Inflammatory Bowel Disease (IBD) is a term used to describe any disorder that causes long-term inflammation of the digestive tract. Though previously thought to be an autoimmune condition (that is, one in which the body’s immune system attacks healthy cells and tissue), more recent evidence suggests that IBD is caused by an abnormal immune response to gut microbes 1.
The two major types of IBD are ulcerative colitis and Chron’s disease, both of which can cause severe diarrhea, abdominal pain, weight loss and fatigue. Both forms of IBD do not have a cure, but treatment and lifestyle changes can help patients manage their symptoms and preserve their long-term health.
Different Types of IBD
The two major types of IBD are ulcerative colitis and Chron’s disease. Both conditions are characterized by long-term inflammation of the digestive tract, and often cause similar symptoms. However, there are some key differences between the two that affect how each disease responds to treatment, and the development of further complications 2.
Ulcerative colitis causes inflammation in the top layers of the colon (the large intestine).
There are five different types of ulcerative colitis, which are characterized based on their location in the colon 3:
- Acute severe ulcerative colitis affects the entire colon
- Left sided colitis causes inflammation in the descending colon and rectum
- Pancolitis affects the entire large intestine and is characterized by blood persistent diarrhea
- Proctosigmoiditis affects the lower colon and rectum
- Ulcerative proctitis only affects the rectum
While ulcerative colitis only affects the colon, Crohn’s disease can cause inflammation in any part of the gastrointestinal (GI) tract between the mouth and anus. It can also cause complications relating to the skin, eyes, liver, kidneys and joints 4.
As the symptoms of Crohn’s disease typically worsen after eating, patients will often avoid food, resulting in weight loss. Unlike ulcerative colitis (which only affects the top layers of the colon), Crohn’s disease can cause inflammation in all layers of bowel walls.
Signs and Symptoms of IBD
The two major types of IBD (ulcerative colitis and Crohn’s disease) can cause similar symptoms, most of which affect the gastrointestinal tract.
Common symptoms of both ulcerative colitis and Crohn’s disease include:
- Overactive bowel movements and severe diarrhea
- Bloody stools
- Abdominal pain and discomfort
- Loss of appetite
- Weight loss
- (In women) irregular menstrual cycles
Symptoms of Ulcerative Colitis By Type
There are five different types of ulcerative colitis, each of which is classified based on its location in the bowel. The symptoms of ulcerative colitis may vary according to type:
Symptoms of acute severe ulcerative colitis may include:
- Severe abdominal pain
- Severe diarrhea
- Bloody stools
- Difficulty eating, or inability to eat
Symptoms of left sided colitis may include:
- Abdominal cramping
- Pain on the left side of the abdomen
- Bloody diarrhea
- Weight loss
Symptoms of pancolitis may include:
- Abdominal cramping
- Bouts of severe and bloody diarrhea
- Weight loss
Symptoms of proctosigmoiditis may include:
- Abdominal cramps
- Bloody diarrhea
- Inability to move bowels despite an urge to do so (also known as tenesmus)
Symptoms of ulcerative proctitis may include:
- Rectal bleeding
Symptoms Exclusive to Crohn’s Disease
Because Crohn’s disease can affect the entire GI tract, it may cause symptoms that are usually not observed in people with ulcerative colitis (which only affects the colon). Crohn’s disease may also cause symptoms affecting the eyes, skin, mouth and joints, and might include 5:
- Nausea and vomiting
- Mouth ulcers
- Pain in the joints
- Patches of painful, inflamed skin (typically on the legs)
- Sore, red eyes
In both Crohn’s disease and ulcerative colitis, symptoms tend to come and go in cycles. ‘Flare-ups’ of IBD are characterized by worsening symptoms, after which there will be a period of remission in which the individual experiences few or no symptoms.
Causes of IBD
The exact causes of IBD are, as yet, unknown. However, studies into IBD have concluded that the condition is likely triggered by an abnormal and uncontrolled immune response to usually-harmless gut microbes.
Genetics - One of the factors that is known to play a role is a person's genetics. Studies have found that 15% of patients with Crohn’s disease have a family member with IBD, suggesting that the disease may be caused by mutations in certain genes relating to immune function .
Environment - IBD is also known to be more prevalent in industrialized countries, and incidence rates are on the rise in rapidly-developing nations across Asia, South America and the Middle East 7. These findings suggest a possible correlation between incidence rates of IBD and over-zealous hygiene practices, which can lead to reduced exposure to microbes in early life.
