The approach to Irritable Bowel Syndrome (IBS) has changed. Years ago, the diagnosis of IBS was one of "exclusion." That is no longer the case. We now make the diagnosis of IBS clinically using the Rome IV criteria and with a few select tests. Rome IV criteria were developed to help make a diagnosis of IBS without resorting to extensive testing. These criteria are also used for research purposes.

Before reviewing the Rome IV criteria, we must understand the fact that screening colonoscopy to evaluate a patient for colon cancer is recommended for persons over 50, according to the U.S. Multi-Society Task Force (MSTF), which represents the American College of Gastroenterology, the American Gastroenterological Association, and The American Society for Gastrointestinal Endoscopy.[19] Many of our older patients being evaluated for IBS may have had a previous screening colonoscopy. If not, they need it. When considering IBS in patients younger than 50, the Rome IV criteria guide us to be very selective in performing colonoscopies, since they will be extremely low yield tests.

Rome IV Criteria for Irritable Bowel Syndrome [1]

Patient has recurrent abdominal pain (greater or equal to 1 day per week on average in the previous 3 months), with an onset greater or equal to 6 months before diagnosis.

Abdominal pain is associated with at least two of the following symptoms:

  • Pain related to defecation
  • Change in frequency of stool
  • Change in form (appearance) of stool

The specificity of Rome IV criteria in diagnosing IBS ranges up to 97.1%.[2] Alarm features raise the possibility of disorder other than IBS being present, although most patients even with alarm features will have a negative evaluation.

Alarm Features [3]

  • Age of onset after age 50
  • Rectal bleeding or melena
  • Nocturnal diarrhea
  • Progressive abdominal pain
  • Unexplained weight loss
  • Lab abnormalities including iron deficiency anemia, elevated C-reactive protein (CRP), abnormal calprotectin/lactoferrin
  • Family history of Inflammatory Bowel Disease or colon cancer

Of importance is that the Rome IV criteria now also include psychological and social situations that can affect IBS. Stress and poor coping skills can lead to family or work-related crises that exacerbate Irritable Bowel Syndrome. Clinicians realize these situations are extremely important in managing IBS. It also re-emphasizes the fact that IBS is multifactorial, as a result of both physiology and other factors as mentioned above.

The epidemiology is significant. [3]

  • IBS affects 10-15% of the population
  • Less than 33% of the patients see a provider
  • IBS has an estimated prevalence of 14% in women and 9% in men
  • Although IBS usually occurs before age 50, it can appear at any age[18]

Irritable Bowel Syndrome can be subtyped into Irritable Bowel Syndrome with constipation (IBS-C), Irritable Bowel Syndrome with diarrhea (IBS-D) and Irritable Bowel Syndrome mixed diarrhea and constipation (IBS-M). Most patients with IBS have the mixed type. These patients can rapidly change from diarrhea to constipation and back again to diarrhea.

There are many theories on the etiology of IBS including brain gut signal dysfunction, changes in microbiome, hypersensitivity, genetics, food allergies and motor disorders. Coexisting depression and somatization may also affect the immune system. However, the answer remains elusive.

When caring for patients with IBS, it is extremely important to consider their perspective. Frequently patients with IBS feel minimized, over tested, ignored and told that they have psychiatric issues.[4] Understanding their frustration and dealing with it is one of the keys to success. Herein lies one of the most important points in this article. Spending extra time with the IBS patient can lead to a more successful and satisfying therapeutic experience for both the patient and the provider.

Consider the following scenario: Your 53-year-old patient with IBS has moved three times in the last 4 years. Each time she has a full GI evaluation including endoscopy, colonoscopy and a battery of blood and radiology tests only to be told that "nothing was found." Ultimately caring for IBS does not necessarily translate into more testing. Often, it means more listening.

Now let's do some introspection. Why do we get stressed when we treat patients with IBS?

  • They are time consuming
  • There can be issues with drug abuse and mental health problems
  • They may have seen multiple providers
  • They test our patience and skills[5]

Case Presentation - Ed

Picture of Ed

Ed is a 52-year-old malpractice attorney working 18-hour days. He has mild abdominal pain, diarrhea about 70% of the time, alternating with constipation (IBS-D). He also has occasional blood mixed with stool for the past 3 months. He has a history of "hemorrhoid" and family history of colon cancer, both mom and dad at ages 55 and 63. His last colonoscopy 3 years ago was a good prep and normal. Recent labs include a CBC with normal hemoglobin and hematocrit.

