Irritable bowel syndrome (IBS) is a set of symptoms that affects the large intestine. While it’s common, it can affect people differently. Symptoms may differ from person to person. Frequent symptoms of IBS include:
- Abdominal pain
- Fullness or bloating
Both the symptoms and intensity of the symptoms can vary in people with irritable bowel syndrome. Women with IBS mainly report abdominal pain and constipation (IBS-C). Men with IBS more often report diarrhea (IBS-D) as the main complaint.
IBS is not believed to have a physical, structural, or biochemical cause, which can often feel frustrating for people living with symptoms. IBS is a diagnosis of exclusion, meaning that other potential conditions with similar symptoms need to be excluded before diagnosing IBS.
More research is needed to determine the causes of IBS. As we learn more about the pathology behind IBS, research will accelerate the development of new therapy options.
At Cara Care, we’ve developed a program intended specifically for people with IBS. It includes unlimited chat with a dietician, guided gut-directed hypnosis, and a 12-week IBS-friendly diet. You can check it out by downloading the Cara Care app.
When do symptoms of IBS appear?
IBS symptoms can start gradually or suddenly. Some people affected by IBS say they have always had a sensitive stomach until they seek help with more severe symptoms. In other cases, irritable bowel symptoms develop after a gastrointestinal infection (known as post-infectious IBS) or after taking antibiotics. Often, the first noticeable thing is a change in the frequency of bowel movements and shape of the stool.
The symptoms do not appear equally in all people. Some people describe symptoms from time-to-time and experience days, weeks, and even months, during which they are almost symptom-free. In periods of increased stress** and mental tension, the symptoms might often be more pronounced than more stress-free times, like on the weekend or while on vacation.**
Typically, intestinal complaints appear in the morning after waking and throughout the day. IBS symptoms are usually not bothersome when sleeping.
The symptoms of irritable bowel syndrome are often related to bowel movements, meaning that IBS patients might experience either an improvement or worsening of abdominal pain after a bowel movement. Some people with IBS also feel that they cannot empty their bowels completely.
What are the different IBS symptoms?
IBS can be divided into four different subtypes:
- Constipation type (IBS-C)
- Diarrhea type (IBS-D)
- Mixed type (IBS-M), in which both diarrhea and constipation occur
- Unclassified type (UBS-U), in which bowel movements cannot be accurately classified in one of the 3 subtypes mentioned above
Before an IBS diagnosis can be made, other causes with similar symptoms, such as food intolerance or chronic inflammatory bowel disease (IBD) like Crohn's disease or ulcerative colitis, should be ruled out.
Once the diagnosis is made, people with IBS symptoms often start a long search to identify triggers and manage their symptoms.
The symptoms often manifest themselves in a change in the frequency of bowel movements and the shape and nature of the stool. The symptoms are variable and affect not only the gastrointestinal tract, but also the autonomic nervous system. This part of the nervous system supplies the internal organs and blood vessels. The most common IBS symptoms are explained in more detail below.
1. Bowel urgency as an IBS symptom
IBS patients frequently feel the urge to have a bowel movement. Some people experience this symptom especially in the morning. Average bowel movement frequency can include up to three bowel movements a day in a person without IBS. A change in bowel movement frequency, for example from one bowel movement to four bowel movements a day, could be an indication of newly developed IBS.
2. Diarrhea as an IBS symptom
The Bristol stool scale is a classification of different stool types. It defines diarrhea as watery stool without any solid pieces.
Many people who experience IBS also experience soft bowel movements with little or no firm lumps, occuring with increased frequency. Other gastrointestinal causes of diarrhea should be ruled out before a person is diagnosed with IBS.
Functional diarrhea is a disorder that is distinct from IBS with diarrhea, or IBS-D. Functional diarrhea is a diagnosis that describes loose or watery bowel movements that are present in more than 25 percent of all bowel movements within the last three months. Symptoms should have started at least six months prior to the diagnosis. Abdominal pain and bloating may be present but are not the main complaints.
3. Constipation as an IBS symptom
Constipation is often associated with pain during bowel movements, since the stool is composed of several firm lumps that are hard to pass. Very lumpy, hard, sausage-shaped stool can also be a sign of constipation. Along with hard stool and painful bowel movements, the frequency of bowel movements is usually reduced. As long as the shape of the stool is soft and smooth-edged, a stool every two days is considered normal. Changes in stool frequency should be followed up by a healthcare provider.
