Although there are many distinctions between the two, one key differentiator is that IBD involves swelling (or the destruction) of the intestines, whereas IBS does not. These conditions require very different treatments, and as such, an accurate diagnosis is vital to ensure proper management.
Read on to learn more about IBD and how it differs from IBS.
What is IBS?
- Abdominal pain
- Constipation or diarrhea
- Bloating and gas
The cause of IBS is unclear, but it is thought to arise due to a miscommunication between the gut and the brain. Many people with IBS report triggers such as stress, infection, or hormonal changes, all of which can make symptoms worse.
IBS can severely impact your quality of life. While some people can continue their daily activities and find their gut symptoms to be manageable, for others, IBS can be incapacitating. Some people even find that IBS affects many areas of their life— from their relationships and work to their mental health.
IBS can often come with a higher likelihood of developing other conditions. For instance, people with IBS are more likely to have other functional disorders such as fibromyalgia and chronic fatigue syndrome. What's more. IBS is often associated with conditions such as anxiety, even though IBS is not thought to be a psychological disorder.
Subtypes of IBS
There are different subtypes of IBS that are classified based on symptoms:
- IBS-C (IBS with constipation): Constipation is the main symptom. There are fewer bowel movements overall, and you may strain to pass them. At least a quarter of stools are hard and lumpy, and less than a quarter are loose. IBS-C is the most common subtype of IBS.
- IBS-D (IBS with diarrhea): Diarrhea is the main complaint. More than a quarter of stools are loose, while less than a quarter are hard and lumpy. You may experience more frequent bowel movements.
- IBS-M (IBS with mixed bowel habits): Symptoms of constipation and diarrhea may alternate. Your stools on abnormal bowel movement days may be both hard and lumpy or loose and watery. Both must occur at least one-quarter of the time to have IBS-M.
What is IBD?
Inflammatory bowel disease (IBD) refers to two disorders that involve inflammation of the bowels: ulcerative colitis and Crohn's disease. Both conditions involve inflammation and ulcers on the superficial lining of your large intestine (colon) and rectum.
IBD can cause similar symptoms to those in IBS, such as abdominal pain, constipation, diarrhea, bloating, cramping and gas. However, IBD may also cause additional symptoms such as:
- Rectal bleeding
- Eye, skin, or joint inflammation
- Weight loss
- Bloody stools
IBD may cause the intestines to bleed or become anemic. This may result in an inability to eat, resulting in weight loss and malnutrition. The structural damage caused by IBD may result in abnormal findings such as a mass in the abdomen, an anal abscess (a collection of puss), or physical features of malnutrition.
Inflammation may also occur beyond the gut, such as in the skin, joints, and eyes. Dermatitis, arthritis, and iritis (sore eyes) related to IBD can be severe symptoms in themselves, and cause bleeding and sores.
The exact cause of IBD is not known. However, research suggests an immune system malfunction may cause IBD in people with a genetic predisposition.
What's the difference between IBS and IBD?
Unlike IBD, IBS isn't truly classified as a disease. IBS is a 'functional' disorder, meaning it produces symptoms without a clear cause. However, this does not mean that IBS is 'all in a person's head' and a psychological condition. The symptoms of IBS are real and can often be debilitating.
Where is IBS and IBD pain normally located?
In IBS, the pain is usually spread over a wider area of the abdomen but is usually located in the lower half. In IBD, the pain can occur anywhere in the abdomen, and its location may suggest the type of IBD you have. Crohn's disease usually causes pain in the lower right side of your belly. The other primary type of IBD, ulcerative colitis, leads to pain in the left side of your abdomen.
The difference in IBS and IBD prevalence
IBS is common and affects up to 15% of individuals worldwide, whereas IBD affects fewer than 1% of people worldwide. Both conditions affect people of all ages, although IBS is more prominent in younger people. Women are about twice as likely to have IBS than men, but IBD is equally common in both genders.
How are these conditions diagnosed?
IBS does not produce physiological damage or disease to the gut, and the condition is diagnosed based on symptoms. In contrast, IBD causes physiological changes to the gut and is diagnosed using physiological markers (measurable signs of disease).
The ROME IV criteria is generally used to diagnose IBS. These require symptoms of abdominal pain for at least one day a week for the past three months, accompanied by at least two of these factors:
- Changes in abdominal pain and discomfort after defecation
- Changes in the frequency of defecation
- Changes in stool consistency
Your doctor may also recommend blood tests, stool tests, breath tests, or imaging examinations to rule out other conditions.