Some scientists have suggested that lack of childhood exposure to infectious agents could result in a greater likelihood of immune hypersensitivity later on 8. This could make individuals in industrialized, ‘hyper-hygienic’ countries more likely to develop inflammatory conditions, such as IBD.
IBD Risk Factors
Certain genetic, environmental and lifestyle factors can increase your risk of developing IBD.
Common IBD risk factors include:
Age - Most people with IBD receive a diagnosis by the time they are 30 years old. However, some individuals develop IBD later in life (in their 50s or 60s).
Genetics - People with family history of IBD have a higher risk of developing the disease. If you have a close relative (parent, child or sibling) with Crohn’s disease or ulcerative colitis, you may be genetically susceptible to IBD.
Race and Ethnicity - IBD can occur in people of all races and ethnicities, though the disease is most commonly seen in people of caucasian descent. The highest rate of IBD is seen in people of Ashkenazi Jewish descent.
Use of Nonsteroidal Anti-Inflammatory Medications (NSAIDs) - Using NSAIDs (such as ibuprofen, naproxen and diclofenac) may increase your risk of developing IBD. They may also worsen symptoms in individuals with IBD.
Smoking - Cigarette smoking has been found to increase the risk of developing IBD.
Location - Studies have shown that people living in industrialized countries are more likely to have IBD. People living in northern climates also appear to be at greater risk. Therefore, there is likely an environmental factor (such as diet or lifestyle) that plays a role in the development of IBD.
IBD is a chronic condition and can lead to further medical complications over time. Many of these complications can develop with either ulcerative colitis or Crohn’s diseases, but others are specific to one type of IBD 9.
Complications of Both Ulcerative Colitis and Crohn’s Disease
Colon Cancer - People with IBD have a greater risk of developing colon cancer. If you have IBD, your doctor may recommend more regular screening for colon cancer. The guidelines for people without IBD recommend a colonoscopy every 10 years from the age of 50.
Inflammation of The Skin, Eyes and Joints - Also known as extraintestinal manifestations, symptoms affecting other parts of the body are common among IBD patients. These may affect the joints, skin or eyes, and are discussed in more detail below.
Side Effects Linked to IBD Medications - Some commonly prescribed IBD medications can slightly increase the patient’s risk of developing certain cancers. Other medications, such as corticosteroids, are linked to an increased risk of high blood pressure, osteoporosis and other medical conditions.
Blood Clots - People with IBD have a greater risk of developing blood clots in their veins and arteries.
Primary Sclerosing Cholangitis - Primary sclerosing cholangitis occurs in around 5% of IBD patients 10. This inflammatory condition causes scar tissue to build up in bile ducts, eventually causing them to become blocked. This leads to a build-up of bile in the liver, which can cause cirrhosis or fibrosis of the liver 11.
Complications of Crohn’s Disease
Some medical complications are only seen in people with Crohn’s disease, which include:
Bowel Obstruction - Crohn’s disease causes parts of the intestinal wall to thicken and the bowel to narrow. This can obstruct the movement of waste materials through the intestine, and may require surgery to fix.
Ulcers - Crohn’s disease is characterized by chronic inflammation of the digestive tract. Ulcers can develop as a result, and may appear in any part of the GI tract, including the mouth, anus and genital area.
Fistulas - A fistula is a severe type of ulcer, one that extends completely through the intestinal wall and creates a hole. These most commonly develop near or around the anal area. In some cases, fistulas can become infected and form abscesses.
Anal Fissure - Painful bowel movements can cause small tears to develop in the anal wall. These are called anal fissures, and may lead to the development of fistulas.
Malnutrition - The symptoms of Crohn’s disease often flare up after a meal, making it difficult or even impossible for the patient to eat. Persistent diarrhea can also make it difficult for the intestine to absorb nutrients, leading to malnutrition.
Complications of Ulcerative Colitis
Some IBD complications are only observed in people with ulcerative colitis, and may include:
Toxic Megacolon - Toxic megacolon is a serious complication that occurs when the large intestine rapidly widens and swells. When this happens, the colon is unable to expel gas or feces, and may eventually rupture as a result.
Perforated Colon - Holes may form in the large intensive, usually as a result of toxic megacolon. However, this can also happen in cases where toxic megacolon is not present.
Severe Dehydration - Persistent and severe diarrhea can cause IBD patients to become dehydrated.
Effects of IBD on Other Parts of the Body (Extraintestinal Manifestations)
IBD primarily affects the digestive tract, but it can also cause problems in several other parts of the body. Extraintestinal complications are common in both forms of IBD, and affect up to 40% of people with either ulcerative colitis or Crohn’s disease 12.
