Irritable Bowel Syndrome

Functional disorders of the gastrointestinal tract with a special International working group in 1999 are characterized as variable combination of chronic or recurrent symptoms unexplained by structural or biochemical changes.

The Rome classification of functional disorders of the digestive system (1999):

  • A. Functional esophageal disorders.
  • A1. Esophageal spasm (lump in throat).
  • A2. Rumination syndrome (syndrome of the cud; regurgitation).
  • A3. Functional chest pain, presumably of esophageal origin.
  • A4. Functional heartburn.
  • A5. Functional dysphagia.
  • A6. Unspecified functional disorder of the esophagus.
  • B. Functional gastroduodenal disorders.
  • B1. Functional dyspepsia.
  • В1а. Ulcer-like dyspepsia.
  • В1в. Desmotomy dyspepsia.
  • В1с. Unspecified (nonspecific) dyspepsia.
  • B2. Aerophobia.
  • B3. Functional vomiting.
  • C. Functional bowel disorders.
  • C1. The irritable bowel syndrome.
  • C2. Functional bloating (rumbling) stomach.
  • Sz. Functional constipation.
  • C4. Functional diarrhea.
  • C5. Unspecified functional bowel disorder.
  • D. Functional abdominal pain.
  • D1. Functional abdominal pain syndrome.
  • D2. Unspecified functional abdominal pain.
  • E. Functional disorders of the biliary tract and the pancreas.
  • E1. Dysfunction of the gallbladder.
  • E2. The sphincter of Oddi dysfunction.
  • F. Functional anorectal disorders.
  • F1. Functional fecal incontinence.
  • F2. Functional anorectal pain.
  • F2a. Syndrome elevatorov (levator ani).
  • F2b. Proctalgia (coming pain in the rectum).
  • F3. Dissynergy pelvic floor.
  • G. Functional disorders in children.

Irritable bowel syndrome is polietiologic disease, representing various forms of functional disorders of motility, absorption and secretion, predominantly of the colon. It refers to the so-called functional disorders of the intestine, prompting the doctor to exclude more serious disease before putting this diagnosis.

History of irritable bowel syndrome dates back to the nineteenth century, when W. Gumming (1849) described the typical clinical picture of a patient with this syndrome, and then W. Osier (1892) designated this condition as IBS. In the subsequent terminology of the disease was represented by such definitions as spastic colitis, intestinal neurosis, etc. At the same time widely used diagnostic term “chronic spastic colitis” does not reflect the substance of the pathological process, as it implies inflammation of the mucous membrane of the colon. When irritable bowel syndrome the histological picture corresponds more degenerative changes than inflammatory.

The term “irritable bowel syndrome” was introduced by De-Lor in 1967, Despite the fact that the word “syndrome” indicates the presence of certain symptoms, not the disease, the concept of irritable bowel syndrome is more consistent with nosologic unit. Histological examination of biopsy specimens of the mucosa of the colon obtained from patients with this syndrome, often determined by moderate infiltration of lymphoid cells with a minimum number polinucleares.

Approximately 14-30 % of people worldwide suffers from this disease. At the same time in the structure of gastroenterological patients, this figure increases to 49-70 %. On the other hand, are aware of the fact that many patients with this disease doctors do not treated and only one third of them is a specialized examination and treatment. Often irritable bowel syndrome occurs in women, although some authors claim that the ratio of men and women is the same. The average age of onset is 30-40 years. However, we must always remember that if characteristic symptoms of irritable bowel syndrome appears in individuals over 60 years of age, then they should be excluded organic disease, primarily colon cancer.


A number of factors, alone or in combination with each other lead to the development of irritable bowel syndrome. This disruption of the Central and autonomic nervous systems, intestinal microflora (dysbiosis), malabsorption, mental disorders, lack of ballast substances in the food, social and emotional factors. Since 2001 there has been more talk about the external stimuli (stress) as the most important starting mechanism not only irritable bowel syndrome, but all functional disorders of the gastrointestinal tract.

Pathogenetic model for the development of irritable bowel syndrome in a simplified form can be presented as follows. Under the influence of psychosocial factors, there is alteration of intestinal motility and sensitivity to neurohumoral and mechanical stimulation. These changes form a vicious circle. The most important in the irritable bowel syndrome is the change in the motor function of the colon. In 2002-2004 it has been shown that one reason for this may be impaired production of endogenous morphine and morphine-like mediators in the intestinal wall, slowing down transit through the gut by reducing the propulsive contractions. A number of patients were found high levels of serotonin in the mucosa of the intestine compared to the submucosal layer. Such a violation of the distribution of serotonin can lead to disorders of conduction of nerve impulses and decrease the propulsive contractions. In other works there was a reduction in the number of cells producing serotonin and glucagon. In the study using biomechanical and electrophysiological methods in irritable bowel syndrome have been allocated the following types of motor activity of the colon:

  • giperfermentemii hyperkinesis (52% of patients) — increased activity of the intestinal wall with predominance in the spectrum of low-amplitude waves and segmental contractions;
  • dystonic Hypo – or akinesia (36% patients) — a sharp decrease in motor activity, accompanied by different changes in the wave spectrum and severe disturbances of tone of the intestinal wall;
  • antiperistaltics hyperkinesis (12 % of patients) — increased motor activity with the presence of antiperistaltics complexes.