To diagnose IBD, various tests may be performed to confirm systemic changes and signs of damage to the gastrointestinal tract. These include:
- Blood tests: to check for anemia, a condition in which there are too few red blood cells to carry adequate oxygen or infection.
- Stool tests: to check for microorganisms such as parasites in your stool.
- Colonoscopy: the doctor views your entire gastrointestinal tract using a thin, flexible, lighted tube with a camera at the end. A biopsy (a small sample of tissue) may be collected for laboratory analysis.
- X-ray imaging: if the pain is severe, you may require an abdominal X-ray to rule out serious complications, such as a colon perforation (a hole in your colon).
- Magnetic resonance imaging (MRI): a type of imaging that uses a magnetic field and radio waves to produce detailed images of organs. It is especially helpful to evaluate signs of a fistula (abnormal opening) around the anal area or the small intestine.
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IBS vs. IBD treatments
Treatment for IBS and IBD differ significantly. It is best to consult a doctor if you are experiencing symptoms and seek advice on treatment options.
There is no cure for IBS; the goal of treatment is to reduce the severity of symptoms. Treatment for IBS includes dietary changes, psychological therapies including hypnosis, and some drug treatments.
Medication for IBS
Certain IBS medications are used to treat IBS-C and IBS-D. IBS with constipation may be treated with linaclotide (Linzess), lubiprostone (Amitiza), and supplements, such as fiber and laxatives. In contrast, IBS with diarrhea may be treated with alosetron (Lotronex) and loperamide (Imodium).
Mind-body therapies for IBS
There are several approaches to treating IBS using mind-body and psychological therapies without medication. These include hypnotherapy, cognitive behavioral therapy, and brief psychodynamic psychotherapy, all of which have been proven effective in clinical trials. Yoga and meditation have also been shown effective in reducing symptoms of IBS. These approaches work on restoring signals between the gut and the brain.
There's no single diet that works for everyone with IBS. However, certain foods have been shown to worsen symptoms. These include foods and beverages containing caffeine, gluten, dairy, artificial sweeteners, fried foods, beans and legumes, alcohol, garlic, and onions.
The low FODMAP diet has been designed to remove foods that commonly trigger IBS and has been shown to reduce symptoms of IBS in several clinical trials.
Treatment for IBD generally involves lowering inflammation. In the best-case scenario, this will result in long-term remission and reduced risk of complications. IBD treatment usually involves drug therapies or surgery.
IBD anti-inflammatory drugs
Anti-inflammatories are often the first treatment approach for IBD. These drugs include corticosteroids and aminosalicylates. Which one you take will depend on which part of your colon is affected.
IBD immune system suppressors
These drugs work in various ways to suppress the immune response that releases inflammatory chemicals into the bloodstream. The release of these factors can damage the lining of the digestive tract. A few examples of immunosuppressive drugs include azathioprine (Azasan), mercaptopurine (Purinethol), and methotrexate (Trexall).
Antibiotics may be used to treat IBD if an infection is contributing to symptoms. Commonly prescribed antibiotics for IBD include metronidazole (Flagyl) and ciprofloxacin (Cipro).
Biologics are a newer type of therapy that work by targeting and neutralizing the proteins that cause inflammation. Examples include infliximab (Remicade), certolizumab (Cimzia), adalimumab (Humira), and golimumab (Simponi).
It is estimated that 20% of people with ulcerative colitis have severe symptoms that do not improve with medicine. In these cases, surgery may be needed. This may involve the removal of the damaged section of the bowel or the entire colon and rectum. Around 60% of people with Crohn's disease will need surgery to repair the damage to their digestive system and to treat the complications of the disease.
What is the outlook for these conditions?
IBD is a lifelong condition for which there is currently no cure. Symptoms may flare up and then subside in cycles. People with ulcerative colitis or Crohn's disease are at an increased risk of getting bowel cancer. Your doctor may recommend regular bowel check-ups (endoscopy) to assess your risk of cancer.
IBS can be painful and disrupt one's life but usually doesn't cause any severe long-term complications. Many patients can significantly improve their condition by understanding IBS and adhering to a management plan.
IBS and IBD are two very different conditions with similar-sounding names that both affect the gastrointestinal tract. IBS is essentially a collection of gut symptoms that commonly occur together, without a clear cause, whereas IBD is associated with inflammation and swelling of the gastrointestinal tract. It is essential to get a medical diagnosis if you think you may be experiencing symptoms of IBS or IBD, as treatment approaches differ significantly.