Thursday, May 23, 2024
HomeHealthDigestionComplete Guide To Irritable Bowel Syndrome

Complete Guide To Irritable Bowel Syndrome

Irritable Bowel Syndrome, in short IBS or Spastic colon, is a Gastrointestinal disorder that affects the Large Intestine (large bowel/colon). It is usually characterized by an abnormal bowel movement, Abdominal Pain, Diarrhea, and constipation.    


When we eat food, it goes through our digestive tract, also known as the Alimentary canal. The digestive tract is ringed with muscles that contract in a wave-like motion called Peristalsis. These rhythmic muscle contractions are central to food movement through the lot. The food gets digested as it moves through the tract. 

It proceeds from the mouth to the stomach, where it gets acted on by digestive juices and enzymes before entering the Small Intestine. Every last bit of useful material is absorbed except water. The remaining product moves through the final stage; The large Intestine, where, by peristaltic contraction, the food moves through at a rate where an adequate amount of water can be reabsorbed. 

In Irritable Bowel Syndrome, there is an abnormal contraction of muscle responsible for Peristalsis, leading to faster contraction as food mass moves through the Large Intestine. 

Little water is reabsorbed due to this, and it leads to a watery stool. Or slower contractions, leading to more water being reabsorbed as the food mass moves through the Large Intestine, which increases the solidity of mass and subsequent constipation. Irritable bowel syndrome (IBS) affects between 6–18% of people worldwide.

Risk factors associated with the condition are; Anxiety and Depression, Family History of IBS. Gender also plays a role as it appears more in females than in males and people below 50.

No test can out rightly diagnose Irritable Bowel Syndrome. Physicians employ the Rome IV criteria for diagnosing IBS; It requires that the patient has had recurring stomach discomfort at least one day per week for the past three months. It is accompanied by excretion with or without relief or changes in stool frequency, appearance, or form.

4 Categories of IBS Symptoms:

1. IBS -D (diarrhea-predominant)

2. IBS- C (constipation-predominant)

3. IBS-M (mixed diarrhea and constipation)

4. IBS- U (Unclassified, patients with symptoms that do not belong to the categories mentioned earlier. )

 To make a diagnosis, Physicians perform a Physical examination and medical history. They’ll ask questions about symptoms you, as the patient, have been experiencing. The frequency with which you experience Bloating, abdominal pain, and cramps, how often constipation and diarrhea occur, or alternation between constipation and diarrhea and stool consistency, and for how long these symptoms occur.

This is done to rule out other conditions with symptoms similar to IBS. Including Organic bowel disease, Celiac disease, Ulcerative Colitis.Adverse medication effects of drugs such as Antacids, Food intolerance including Lactose, Fructose, and FODMAPS (Fermentable, Oligosaccharides, Disaccharides, Monosaccharides, and Polyols) — which are common triggers of IBS.

How IBS Is Diagnosed


An endoscopic exam where a long, flexible tube is inserted into the anus passed through Rectum into the Large Intestine. A camera at the front end of the device allows viewing of the colonic tract, its contents, and the surrounding walls.

Upper Endoscopy

Also employs a long, flexible tube inserted into the mouth, down the throat, into the stomach. The camera at the front end relays images of inspection of the stomach content and walls of the digestive tract.


Using a contrast agent (Barium— which increases the contrast between tissues and makes the problem more visible) produces images of the Abdomen and Pelvis.

Other Tests For IBS 

Erythrocytes Sedimentation Rate (ESR) 

For screening out inflammation

Hydrogen Breath Test 

To exclude bacterial overgrowth in patients with diarrhea.

Lactose Intolerance

To determine whether your body can produce Lactase, an enzyme responsible for breaking down sugar content, i.e., Lactose, in diary products. The inability of the body to produce Lactase results in abdominal pain, diarrhea, and flatulence when dairy products are consumed. These symptoms are similar and can be mistaken for IBS.

 Stool test

An examination of your stool for bacteria to rule out bacterial infection.

Blood test

To check for anemia to rule out Celiac disease— caused by the immune response to gluten, a protein found in wheat and Barley, resulting in inflammation of the Small Intestine, malabsorption of nutrients fatigue, diarrhea, bloating, and anemia.

gi tract

Cause Of IBS 

Clinical experts are not sure of what causes it. Some theory suggests the large Intestine becoming hypersensitive to mild stimulation, meaning instead of the normal rhythmic wave-like contractions, the muscle contracts abnormally, which affects the movement of food mass across the large Intestine.

