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Irritable Bowel Syndrome (IBS)

Medically Reviewed by Jabeen Begum, MD on October 18, 2021

What Is Irritable Bowel Syndrome (IBS)?

IBS is a mix of belly discomfort or pain and trouble with bowel habits: either going more or less often than normal (diarrhea or constipation) or having a different kind of stool (thin, hard, or soft and liquid). Doctors used to call IBS other names including:

  • IBS colitis
  • Mucous colitis
  • Spastic colon
  • Nervous colon
  • Spastic bowel

There are four types of the condition:

  • IBS with constipation (IBS-C)
  • IBS with diarrhea (IBS-D)
  • Mixed IBS (IBS-M) alternates between constipation and diarrhea
  • Unsubtyped IBS (IBS-U) for people who don't fit into the above types

IBS isn’t life-threatening, and it doesn't make you more likely to get other colon conditions, such as ulcerative colitis, Crohn's disease, or colon cancer. But it can be a long-lasting problem that changes how you live your life. People with IBS may miss work or school more often, and they may feel less able to take part in daily activities. Some people may need to change their work setting: shifting to working at home, changing hours, or even not working at all.

IBS Symptoms

People with IBS have symptoms that can include:

  • Diarrhea (often described as violent episodes of diarrhea)
  • Constipation
  • Constipation alternating with diarrhea
  • Belly pains or cramps, usually in the lower half of the belly, that get worse after meals and feel better after a bowel movement
  • A lot of gas or bloating
  • Harder or looser stools than normal (pellets or flat ribbon stools)
  • A belly that sticks out
  • Mucus in your poop
  • Feeling like you still need to poop after you just did
  • Food intolerance
  • Tiredness
  • Anxiety
  • Depression
  • Heartburn and indigestion
  • Headaches
  • Needing to pee a lot

Other things may cause these symptoms sometimes. If it’s IBS, you’ll likely have these symptoms weekly for 3 months, or less often for at least 6 months. Women with IBS may have more symptoms during their period. Some people also have urinary symptoms or sexual problems. Stress can make symptoms worse.

When to call your doctor

If you have an IBS symptom that lasts a long time, you get a new symptom, or your pain is worse than usual or you have new pain, see your doctor. If you usually take over-the-counter medications but now they don’t ease problems like diarrhea, gas, or cramping, you also need to see a doctor.

Even if you don’t think a problem is physically part of IBS, but it bothers you, tell your doctor. For example, if you’re stressed out or anxious about it, or if you’re losing sleep over the problem, let your doctor know.

IBS usually doesn’t lead to more serious diseases, but there are “red flags” to look for that could mean something more serious is going on. A red-flag symptom is one that isn’t usually seen with IBS. If you have one or more, see your doctor. You’ll need tests to find out what’s going on.

Red-flag symptoms include:

  • Rectal bleeding: It could just be a side effect from your irritable bowel syndrome constipation, caused by a tear in your anus. The bleeding also might be caused by a hemorrhoid. But if you have a large amount of blood in your stool, or if the bleeding just won’t go away, you should get medical attention as soon as possible.
  • Weight loss: If you find you’re losing weight for no reason, it’s time to get it checked out.
  • Fever, vomiting, and anemia: If you have one or more, or think you do, you should call your doctor.

IBS Causes and Risk Factors

While several things are known to trigger IBS symptoms, experts don't know what causes the condition.

Studies suggest that the colon gets hypersensitive, overreacting to mild stimulation. Instead of slow, rhythmic muscle movements, the bowel muscles spasm. That can cause diarrhea or constipation.

Another theory suggests it may involve chemicals made by the body, such as serotonin and gastrin, that control nerve signals between the brain and digestive tract.

Other researchers are studying to see if certain bacteria in the bowels can lead to the condition.

