Irritable Bowel Syndrome (IBS)
Signs and Symptoms
IBS is not a single entity. It’s a collection of abdominal and bowel-related symptoms. Symptoms common in IBS that support a diagnosis are:
- Abdominal pain
- Abnormal stool frequency
- Abnormal stool from
- Straining at defecation
- Feeling like you haven’t completely emptied your bowels
- Mucus in stool
While most people experience digestive troubles once in a while, what sets IBS apart is abdominal pain and diarrhea or constipation that comes back again and again. At times, the pain and discomfort of IBS symptoms may be severe and debilitating, and at other times, they may improve or even disappear completely.
Signs & symptoms of IBS with constipation (IBS-C)
When living with IBS-C, symptoms may suddenly worsen (flare) and then improve for no apparent reason. When symptoms flare, they may be severe, debilitating and last for days or months. Possible signs and symptoms of IBS-C are:
- abdominal pain or discomfort
- gas, bloating and abdominal distention
- straining when having a bowel movement
- a sense that something is blocking your rectum
- infrequent bowel movements (less than three per week)
- feeling like you have not completed your bowel movement other illnesses so that those can be ruled out.
- diarrhea or loose, watery stools, especially in the morning or after meals
- passing stools three or more times per day
- sudden urgency before bowel movements
- feeling of incomplete emptying after bowel movements
- abdominal pain or cramping
- loss of bowel control or soiling yourself
What causes irritable bowel syndrome (IBS)?
The exact cause of IBS is unknown, however, it is believed that IBS may be caused by one of several factors. In some patients, it may be linked to a prior infection or event which disrupts the normal functioning of the intestines. It is common for people to develop IBS following a gastrointestinal infection, food poisoning, traveller’s diarrhea, surgery, a change in diet or the use of antibiotics or new medications. In others, an imbalance of intestinal bacteria or a change in the body’s level of hormones, immune signaling in the bowel wall or neurotransmitters (brain chemicals) may also lead to the development of IBS. Currently, there is a great deal of interest in possible alterations in the number or type of bacteria within the intestine, but the exact role this may play in IBS is not yet known. In people with IBS, bowel function can be altered in several ways:
- Motility (movement of contents through the intestines): Normally, waves of coordinated intestinal muscle contractions (peristalsis) transport digested food through the intestines. In people with IBS, the rhythm and coordination of these contractions may be altered. This altered motor function can result in the bowel moving too quickly (causing diarrhea) or too slowly (causing constipation) and can lead to spasm and pain.
- Sensitivity (how the brain interprets signals from the intestinal nerves): The network of nerves surrounding the digestive organs may become unusually sensitive. For some people with IBS, even a small change in intestinal activity can trigger the nerves to send messages to the brain causing abdominal pain.
- Brain-gut dysfunction:In IBS, there may be problems in how the brain receives and processes sensations coming from the intestines. A malfunction may occur along the many different pathways that connect the brain and gut, interfering with the normal function of the intestines. Many aspects of everyday living can trigger or aggravate IBS symptoms. Triggers vary from person to person, but the most common ones include certain foods, medications, emotional stress and hormone fluctuations. In particular, foods such as caffeine, alcohol, carbonated drinks, fatty foods, certain fruits and vegetables, as well as lactose, fructose and gluten (wheat protein) can cause problems for people with IBS.
Risk factors of IBS
- Age: IBS can affect people of all ages, but it often begins in the teen years or early adulthood.
- Gender: IBS affects more women than men.
- Family history of IBS: People with a first-degree relative (parent or sibling) with IBS are at greater risk of developing the condition.
What causes IBS with constipation (IBS-C)?
The cause of IBS-C is not yet known; however, there are a variety of factors that may contribute to the disorder. These include:
- Intestinal motility: The walls of the intestines are lined with layers of muscles that contract and relax in a coordinated rhythm as they move food from your stomach to your intestines through a process called peristalsis. For those with IBS-C, contractions within the intestine may be reduced or delayed causing gas, bloating and stool to move slower than normal.
- Nerve Hyper-Sensitivity: Poorly coordinated signals between the brain and the gut can make your body overreact to the activities taking place during digestion causing increased sensitivity. This may explain why those with IBS-C experience abdominal pain and discomfort. Excess fluid absorption: Constipation results when the intestine absorbs too much fluid from the stool, which can occur because of reduced or delayed contractions. Brain-bowel connection: There is a strong connection between our brain and bowel. This is sometimes called the brain-gut connection. In individuals with IBS-C, a possible disconnect or miscommunication between the mind and gut, may impact motility, pain sensitivity and fluid absorption. This disconnect may result in abdominal pain, discomfort and constipation.
Risks associated with IBS-C
If left untreated, IBS-C can potentially lead to additional health complications. These include:
- Hemorrhoids: enlarged veins (blood vessels) in the rectum that may bleed or descend through the anus
- Anal fissure: a crack in the lining of the anus caused when large or hard stools stretch the anal sphincter
- Fecal impaction: a mass of hard stool that cannot be excreted by a normal bowel movement and may need to be removed manually
- Rectal prolapse: rectal tissue pushes out through the anus
- Lazy bowel syndrome: caused from frequent use of laxatives to have bowel function properly
What causes irritable bowel syndrome with diarrhea (IBS-D)
Although the exact cause of IBS-D is unknown, it is believed that IBS-D may be caused by one of several factors:
- Brain-gut dysfunction: There is a dynamic bidirectional communication between the gut and the brain. A malfunction may occur along the many different pathways that connect the brain and gut and changes in one pathway ultimately cannot affect others.
- Bacterial Infection: Food poisoning, traveler’s diarrhea. These infectious agents are cleared from the body typically within days but lead to chronic alterations in motility (gut too fast or too slow) and abnormal sensory signalling to the brain.
- Bile acids: These are normally absorbed in the small bowel but some patients spill too many into the large bowel (colon) and this can trigger diarrhea and cramps.
- Food Sensitivity: Many patients have meal-induced symptoms. Some patients have a hypersensitive gut and meals induce gut motility (e.g. distention) that can cause symptoms. There is also growing evidence that some food may also have specific actions on gut motility and this could involve alterations in the microbiome or that an individual’s microbiome might also make them more susceptible to specific foods. However much more research is needed in this area.
- Use of antibiotics or new medications: Antibiotics can cause an imbalance of intestinal bacteria and other medications a change in the motility in the gut.
- Stress and anxiety: These are not the cause of lBS-D but are recognized as a common trigger of symptoms in some individuals.
- Heredity: IBS-D can run in families but it is unclear how much of this association is related to some common environment or genetics. Recent research has identified one or more genetic defects that could be involved in a sub-set of IBS but further studies are needed to determine whether these defects are important. Consequently, genetic testing is not indicated.
Risks associated with IBS-D
If left untreated, IBS-D can potentially lead to additional health complications. These include:
- Diarrhea may aggravate hemorrhoids in people who already have them.
- Eliminating many foods from the diet may result in a diet that is too limited in nutrients that could cause health problems.
- Stress and anxiety can result from the pain, and can impact a person’s quality of life.
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