What would you do next?

  1. Symptomatic care of the hemorrhoid and diarrhea since the colonoscopy 3 years ago was normal
  2. Follow up hematocrit (Hct); if it drops, then consider a colonoscopy
  3. Colonoscopy now

The correct answer is to perform a colonoscopy now.

This 52-year-old presents with rectal bleeding and a significant familial history of colon cancer diagnosed at an early age.

Rectal bleeding is an alarm feature. Alarm features are an indication that there may be a significant process occurring which would necessitate colonoscopy evaluation. The patient indeed has a hemorrhoid, but it is always possible to have a hemorrhoid and a colon cancer at the same time. Of course, a cancer will not often be found, but we are erring on the side of caution by performing a colonoscopy. Symptomatic care of hemorrhoids and follow up hematocrits would delay the colonoscopy. The presence of alarm features identifies patients more likely to have organic disease. It is NOT absolute in making such identifications.[6]

How much testing is sufficient to diagnose IBS? Without a specific test for IBS, we rely on clinical criteria (Rome IV) and selective testing to avoid exhaustive testing.[7]

If there are no alarm features some clinicians order:

  • Complete Blood Count (CBC) - will indicate anemia and infections
  • C- reactive protein (CRP) - to determine whether there is any systemic inflammation
  • Tissue transglutaminase (tTG) - serum test used to evaluate for Sprue/Celiac Disease
  • Fecal Calprotectin - protein which is increased in bowel inflammation and infections

The usefulness of colonoscopy in evaluating IBS at any age is very limited. Colonoscopy does not affect the diagnosis in 98.1% of cases with IBS-D.[8] Utilizing colonoscopy in suspected IBS patients who have alarm features will be much more cost effective.

The differential diagnosis of IBS-D is massive and can include:

  • Inflammatory Bowel Disease
  • Sprue
  • Lactose intolerance
  • Microscopic colitis
  • Hyperthyroidism
  • Infectious diarrhea
  • Colon cancer

Does the intensity of pain help distinguish IBS from other illnesses? No, there is no good way to assess the degree of pain. IBS pain is multifactorial due to:

  • Physiology
  • Stress/emotions
  • Food
  • Poor sleep
  • Gut bacteria, etc.

Which of the following helps distinguish Irritable Bowel Syndrome from Inflammatory Bowel Disease?

  1. Anemia
  2. Rectal bleeding
  3. Weight loss
  4. Fever
  5. All the above

The correct answer is all of the above.

Remember IBS is not associated with any of the alarm features. Indeed, if you have a patient with IBS who now develops alarm features, strong consideration should be given to re-evaluate the patient for other illnesses.

Does the intensity of pain lead to more GI consults? It may lead to more GI consults. When the patient tells the provider it's the "worst pain I've ever had" and "I know that something is being missed," it's the right time to consider GI back up to confirm your diagnosis. Certainly, a conversation with the gastroenterologist would be useful and help reduce additional tests.

Case Presentation - Charlie

Picture of Charlie

Charlie is a 71-year-old very healthy man who was well until 6 months ago. At that point, he suddenly developed profound nausea, vomiting, and diarrhea after babysitting his sick grandkids. He was admitted for dehydration and workup, including bloods and stools, all were normal. Colonoscopy and biopsies were performed. No abnormalities on observation or biopsy. Although the diarrhea is much improved, he still has a bowel movement seven times a day.

What do you recommend as the next step?

  1. Metronidazole
  2. Repeat colonoscopy
  3. Symptomatic care and anti-diarrhea medications, as necessary
  4. Fecal immunochemical test of stool (FIT)

The correct answer is symptomatic care and anti-diarrhea medications, as necessary.

This is a case of Post Infectious Irritable Bowel Syndrome.[9] The mechanism has not been elucidated, but it can occur in 10% of patients who have diarrhea. There may be a genetic predisposition and perhaps even an enhanced immunity. The symptoms can last weeks to months. Post infectious diarrhea is treated symptomatically and has an excellent prognosis.