In the study of the functional state of the colon by using the most physiological method of interecocentre — has found that irritable bowel syndrome is characterized by accelerated transit of intestinal contents in the distal parts of the colon and slow — proximal.

So, the acceleration of transit in the sigmoid colon was noted in 49 % of cases, and the acceleration of transit in almost all of the colon in 17 % of cases.

The vast majority of patients with irritable bowel syndrome diagnosed neurosis, neurotic development of personality or psychopathy. There are autonomic disorders with a predominance of parasympathetic influences.

In recent years, more attention has been paid to the study of visceral hypersensitivity, which is an important factor in the pathogenesis of irritable bowel syndrome. Despite the fact that since the 70-ies of the last century, research on visceral hypersensitivity in irritable bowel syndrome, began to appear in the literature, only now becoming more or less clear in its role. One of the manifestations of visceral hypersensitivity is visceral hyperalgesia. Pain impulses arise from the irritation of afferent nerve endings of the vagus nerve and spinal nerves. Then they are transmitted to the brain. Various factors that affect these nerve endings can affect both the motor and secretory activity of the intestine, causing constipation or diarrhea. In turn, the effect on afferent nerve endings may resolve the symptoms. In recent years, data were obtained indicating changes interesoval nervous system, reflected in increased activity of mechanoreceptors that perceive the expansion and contraction of intestinal muscles, and the participation of M-methyl–aspartate or Sa-dependent peptide receptors. Currently very popular hypothesis that explains the occurrence of abdominal pain in irritable bowel syndrome disorders in the Central nervous system control of ascending pain impulses.


In 1992. An international group of researchers has published criteria to diagnose irritable bowel syndrome. Currently they are known as Rome criteria I.

I. The presence of permanent or recurrent within 3 months. symptoms:

  • pain or discomfort in the stomach, subsiding with defecation or associated with changes in the frequency of bowel movements or consistency of stool.

II. The presence of two or more symptoms present at least 1 time in 4 days:

  • changes in stool frequency (more than 3 impulses a day, at least 3 impulses per week);
  • changes in stool consistency (thick, liquid);
  • changed defecation (straining, urgency, feeling of incomplete evacuation);
  • mucus;
  • flatulence.

Despite the diversity of clinical picture of irritable bowel syndrome, the most common symptoms are abdominal pain (80-90 % of cases) and diarrhea or constipation (about 75 % of cases), which can alternate in the same patient. In General, the symptoms in this disease is associated primarily with disorders of intestinal motility and increased visceral sensitivity. At the present time, given that irritable bowel syndrome is a combination of chronic and recurrent gastrointestinal symptoms, presented in the form of abdominal pain, bloating and disturbance of bowel movements, classification of it is based on the predominance of:

  • abdominal pain and the presence of flatulence;
  • constipation;
  • diarrhoea.

An important diagnostic criteria to distinguish irritable bowel syndrome from other diseases, primarily of an organic nature, are the criteria of manning. They concluded that:

  • abdominal pain subsides after a bowel movement;
  • the stool is accompanied by pain;
  • marked abdominal distension;
  • defined the admixture of mucus in stool or nausea with mucus;
  • feeling of incomplete emptying.

In 1999. The international working group to develop criteria for functional disorders the proposed clinical criteria of irritable bowel syndrome, identified as Rome criteria II.

For the past 12 weeks. or longer during the previous 12 months. the presence of abdominal pain or discomfort, in which identified 2 of the 3 following characteristics:

  • relief associated with defecation;
  • symptoms associated with change in stool frequency;
  • symptoms associated with changes in stool consistency.

Then irritable bowel syndrome was defined as “a functional bowel disorder in which abdominal pain is associated with defecation or changes in intestinal condition with characteristic abnormalities of defecation and stretching”.

It should be noted the fact that, in addition to clinical criteria for diagnosis of irritable bowel syndrome, special attention was paid to the exclusion criteria diagnosis or, as they were called by the authors, the symptoms of anxiety. The allocation of these symptoms are aimed at excluding organic diseases of the intestine:

  • bleeding from the rectum in the past;
  • reduction of body weight;
  • fever;
  • onset of symptoms at age over 50 years old.
  • night symptoms;
  • presence of colon cancer or inflammatory bowel disease in relatives.

