Irritable bowel syndrome (IBS): Definition, Causes, Symptoms

Irritable bowel syndrome (IBS): Definition, Causes, Symptoms
Photo source: Getty images

Irritable bowel syndrome is a functional and not an organic disease of the digestive tract. It is caused by a combination of various risk factors, such as stress. It is characterized by abdominal pain, bloating and problematic defecation. Treatment may or may not be simple.


Irritable bowel syndrome is a chronic functional disease of the digestive tract, i.e. the intestine. There is a multifactorial action behind its occurrence, but the exact cause is unknown.

It is a functional and not an organic disease. That is, the intestine is not affected by a change in structure, structure, but its function is disturbed.

What is this disease and how is it manifested?
How is it diagnosed?    
What is effective in fighting it and what will help the treatment? 

It is also referred to as IBS, which is short for irritable bowel syndrome. It is named a syndrome because it is characterised by the presence of a variety of symptoms.

On the internet and in the literature, we can also encounter other names, such as irritable bowel, lower functional dyspepsia or dysfunctional bowel syndrome, or irritable bowel syndrome. However, all these names have a common problem.

In medical terms, IBS is defined as recurrent abdominal pain or discomfort for at least three days in one month, in the past three months, but with onset at least 6 months ago.

There are at least two symptoms:

  1. the pain subsides, i.e. it is milder after bowel movements, i.e. defecation
  2. initial changes in stool frequency, such as diarrhoea or constipation
  3. initial changes in stool characteristics such as its consistency, appearance and form

Since IBS is not an organic disease, normal physical findings on examination are a prerequisite for diagnosis. This is true for the digestive tract as well as for other organ systems. The main role in the diagnosis is played by the medical history and the subjective difficulties of the person concerned.

IBS - three cubes with the inscription I - B - S on a brown background
It is a functional disease, not organic damage to the intestine. Photo source: Getty images

Other investigative methods do not show a definite disease. Therefore, difficulties are often and mistakenly classified under psychological disorders. However, the psyche is not the only factor behind the outbreak of unpleasant and life-annoying difficulties.

What is irritable bowel syndrome?
Long-term indigestion associated with abdominal pain, defecation disorders. When diarrhoea or cough, or their alternation, is present, with associated bloating and gurgling stomach noises.

Irritable bowel syndrome affects women to a greater extent. Supposedly due to hormonal interplay. The age range is wide, from 20 to 50 years of age. IBS occurs mainly in life-embracing, dominant, commanding, combative people, in leadership positions and in individuals working under prolonged stress.

It affects 10-15% of people.

It is associated with a fast pace of life, inappropriate regime measures and lifestyle. With onset during adolescence and young adulthood, with persistence over decades. Periods of calm alternate with bouts of intense discomfort or occur in mild form on a daily basis.

In any case, IBS impairs quality of life, concentration and work engagement, and daily existence. It is aggravated by stress, tension, pressure, but also by infectious diseases and long-term antibiotic treatment. Many times it is associated with food intolerance.

IBS may also be associated with:
celiac disease,
histamine intolerance or 
lactose intolerance

ENS = enteric nervous system

Just as the mental state affects the gut, digestion and the entire gastrointestinal tract, the reverse is also true. Thus, discomfort and disease processes in it will reflect on the overall health and psychological condition.

It has been found that long-term stress also negatively affects the intestine, digestion, intestinal microflora and the digestive tract, which may correspond to irritable bowel syndrome.

Also worth mentioning is...

ENS, i.e. enteric nervos system.

This independently active part of the nervous system is located in the digestive tract. It has an autonomic status although it is influenced by the autonomic nervous system - sympathetic and parasympathetic. Plus, it is also in connection with the central nervous system - CNS.

It regulates the activity of digestion, the intestine and certain organs associated with digestion. An example is the effect on:

  • motility - motility of the stomach, intestines and therefore the speed of digestion
  • production of gastric and other digestive juices, acids, enzymes, mediators + hormones, and pancreatic enzymes - insulin, gallbladder and bile secretion 
  • blood flow through the gastrointestinal tract and absorption of nutrients into the blood
  • mucosal cell renewal
  • effective and important for the body's defences

The ENS is also referred to as the second brain.
It contains about as many nerve cells as the spinal cord.
It takes over the activity of the digestive system, instead of the brain.
It is autonomous but influenced by the CNS and autonomic nervous system.

It contains several types of nerve fibres, such as the plexus myentericus - the myenteric plexus (Auerbach's plexus), which affects the smooth muscles of the digestive system. Plexus submucosus - the submucosal plexus (Meissner's plexus), which innervates the mucosa and submucosa of the intestines. 

The nervous systems are interconnected.