IBS affects between 25 million and 45 million Americans. Some things seem to make people more likely to have it than others:

  • Being a woman. About twice as many women as men have the condition. It’s not clear why, but some researchers think the changing hormones in the menstrual cycle may have something to do with it. So far, studies haven’t borne this out.
  • Age. IBS can affect people of all ages, but it's more likely for people in their teens through their 40s.
  • Family history. The condition seems to run in families. Some studies have shown that your genes may play a role.
  • Emotional trouble. Some people with IBS seem to have trouble with stress, have a mental disorder, or have been through a traumatic event in their lives, such as sexual abuse or domestic violence. It's not clear what comes first -- the stress or the IBS. But there's evidence that stress management and behavioral therapy can help relieve symptoms in some people with the condition.
  • Food sensitivities. Some people may have digestive systems that rumble angrily when they eat dairy, wheat, a sugar in fruits called fructose, or the sugar substitute sorbitol. Fatty foods, carbonated drinks, and alcohol can also upset digestion. There's no proof any of these foods cause IBS, but they may trigger symptoms.
  • Medications. Studies have shown a link between IBS symptoms and antibiotics, antidepressants, and drugs made with sorbitol.
  • Other digestive problems, like stomach flu, traveler's diarrhea, or food poisoning. A small study published in January 2021 suggests that a GI tract infection can change the immune system so that it responds to certain foods as if they're a threat, like germs or viruses. Researchers are looking into these early findings.

IBS Diagnosis

There are no specific lab tests that can diagnose IBS. Your doctor will see if your symptoms match with the definition of IBS, and they may run tests to rule out conditions such as:

Your doctor may do some of the following tests to decide if you have IBS:

IBS Treatment and Home Care

Nearly all people with IBS can get help, but no single treatment works for everyone. You and your doctor will need to work together to find the right treatment plan to manage your symptoms.

Many things can trigger IBS symptoms, including certain foods, medicines, the presence of gas or stool, and emotional stress. You’ll need to learn what your triggers are. You may need to make some lifestyle changes and take medication.

Diet and lifestyle changes

Usually, with a few basic changes in diet and activities, IBS will improve over time. Here are some tips to help ease symptoms:

  • Avoid caffeine (in coffee, tea, and soda).
  • Add fiber to your diet with foods like fruits, vegetables, whole grains, and nuts.
  • Drink at least three to four glasses of water per day.
  • Don't smoke.
  • Learn to relax, either by getting more exercise or by reducing stress in your life.
  • Limit how much milk or cheese you eat.
  • Eat smaller meals more often instead of big meals.
  • Keep a record of the foods you eat so you can figure out which foods bring on bouts of IBS.

Common food "triggers" are red peppers, green onions, red wine, wheat, and cow's milk. If you're concerned about getting enough calcium, you can try to get it from other foods, like broccoli, spinach, turnip greens, tofu, yogurt, sardines, salmon with bones, calcium-fortified orange juice and breads, or calcium supplements.

Your doctor may suggest you try something called a low FODMAP diet that cuts down on hard-to-digest carbs such as wheat, beans, and certain fruits and vegetables.  

Medications

The following types of drugs are used to treat IBS:

  • Bulking agents, such as psyllium, wheat bran, and corn fiber, help slow the movement of food through the digestive system and may also help relieve symptoms.
  • Antibiotics, such as rifaximin (Xifaxan), can change the amount of bacteria in your intestines. You take pills for 2 weeks. It can control symptoms for as long as 6 months. If they come back, you can be treated again.

Other treatments can help with symptoms of IBS:

Belly pain and bloating

  • Antispasmodics can control colon muscle spasms, but experts are unsure that these drugs help. They also have side effects, such as making you drowsy and constipated, that make them a bad choice for some people.
  • Antidepressants may also help relieve symptoms in some people.
  • Probiotics, which are live bacteria and yeasts that are good for your health, especially your digestive system; doctors often suggest them to help with digestive problems.

Constipation

  • Linaclotide (Linzess) is a capsule you take once daily on an empty stomach, at least 30 minutes before your first meal of the day. It helps to relieve constipation by helping bowel movements happen more often. It’s not for anyone 17 years old or younger. The drug's most common side effect is diarrhea.
  • Lubiprostone (Amitiza) can treat IBS with constipation in women when other treatments have not helped. Studies haven’t fully shown that it works well in men. Common side effects include nausea, diarrhea, and belly pain. More serious side effects may include fainting, swelling of the arms and legs, breathing problems, and heart palpitations.
  • Plecanatide (Trulance) has been shown to treat constipation without the usual side effects of cramping and belly pain. The once-a-day pill can be taken with or without food. It works to increase gastrointestinal fluid in your gut and encourage regular bowel movements.
  • Polyethylene glycol (PEG) is an osmotic laxative and causes water to remain in the stool, which results in softer stools. This medication may work best for those who can't tolerate dietary fiber supplements.
  • Tegaserod is a drug for women. It works by speeding up the motion in your gut. This effect shortens the time stool remains in the bowel, and helps lessen symptoms such as belly pain and constipation.
  • Tenapanor (IBSRELA) increases bowel movements and decreases belly pain.