The presence of at least one of the symptoms (alarms) makes necessary a complete examination of patients to exclude organic diseases of the gastrointestinal tract.

The differential diagnosis of irritable bowel syndrome should be carried out in dependence on the presence in patients of constipation or diarrhea.

With the disease the differential diagnosis is carried out with the diarrhea of infectious Genesis, inflammatory colon diseases (ulcerative colitis, Crohn’s disease), pancreatic insufficiency, short bowel syndrome, abuse of laxatives, rectal cancer, carcinoid syndrome, syndrome of zollingerellison, hyperthyroidism, lactase deficiency, celiac disease, food allergies, Whipple disease, intestinal lymphoma, immune deficiency, amyloidosis, diabetic enteropathy.

At the same time in patients with constipation and abdominal pain the differential diagnosis is carried out with diverticulitis, appendicitis, cholelithiasis and cholecystitis, gastric ulcer and duodenal ulcer, stomach cancer, porphyria, cancer of the colon and pancreas, lead poisoning, tabes spinal cord, ischemic colitis, hernia, endometriosis, ischemic heart disease, urogenital diseases.

In the section “Functional intestinal disorders” identified functional constipation as an independent nosological unit, which refers to a condition manifested by “persistent difficult, infrequent or seemingly incomplete defecation”.

The diagnosis of functional constipation can be supplied with two or more symptoms existing for at least 12 weeks, which may not necessarily be consecutive within the preceding 12 months.:

  • straining during bowel movements;
  • fragmented or hard stool in more than a quarter of bowel movements;
  • sensation of incomplete evacuation in more than a quarter of bowel movements;
  • sensation of anorectal obstructions/block in more than a quarter of bowel movements;
  • hand allowance more than a quarter of bowel movements (e.g., finger evacuation, support of the perineum with the hand) and/or less than 3 bowel movements per week.

While these symptoms should not be enough for a diagnosis of irritable bowel syndrome with constipation predominant.

Functional bloating (rumbling) stomach, based on the Roman II criteria include the state when dominated by a feeling of fullness, bloating or visible abdominal distension. Insufficient criteria for other gastrointestinal functional disorders.

Diagnostic criteria for functional diarrhea are loose or watery stools, which is present in more than a quarter of bowel movements, and no abdominal pain. It is all for 12 weeks. for the previous 12 months.


Treatment of irritable bowel syndrome consists of the impact on psycho-emotional sphere, balanced nutrition with the prevalence of foods containing dietary fiber, increase physical activity and medication, to normalize motor activity of the intestine, as well as physical therapy methods.

An important link in the medical activity is the treatment of the existing psycho-vegetative disorders, therefore the patients are often prescribed small doses of antidepressant that helps to stop the pain.

Disbiotic changes in irritable bowel syndrome most often accompanied by a deficiency of bifidobacteria and increase in population the level of conditionally pathogenic microorganisms, emergence of E. coli with altered enzymatic properties. In this regard, in the treatment plan the most effective probiotics, as well as preparations containing bifidobacteria and lactobacilli.

As an antidiarrheal drug is well established loperamide (Imodium). In this state, as prescribed, anticholinergic agents and antispasmodics. While malabsorption of bile acids in patients with diarrhea effective is cholestyramine.

In the presence of constipation, the appointment of laxatives is not always justified. At the same time with no effect from other methods laxative are necessary drugs. In recent years, with the aim of normalizing motility of the colon successfully applied to the drugs belonging to a new class of antagonists of Ca2+ ions. It is shown that these funds have a selective effect on the gastrointestinal tract. This is relevant due to the fact that all smooth muscles are selective transmembrane channels for ion transport of Ca2+ that open when the cell membrane is depolarized. Activation of these channels represents the final common path of all the mechanisms of regulation of the motility of the gastrointestinal tract. The main therapeutic benefit of new drugs of this generation is the lack of side effects on cardiovascular system those doses, which provide their effective impact on the violation of peristalsis of the colon. The most promising direction at the present time is the use of serotonergic drugs. It should be noted that the interaction of serotonin with a variety of receptors can give opposite effects, so the treatment used as agonists and antagonists of specific serotonin receptors.

This trend is confirmed by the works 2004. where it was shown that the most probable therapeutic target in irritable bowel syndrome is an intestinal nervous system, represented by the local sensory receptors, the Central nervous system and immune cells, including fat cells, which primarily react at the above-mentioned drugs.

The prognosis for patients with irritable bowel syndrome often favorable. However, the treatment of these patients requires attention and tact on the part of the doctor, and sometimes consultations with a neuropsychiatrist. Patients with this disease also shown physiotherapy, including acupuncture, hydrotherapy and intestinal health resort treatment.

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