Another idea proposes that it is due to bodily substances such as serotonin and glutamate, which influence nerve signals between the brain and the digestive tract.

Other likely causes or Triggers include;

Food intolerance, poisoning, or allergy.

Gastric infection 

Severe infections such as gastroenteritis resulting from a bacterial or viral infection can cause severe bouts of diarrhea that might develop into IBS.

Stress and Anxiety

People, especially teenagers exposed to stressful events at an early age, tend to have symptoms of IBS.


The common symptoms of IBS include 

Abdominal pain and cramping

The most frequent symptom and a significant component in diagnosis is abdominal pain. Normal digestion is controlled by a partnership between your stomach and brain. 

Hormones, nerves, and signals generated by the beneficial bacteria in your gut play a role in this. These cooperative signals get skewed in people with IBS, resulting in uncoordinated and unpleasant tension in the digestive tract muscles. 

This pain is commonly felt in the lower abdomen or across the stomach, although it is less common in the upper abdomen. Following a bowel movement, the pain usually subsides. Dietary changes, such as consuming low-FODMAP meals, may help with pain and other symptoms. Bowel relaxants, such as peppermint oil, are another option.


Some of the most frequent and aggravating symptoms of IBS are gas and bloating. Bloating can be reduced by eating a low-FODMAPs diet.


The most prevalent IBS is constipation-predominant IBS, which affects approximately half of patients with IBS. Stool transit time may be sped up or slowed down due to a disruption in communication between the brain and the gut. The gut collects more water from feces as transit time slows, making it more difficult to pass. Constipation in IBS typically creates a sense of an incomplete bowel movement, in addition to abdominal pain that improves following a bowel movement. Unnecessary straining arises as a result of this.


Diarrhea-predominant One of the three primary forms of IBS is Irritable Bowel Syndrome (IBS). It affects around one-third of IBS patients. In IBS, accelerated bowel transit can also cause a sudden, intense tendency to go to the bathroom. Some patients report that this is a major cause of worry and that they avoid certain social situations in fear of a rapid start of diarrhea. The stool is usually loose, watery, and may contain mucus.

Alternating Constipation and Diarrhea.

Anxiety and Depression

IBS has also been related to anxiety and depression. It’s unclear if IBS symptoms are a manifestation of mental stress or if the stress of having IBS makes people more susceptible to mental health problems. Anxiety and intestinal IBS symptoms reinforce one other in a vicious spiral, regardless of which occurs first.

Food intolerance

Up to 70 percent of patients with IBS say that certain meals provoke symptoms. Why certain foods induce symptoms is unclear. Food intolerances are not allergies, and trigger foods have no tangible impact on digestion. While each person’s trigger foods are different, popular ones include gas-producing foods like FODMAPs, as well as dairy and gluten-containing food like Wheat and Rye.


Lubiprostone and Linaclotide

They are both drugs that increase fluid secretion and helps with the passage of stool.


This drug ease diarrhea by reducing muscle spasm of the Large Intestine.


This drug is designed to relax the large colon and slow waste through the lower colon. It is prescribed in women with Diarrhea-predominant IBS who haven’t responded to other treatments.

It is only considered when other treatments have failed, and its application is restricted to severely affected patients with IBS due to Alosetron’s serious GI adverse reaction. Doctors that prescribe this drug must be registered with the Alosetron Prescribing Program.


It increases intestinal fluid secretion and accelerated transit. It is prescribed to patients with Constipation-predominant IBS.


This drug increases water secretion into the intestinal tract and accelerates food mass/stool transit time, resulting in softer stool consistency. They are prescribed to adults with Constipation-predominant IBS.

Other Medications in IBS

Tricyclic Antidepressants

These agents have Antidepressant and analgesic properties and effectively treat IBS and reduce abdominal pain.

They include; Imipramine and Amitriptyline.


May play a role in the treatment of IBS by preventing bacterial growth. Example: Rifaximin, antibiotic used in adult patients with Diarrhea-predominant Irritable Bowel Syndrome.

Bulk-forming Laxatives

Made up of natural and synthetic polysaccharides, Cellulose derivatives. They dissolve or swell in intestinal fluids to form smooth, moisturizing gels that facilitate the passage of intestinal contents and promote bowel movement and help prevent constipation.


Promotes bowel evacuation by forming viscous liquid and promoting movement.

Fiber Supplement

Such as Psyllium (Metamucil, Fiberall, Reguloid). These agents also promote bowel movement and evacuation.


