Irritable Colon Syndrome - Diagnosis

Premise

The so-called irritable bowel syndrome consists of a set of chronic intestinal symptoms, referable to the tract of large intestine called colon.

Also known as irritable bowel syndrome, irritable bowel syndrome, spastic colitis or IBS, irritable bowel syndrome affects women more frequently than men (female patients are about twice as many as male patients) and is often associated to disorders of the psychological sphere, such as depression or anxiety.

Irritable bowel diagnosis

The diagnosis of irritable bowel syndrome is the result of a thorough physical examination, a scrupulous medical history (or clinical history) and a series of investigations (including laboratory tests, instrumental examinations, etc.) aimed at excluding all pathologies that, from the symptomatological point of view, they resemble the irritable colon (NB: proceeding by exclusion, in order to identify a disease, is a practice known as differential diagnosis ).

Unfortunately, at the present time, there is no diagnostic test that allows us to specifically identify the irritable colon; in other words, a specific diagnostic test is missing, as could be the biopsy in the case of a neoplasm.

History and diagnostic criteria

Not having a specific test for the identification of the irritable colon, the medical-scientific community has decided to define, during debates and conferences on the subject, a series of diagnostic criteria to be used as a term of comparison with what emerged from the physical examination and above all medical history. In other words, the doctors have compiled a precise list of the symptoms that an individual should present, to be considered sick with irritable bowel syndrome.

The diagnostic criteria referred to are the so-called Manning criteria and the so-called Rome Criteria .

• Manning criteria: formulated in 1978 and still valid, they represent the first diagnostic criteria to be used in the identification of the irritable colon.

  Briefly, Manning's criteria focus attention mainly on: abdominal pain relieved by evacuation, the presence of mucus in the stool, the feeling of incomplete bowel emptying after each evacuation, the change in stool consistency and abdominal swelling.

• Rome Criteria : established between 1992 and 2006, they are the most used diagnostic criteria in the identification of spastic colitis.

  According to the Rome Criteria, an individual suffers from irritable bowel syndrome if, for at least 12 weeks (even non-consecutive) spread over a period of 12 consecutive months, he complained of abdominal pain or discomfort, characterized by at least two of the following three phenomena:

• Attenuation of the painful sensation after evacuation and / or
• Variations in the frequency of evacuations and / or
• Changes in stool consistency.

According to the Rome Criteria, the presence of other symptoms, such as abdominal swelling, the presence of mucus in the stool, a feeling of incomplete evacuation, etc., is important, but not fundamental or significant from a diagnostic point of view.

Table: Manning's criteria.

• Abdominal pain attenuated by evacuation.
• Presence of liquid faeces at the onset of pain.
• Increased frequency of evacuations at the onset of pain.
• Abdominal swelling.
• Presence of mucus in faeces in at least 25% of evacuations.
• Sensation of incomplete bowel emptying in at least 25% of evacuations.

Differential diagnosis

The various tests that make up the so-called differential diagnosis follow, almost always, the execution of the physical examination and the anamnesis, and serve to confirm or deny what was concluded previously.

The differential diagnosis tests prescribed in the presence of a suspected case of irritable bowel syndrome include:

• Faeces analysis for the detection of occult blood (occult blood in stool). It means researching, through laboratory investigations, the presence of traces of blood in the patient's faeces.
• Coproculture, which is the microbiological examination of faeces. It consists of searching for bacteria or parasites in feces. It is indicated in the presence of chronic diarrhea.
• Flexible sigmoidoscopy . It allows to study the state of health of the terminal part of the colon and the rectum. The study tool is a flexible tube, equipped with a camera and a light at the end that the doctor inserts into the patient's anus, during the examination.

  As you can guess, this is a rather invasive procedure.

• Colonoscopy . It is used for complete colon analysis. From the procedural point of view, it is not very different from flexible sigmoidoscopy: even colonoscopy, in fact, involves the introduction through the anus of the investigation instrument, which is a small flexible tube equipped with a camera and light.
• Radiological examination of the digestive tract with barium sulfate contrast agent . Provides fairly clear images of the colon. It allows the identification of any tumor masses or anatomical anomalies.

  Despite being painless, it is still a mildly invasive diagnostic practice, as it involves exposing the patient to a dose of ionizing radiation harmful to the human body.