4. Abdominal pain or stomach pain as an IBS symptom
For many people with IBS, pain is a very stressful irritable bowel symptom that limits activities of everyday life. It’s common for the pain to be spread throughout the abdomen. It may not be possible to pinpoint the pain. The extent of the pain is not always the same, and may vary with each episode. Abdominal pain with IBS might be felt as cramping, aching, stabbing, or dull. The pain might radiate to other internal organs, causing visceral hypersensitivity.
5. Bloating and gas as IBS symptoms
People who experience IBS symptoms may be impacted differently by different foods. Food with a potential for fermentation in particular is metabolized in the large intestine by bacteria that produce gases. An imbalance in the intestinal flora can also lead to increased gas formation and bloating.
In a person without IBS, flatulence is normal up to 20 times per day. Certain nutritional supplements, like creatine monohydrate (used frequently by those interested in fitness), can lead to foul smelling gas. Food intolerance can also be a cause of flatulence.
Functional bloating or distention is a condition distinct from IBS when the following predominant symptoms are present in the last three months:
- Abdominal fullness
- Abdominal pressure
- A feeling of trapped gas
- A measurable increase of the abdominal girth
The onset of the symptoms need to be at least six months prior to the diagnosis. People with functional bloating should not meet criteria for other functional bowel disorders and all other physical and organic causes like lactose intolerance should be ruled out.
6. Feeling of fullness or distended belly as an IBS symptom
While healthy people also experience a feeling of fullness after a particularly rich high-fat meal, people with IBS report a pronounced feeling of fullness even when they eat less.
In people with IBS, this feeling of fullness might not always be associated with increased gas formation. A change in pain perception via the bowel-brain axis could cause hypersensitivity, so even small amounts of gas in the intestine might cause pain. Small intestine colonization with bacteria—also known as small intestinal bacterial overgrowth (SIBO)—may also be responsible for painful gas formation and a bloated stomach.
7. Mental health and IBS symptoms
The intestinal flora, the intestinal (enteric) nervous system, and the brain (central nervous system) are all interdependent. The connection is also called the microbiome-gut-brain axis and plays an important role in the development and maintenance of IBS symptoms. The mutual influence of the gut and brain takes place via certain messenger substances and the autonomic nervous system.
In people with IBS, there is usually an overstimulation of the autonomic nervous system, which can have a negative impact on mental health in the form of restlessness and anxiety.
8. Other possible IBS symptoms
Other symptoms that often occur in combination or as a result of IBS are:
- Fatigue and exhaustion
- Restlessness and nervousness
- Depressed mood, anxiety disorders
- Acidic regurgitation and belching
- Other stool changes, such as mucus in stool
- Headache and body aches
- Sleep and concentration disorders
- Circulatory disorders like low blood pressure
Which symptoms are not typical for IBS? Know the warning signs of something more serious
In the event of acute, unclear severe pain, bleeding, or other suspicious symptoms, a healthcare provider should always be consulted immediately.
Some important warning signs are:
- Blood in the stool
- Weight loss
- Nighttime abdominal pain
- Nocturnal diarrhea (diarrhea at night)
What symptoms lead to an IBS diagnosis?
The typical symptoms described above, such as feeling of fullness or diarrhea, do not automatically meet the diagnostic criteria of IBS.
Likewise, there is no specific combination of symptoms required for an IBS diagnosis. The Rome IV criteria define what should be present in order to diagnose IBS:
- Symptoms must have appeared at least 6 months before the diagnosis is made, and last on average at least one day per week in the last three months
- Recurrent abdominal pain must be present
The abdominal pain must be associated with at least two of the following signs:
- The pain must be related to bowel movements
- The pain is associated with a change in frequency of bowel movements
- The pain is associated with a change in form and appearance of stool
When IBS symptoms impact quality of life, seeking help from a healthcare professional can help ease some of the symptoms. Lifestyle modifications including dietary changes and stress reduction may improve symptoms for some people. In severe cases, medication for IBS may help manage pain and other symptoms.
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