These agents prolong GI transit time and reduce excessive bowel and evacuation, that is, diarrhea. Examples of these agents include Loperamide and Diphenoxylate Hydrochloride plus Atropine sulfate.

Anticholinergics (Antispasmodics)

They are drugs that help relieve symptoms of intestinal spasms in IBS, and they reduce fecal urgency and pain. Useful in patients with diarrhea-predominant symptoms. Examples are Dicyclomine Hydrochloride and Hyoscyamine.

Bile Acid Sequestrants

They are cholesterol-lowering drugs. They operate in the intestines by binding bile acids and lowering stool output when taken orally. They are recommended in patients with Diarrhea predominant IBS.

SSRI Antidepressants

Selective serotonin reuptake inhibitors may help with depression, pain, and constipation. Example; Fluoxetine and Paroxetine.

Pain Relievers 

Such as Pregabalin or gabapentin may help with bloating and severe discomfort.


Surgery is not recommended for IBS treatment because it plays no function in the treatment of Irritable Bowel Syndrome.


Reducing stress and relieving stress through yoga, meditation, and regular exercise can help prevent depression and promote normal bowel movement. Patients should also increase fluid intake.


(fermentable oligosaccharides, disaccharides, monosaccharaides, and polyols.) It is surprisingly the most promising lifestyle change for alleviating symptoms, including bloating and gas. 

In reducing FODMAPs, it’s essential to know and monitor the food consumed. FODMAPS include Fructans(wheat and onion), Fructose (Apples and Blackberries), Lactose (found in Dairy products), Galatians (in beans), Polyols (in alcoholic sugars like Sorbitans and fruits like Peaches).

IBS-friendly Food 

Low in FODMAPs include; Strawberries, bananas, Oranges, Lactose-free Dairy; Lean proteins including Chicken, Eggs; Vegetables such as Tomatoes and Green beans. Sweeteners such as Cane sugar and Maple syrup.

It is also important to identify and avoid trigger food. Additionally, leaving digestive stimulants such as Caffeine, Alcohol, and Carbonated beverages can reduce symptoms. Other food which tends to worsen IBS include; Beans, fried food, high-fat food.

Probiotic supplements help replenish the good bacterial flora in the intestinal tract and also helps in reducing bloating and abdominal distension.


Long-term consequences range from physical health consequences, which include;

Anal Fissures 

Which are small tears in the anus.

Fecal Impaction 

Results when stool is packed tightly in the Rectum, and it’s not coming out through the anus.


Inflamed and swollen veins, leading to rectal bleeding due to excessive pushing and straining of the Rectum.


Certain food that exacerbates IBS is avoided leading to inadequate nutrition and weight loss.

Long-term Mental health consequences can result from living with persistent abdominal pain, diarrhea, constipation, and bloating.

IBS can lead to anxiety over symptoms including withdrawal from others, social circles, and taking off days from work and school. This also causes a lack of motivation. Thus, depression sets in, leading to reduced quality of life (QOL).


Clinical studies are being conducted on Asimadoline, a kappa-opioid agonist. It has a favorable safety profile and has been found to decrease pain, urgency, and stool frequency in individuals with IBS-D.

Dextofisopam, a benzodiazepine receptor modulator, binds to benzodiazepine receptors in the brain rather than the gastrointestinal system and has no sedative effect. It showed promise in animal trials for reducing intestinal motility and gut sensitivity in response to stress. More research is needed to determine the mechanism of action and the safety and efficacy of the drug in humans.

New treatments for IBS are being researched, such as fecal micro biota transplantation (FMT). It is currently under examination. FMT replaces healthy intestinal bacteria by inserting processed stool from another person into the colon of an IBS patient. Fecal transplants are now being studied in clinical trials.

Hypnosis: Through the guidance of trained professionals, IBS patients are taught how to enter a relaxed state and then guided into relaxing their abdominal muscles. Studies show it can help reduce abdominal pain and bloating with long-term effectiveness.


Irritable Bowel Syndrome is a disorder that affects large bowel movement resulting in irregular bowel movement, diarrhea, constipation, bloating, and abdominal pain.

 Causes could be related to stress, medications, or infection

Symptoms are abdominal pain, bloating, gas, cramping, diarrhea, and constipation.

It can be controlled by increasing fiber consumption, managing stress through exercise and yoga, and reducing stress. Medications to take care of IBS range from antispasmodics, antidiarrheals, Antidepressants, or psychological therapy.

External links.

Mayo Clinic



Most Popular