Ulcerative Colitis

Ulcerative Colitis - What is Ulcerative Colitis?

Ulcerative colitis is a chronic condition that affects the large intestines, particularly the colon. It is classified as one of the two inflammatory bowel diseases along with Crohn’s disease.

The condition is characterized by inflammation within the linings of the gut walls.

Causes of ulcerative colitis

Ulcerative colitis is considered to be an autoimmune disease. Normally the body’s immune system works to defend the body against infection and invading microbes. In autoimmune disorders, this goes awry and the immune system attacks body’s own cells.

There are billions of harmless bacteria present in the gut. In inflammatory bowel diseases like Crohn’s disease and Ulcerative colitis, the immune system targets these harmless bacteria inside the colon and in turn attacks the tissues of the colon, causing it to become inflamed.

The inflammation leads to formations of ulcers and painful sores oozing mucus and pus. Both genetic and environmental factors may be responsible for causation of ulcerative colitis.

Symptoms of ulcerative colitis

Symptoms of ulcerative colitis commonly include abdominal pain, bloating, and frequent urge to evacuate bowels, bloody diarrhea and an abnormal weight loss.

The symptoms may range from mild to severe, with the condition fluctuating between extremes of symptoms.

Symptoms can flare up and then disappear for months or even years. Periods of absence of symptoms are termed remission.

Types of ulcerative colitis

The type of ulcerative colitis depends on the part affected:-

  • If only the left side of the colon is affected it is called limited or distal colitis.
  • When the inflammation occurs in the rectum and lower part of the colon it is called ulcerative proctitis.
  • If the entire colon is affected it is called pancolitis.

Ulcerative colitis statistics

Ulcerative colitis is relatively uncommon. In England 1 in every 1000 persons is diagnosed with the condition annually.

The condition is usually detected between the ages of 15 and 30 and nearly equally among men and women.

It affects white people of European descent especially those from Ashkenazi Jewish communities and black people more than others. It is rare among people of Asian descent.

Worldwide incidence rate of ulcerative colitis varies greatly between 0.5–24.5 per 100,000 persons.

It is estimated that as many as 1.4 million persons in the United States suffer from inflammatory bowel diseases including ulcerative colitis and Crohn’s disease.

Diagnosis of ulcerative colitis

Ulcerative colitis is confirmed by examining the insides of the colon using sigmoidoscopy or colonoscopy. This also helps rule out Crohn’s disease and bowel cancers that may have similar symptoms.

Treatment of ulcerative colitis

There is currently no cure for ulcerative colitis. Treatment aims to relieve symptoms during a flare-up and prevent symptoms from returning during remission.

One of the commonest medications used include aminosalicylates and corticosteroids (steroid medications). Serious flare up of symptoms may necessitate hospital admission. Some persons may benefit from colon surgery to remove the affected parts as well.

Without treatment, several complications may occur with ulcerative colitis. For example, inflammation of the bile ducts called primary sclerosis cholangitis may occur leading to jaundice and other features.

Another life threatening complication is toxic megacolon where the gases become trapped inside the colon, causing it to swell. Those with ulcerative colitis are also at a raised risk for developing bowel cancers.

Ulcerative Colitis Causes

The exact cause of ulcerative colitis is not known. It is, however, considered to be an autoimmune disease.

Normally the body’s immune system works to defend the body against infection and invading microbes. In autoimmune disorders, this goes awry and the immune system attacks body’s own cells.

There are billions of harmless bacteria present in the gut. In inflammatory bowel diseases like Crohn’s disease and Ulcerative colitis, the immune system targets these harmless bacteria inside the colon and in turn attacks the tissues of the colon, causing it to become inflamed.

The cause why the immune system behaves in this manner is unclear.

Some of the hypotheses regarding cause of ulcerative colitis include:-

The overactive immune system

After the immune system is done fighting the invading viruses and bacteria that triggers it, it does not switch off. Continued vigilant and active immune system leads to inflammation.