Plus, the gastrointestinal tract also contains other fibres, such as viscerosensitive and visceromotor fibres. These form the connection between the nervous system and also other organs that are synergistic in digestion. And it also contains enteric glia (supporting nervous tissue).


The exact cause of irritable bowel syndrome is unknown. It is thought to be the interplay of several factors. In this syndrome, the problem is a functional disorder. The disease does not have an organic basis.

Thus, the intestine is not affected by a change in structure as in inflammation or cancer.

Up to 50% of patients seen by a gastroenterologist have functional problems, and among them is IBS.

Although people living with an undiscovered cause of difficulty fear the worst, there is no reason to. And just such pressure from an unknown disease can exacerbate an already unpleasant difficulty.

Table: possible causes of irritable bowel syndrome

Possible cause Description
Motility of the digestive system
  • motility is the name for bowel movements
  • assist in moving intestinal contents from the stomach towards the rectum
  • IBS: presumed functional motor disorder
  • i.e. excessive irritation by the central nervous system of the CNS
  • increase the influence of the sympathetic nervous system
  • decrease in parasympathetic nervous system activity
Passage of gases
  • the negative impact of abnormal passage (passage) of intestinal gases is considered
  • in addition to the brain, serotonin is also produced in the GIT (gastrointestinal tract)
  • and to an overwhelming extent
  • its role is various regulations in the GIT, and therefore also influence on intestinal motility
  • overproduction creates extraction
  • intestinal infections are the first thing to think about
  • among other mechanisms may be the cause of serotonin overproduction
  • as a late sequela of rotavirus infection
  • the causative agents are also systemic infections, i.e. those outside the digestive tract
Antibiotic treatment
  • long-term treatment with ATBs results in a disturbance of the intestinal microflora
Microflora disorders
  • as a result of antibiotic treatment, but also inappropriate diet and dietary errors
Irritation of the intestine
  • substances such as lactose, gluten, bile, fatty acids, various allergens and chemicals
Genetic factors
  • familial occurrence is assumed
  • but this can be influenced by upbringing and family habits and customs
  • possible connection with nature:
    • neurotic, anxious
    • aggressive
    • panic, phobia
    • bad mood
    • depression
    • sleep disorders
  • long-term stress
  • workload, senior positions
  • energetic people
  • in women is related to the hormonal influence of fluctuations in estrogen and progesterone levels


IBS has its own characteristic symptoms. It is important to know that its manifestation is not organic changes in the wall of the digestive tube, that is, the intestine. It is a functional disease based on a disturbance of motility and passage of intestinal contents and gases.

A characteristic of IBS is a change in the frequency of defecation, or stool. Diarrhoea or constipation may be present. Both may alternate. In case of diarrhea, there may be some mucus in stool.

Constipation can last for several days. Subsequently, after emptying the stool, it can be replaced by diarrhea. Associated with abdominal pain, these may be crampy in nature. They are accompanied by gurgling stomach noises, cramping in the abdomen. Also, bowel movements may be accompanied by pain.

Read also: Article on bloating.

Pain from the abdomen occasionally radiates into the spine. Instead of pain, it also takes place as a feeling of vague discomfort in the abdomen. After defecation, the person complains of imperfect, insufficient and uncomfortable defecation.

However, it is usually followed by a lessening or even cessation of the discomfort. This with a reversal to a recurrent urge to defecate. The intake of milk or dairy products in some individuals causes a worsening of the course, abdominal pain, stool frequency or distention.

Similarly, stress, psychological strain, workload, sense of responsibility, whether at work or in the family.

IBS - man has abdominal pain, cramps, holding his abdomen, blue plaid shirt, sitting on a sofa
Abdominal pain, cramps, bloating, loud gurgling stomach noises in the abdomen. Photo source: Getty images

A summary of the difficulties accompanying irritable bowel syndrome:

  • change in frequency of defecation
    • diarrhoea, more than 3-5 loose to watery stools in 24 hours
    • constipation, with defecation 1-2 times a week
  • change in stool consistency
    • thin
    • watery
    • hard
    • mucous
    • with an admixture of blood, beware of other GIT diseases
  • stomach ache
    • underbelly
    • entire stomach
    • cramps
    • vague feeling in the abdomen, like discomfort
    • feeling full
    • radiation of pain into the back
    • long-lasting and recurrent nature
  • painful defecation
  • urge to defecate
    • especially in the morning after waking up
  • urgent defecation
    • even shortly after a meal
  • frequent urge to pass stool
  • feeling of imperfect, uncomfortable defecation
  • bloating, flatulence
  • gurgling stomach noises
  • tummy rumbling
  • long-term fatigue
  • exhaustion
  • headache
  • mood changes
  • sleep disorders
  • disturbance of intestinal microflora and weakening of immunity


The diagnosis of irritable bowel syndrome is based on the medical history and clinical picture, and therefore on the subjective difficulties described by the affected person. These lead the doctor to a diagnostic conclusion and to the correct treatment.

