Understanding Irritable Bowel Syndrome (IBS)
Irritable Bowel Syndrome (IBS) - Overview:
Irritable bowel syndrome (IBS) poses something of a dilemma: Physicians readily recognize when a person has it, but describing a consistent pattern of symptoms is nearly impossible. People with an irritable bowel may complain of cramping pain in any part of the abdomen, feeling bloated, gas, constipation, as well as diarrhea and excessive mucus in the stool. Often, the same person may complain of either constipation or diarrhea, later experience another symptom, and then alternate again. The symptom(s) that occurs most frequently also will vary from individual to individual.
Worldwide, IBS affects about one in seven to 10 people. Over 22 million Americans suffer from this condition, which is second only to the common cold as a cause of absenteeism from work. Reports indicate that three times as many women as men are afflicted with irritable bowel syndrome. Researchers speculate that the fluctuation of reproductive hormones during menstrual cycles may increase the occurrence of these symptoms. The truth is that the cause or causes of IBS are not well understood at all. It is very likely that multiple factors are involved.
You can guess at the number of disorders that researchers thought produced IBS by ticking off the names given to this problem over the years. Irritable bowel syndrome has been called psychogenic colitis, mucous colitis, or just plain colitis – suggesting that there is inflammation (or “-itis”) of the lining of the colon. This is a misnomer because no inflammation is present.
Perhaps, as some have suggested, if there is an inflammation it is due to a bowel infection. Nowadays, most physicians do not believe infection is a factor, though they do think that some irritation of the small or large intestine is involved. At one time intolerance to certain foods and food allergies were considered major factors in IBS. While we know that this is a cause, it is unlikely to be the only cause.
Irritable bowel syndrome has also been called psychogenic colitis, or the nervous gut, in the belief that psychologic distress – nerves, depression, or anxiety – causes the onset of symptoms.
Another name for IBS was spastic colitis or spastic colon. This referred to the painful contractions a sufferer would feel inside his or her lower gut. These abnormal, uncoordinated contractions, or dysmotility, may be linked to a change in the firing of electrical signals that control muscular activity. This pacemaker mechanism is similar to the system controlling the contraction of heart muscle. And as with the heart, an abnormal pattern or rhythm—a dysrhythmia—may develop.
Recent research has strongly suggested a central role for abnormal gut sensitivity. According to this view, motility in the gut is normal. However, the nerve endings in the lining of the small and large intestines are unusually sensitive and will react abnormally to even ordinary events such as eating. For example, when ingested food reaches the bowel, the gut wall expands (or distends), causing the nerves to trigger exaggerated patterns of muscular activity. As a result, sometimes, a meal may be followed almost immediately by cramps, and soon after by a bowel movement. Other stimuli that can cause over-reacting include stress, certain medications, drinking milk or swallowing too much air.
In any person with irritable bowel syndrome, it is difficult to pin down the cause because each time, the underlying disorder, or combination of contributing disorders, will likely differ. Thus, there is no specific test you can take that will tell whether or not you have IBS — and no procedure that will allow the doctor to see what's wrong. In medical language, this means IBS is a functional disorder.
Nevertheless, your doctor will frequently order tests because your symptoms might suggest the presence of another, more serious disease. He or she will be particularly alert to this possibility if you have rectal bleeding, weight loss, or severe and/or persistent pain. After analyzing the results of appropriate tests, the doctor will be able to reassure you, for example, that you do not have cancer.
What Is The Difference Between Irritable Bowel Syndrome (IBS) & Inflammatory Bowel Disease (IBD)?
Inflammatory bowel disease (IBD) is easily confused with another condition known as irritable bowel syndrome (IBS). As much as 25% of the population in the United States report symptoms of IBS, and up to 50% of patients seen by gastroenterologists have symptoms of IBS.
IBD and IBS have similar symptoms, particularly cramping and diarrhea, but the underlying disease process is quite different. IBD is inflammation or destruction of the bowel wall, which can lead to deep ulcerations (sores) and narrowing of the intestines. IBS is a disorder of the gastrointestinal (GI) tract for which no apparent cause can be found. A patient can possibly have both IBD and IBS.
Irritable Bowel Syndrome (IBS) - What Is It?
Irritable bowel syndrome is a functional gastrointestinal (GI) disorder, meaning symptoms are caused by changes in how the GI tract works. People with a functional GI disorder have frequent symptoms; however, the GI tract does not become damaged. IBS is a group of symptoms that occur together, not a disease. In the past, IBS was called colitis, mucous colitis, spastic colon, nervous colon, and spastic bowel. The name was changed to reflect the understanding that the disorder has both physical and mental causes and is not a product of a person’s imagination.