Some research shows that the immune system is actually not triggered by harmful invading bacteria but by billions of harmless or friendly bacteria present in the gut. This is a manifestation of the autoimmune hypothesis behind causation of ulcerative colitis.

Genes

There are population studies that reveal that at least 1 in 6 persons with ulcerative colitis have a blood relative who has this condition.

The genetic hypothesis is also strengthened by the fact that some communities are more at risk of this condition than others. It affects white people of European descent especially those from Ashkenazi Jewish communities and black people more than others. It is rare among people of Asian descent.

Researchers have identified several genes that seem to predict if a person would develop ulcerative colitis but the exact mechanism is not yet known.

Environmental factors

It is seen that ulcerative colitis is more common among urban areas in northern parts of Western Europe and America. There have been studies showing an association of ulcerative colitis with several environmental factors including air pollution, diet and hygiene.

It is believed that typical Western diet is high in carbohydrates and fats. This is markedly different from the Asian diet that is lower in carbohydrates and fats. Generations of Westernized diet could be the key to causation of this condition. Studies have shown that ulcerative colitis as well as Crohn’s disease is more prevalent in white collar compared with blue-collar occupations.

In addition, children brought up in increasingly germ-free environments fail to be exposed to necessary microbes that help in strengthening the immune system. This is called the hygiene hypothesis and suggests why those living in developing and poorer countries with lower hygiene standards are relatively less likely to develop ulcerative colitis. This along with other hypotheses like oral contraceptive use, atypical mycobacterial infections etc. have not been proven to raise the risk of ulcerative colitis specifically.

Smoking is another notable environmental factor. Ulcerative colitis is more prevalent among ex-smokers and non-smokers while Crohn’s disease is more prevalent among smokers.

Ulcerative Colitis Diagnosis

Diagnosis of ulcerative colitis is based on evaluation of medical history, family history of the condition and also on certain imaging and laboratory tests.

Medical history

Detailed history of symptoms, age of onset, severity of symptoms, possible triggers for flare ups is obtained. Family history of the condition is enquired as genetics possibly plays a role in inheritance of ulcerative colitis.

Physical examination

The next step is physical examination of the patient. General health, signs of malnutrition are vital for diagnosis and management of ulcerative colitis. The patient is examined for anemia and pain over the abdomen.

Blood tests

These are undertaken to detect abnormalities and presence of inflammation. Routine blood tests help to detect presence of anemia from low red blood cell counts and pale RBCs.

There are two specialised blood tests known as the erythrocyte sedimentation rate (ESR) test and the C reactive protein (CRP) test that are checked in suspected cases of inflammation. These are non specific tests however and may give a positive result if there is an infection present in any part of the body.

Antibody markers and in-depth blood tests

These new blood tests look for antibodies that are produced by the immune system as part of the inflammatory processes. The ones tested include Perinuclear anti-neutrophil antibodies (pANCA) and Anti-Saccharomyces Cerevisiae antibody (ASCA). These antibodies are called biomarkers.

Many patients with ulcerative colitis have the pANCA antibody in their blood while patients with Crohn’s disease are more likely to have ASCA in their blood. However, these antibody tests are not absolute and foolproof. In some cases, patients have neither antibody while sometimes the antibodies may be positive in patients without either disease.

Stool examination

Samples of stools are examined for presence of inflammatory cells, mucus and traces of blood. These indicate presence of an active inflammation in the gut.

Barium enema X rays

A solution of Barium is given to the patient to drink and after an appropriate time an X ray of the abdomen is performed. Since the compound is radio-opaque and shows up on X rays, the outlines of the gut walls may be seen clearly. This may help in diagnosis.

Sigmoidoscopy and Colonoscopy

This is a more confirmatory test that detects and diagnoses ulcerative colitis. A Sigmoidoscopy or Colonoscopy detects the level and extent of the inflammation of the bowel.

It involves inserting a flexible tube containing a light and a camera on its tip via the anus into the gut. This is not a painful procedure and is performed under sedation. It usually takes around 15 minutes to half an hour to complete.