Extraintestinal complications of IBD may affect:
- Joints - Inflammation of the joints (also known as arthritis) is common among people with IBD.
- Skin - Skin problems are a common complication of IBD. These may consist of raised, tender and red swellings on the legs (erythema nodosum) or tender, red nodules on the face, neck and upper limbs (Sweet’s syndrome).
- Mouth - Mouth ulcers are fairly common in people with IBD. These sores tend to appear during IBD flare-ups and usually disappear within a few weeks.
- Eyes - Inflammation of the eyes is often seen in people with IBD. The most common eye complaint is episcleritis, which causes the whites of the eyes to become red, inflamed and painful.
- Bones - Loss of bone density is often seen in patients with IBD. This can be due to a variety of factors including inflammation, poor calcium absorption, or as a side effect of certain IBD medications.
- Liver - IBD can also affect functioning of the liver, and people with the condition are likely to develop gallstones. IBD patients are also more likely to develop primary sclerosing cholangitis (described above).
- Kidneys - People with IBD are at greater risk of developing kidney stones, which can harm kidney function.
- Blood (Anemia) - Also known as iron deficiency, anemia is a common complication of IBD. Causes include chronic blood loss and reduced iron absorption in the gut as a result of inflammation.
If you suspect you may have IBD, the first step towards diagnosis will be a consultation with your doctor, during which you will be asked to describe your symptoms, medical history and general health.
Diagnosis of IBD is usually confirmed with the aid of one or more tests and examinations, which may include:
Physical Examination - During a physical examination, the doctor will check for signs of anemia (characterized by paleness) and inflammation, which may cause abdominal tenderness.
Blood Tests - A blood test can confirm whether or not you have anemia (a common complication of IBD), and for signs of inflammation.
Fecal Tests - Your doctor may want to check for signs of blood in your stool, as this is a common indicator of IBD.
Imaging Tests - Imaging procedures such as X-rays, CT scans and MRI scans may be performed to examine tissues in the bowel. These are used to identify and evaluate damage to the tissues, such as fistulas or perforations in the colon.
Endoscopic Procedures - Endoscopy is a medical procedure in which a tiny camera is used to examine internal parts of the body. In the case of an IBD diagnosis, this would involve the examination of the colon.
There are various endoscopic procedures that your doctor may recommend for IBD diagnosis, including:
- Colonoscopy - During a colonoscopy, the entire colon is examined using a tiny camera attached to a thin, flexible, lighted tube.
- Flexible Sigmoidoscopy - A thin, flexible, lighted tube is used to examine just the last part of the colon (the rectum and sigmoid). If the colon is very inflamed, this procedure may be performed in place of a full colonoscopy.
- Upper Endoscopy - During an upper endoscopy, the oesophagus, stomach and upper small intestine are examined. An upper endoscopy is usually performed in patients who experience nausea, vomiting, difficulty eating or upper abdominal pain.
- Capsule Endoscopy - A capsule endoscopy may be used to diagnose IBD of the small intestine. For this procedure, you would be asked to swallow a capsule containing a tiny camera, which will travel through your GI tract before passing out of your body in your stool.
- Balloon-Assisted Enteroscopy - If a capsule endoscopy reveals abnormalities in the small intestine, but a diagnosis is not confirmed, the doctor may perform a balloon-assisted endoscopy. During this procedure, an endoscope is inserted into the small intestine to examine regions that normal endoscopes aren’t able to reach.
There is no cure for IBD. However, there are several treatment options available that can help the patient manage their symptoms and keep the disease in remission.
Medical Treatment of IBD
Anti-Inflammatory Drugs - Anti-inflammatory drugs are used to reduce inflammation in the gut and reduce the symptoms of IBD. These medications are usually the first line of defence against IBD.
Corticosteroids - In cases where milder anti-inflammatory drugs are ineffective, a doctor may prescribe corticosteroids. These fast-acting anti-inflammatories can reduce symptoms during a flare-up, but should not be used long term as they may ultimately make the symptoms of IBD more severe.
Immune Suppressors - IBD is caused by an abnormal immune response to harmless gut microbes. Immune suppressors can reduce the action of the immune system, preventing it from attacking cells in the GI tract. However, these treatments can take around 3 months to show results, and may increase the patient’s risk of developing an infection.
Biologic Therapies - Biological therapies use antibodies to reduce inflammation, which can lessen the symptoms of IBD.
