Ulcerative colitis is classified as a chronic inflammatory bowel disease (IBD). This pathology, the causes of which remain unknown, affects the lining of the large intestine and is manifested by flare-ups.

While Crohn's disease affects the entire digestive system (stomach, intestines and oesophagus), ulcerative colitis specifically concerns the mucosa of the large intestine. It is an inflammatory disease, which evolves in the form of symptomatic attacks, interspersed with periods of well-being. The main clinical signs are stomach pains associated with bloody and mucusy diarrhoea. According to the IBD dossier published by the Medical Research Foundation in 2022, ulcerative colitis (also known as ulcerative colitis) affects 5 new cases per 100,000 inhabitants each year. The causes of the disease are still unknown, and its treatment is, to date, purely symptomatic.

1. Definition of ulcerative colitis

In France, nearly 200,000 people suffer from chronic inflammatory bowel disease, or IBD (Foundation for Medical Research). This classification essentially encompasses two pathologies: ulcerative colitis (or haemorrhagic rectocolitis) and Crohn's disease. Unlike Crohn's disease, which affects the entire digestive system (stomach, intestines and oesophagus), ulcerative colitis focuses on the mucous membrane of the large intestine. The inflammation starts above the anus, in the lower part of the colon, and progresses upwards through the intestine.

Every year, about 5 new cases per 100,000 inhabitants are recorded in France (Foundation for Medical Research). The disease can occur at any age, in both men and women. But the majority of patients who suffer from it are between 20 and 30 years old (according to the file on chronic inflammatory bowel diseases published by Inserm in 2017). In patients, the disease manifests itself in the form of painful and unpredictable attacks. These are characterised by severe abdominal pain, accompanied by bloody and mucusy diarrhoea. To date, the causes of ulcerative colitis are unknown. Furthermore, there is no treatment that can effectively prevent outbreaks. The management of patients is mainly based on the treatment of symptoms, which can have a significant impact on quality of life.

2. Symptoms of ulcerative colitis

People with ulcerative colitis experience symptomatic and painful flare-ups. These unpredictable attacks occur intermittently, with varying periods of wellness between them. Often the first attack of ulcerative colitis occurs acutely within a few days. Symptoms vary depending on the patient and the course of the disease (location, severity of inflammation). Most of the symptoms are related to defecation, but some non-digestive complaints may also accompany the outbreaks. According to the article on ulcerative colitis published by the MSD Manual in 2021, patients with ulcerative colitis may have :

diarrhoea containing blood and mucus ;
Urgent, painful and particularly frequent bowel movements: up to 20 per day;
abdominal and anal pain
fever;
loss of appetite, weight loss and/or nausea;
anaemia: which can lead to fatigue, shortness of breath and paleness;
Vitamin and mineral deficiencies, protein loss;
Inflammation of the joints: the inflammation may spread to the spine, and to the joints of the legs and arms;
inflammation of the eye: localized in the iris, sclera or episclera;
skin rashes or swellings;
Mouth ulcers.

If left untreated, ulcerative colitis can lead to serious, life-threatening complications. These can include (according to the MSD Manual): severe intestinal bleeding, perforation of the intestine, colon cancer (the risk increases with long attacks), or colectasis (toxic megacolon).

3. Causes of ulcerative colitis

Although several avenues are being explored by researchers, the precise causes of ulcerative colitis remain unknown. According to the comprehensive file on ulcerative colitis published by the Canadian Society for Intestinal Research in 2021, the disease may be linked to:

genetic predisposition: increased risk if a family member has it, but no genetic markers has been identified to date;
environmental factors: smoking, diet (link still controversial), stress, etc. ;
immune dysfunction: ulcerative colitis may be an autoimmune disease. Through genetic and environmental factors, the patient's immune system could attack the intestinal mucosa. According to the researchers, the trigger (virus, bacteria, food or environmental substance) could differ from one individual to another;
certain intestinal bacteria.

It should be noted that this inflammatory disease mainly affects Western countries (Europe and North America) and urban areas. But recently, it has also become increasingly present in the Maghreb countries. According to the dossier on ulcerative colitis published by Orphanet in 2010, ulcerative colitis mainly affects Caucasian populations, with an incidence 5 to 6 times higher in individuals of Jewish origin.

