What is the disease?

Inflammatory bowel diseases (IBD) are chronic, non-curable, immune-mediated diseases of the digestive tract. IBD encompasses three distinct illnesses: Crohn's disease, ulcerative colitis and unclassified colitis (when it is not possible to distinguish between the first two). IBD is often diagnosed at a young age and has a significant impact on quality of life. Although its cause is not yet well defined, it seems to result from a complex interaction between various factors (genetic, environmental, immune system and intestinal flora) that lead to the development of chronic inflammation in the bowel.

Chronic inflammation of the gastrointestinal tract is a common trait of these diseases, although they also differ in other aspects. Ulcerative Colitis only affects the rectum and colon (large intestine), wih the inflammatory process usually extending continuously from the rectum to the colon and is restricted to the innermost layer of the intestine (also known as the mucosa). Crohn's disease, on the other hand, can affect any segment of the digestive tract, from the mouth to the anus, in a discontinuous way, with areas of inflammation and healthy areas. In Crohn's disease, inflammation extends to all layers of the digestive tract, which can lead to complications such as stenosis ("tightening" of the intestinal lumen), fistulas and abscesses in the affected areas.

What about symptoms?

Symptoms' severity varies and depends on the type of IBD, the affected area of the digestive tract and inflammation intensity. The disease can manifest itself insidiously and with subtlety, which leads to a delay in diagnosis and consequent progression of the disease.

In Ulcerative Colitis, the most common symptom is bloody diarrhoea, including at night, which is present in 80% of cases. Other symptoms include mucousy stools, abdominal pain, faecal urgency and tenesmus. In the most severe forms of the disease, which occur in 30% of patients, systemic symptoms such as fever, anaemia and weight loss may be present.

In Crohn's Disease, the most common symptoms are abdominal pain, weight loss and diarrhoea (although the presence of blood and mucus in the stools is less frequent than in Ulcerative Colitis). There may also be anaemia, weight loss, anorexia, vomiting and nausea. If the small intestine is affected, the ability to absorb nutrients may be compromised which can lead malnutrition. Another symptom that is much more frequent in Crohn's Disease than in Ulcerative Colitis is perianal involvement (disease of the anus and rectum), namely fistulas and abscesses, which affect 30 % of patients and may be the initial manifestation of the disease ( 10% of the cases). In these cases, the symptoms are perianal pain, mucopurulent drainage, fever and pain during sexual intercourse. This form of the disease has a significant negative impact on quality of life.

Extraintestinal manifestations may appear both in Crohn's Disease and Ulcerative Colitis, with involvement of organs other than the gastrointestinal tract, due to the inflammatory process. In this case, the joints are the most affected, with peripheral arthropathies (involvement of the joints of the hands, knees and ankles) and axial arthropathies (involvement of the lumbar spine and sacroiliac joints), which manifest by inflammatory joint pain (more intense in the morning and which improves with movement). Other frequent extraintestinal manifestations are involvement of the mouth (oral aphthosis with mouth ulcers), the skin, in particular erythema nodosum (skin lesions that appear as red, painful nodules, especially on the legs), the eyes, the liver (for example primary sclerosing cholangitis, which can develop into liver cirrhosis) and the pancreas. In rare cases, there may also be pulmonary, neurological and cardiac involvement. The symptoms that arise due to this extraintestinal involvement may or may not coincide with the inflammatory activity of the disease.

What about medical tests?

Como se trata de uma doença crónica, existe a necessidade de repetir os exames complementares. Estes fornecem informações acerca do estado e gravidade da doença que, aliado aos sintomas, são a base para a otimização do tratamento da doença.

As there is no single method capable of establishing the diagnosis of IBD on its own, the diagnosis of these diseases involves clinical assessment, blood and stool tests and endoscopic examinations, particularly colonoscopy with biopsies. In Crohn's disease, it will also be necessary to carry out an imaging examination (such as a CT scan or MRI of the small intestine) and/or endoscopic videocapsule to assess the extent and severity of the disease in the small intestine. If there is perianal involvement, pelvic MRI will be necessary. Since these are chronic diseases, it will be necessary to repeat examinations over time. These provide information about the state and severity of the disease which, in combination with the symptoms, are the basis for optimizing the treatment.

Authors Young GEDII: Paula Sousa, Joana Roseira, Maria Manuela Estevinho, Sónia Bernardo Ana Catarina Carvalho (Centro Hospitalar Tondela-Viseu), Sofia Ventura (Centro Hospitalar Tondela-Viseu), Francisco Pires (Centro Hospitalar Tondela-Viseu), Cláudio Rodrigues (Centro Hospitalar Tondela-Viseu), João Correia (Centro Hospitalar Vila Nova de Gaia/Espinho), Edgar Afecto (Centro Hospitalar Vila Nova de Gaia/Espinho), Juliana Serrazina (Hospital Santa Maria – Centro Hospitalar Universitário Lisboa Norte), João António Cunha Neves (Centro Hospitalar Universitário do Algarve), Viviana Alexandra Sequeira Martins (Centro Hospitalar Universitário do Algarve)

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