosis
While IBD can limit quality of life because of pain, vomiting, diarrhea, and other socially unacceptable symptoms, it is rarely fatal on its own. Fatalities due to complications such as toxic megacolonToxic megacolon
Toxic megacolon is an acute form of colonic distension. It is characterized by a very dilated colon , accompanied by abdominal distension , and sometimes fever, abdominal pain, or shock....
, bowel perforation and surgical complications are also rare.
While patients of IBD do have an increased risk of colorectal cancer
Colorectal cancer
Colorectal cancer, commonly known as bowel cancer, is a cancer caused by uncontrolled cell growth , in the colon, rectum, or vermiform appendix. Colorectal cancer is clinically distinct from anal cancer, which affects the anus....
, this is usually caught much earlier than the general population in routine surveillance of the colon by colonoscopy, and therefore patients are much more likely to survive.
New evidence suggests that patients with IBD may have an elevated risk of endothelial dysfunction and coronary artery disease
The goal of treatment is toward achieving remission, after which the patient is usually switched to a lighter drug with fewer potential side effects. Every so often, an acute resurgence of the original symptoms may appear; this is known as a "flare-up". Depending on the circumstances, it may go away on its own or require medication. The time between flare-ups may be anywhere from weeks to years, and varies wildly between patients - a few have never experienced a flare-up.
Research
The following treatment strategies are not used routinely, but appear promising in most forms of inflammatory bowel disease.Initial reports suggest that "helminthic therapy
Helminthic therapy
Helminthic therapy, a type of immunotherapy, is the treatment of autoimmune diseases and immune disorders by means of deliberate infestation with a helminth or with the ova of a helminth. Helminths are parasitic worms such as hookworms and whipworms....
" may not only prevent but even control IBD: a drink with roughly 2,500 ova of the Trichuris suis
Trichuris suis
Trichuris suis is a whipworm; the variations in thickness of the anterior and posterior segments give the parasite the characteristic “whip-like” appearance. Adult females measure 6 to 8 cm and adult males 3 to 4 cm. T. suis eggs are oval and yellow-brown with bipolar plugs.T...
helminth taken twice monthly decreased symptoms markedly in many patients. It is even speculated that an effective "immunization" procedure could be developed—by ingesting the cocktail at an early age.
Prebiotics and probiotics are showing increasing promise as treatments for IBD and in some studies have proven to be as effective as prescription drugs.
In 2005 New Scientist
New Scientist
New Scientist is a weekly non-peer-reviewed English-language international science magazine, which since 1996 has also run a website, covering recent developments in science and technology for a general audience. Founded in 1956, it is published by Reed Business Information Ltd, a subsidiary of...
published a joint study by Bristol University and the University of Bath
University of Bath
The University of Bath is a campus university located in Bath, United Kingdom. It received its Royal Charter in 1966....
on the apparent healing power of cannabis
Cannabis
Cannabis is a genus of flowering plants that includes three putative species, Cannabis sativa, Cannabis indica, and Cannabis ruderalis. These three taxa are indigenous to Central Asia, and South Asia. Cannabis has long been used for fibre , for seed and seed oils, for medicinal purposes, and as a...
on IBD. Reports that cannabis eased IBD symptoms indicated the possible existence of cannabinoid receptors in the intestinal lining, which respond to molecules in the plant-derived chemicals. CB1 cannabinoid receptors – which are known to be present in the brain – exist in the endothelial cells which line the gut, it is thought that they are involved in repairing the lining of the gut when damaged. The team deliberately damaged the cells to cause inflammation of the gut lining and then added synthetically produced cannabinoids; the result was that gut started to heal: the broken cells were repaired and brought back closer together to mend the tears. It is believed that in a healthy gut, natural endogenous cannabinoids are released from endothelial cells when they are injured, which then bind to the CB1 receptors. The process appears to set off a wound-healing reaction, and when people use cannabis, the cannabinoids bind to these receptors in the same way. Previous studies have shown that CB1 receptors located on the nerve cells in the gut respond to cannabinoids by slowing gut motility, therefore reducing the painful muscle contractions associated with diarrhoea. The team also discovered another cannabinoid receptor, CB2, in the guts of IBD sufferers, which was not present in healthy guts. These receptors, which also respond to chemicals in cannabis, appear to be associated with apoptosis – programmed cell death – and may have a role in suppressing the overactive immune system and reducing inflammation by mopping up excess cells.