4. Ulcerative colitis: when to consult?

To alleviate symptoms and avoid complications, it is important to seek medical attention as soon as the first attack occurs. Symptoms that should prompt an appointment are: more or less intense stomach pains, recurrent diarrhoea with bloody and slimy stools, and unexplained weight loss. As flare-ups cannot be prevented, each of them should lead to prompt medical attention. Patients with ulcerative colitis should be monitored regularly and treated accordingly. Any new symptoms should be checked by a doctor, especially joint, eye, skin and liver problems.

It should also be noted that one of the most serious complications of the disease is toxic megacolon (an excessive dilation of the colon with a real risk of perforation). In case of severe pain, fever, vomiting or suspicious swelling of the abdomen, an emergency consultation is necessary. Although ulcerative colitis is not a contraindication to pregnancy, pregnant women who suffer from it must be constantly monitored (gynaecologist and gastroenterologist). Finally, patients who have had the disease for 10 to 15 years have a higher risk of colorectal cancer (according to the Canadian Society for Intestinal Research). It is recommended that they be screened earlier than usual. According to the dossier on ulcerative colitis, published by the Berne Abdominal Centre in 2022, the ideal is to perform a colonoscopy 8 years after diagnosis and then every 1-2 years.

5. Examinations and diagnosis of ulcerative colitis

During the consultation, the doctor will examine the patient clinically and ask questions to find out about the patient's symptoms and personal and family history. In some patients, this information is sufficient to make a diagnosis. But the doctor may also carry out additional tests to confirm the diagnosis:

a blood test: to look for a high level of white blood cells, which indicates an immune dysfunction;
a stool test: to check for bacterial infection in the colon;
a colonoscopy: to examine the walls of the intestine. The doctor inserts a flexible tube, the colonoscope, equipped with a microscopic camera, through the rectum and into the colon. The examination shows the extent of the inflammation and checks that it is not Crohn's disease;
rectosigmoidoscopy: an examination similar to colonoscopy, but limited to the rectum and sigmoid colon;
ileocoloscopy: an examination similar to rectosigmoidoscopy which explores the upper parts of the intestine;
a barium enema: the doctor injects barium into the intestine (a product that generates contrasts), and observes the rectum, the colon and part of the small intestine in images. This uncomfortable examination only takes about twenty minutes;
Ultrasound or MRI: when endoscopic examinations are not possible (colon is dilated or too fragile).

In patients with ulcerative colitis, regular examination of the large intestine is necessary to prevent the development of tumours. In addition, other tests may be useful as the disease progresses.

6. Treatments for ulcerative colitis

At present, there is no effective treatment that can cure ulcerative colitis in the long term. The treatment of the disease is strictly symptomatic. It has two objectives: to relieve the patient's flare-ups and to limit the risk of complications. The proposed therapy is similar to that prescribed by doctors for Crohn's disease. However, as the inflammation is limited to the mucous membrane of the colon, locally acting drugs are preferred. These are mainly locally acting steroids or aminosalicylates (according to the Abdominal Centre in Bern).

If these local treatments are not effective, patients may also be prescribed corticosteroids. However, these powerful anti-inflammatory drugs can cause significant side effects. They are therefore prescribed for short periods of time, with the aim of containing acute flare-ups. As a last resort, doctors may turn to immunomodulators, such as azathioprine or 6-mercaptopurine, to stabilise immune reactions. In some cases, biotherapies are offered to the patient. These are based on artificially modified antibodies that block certain molecules that are essential for the activation of the immune system. In case of complications, doctors may opt for surgical therapy. This involves removing the inflamed part of the colon, or sometimes the entire colon (colectomy).

7. How can ulcerative colitis be prevented?

The causes of the disease are still unknown. Therefore, there are no really effective preventive measures. Patients who have had ulcerative colitis for more than 5 years are advised to see their gastroenterologist once a year. For the others, it is recommended to monitor the evolution of the symptoms carefully. There are no proven recommendations for diet. Each patient is invited to study the diet that best suits him or her, based on his or her own observations, as well as on the advice of a specialist.

Sources :

Fondation pour la recherche médicale, Institut national de la santé et de la recherche médicale, Le Manuel MSD, Société canadienne de recherche intestinale, Portail des maladies rares et des médicaments orphelins Orphanet, Centre abdominal de Berne