The images of the gut walls are transmitted to a computer from where the physician may get to see the inside walls of the gut.

The sigmoidoscope is only capable of looking at the rectum and lower part of the colon while the colonoscope covers the entire colon up until the ileocecal junction. These tests serve another purpose of ruling out other bowel conditions with similar symptoms including bowel cancers.

Another similar test is the EGD (Esophagogastroduodenoscopy) that uses the same principles to examine the linings of the esophagus, stomach, and duodenum. This is helpful in ruling out Crohn’s disease as this condition may affect the upper gastrointestinal tract as well.

Capsule Enteroscopy uses as small capsule with sensors and a camera that is taken as a pill and that transmits the images from within the gut.

ERCP (Endoscopic retrograde cholangiopancreatography) is another test that examines the bile ducts in the liver and the pancreatic duct.  This helps to rule out Primary Sclerosing Cholangitis (PSC) that is seen in some patients with ulcerative colitis.

CT scans

CT scans or Computerized tomography scans may be used to detect complications of ulcerative colitis including abscesses, fistulas, and intestinal blockages. These can also help diagnosing and ruling out bowel cancers.

Other imaging studies

Other imaging studies include CT Enterography, Magnetic Resonance Enterography (MR Enterography), MRI of Pelvis etc. These also give a clearer view of the structures around the gut and the extent of damage caused to the intestines and other organs by the disease.

White Blood Cell scan

A relatively newer test is the Leukocyte scintigraphy or the White Blood Cell scan. During inflammation the WBCs crowd at the sites of inflammation. This test can see where these WBCs gather during flare ups.

For this test a small sample of blood is taken from the arm and the WBCs are then tagged using harmless radioactive labels. This blood is injected back into the body. Special detectors can then monitor where these tagged WBCs go during an inflammation.

Endoscopic ultrasound

Endoscopic ultrasound (EUS) is another imaging study that can be used. In this an ultrasound probe is attached to an endoscope that helps to look under the lining of the intestines as well as the intestinal walls. These can help detect fistulas and the extent of spread of ulcers in the inflammatory bowel diseases.

Ulcerative Colitis Epidemiology

Ulcerative colitis is one of the two major inflammatory bowel diseases. It affects around one in every 500 people in the United Kingdom.

Gender prevalence

Unlike Crohn’s disease that affects women slightly more frequently than men, Ulcerative colitis seems to affect both sexes equally or may affect men slightly greater than women.

Age of onset

Ulcerative colitis may start at any age. However, it is rare in children under the age of 5. In most cases the symptoms begin to appear when the person is between ages of 10 and 40 years.

Ethnic, geographical and racial prevalence

Ulcerative colitis is most common in white people of European descent, especially those descended from Ashkenazi Jews. It is seen more commonly among people who have lived for generations in Eastern Europe and Russia. The condition is also common in black individuals but is rarer among those of Asian descent.

The reason for higher prevalence in urban areas and in northern developed countries in Western Europe and America compared to rural areas is unknown. However it has been seen that the prevalence and incidence of new cases is on the rise in developing nations as well.

Overall incidence and prevalence of ulcerative colitis

There are no incidence figures available for either ulcerative colitis or Crohn’s disease until the 1930s. Between 1934 and 1944 the incidence rates of Ulcerative colitis were first reported in two studies done retrospectively in Rochester, Minnesota. The studies found that annually there were 6 cases of Ulcerative colitis per 100 000 population. After this the numbers have been on a steady rise both in Europe and in the Americas.

There has been a lack of gold standard criteria for diagnosis, inconsistent assessment of cases and misclassification of the diseases that has made epidemiological studies of these diseases in large populations difficult.

According to the Centers of Disease Control and Prevention (CDC) the worldwide incidence or diagnosis of new cases of Ulcerative colitis varies considerably between 0.5 and 24.5 per 100.000 populations. Overall prevalence of inflammatory bowel disease worldwide is 396 per 100,000 persons. Nearly 1.4 million persons in the United States suffer from these diseases.