Case Presentation - Marie

Picture of Charlie

Marie is a 33-year-old with two full NEGATIVE workups for Irritable Bowel Syndrome with diarrhea. She also has chronic pelvic pain that has been fully worked up including a laparoscopy.

Workup details include:

  • CBC, Gen Chem, CRP
  • Endoscopy, Biopsy
  • Colonoscopy, Biopsy
  • Free T4 test (T4) / Thyroid Stimulating Hormone (TSH)
  • tTG
  • Stool Ova and Parasites, Culture and Sensitivity, Clostridium Difficile
  • Lactose tolerance test

She is on Oxycodone 10 mg tid for her pain, which also helps her diarrhea. She tells you that this is the only medicine that works.

What other comments can you make? The use of narcotics makes it very difficult to treat IBS.

  • Narcotics are not indicated in the treatment of IBS.
  • Are we dealing with a patient who is a drug seeker, or someone who is willing to consider other approaches?
  • If she is willing to consider medications other than narcotics for symptom relief, we can offer antispasmodics. NSAIDs may also be considered if she does not have risk factors to their use. The use of NSAIDs here is for pain control and NOT a therapy for IBS. Antidepressants can be offered but remember they take at least 3-4 weeks to become effective and are used at lower doses than for the treatment of depression.
  • If the patient is willing to stop the narcotics, we must ensure that a practitioner is readily available to help detoxify her. If there is a delay in making this transition to detoxification, treatment failure is inevitable.

Case Presentation - Jamie

Picture of Charlie

Jamie is a 46-year-old Advanced Practice Registered Nurse (APRN) with IBS-D for 26 years.

Jamie asks, "what foods should I avoid?"

Patients with IBS often place undue emphasis on foods as a source of symptomatology.[10] IBS is multi factorial and dietary therapy plays a role. There have been many diets studied. What has emerged is a 50% improvement in symptoms using a low FODMAP (fermentable oligo, disaccharide, monosaccharides and polyols diet).[7] Soluble fiber (oatmeal, bran, apples, beans, etc.) is beneficial to many patients with IBS. Occasionally, we find an excess intake of diet foods containing sorbitol, cruciferous vegetables, sodas, caffeine and greasy foods are the dietary source of the patient's IBS issues. Patients with IBS need to write a careful diet diary from which we can determine foods or categories of foods that can exacerbate their symptoms.

How are low FODMAP diets used in treating IBS symptoms? Fermentable oligo, disaccharide, monosaccharides and polyols (FODMAP) are dietary sugars found in dairy products, wheat, grains, fruits and vegetables. A low FODMAP diet has been shown to be helpful in treating IBS symptoms.[12] Unfortunately, a low FODMAP diet is one of the most difficult to follow. A low FODMAP diet cannot simply be given as a diet sheet with the expectation that the patient will follow it. Several visits with a dietician are needed to review the restrictions, but also to re-introduce foods. Patients will find it difficult to continue more than a few weeks because of the restrictions.[13]

Jamie also asks, "will the IBS ever get better?"

Having an appropriate answer strengthens the patient-provider relationship. Can you imagine how a patient would feel if you told them "you will always have symptoms"? Similarly, can you imagine how a patient would feel if you tell them it will get better, despite many visits and telephone calls that contradict this statement? Finding the correct words like: "dealing with IBS is like sailing on the ocean; occasionally there will be calm seas and occasionally there will be storms." Adding that we, as providers, will help them chart a course can be very reassuring for patients.

What are some non-medication pearls in treating IBS?

If you don't have ample time for patients with IBS, you will not successfully treat them. This is not to imply that every visit requires an hour, but you need to be open and available to address their concerns. Looking away from the EMR and directly at the patient is an important start.

Shared Decision Making: Make your patient a partner
The patient needs to know that there will be an open discussion of options, including alternative medicine.

Address cancer phobia from the beginning
Oftentimes, patients with IBS have the idea that with negative test results, something must be missed, and on top of their minds is cancer.

Let your patient know from the beginning that the treatment of IBS is a process that takes time
We should reinforce the fact that we'll be there to guide them through this illness.