• Abdominal and pelvic CT . Provides detailed three-dimensional images of the organs located in the abdomen and pelvis. It allows the identification of possible tumor masses and anatomical anomalies at the level of the organs present in the aforementioned districts.

  Despite being painless, it is considered an invasive test, as it exposes the patient to a non-negligible dose of ionizing radiation.

• The breath test for the diagnosis of lactose intolerance . It allows to establish if the patient under investigation produces sufficient quantities of lactase, that is the fundamental enzyme for the digestion of lactose.

  Readers are reminded that the lack or reduced ability to digest lactose due to the absence of the enzyme lactase leads to symptoms such as: abdominal pain, meteorism and diarrhea following the ingestion of milk and derivatives.

• A breath test for the determination of bacterial colonization of the intestine . It is used to search for possible contamination of the small intestine by bacteria. It involves the administration to the patient of glucides such as glucose, lactulose or xylose.
• In-depth blood analysis . They are useful in assessing the presence of a disorder such as celiac disease, which causes symptoms and signs very similar to irritable bowel syndrome, but has decidedly more serious complications.

If nothing significant emerges from these laboratory and diagnostic imaging tests, and if the symptoms meet the criteria of Manning or the Rome Criteria, the possibility that the patient under investigation suffers from irritable bowel syndrome is highly concrete.

Hazardous symptoms and signs that exclude irritable bowel syndrome

The presence of certain symptoms and signs, including weight loss, rectal bleeding, fever, nausea, vomiting etc., suggests that a different and more serious illness of the irritable bowel is in progress (eg, bowel cancer, cancer of the ovary, an inflammatory bowel disease, celiac disease, endometriosis, etc.).

It is for this reason that, in the presence of such a symptomatology, the doctors decide, with immediate effect, to subject the patient to further diagnostic tests.

Main signs that suggest the presence of a more serious irritable bowel disease:

• Appearance of symptoms after 50 or even more advanced
• Anorexia and weight loss
• Symptomatology with acute and non-chronic features
• Rectal bleeding
• Temperature
• Recurrent nausea and vomiting
• Severe abdominal pain, also and especially during the night
• Persistent diarrhea; diarrhea on waking
• steatorrhea
• Iron deficiency anemia

Clinical classification

Possible clinical classification of an individual with irritable bowel syndrome

1. Alve alterations (NB: in medicine, "alvo" indicates the intestinal canal as a whole and the function of defecation):
1. Variability of constipation, with the appearance of arid and ribbon-like stools, abdominal pain, reduction in the frequency of evacuations; resistance to laxatives.
2. The episodes of diarrhea are characterized by almost liquid stools and reduced volume; there is urgency to evacuation and increase in frequency in the number of evacuations.
3. Urgent evacuation after meals.
4. "Stipsi-diarrhea" alternation; in some subjects constipation predominates, in others instead, diarrhea.
2. Abdominal pain :
1. It is frequent and, as a rule, is located between the lower abdomen and the left quadrants of the abdomen; sometimes it spreads to the entire abdominal region.
2. Episodes of acute pain alternating with moments of remission of painful symptoms.
3. Meals can trigger a painful crisis, which evacuation helps resolve or alleviate.
3. Abdominal distention :
1. Increased abdominal distention, presence of gas and flatulence.
2. Increase in abdominal circumference during the day, associated with an unusual feeling of impatience.
4. Mucus in feces (or mucorrhea) :
1. Clear or whitish mucus.
5. Symptoms not referable to the colon or, in any case, extraddominal :
1. Vomiting, nausea, retrosternal burning, back pain, sexual dysfunction (dyspareunia or reduced libido), increased frequency of urination up to urgency and urgency urinary incontinence.
2. Accentuation of symptoms during the perimestrual period (in female patients, of course).
3. Fibromyalgia (chronic widespread muscle pain, associated with stiffness).
6. Symptoms belonging to the psychological sphere :
1. Episodes of anxiety.
2. Depression.

Conclusions

Making a diagnosis of irritable bowel syndrome is by no means simple. To complicate matters are mainly: the already mentioned impossibility of being able to count on a specific diagnostic examination, the non-specificity of the symptoms and the extreme variability of symptoms between patient and patient.

Achieving the diagnosis of irritable bowel syndrome can take some time, even for an experienced doctor.