Other medications that can be used to reduce the symptoms of IBD include:
- Anti-diarrheal medication
- Dietary supplements (to counteract nutritional deficiencies caused by IBD)
Surgical Treatment of IBD
Surgery is a common treatment option for people with IBD. An estimated 70% of patients with Crohn’s disease and 25% of those with ulcerative colitis will need surgery at some point in their lives 13. Patients with IBD usually get surgery for one of the following reasons:
- Poor response to medication
- (In children) stunned or delayed growth
- Formation of abscesses or fistulas
- Strictures (narrowing of the intestine, which can lead to bowel obstruction)
- Emergency situations (such as toxic megacolon)
The type of surgery varies depending on the extent and location of the damage to the bowel, and usually involves removal of the affected region.
The main types of surgery performed as treatment for IBD include:
Strictureplasty - Strictureplasty is used to widen parts of the bowel that are affected by strictures, which cause the gut to narrow and may lead to obstructions. This is typically performed in patients with Crohn’s disease, and does not involve removal of any part of the bowel.
Resection - Resection involves the removal of part of the intestine, usually in areas with very long strictures or where there are many strictures close together. During resection, the surgeon will remove the diseased portion of the bowel and sew the healthy sections back together.
Colectomy - In cases of severe and extensive IBD, a colectomy may be performed. This involves the removal of the entire colon. In cases where the rectum is unaffected by IBD, it may be attached to the small intestine.
Proctocolectomy - Proctocolectomy involves the complete removal of both the colon and rectum. Often, this is performed alongside an ileostomy, in which a small hole (called a stoma) is made in the lower abdomen. The end of the small intestine is brought through this hole to allow waste materials to leave the body.
Ileostomy (Stoma Surgery) - An ileostomy is performed when it is not possible to reconnect healthy parts of the bowel back together. The stoma allows waste to leave the body, and diverts feces into a bag that is worn outside the body. Stoma may be temporary or permanent, depending on whether or not your gastrointestinal tract can be reconnected at a later date.
It is important to note that, like medications, surgery is not a cure for IBD. Often, the disease will re-emerge in a different part of the bowel or elsewhere in the GI tract.
Lifestyle Changes for IBD Management
Various lifestyle changes may help IBD patients to manage the symptoms of their condition.
There is no specific diet for the management of IBD, but some people may experience flare-ups of symptoms after consuming certain foods. Keeping a journal can help individuals identify which foods exacerbate their symptoms, and many report feeling better when they:
- Avoid dairy
- Avoid greasy or highly-processed foods
- Reduce their intake of high-fibre foods (like whole grains and raw vegetables)
- Avoid foods known to cause gassiness (like beans, cauliflower and other cruciferous vegetables)
- Minimize or eliminate caffeine and alcohol
It can be beneficial for people with IBD to limit their diet to well-cooked vegetables.
Smoking has a number of serious health implications, and can trigger flare-ups of symptoms in people with IBD. Quitting can reduce flare-ups, and can also reduce the need for medical and surgical treatments of IBD.
NSAIDs are known to exacerbate the symptoms of IBD. Avoid or minimize your use of these drugs wherever possible.
Stress is not a cause of IBD, but it can trigger symptom flare-ups. Stress management techniques such as meditation, yoga, breathing exercises and cognitive behavioral therapy can all help to reduce the symptoms of IBD.
Current IBD Clinical Trials
- An Active and Placebo-Controlled Study of Brazikumab in Participants With Moderately to Severely Active Crohn's Disease - United States
- A Study to Evaluate the Efficacy and Safety of PF-06480605 in Adult Participants With Moderate to Severe Ulcerative Colitis - United States
- Safety and Efficacy Study of JNJ-64304500 in Participants With Moderately to Severely Active Crohn's Disease - United States
- Transcutaneous VNS to Treat Pediatric IBD - New York, New York, United States
- Treating IBD With Inulin - Philadelphia, Pennsylvania, United States
Quick Facts About IBD
- The incidence rates of IBD are highest in Europe and North America, where the condition affects over 0.3% of the population 14.
- Incidence rates of IBD have also been rising in newly developed countries across Africa, Asia and South America since 1990.
- IBD generally affects males and females at a similar rate, though some studies have shown a slightly higher incidence rate in females than in males 15.
- While IBD is usually diagnosed before the age of 30, studies have shown the prevalence of the disorder increases with age 16.
- In adult and elderly populations, ulcerative colitis is more common than Crohn’s disease.
- In children and young adults, the incidence of Crohn’s disease is higher than that of ulcerative colitis.
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