What are some "natural" medications for treating IBS-D? Many patients these days are seeking natural remedies for their illnesses. Depending where you practice, this may be a major issue you face.

  • Glutamine (an amino acid) in varying doses can treat some patients with IBS-D[14]
  • Peppermint oil or capsules, the most studied of the "natural" products, can successfully treat IBS-D[7]

What medications treat IBS-C? Failure of soluble fiber to treat constipation leads us to consider several options. Patient age, severity of illness, and other medical conditions are always considered when making choices. When considering medications from this group, even standard dosing can sometimes cause severe diarrhea in the elderly.

  • Surfactants (Colace®)
  • Lactulose (several brand names)
  • PEG Solutions (several brand names)
  • Milk of Magnesia
  • Senna
  • Bisacodyl
  • Docusate

Newer treatments for IBS-C:

  • Lubiprostone (AMITIZA®)
  • Linaclotide (LINZESS®)
  • Plecanitide (Trulance®)
  • Prucalopride (Motegrity™)

When considering medications from this group, we must be aware of:

  • Dosage
  • Restrictions in use
  • Adverse effects
  • Contraindications
  • Drug interactions
  • Costs - These are medications whose proper use requires a thorough review by the prescriber.

What are some adverse effects associated with these newer treatments? None should be used in patients suspected of having intestinal obstruction. Diarrhea, abdominal pain, dehydration, dizziness, headaches, and nausea have been reported in varying percentages for each of the above products.

Are probiotics effective in treating IBS? Probiotics improve the global symptoms of bloating and flatulence. As of today, there have not been double blinded studies comparing one brand against another. Moreover, we still don't know whether a larger number of organisms is more effective than fewer. In addition, we don't know whether a combination of organisms is more effective than a single organism.

Are there risks in using probiotics? There are theoretical risks in using probiotics including the development of autoimmune illnesses. Also, there is a theoretical risk of developing an infection in immune compromised patients.[15]

What medications treat IBS-D? When considering medications for diarrhea, even standard doses can sometimes cause profound constipation in the elderly. There are several commonly used medications for diarrhea including:

  • Bismuth subsalicylate (several brand names)
  • Loperamide (several brand names)
  • Diphenoxylate/atropine (Lomotil®)
  • Diphenoxin/atropine (Motofen®)
  • Cholestyramine (several brand names)

Are there risks in using these medications? Aside from the risk of constipation, it is important to emphasize that Loperamide when used in higher than recommended doses can result in cardiac arrythmias, cardiac arrest and even death.[16]

What are the newer treatments for IBS-D?

  • Rifaximin (Xifaxan®)
    • Should not be routinely recommended in all patients with IBS
    • Is a non-absorbable antibiotic that has been shown to relieve bloating and loose stools in patients with Irritable Bowel Syndrome who have not had a response to other therapies
    • When considering this medication, we must be aware that it is to be used for 14 days. Repeat doses may be needed
    • The prescriber must be aware of potential adverse effects and limitations of this therapy
  • Eluxadoline (Viberzi®) - When considering this medication, clinicians must be aware of:
    • Dosage
    • Restrictions in use
    • Adverse effects
    • Contraindications
    • Black box warning
    • Drug interactions
    • Cost
    • This is a medication whose proper use requires a thorough review by the prescriber
    • Is indicated for IBS-D, but we must be aware of the restrictions mentioned in the PDR including[17]:
      • Should not be used in a patient without a gallbladder
      • Should not be used in a patient with biliary obstruction
      • Should not be used with a history of pancreatitis
      • Should not be used in alcoholism, severe liver disease, or patients consuming more than 3 drinks a day

The Use of Antidepressants in IBS
When prescribing antidepressants for IBS, remember that tricyclics have been shown to be more consistently effective than selective serotonin reuptake inhibitors (SSRI) or serotonin norepinephrine reuptake inhibitors (SNRI). They decrease visceral sensitivity and pain sensation. Doses of these medications are much lower than for antidepressant use.

Keep in mind that:

  • Their use is "off label"
  • They take three weeks or more to be effective
  • They are prescribed in lower doses than for depression
  • Choose specific medications depending on the patient's symptoms and use side effects like drowsiness with TCA use for patients who may have difficulty sleeping

Side Effects in Using Antidepressants
The use of antidepressants in general and specifically for the treatment of Irritable Bowel Syndrome should only be managed by those with knowledge of the numerous medications now available.