IBS is diagnosed when a person has had abdominal pain or discomfort at least three times a month for the last 3 months without other disease or injury that could explain the pain. The pain or discomfort of IBS may occur with a change in stool frequency or be relieved by a bowel movement.
IBS is often classified into 4 subtypes based on usual stool consistency. These subtypes affect types of treatment most likely to improve symptoms. The 4 subtypes of IBS are:
IBS with constipation (IBS-C):
Hard or lumpy stools at least 25% of the time. Loose or watery stools < 25% of the time.
IBS with diarrhea (IBS-D):
Loose or watery stools at least 25% of the time. Hard or lumpy stools < 25% of the time.
Mixed IBS (IBS-M):
Hard or lumpy stools at least 25% of the time. Loose or watery stools at least 25% of the time.
Unsubtyped IBS (IBS-U):
Hard or lumpy stools < 25% of the time. Loose or watery stools < 25% of the time.
How common is IBS and who is affected?
Studies estimate IBS affects 3%-20% of the adult population, with most studies ranging from 10%-15%. However, only 5%-7% of the adult population has been diagnosed with the condition. IBS affects about twice as many women as men and is most often found in people younger than age 45.
What are the symptoms of IBS?
The most common symptoms of IBS are abdominal pain or discomfort, often reported as cramping, along with changes in bowel habits. To meet the definition of IBS, pain / discomfort will be associated with at least 2 of the following 3 symptoms:
Bowel movements that occur more or less often than usual.
Stool that appears less solid and more watery, or harder and more lumpy, than usual.
Bowel movements that improve the discomfort.
Other symptoms of IBS may include:
Diarrhea—loose, watery stools 3+ times per day & feeling urgency to have bowel movements.
Constipation—having fewer than three bowel movements a week.
Feeling that a bowel movement is incomplete.
Passing mucus—a clear liquid made by the intestines that coats tissues in the GI tract.
Symptoms often occur after eating. To meet the definition of IBS, symptoms must occur 3x / month.
What causes IBS?
Causes of IBS are not well understood. Researchers believe a combination of physical & mental health problems can lead to IBS.
Brain-Gut Signal Problems: Signals between the brain and nerves of the small and large intestines, also called the gut, control how the intestines work. Problems with brain-gut signals may cause IBS symptoms, such as changes in bowel habits and pain or discomfort.
GI Motor Problems: Normal motility, or movement, may not be present in the colon of a person who has IBS. Slow motility can lead to constipation and fast motility can lead to diarrhea. Spasms, or sudden, strong muscle contractions that come and go, can cause abdominal pain. Some people with IBS also experience hyperreactivity— increase in bowel contractions in response to stress or eating.
Hypersensitivity: People with IBS have a lower pain threshold for bowel stretching caused by gas or stool compared with people who do not have IBS. The brain may process pain signals from the bowel differently in people with IBS.
Mental Health Problems: Psychological problems such as panic disorder, anxiety, depression, and post-traumatic stress disorder are common in people with IBS. The link between these disorders and development of IBS is unclear. GI disorders, including IBS, are often found in people who have reported past physical or sexual abuse. Researchers believe people who have been abused tend to express psychological stress through physical symptoms.
Bacterial Gastroenteritis: Some people who have bacterial gastroenteritis—an infection or irritation of the stomach and intestines caused by bacteria—develop IBS. Researchers do not know why gastroenteritis leads to IBS in some people and not others, though abnormalities of the GI tract lining and psychological problems may be factors.
Small Intestinal Bacterial Overgrowth: Normally, few bacteria live in the small intestine. Small intestinal bacterial overgrowth is an increase in the number or a change in the type of bacteria in the small intestine. These bacteria can produce extra gas and may also cause diarrhea and weight loss. Some researchers believe that small intestinal bacterial overgrowth may lead to IBS, and some studies have shown antibiotics to be effective in treating IBS. However, more research is needed to show a link between small intestinal bacterial overgrowth and IBS.
Body Chemicals: People with IBS have altered levels of neurotransmitters—chemicals in the body that transmit nerve signals—and GI hormones, though the role these chemicals play in developing IBS is unclear. Younger women with IBS often have more symptoms during their menstrual periods. Post-menopausal women have fewer symptoms compared with women who are still menstruating. These findings suggest that reproductive hormones can worsen IBS problems.
Genetics: Whether IBS has a genetic cause, meaning it runs in families, is unclear. Studies have shown IBS is more common in people with family members who have a history of GI problems. However, the cause could be environmental or the result of heightened awareness of GI symptoms.
Food Sensitivity: Many people with IBS report that symptoms are triggered by foods rich in carbohydrates, spicy or fatty foods, coffee, and alcohol. However, people with food sensitivity typically do not have clinical signs of food allergy. Researchers have proposed that symptoms may result from poor absorption of sugars or bile acids, which help break down fats and get rid of waste.