Diarrhea

  • Alosetron (Lotronex) can help relieve stomach pain and slow your bowels to relieve diarrhea, but there can be serious side effects, so it’s only to be used by women with severe IBS-D whose symptoms aren’t helped by other treatments.
  • Bile acid sequestrants are cholesterol-lowering medications. Taken orally, they work in the intestines by binding bile acids and reducing stool production.
  • Eluxadoline (Viberzi) is prescribed to help reduce bowel contractions, belly cramps, and diarrhea.
  • Loperamide (Imodium) works by slowing down the movement of the gut. This decreases the number of bowel movements and makes the stool less watery.

Make sure to follow your doctor's instructions when taking IBS medications, including laxatives, which can be habit-forming if you don’t use them carefully.

10 questions to ask your doctor

Going to the doctor can be intimidating. You might feel rushed and forget to ask questions that are important. It's always a good idea to know what to ask beforehand and to take notes while with the doctor.

Some of the questions below may be worth asking. Print out these questions and take them with you to your next appointment:

1. Could some other condition be causing my IBS symptoms? Could I have inflammatory bowel disease or colon cancer?

2. Should I keep a diary of my IBS symptoms, and, if so, what should I write down?

3. Should I take laxatives or other over-the-counter medications? If so, what type, and how often is it safe to take them?

4. Would it help my IBS symptoms to add more fiber to my diet? If so, how much and what kind?

5. Are there other dietary changes you would recommend for IBS, and should I consult a dietitian?

6. Could relaxation therapy, counseling, or exercise help my IBS?

7. Should I take prescription medications for my IBS symptoms? If so, what side effects should I expect?

8. Are there any tests you would recommend now or in the future?

9. Are there any other approaches or treatments I should know about?

10. How soon should I have a follow-up appointment?

IBS Complications

Because finding an IBS treatment that works can take time, other health problems can crop up in the meantime. None of the complications are life-threatening, though. IBS doesn't lead to cancer or other more serious bowel-related conditions. Here are some of the health issues it can cause:

  • Impacted bowel: If you're constipated for a long time, stool can get blocked in your colon. Sometimes it can get so hard that you can't push it out. This is known as a fecal impaction. It can hurt and cause things like headache, nausea, and vomiting. It happens most often with older adults. See your doctor right away if you have signs this may be happening.
  • Food intolerance: Certain foods can make your IBS symptoms worse. What they are can be different for everyone. But some people feel better when they cut out wheat, dairy, coffee, eggs, yeast, potatoes, and citrus fruits. And fats and sugars can make diarrhea worse. Your doctor may suggest you try a FODMAP diet to cut out some carbohydrates that are hard to digest.
  • Malnourishment: Cutting back on some types of foods can ease your IBS symptoms. But your body may not get all the nutrients it needs. A dietitian can help you find a diet that works for you.
  • Hemorrhoids: Swollen blood vessels around your anus, the opening where stool comes out, can hurt and bleed. Very hard or very loose stools can make the situation worse. If the swollen vessels are inside your anus, they may fall far enough to stick out.
  • You can often treat hemorrhoids at home with an over-the-counter cream. You also might try sitting on a cold ice pack. And be sure to keep the area clean.
  • Pregnancy complications: Hormone changes and the physical pressure a baby puts on the bowel wall can cause digestive issues. Many women also choose to stop any IBS drugs they're taking. This can be better for the baby. But it can make moms-to-be more likely to have things like heartburn and indigestion.
  • Quality of life: Flare-ups can happen without warning. Also, you may have diarrhea for a time and then be constipated. Not being able to predict how you'll feel can make it hard to go about your daily life.
  • You also probably need to see your doctor often and are likely to miss more work than other people. It may be harder to focus when you're at your job. Managing stress, for example through exercise or meditation, can help.
  • Depression and anxiety: It's common for people who have IBS to feel like they're losing control over their lives. If your symptoms are bad, you may find yourself always trying to map out the nearest bathroom.
  • Because there's a link between your brain and gut, this kind of stress can make your IBS worse. The pain and the awkward symptoms you're dealing with can affect your mood. It may help to talk to a counselor about what's going on with you.
WebMD Medical Reference

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