Psychological Therapies
Patients with IBS will benefit from psychological therapies including cognitive-behavioral, hypnotherapy, relaxation therapy, etc. The science of using psychological therapies in IBS has yet to catch up with clinical practice. Barriers to this include the extreme difficulty of creating a true controlled study without biasing the results. In addition, there are few studies comparing medications with medications and psychological therapies.

In summary, how does this all come together? People with IBS may be among our most challenging patients to treat. Proper care of IBS requires a careful history and physical and basic testing. It also necessitates our awareness of Rome IV criteria and the lower GI alarm features. These lower GI alarm features help guide the necessity of additional testing. Successful treatment of IBS requires a special listening ability, careful patient interaction and reassurance. The implementation of shared-decision making creates a bond with our patients that ultimately leads to a much higher rate of successful treatment.


  1. Drossman D and Hassler W. Rome IV Functional GI Disorders: Disorders of Gut-Brain interaction. Gastroenterology 2016:150;1257.
  2. Simnen M et al. Update on Rome IV Criteria for Colorectal Disorders: Implications for Clinical Practice. Curr Gastroenterol Rep 2017:19;5.
  3. Brandt LJ et al. An Evidence-Based Position Statement on the Management of Irritable Bowel Syndrome; American College of Gastroenterology Task Force on Irritable Bowel Syndrome. Am J Gastroenterol 2009:104; Suppl 1:S1.
  4. Halpert H. Irritable Bowel Syndrome: Patient-Provider Interaction and Patient Education. Journal of Clinical Medicine 2018:7;3.
  5. Groves JE. Taking Care of the Hateful Patient. NEJM 1978:298;883.
  6. Hammer J et al. Diagnostic Yield of Alarm Features in Irritable Bowel Syndrome and Functional Dyspepsia. Gut 2004:53;666.
  7. Ford AC et al. American College of Gastroenterology Monograph on the Management of Irritable Bowel Syndrome. Am J Gastroenterol 2018:113;1.
  8. Chey WD et al. The Yield of Colonoscopy in Patients With Non Constipated Irritable Bowel Syndrome. Am J Gastroenterol 2010:105;859.
  9. Lee YY et al. Post Infectious Irritable Bowel Syndrome. Current Gastroenterology Reports 2017:19;56.
  10. Hopper AD et al. Pre Endoscopy Serological Testing for Coeliac Disease: Evaluation of a Clinical Decision Tool. BMJ 2007:334;729.
  11. Gibson P and Shepherd S. Evidence-Based Dietary Management of Functional Gastrointestinal Symptoms: the FODMAP Diet. Journal of Gastroenterology and Hepatology 2010:25;252.
  12. Dugum M et al. Managing Irritable Bowel Syndrome: The Low FODMAP Diet. Cleveland Clinic J of Med 2016:83;655.
  13. Coeffler M et al. Intestinal Permeability in Patients With Diarrhea - Predominant Irritable Bowel Syndrome: Is There a Place for Glutamine Supplementation? Gastroenterology 2015:148;1079.
  14. Doron S and Snydman DR. Risks and Safety of Probiotics. Clin Infect Dis 2015:60;suppl 2;s129.
  15. Vaughn P et al. Electrocardiographic abnormalities, malignant ventricular arrythmias, and cardiomyopathy associated with loperamide abuse. Cardiovascular Electrophysiology 2016:27;1230.
  16. Eluxadoline: Drug Information 2020. Lexicomp Online; Eluxadoline; Wolters Kluwer Clinical Drug Information, Inc. Copyright 1978-2000; Hudson, OH.
  17. DynaMed (Internet). Ipswich (MA): EBSCO Information Services. 1995-. Record No T113627, Irritable Bowel Syndrome (IBS); updated 2018 Nov 30.
  18. Ford AC et al. Irritable Bowel Syndrome. NEJM 2017:376;2566.
  19. Rex DK et al. Colorectal cancer screening: Recommendations for physicians and patients from the U.S. Multi-Society Task Force on Colorectal Cancer. Gastrointestinal Endoscopy 2017:Vol 86, No 1;18-33.