IBS, which refers to irritable bowel syndrome, is commonly and sometimes carelessly used to describe gastrointestinal (GI) symptoms of abdominal pain and bloating.
Many do not understand the causative factors attributed to IBS, criteria in making the diagnosis, and management options. I hope to unravel the mystery of IBS for you.
IBS is a common and chronic disorder that’s affects approximately 5% of the U.S. population. Symptoms of IBS can vary from mild to debilitating, and there can be a significant impact on quality of life leading to higher rates of school or job absenteeism. IBS is part of a group of disorders that is referred to as functional gastrointestinal disorders (FGIDs), or disorders of the gut-brain interaction.
FGIDs are a group of conditions that can affect any part of the GI tract, including the esophagus, stomach and intestines. The most common of these disorders is IBS. They are disorders of function (how the GI tract works), not structural or biochemical abnormalities. In patients with FGIDs, the digestive tract looks normal, but may not work as it should.
Patients may experience a variety of symptoms ranging from nausea, vomiting, belching, abdominal discomfort or pain, bloating, constipation, and diarrhea. Often, x-rays, blood tests and endoscopies can show essentially normal results.
FGIDs account for a significant percentage of a gastroenterologist’s practice.
Fifty to eighty percent of persons with a functional GI disorder do not consult physicians, although they may take over-the-counter medications.
IBS is a specific type of FGID with a diagnostic criteria termed Rome IV. IBS is characterized by symptoms of recurrent abdominal pain at least once weekly in association with a change in stool frequency or a change in stool form, and/or relief or worsening of abdominal pain related to defecation. Bloating is a common symptom but not mandatory.
IBS is broken into 3 subtypes: constipation predominant, diarrhea predominant, or mixed constipation and diarrhea.
The cause of FGIDs like IBS is multifactorial and may include the following factors:
1. Brain-Gut Dysfunction: Brain-gut dysfunction relates to the abnormalities in the way the brain and GI system communicate. The interaction between the brain (nervous system) and gut may be impaired, and this can lead to increased pain and bowel difficulties which can be worsened by psychological stress.
2. Abnormal Motility: Motility is the muscular activity of the GI tract. Normal motility or peristalsis is an orderly sequence of muscular contractions from the beginning to end of the GI tract. Motility may be abnormal — there can be muscular spasms that can cause pain, and the contractions can be very rapid (fast motility is diarrhea) or very slow (slow motility is constipation).
3. Visceral Hypersensitivity: Sensation is how the nerves of the GI tract respond to stimuli (for example, digesting a meal). In FGIDs where pain is the main symptom, the nerves are sometimes oversensitive, and even normal contractions can bring on pain or discomfort. This is referred to as visceral hypersensitivity.
4. Gut Microbiome: A microbiome is the community of microorganisms — such as bacteria, fungi, and viruses—that inhabit an ecosystem. Our intestines have their own unique microbiome. Trillions of organisms inhabit our intestinal tract that aid in digestion, immune regulation, and even may affect the central nervous system. There is a delicate balance of healthy and unhealthy microbes.
When there is an imbalance it is referred to as gut dysbiosis. Symptoms of IBS can often be precipitated by antibiotics and after intestinal infections. The role of the gut microbiome on intestinal disorders has become an area of intense research within gastroenterology.
5. Diet: Food have a role in precipitating IBS symptoms. Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols — or FODMAPS — are certain poorly absorbed carbohydrates, starches, sugars, and fibers which can result in abdominal pain, gas, bloating, and diarrhea.
Often, IBS can be diagnosed simply by the doctor listening carefully to your symptoms. Other times, they may explain the need to perform further tests to exclude other causes, or to further clarify your intestinal function.
These tests may include: physical examination, blood tests for hemoglobin, liver function, thyroid function, or celiac disease, stool studies, colonoscopy (insertion of a flexible scope to evaluate the inside the colon), upper endoscopy (insertion of a flexible scope to evaluate the lining of the esophagus, stomach and small intestine), imaging tests, (x-rays, ultrasound, CT, or MRI), and/or specific motility tests for different parts of the GI tract.
Once the diagnosis of IBS and the subtype is determined, a treatment can be tailored to help manage the symptoms and make patients more comfortable.
Often treating IBS is a collaboration between the doctor and patient. IBS is generally managed to avoid triggers, and provide symptoms relief. There are a variety of treatment approaches that target the above mechanisms. It is important to know that not every patient responds to a specific treatment.
Here are some approaches:
1. Exercise: This is a key element to maintaining general and mental health. Studies have shown protection against GI symptoms, and improvement in constipation.
2. Diet: A low FODMAP diet has been shown in reducing IBS symptoms across several trials. It is best not to eliminate all FODMAPs long term, but to find specific triggers. Working with an experienced dietician may help.
3. Fiber: Soluble fiber, such as psyllium, can improve both stool viscosity and frequency.
4. Probiotics: As a group, there are beneficial effects on bloating and flatulence in some studies.
5. Antispasmodics: A group of medications which reduce spasm and may improve symptoms of pain.
6. Prescription treatments approved for IBS: There are a variety of FDA approved medications for constipation and diarrhea predominant IBS that target receptors on the GI tract for symptom improvement. Your GI provider can discuss the benefits of these medications.
7. Antidepressants and psychological therapy: IBS is not a psychiatric disorder, although stress and psychological difficulties can make symptoms worse. In low doses, certain antidepressants treat hypersensitivity of the GI tract and are a proven treatment for abdominal pain related to IBS. Behavioral treatments such as relaxation therapy, hypnotherapy, and psychological therapy target the brain-gut axis.
8. Complementary and Alternative Medications: There is emerging evidence for peppermint oil, capsaicin, STW5, and acupuncture on symptoms of bloating and IBS.
IBS is common and affects a significant percentage of the population. A number of potential mechanisms exist. Ruling out other GI conditions is generally necessary, but ultimately a collaboration between the patient and GI provider is crucial to diagnosis and treatment. The doctors at Arizona Digestive Health are here to partner with you.
Editor’s Note: Nayan Patel DO is a gastroenterologist and hepatologist with Arizona Digestive Health in Scottsdale.