Examinations to be done with irritable bowel

The diagnosis of irritable bowel syndrome is clinical, in the sense that it is based on the symptoms reported by the patient and those detectable by the doctor during the office visit. But, in some cases, it may also require some laboratory investigations and instrumental examinations, more or less invasive, which serve to exclude the presence of more serious diseases.

Irritable bowel, also referred to as irritable bowel syndrome, is a functional disorder, i.e. not associated with characteristic anatomical lesions or other alterations that can be detected with the available diagnostic tests.

For this reason, the diagnosis is based only on the presence of certain symptoms, which must however meet precise criteria, called “Rome Criteria” as defined by an international panel of medical experts in diseases of the gastrointestinal tract during a conference held in Rome in 1990.

After the first draft (“Rome I Criteria”), with the increase of scientific knowledge on functional gastrointestinal disorders, the diagnostic criteria have been updated several times, up to the 2016 version, the “Rome IV Criteria”, currently in use.

Telltale symptoms

The symptoms of irritable bowel syndrome can vary from person to person and may include abdominal pain, bloating, tension, bloating and flatulence, changes in intestinal motility (constipation or acute or chronic diarrhea), presence of mucus in the stool.

For diagnosis, the main symptom that must be present is abdominal pain, which must necessarily be accompanied by at least two of the following occurrences:

• pain is eased by defecation;
• changes in the frequency of evacuations;
• changes in stool consistency.

This symptomatology must be present for at least 12 weeks (even if not necessarily consecutive) during the last 12 months. Other disorders may be present, but they are not fundamental elements for diagnostic purposes.

Often, however, before arriving at a certain diagnosis of irritable bowel syndrome, it is necessary to exclude other intestinal diseases that present with the same symptoms, but that require different treatment. For this purpose, the doctor may prescribe one or more laboratory or instrumental in-depth tests, which allow to clarify the diagnosis and to identify the most appropriate therapeutic approach, able to improve the intestinal well-being and quality of life of the patient. Let’s see which are the main ones.

Medical history and physical examination

First of all, the doctor will have to investigate if there are warning symptoms for more serious intestinal pathologies, in which case specific investigations will be prescribed to highlight the alteration of some indicative biomarkers or the presence of characteristic lesions at the level of the mucous membranes of the digestive system.

A thorough examination must then aim to exclude the presence of hepatomegaly (enlarged liver), abdominal masses (potentially referable to neoplasms) or signs of intestinal obstruction (total closure of the lumen of the intestine with consequent blockage of the transit of feces).

As for laboratory tests, some are carried out routinely, while others are necessary only in doubtful cases.

Blood test

To get an overview of the state of health of the patient with symptoms at the level of the gastrointestinal tract, the following examinations are usually performed:

• blood count (detects amounts and percentage ratios between different types of blood cells; signals infections and suggests the presence of several other diseases, including some cancers)
• sideremia (concentration of iron in the blood, reduced in case of anemia due to malabsorption or gastrointestinal blood loss, including microscopic but persistent)
• transaminases (liver enzymes that increase in the presence of liver disease)
• glycemia and glycosylated hemoglobin (parameters used for the diagnosis of diabetes, which measure the concentration of sugar in the blood)
• creatinine (concentration of creatinine in the blood, a substance used as an indicator of kidney function)
• electrolyte analysis (the main ones are Na+, K+, Cl-, Ca++, Mg++ and suggest the presence of poor hydration of the body and alterations of intestinal absorption; they are reduced / altered by repeated watery diarrhea and vomiting).

In young subjects presenting with diarrhoea, possibly associated with malabsorption of nutrients and weight loss, it may be useful to measure antigliadin (Aga) and antiendomysium (Ema) antibodies to assess whether there is celiac disease (gluten intolerance).

Both parameters are measured after an onward blood sample has been taken. In case of detection of these antibodies and consequent suspicion of celiac disease, a gastroduodenoscopy will then be prescribed to take samples of intestinal mucous membranes, to be subjected to microscopic investigation.

In this regard, it should be remembered that celiac disease itself is a food intolerance that affects about 1% of the population, due to a specific immune reaction of the body against wheat, wheat and other cereals proteins (barley, rye, spelt, kamut, etc.), which is mainly established at a young age, but in a minority of cases it can develop even after 30-40 years and in the elderly.

Food Tests

The presence of allergies and / or food intolerance other than celiac disease (for example, lactose, yeast or glutamate) will be investigated by Vega test or, better, food biohematological investigations (IBA test), which allow to examine the level of tolerance of the organism towards various foods and better understand apparently causeless disorders.

In addition to symptoms affecting the gastrointestinal tract, in fact, allergies and food intolerances can be at the origin of dermatitis, skin rashes, headaches, unjustified physical and mental fatigue, dizziness and inflammatory states affecting various organs or systems.

When there is a strong suspicion of allergic sensitization (food or otherwise) specific allergy tests on the blood, called Rast (Radio-Allergo-Sorbent Test), may be required. They are performed after a common sampling and signal the level of reactivity of the immune system towards the most common allergens (production of immunoglobulins E, IgE).