However, a definitive diagnosis of IBS must be preceded by a differential diagnosis, in which the aim is to exclude another causative agent. Which could be, for example, inflammation of the GIT, infection anywhere in the body, colon cancer, and others. The symptoms mentioned above can be a consequence of organic and even more serious disease. If problems persist, a professional examination is necessary.

6 years = usual average from first symptom to diagnosis

For the diagnosis of IBS, a normal physical finding of all other examinations is a prerequisite. Since it is a functional and not an organic disease. This means that the intestine does not have an altered structure, the intestinal wall and other parts of the digestive tract are not affected in this way either. Also, other body systems such as the heart, lungs, kidneys or gynaecological system need to be checked.

In the search for a diagnosis, some examinations may be performed:

  • laboratory examination
    • blood
    • stool
    • urin
    • CRP - inflammatory marker
    • complete blood count
    • liver tests
    • minerals
    • glycaemia
  • parasites
  • USG, or abdominal sonography
  • endoscopic examination
    • colonoscopy
  • X-ray
  • CT
  • MRI


The disease typically progresses when periods of calm alternate with bouts of distress. The initial change in the frequency of stool emptying is associated with a change in its consistency. That is, repeated diarrhea occurs, emptying of thin stools. In other cases, constipation is present during defecation 1-2 times a week. 

Alternatively, these states alternate with each other.

Urge stools are especially in the morning and also shortly after eating. Bloating, flatulence, pain and cramps in the abdomen are associated. At other times it may be mild, such as a feeling of discomfort in the abdominal cavity or a feeling of fullness. There may be heaviness, a feeling of nausea to vomiting

The pain may be in the lower abdomen, in the whole abdomen or radiating to other parts such as the back.

Usually, after passing stool, the phase of remission or at least alleviation of the discomfort continues. However, this may be interspersed with an urge to defecate.

The person may have the feeling of incomplete or uncomfortable bowel movements.

Difficulties are provoked and exacerbated by stress, feelings of burden and tension. The urge to defecate significantly limits the quality of life of the affected individual. Since IBS also affects people with significant responsibilities, in positions of leadership, it makes them uncomfortable for important meetings and the performance of duties.

Examples include increased stress in the home environment, with children, or unrest between partners.

In women, an association with hormonal changes during the cycle is observed. The disruption of the microbial flora in the intestine also has an impact, and this arises after antibiotic treatment, but also on the basis of inflammation of the intestine or other systemic infections.

This is also why the use of probiotics in antibiotic treatment is quite significant.

Appropriate diet essential

Difficulties in this disease are provoked to a large extent by stress. We can influence this to some extent by the treatment practices mentioned above.

Diet is also of great importance in irritable bowel. What we eat can improve the passage of intestinal contents through the gut. Yes, we are talking about fiber and junk food.

Fibre needs to be gradually added to the diet. So we start buying more leafy greens, peel our tomatoes, cook our carrots. The best fruits are apples, bananas or kiwis. Then we can also add oatmeal, any cooked and raw vegetables.

We limit foods with a high ratio of saturated fatty acids. Food intolerances are often associated with IBS. So watch out for milk, gluten and histamine intolerance.

Meals should be taken in peace. One should not do other activities at the same time. When he is having breakfast, lunch or dinner, he should devote himself exclusively to that at that moment. In addition, there are appropriate and inappropriate foods that can improve or worsen the course of this unpleasant disease.

Table: suitable and unsuitable foods, substances or food groups

Food/nutrition Is it or is it not helpful against disease?
Fried foods, fats, oils No
Saturated fatty acids - fats No
Refined foods full of sugars and preservatives No
Sweetened drinks, energy drinks No
Gluten No
Spicy food, spices in general, cayenne pepper, hot pepper No
Milk and milk products No
Alcohol, cigarettes No
Caffeine No
Garlic, lemons, grapefruit, lime, stevia Yes
Yoghurts containing live cultures, i.e. probiotics Yes
Whole grain rice, oats, herbs Yes
Bananas Yes
Cooked but also raw vegetables Yes
Prebiotics and probiotics such as Psyllium Yes

How it is treated: Irritable bowel syndrome

Treatment of irritable bowel syndrome + How to fight it effectively? + Diet

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Interesting resources

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  • "Treatment for Irritable Bowel Syndrome". NIDDK. February 23, 2015. Archived from the original on April 6, 2016. Retrieved March 29, 2016.
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