How is IBS Diagnosed?
To diagnose IBS, a health care provider will conduct a physical exam and take a complete medical history. The medical history will include questions about symptoms, family history of GI disorders, recent infections, medications, and stressful events related to the onset of symptoms. An IBS diagnosis requires that symptoms started at least 6 months prior and occurred at least three times a month for the previous 3 months. Further testing is not usually needed, though the health care provider may perform a blood test to screen for other problems.
Additional diagnostic tests may be needed based on the results of the screening blood test and for those who also have signs such as: fever, rectal bleeding, weight loss, anemia, family history of colon cancer, IBD and/or Celiac Disease--an abnormal immune reaction to gluten, a protein found in wheat, rye, and barley, that damages the lining of the small intestine & prevents nutrient absorption.
Additional diagnostic tests may include a stool test, lower GI series, and flexible sigmoidoscopy or colonoscopy. Colonoscopy is also recommended for people at age 50 to screen for colon cancer.
A stool test is the analysis of a sample of stool. The health care provider will give the person a container for catching and storing the stool. The sample is returned to the doctor or a commercial facility and sent to a lab for analysis. Stool tests can show presence of parasites or blood.
A lower GI series is an x ray that is used to look at the large intestine. The test is performed at a hospital or an outpatient center by an x-ray technician, and the images are interpreted by a radiologist—a doctor who specializes in medical imaging. Anesthesia is not needed. The health care provider may give written bowel prep instructions to follow at home before the test. The person may be asked to follow a clear liquid diet for 1-3 days before the procedure. A laxative or an enema may be used before the test. A laxative loosens stool and increases bowel movements. An enema involves flushing water or laxative into the anus using a special bottle.
For the test, the person will lie on a table while the physician inserts a flexible tube into the person’s anus. The large intestine is filled with barium, making signs of problems more apparent on x rays.
For several days, traces of barium in the large intestine cause stools to be white or light colored. Enemas and frequent bowel movements may cause anal soreness. A doctor will provide specific instructions about eating/drinking after the test.
Flexible sigmoidoscopy and colonoscopy are similar, although colonoscopy is used to view the rectum and entire colon, while flexible sigmoidoscopy is used to view just the rectum and lower colon. These tests are performed at a hospital or an outpatient center by a gastroenterologist—a doctor who specializes in digestive diseases. Before either test, a health care provider will give written bowel prep instructions to follow at home. The person may be asked to follow a clear liquid diet for 1 - 3 days before either test. The night before either test, the person may need to take a laxative or enema. Additional enemas may also be required ~2 hrs before a flexible sigmoidoscopy.
In most cases, light anesthesia and possibly pain medication help people relax during colonoscopy. For either test, the person will lie on a table while the gastroenterologist inserts a flexible tube into the anus. A small camera on the tube sends a video image of the intestinal lining to a computer screen. The tests can show signs of problems in the lower GI tract.
The gastroenterologist may also perform a biopsy, a procedure involving taking a piece of intestinal lining for examination with a microscope. The person will not feel the biopsy. A pathologist examines the tissue in a lab.
Cramping or bloating may occur during the 1st hour after either test. Driving is not permitted for 24hrs after a colonoscopy to allow sedatives time to wear off. Before the appointment, plan for a ride home. Recovery is expected by the next day.
How is IBS treated?
Though IBS does not have a cure, the symptoms can be treated with a combination of: changes in eating, diet, and nutrition, medications, probiotics and/or therapies for mental health problems.
What other conditions are associated with IBS?
People with IBS often suffer from other GI and non-GI conditions. GI conditions such as gastroesophageal reflux disease (GERD) and dyspepsia are more common in people with IBS than the general population. GERD is a condition in which stomach contents flow back up into the esophagus—the organ that connects the mouth to the stomach—because the muscle between the esophagus and the stomach is weak or relaxes when it should not. Dyspepsia, or indigestion, is upper abdominal discomfort. Dyspepsia may be accompanied by bloating, nausea, or other symptoms.
How does stress affect IBS?
Stress can stimulate colon spasms in people with IBS. The colon has many nerves that connect it to the brain. These nerves control the normal contractions of the colon and cause abdominal discomfort at stressful times. In people with IBS, the colon can be overly responsive to even slight conflict or stress. Stress makes the mind more aware of the sensations that arise in the colon. IBS symptoms can also increase a person’s stress level.
Some options for managing stress include: participating in stress reduction and relaxation therapies such as meditation, getting counseling and support, taking part in regular exercise such as walking or yoga, minimizing stressful life situations as much as possible and/or getting enough sleep.