Based on the outcome of these tests, the allergist may provide for a temporary exclusion diet and subsequent reintroduction of foods deemed at risk to have diagnostic confirmation.

Stool analysis

The analysis of the stool is used to reveal the possible presence of fecal parasites and their eggs, so as to exclude that the symptomatology is due to intestinal parasitosis. The main intestinal parasites that can be contracted are amoebiasis, giardiasis, teniasis (or cysticercosis) and oxyuriasis.

In addition, faecal testing with coproculture may be required to characterize the microorganism responsible for aqueous diarrhea with repeated discharges, of suspected bacterial origin, worthy of specific antibiotic therapy, especially in people who have frequented risk areas or who have drunk or eaten liquids or potentially contaminated foods.

Fairly common intestinal bacterial infections are, for example, due to some strains of Escherichia coli, Clostridium difficile, Salmonella, Shigella, Campylobacter and Listeria monocytogenes. With a similar investigation, viruses often responsible for viral gastroenteritis in children, such as rotaviruses, as well as adenoviruses and enteroviruses, can also be sought.

These and other microorganisms are among those responsible for traveler’s diarrhea that frequently affects people staying in areas characterized by precarious hygienic-sanitary conditions or without drinking water. In these cases, as a rule, the disorder resolves on its own within a few days: it is sufficient to ensure good hydration and a light and nutritious diet; If the discharges are numerous, you can resort to taking antidiarrheal drugs.

Alternatively, in the presence of abdominal pain associated with diarrheal discharge, malabsorption, persistent meteorism and flatulence, to assess the possible presence of an excessive bacterial load or an increase in intestinal motility, the lactulose breath test (a sugar that is fermented by intestinal microorganisms) can be performed. The test is carried out on an empty stomach, with the collection of exhaled air samples, after the ingestion of a solution of water and lactulose.

Targeted stool investigations have also been carried out for some years for the initial non-invasive diagnosis of chronic inflammatory bowel diseases (IBD), such as ulcerative colitis and Crohn’s disease. In this case, the biomarker primarily used as a reference is a protein called fecal calprotectin, whose levels increase dramatically in the stool of people who have IBD. For diagnostic confirmation of IBD, however, endoscopic evaluation (colonoscopy and ileoscopy) is also required.

In some cases, the search for fecal occult blood is also done, which serves to exclude any bleeding of the intestine that is not macroscopically visible. This type of investigation is usually offered to people over 50 in the context of screening programs for the early detection of colorectal cancer.

Rectal examination

Rectal examination is performed if there has been evidence of blood (and mucus) in the stool or there are symptoms of rectal incontinence.

Subsequently, rectal manometry can also be prescribed, which evaluates the pressure and functioning of the sphincter.

It is not a much-loved examination, but it is quick, simple and painless and can provide the doctor with valuable information about the state of the last stretch of the intestine, including muscle tone and the possible presence of hemorrhoids or ulcerations.

Colonoscopy

It should be carried out especially if gastrointestinal disorders arise over 50 years or in younger subjects with a family history of colon cancer or with alarm symptoms (presence of blood and mucus in the stool or blood alone; persistent diarrhea that does not regress with therapy; unexplained weight loss).

In some cases, it may be appropriate to obtain colon biopsies to rule out collagenopathy or lymphocytic colitis.

In addition, colonoscopy (sometimes associated with ileoscopy) is necessary to confirm the diagnosis of chronic inflammatory bowel disease, verify the level of impairment of the mucous membranes of the gastrointestinal tract, and for ongoing monitoring of IBD (response to medication and control of inflammation over time).

Abdominal ultrasound

Ultrasound of the abdomen is one of the first tests that are performed in case of abdominal pain. It allows you to view and control the location, size, ratios and morphology of internal organs and to detect structural anomalies, inflammatory phenomena or the presence of calcifications, enlargements or suspicious neoformations.

It can reveal the presence of liver and pancreas abnormalities, gallbladder stones or diseases of the kidneys, urinary tract, bladder, genital organs, especially the ovaries (in the latter case, however, it is often preferable to perform transvaginal gynecological ultrasound).

To provide reliable information, it must be carried out after a few days of light diet and at least 6 hours of fasting; If the examination is carried out on the entire abdomen (complete abdomen ultrasound) it is generally required to present with a full bladder to obtain a better visualization of the organs of the pelvic area.

Matt enema

The opaque enema consists of taking a series of radiographs after administration of a solution of water and barium (contrast medium) and the subsequent introduction of air, with a probe rectally. It provides for a preparation based on precise dietary indications, to be respected in the three days prior to the procedure.

This examination is usually performed to rule out colic diverticulosis (development of extroflexions of the intestinal wall that can become inflamed and infected causing abdominal pain) or other anatomical alterations in the colon and rectum (including neoplasms), or to investigate the causes of a sudden and apparently unjustified change in intestinal transit, such as the appearance of constipation that does not respond to laxatives or alternation of constipation and diarrhea.