Irritable Bowel Syndrome (IBS): Causes, Symptoms, Diet, and Treatment

肠易激syndrome is a gastrointestinal disorder characterized by the presence of a cluster of symptoms and signs in adults or children that include cramping,abdominal pain, increased gas, altered bowel habits, food intolerance, and bloating (distention).

肠易激syndrome is a "functional" disorder. This term refers to the changes in the functioning of thedigestive systemthat results in the collection of symptoms referred to as IBS, meaning that it is a problem with the movement (motility) rather than any damage to the tissues of the digestive system.

In the past,irritable bowelsyndrome was also called spastic colon or bowel, functional bowel disease, mucouscolitis, or nervous colon.

肠易激syndrome is characterized mostly by abdominalpainand cramping. Other symptoms and signs include:

• Diarrhea. IBS with diarrhea (IBS-D) can come with sudden urges to have bowel movements andloose stools.
• Constipation. IBS with constipation (IBS-C) can be accompanied by straining during bowel movements and infrequent stools.
• Increased gas
• Abdominal swelling或bloating
• Abdominalpain或discomfort
• Cramping pain after eating certain foods
• Nausea
• Mucousy or foamystool
• Unexplainedweight loss
• Loss of appetite

While not technically a symptom, nearly 70% of people with IBS also experienceindigestion.

Symptoms are often relieved by bowel movements. Women with IBS may have more symptoms during their menstrual periods.

The exact cause of irritable bowel syndrome is unknown. It is believed to be due to a number of factors, including alteration in the gastrointestinal (GI) tract motility, abnormal nervous system signals, increased sensitivity to pain, and food intolerances. The following are risk factors thought to cause IBS:

• Abnormal movements of the colon and smallintestines(too fast or slow, or too strong)
• Hypersensitivity to pain from a full bowel or gas
• Food sensitivities, possibly caused by poor absorption of sugars or acids in food
• Gastroenteritis("stomach flu" or "stomach bug"), a viral or bacterial infection of the stomach and intestines, may trigger IBS symptoms
• Psychological conditions such asanxiety或depressionare observed in many people with IBS, though these conditions have not been found to be a direct cause of IBS.
• Reproductive hormones or neurotransmitters may be off-balance in people with IBS.
• Small intestinal bacterial overgrowth(SIBO)
• Genetics is thought to be a possible cause of IBS, but so far, this hereditary link has not been proven.

What you eat and how you eat can affect symptom of this condition. While it may not be possible to completely prevent IBS symptoms, you may find that certain foods trigger IBS symptoms. To help figure out which foods cause you symptoms, a doctor may suggest keeping a food diary.

Some foods can help in thepreventionof symptoms.

Foods to eat that may provide symptom relief (home remedies and others) for some people:

• Dietary fibersupplements
• 水
• Low-fat foods
• High-carbohydrate foods (such as whole wheat pasta, brown rice, and whole grain breads)
• Probiotics(containingLactobacillus acidophilusa andBifidobacterium) and prebiotics
• Some people report kefir or Aloe Vera juice helps symptoms. Talk to a doctor about these home remedies.
• A high-fiberdietmay help relieve constipation in some cases of IBS, but it may also worsen some symptoms such as bloating and gas. The current recommended daily fiber intake is 20-35 grams daily. Most people fall short of this daily fiber intake and can benefit from a small increase in fiber, but it is best to increase the amount in your diet slowly to reduce gas.

Foods to avoid or limit if you have IBS

• Dairy products, including milk and cheese (Lactose intolerancesymptoms can be similar to IBS symptoms.)
• Certain vegetables that increase gas (such as cauliflower, broccoli, cabbage, Brussels sprouts) and legumes (such as beans)
• Fatty or fried foods
• Alcohol,caffeine, or soda
• Foods high in sugars
• Artificial sweeteners
• Chewing gum
• Nuts

Alow FODMAP dietmay also help relievesymptoms of IBS.FODMAPrefers to a group of short-chain carbohydrates (Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols) that are not well absorbed in the small intestine and are rapidly fermented by bacteria in the gut. These bacteria produce gas, which can contribute to IBS symptoms.

The lists of foods both high and low inFODMAPsare extensive. The International Foundation for Functional Gastrointestinal Disorders, Inc. (IFFGD) has suggestions of foods to eat and foods to avoid if you follow the FODMAP diet for IBS. Talk to your doctor for more information.

• IBS-Dstands for irritable bowel syndrome with diarrhea. The most common symptoms of IBS-D include:
  • Frequent stools
  • Feeling as if you are unable to completely empty your bowels during bowel movements
  • Nausea.
  • People withIBS-Dalso may experience signs and symptoms of:
    • Gas
    • Abdominal pain or discomfort
    • Sudden urges to have a bowel movement
    • Loose stools
• IBS-Cstands for irritable bowel syndrome with constipation. The most common symptoms of IBS-C include:
  • Infrequent stools
  • Straining during bowel movements
  • Feeling as if you are unable to completely empty your bowels during bowel movements
  • Feeling as if you need to have a bowel movement but are unable
  • Abdominal pain
  • Bloating
  • Gas

While both irritable bowel syndrome (IBS) andinflammatory bowel disease(IBD) can have similar symptoms including abdominal pain, diarrhea, and urgent bowel movements, IBS is not the same asIBD.

• IBDis a group of separate diseases that includesulcerative colitisand Crohn's disease, and is a more severe condition.
• IBS or Irritable bowel syndrome is considered a functional gastrointestinal disorder because there is abnormal bowel function. IBS is a group of symptoms and not a disease in itself, which is why it’s called a ‘syndrome,’ and it is considered less serious than IBD.
• IBS does not cause inflammation likeinflammatory bowel disease, and it does not result in permanent damage to the intestines, intestinal bleeding,rectal bleeding, ulcers, or the harmful complications that are often seen with IBD.

Small intestinal bacterial overgrowth(SIBO) is considered one of the factors that may produce signs andsymptoms of irritable bowel syndrome(IBS). The medical data from studies done on SIBO are conflicting.

Some studies show an increase in gas production by intestinal bacteria as a cause of the pain and bloating associated with IBS. However, other studies done to determine if SIBO is the cause of IBS and if antibiotic treatment of SIBO is helpful in reducing or eliminating IBS symptoms have not been conclusive.

肠易激syndrome is diagnosed by excluding other GI disorders that can cause similar symptoms. A complete history and physical is taken to determine the duration and frequency of symptoms. To be diagnosed with the condition, the duration of symptoms should be at least 6 months and should occur at least 3 times a month.

A doctor may order tests, including blood tests,stooltests,X-rays, orCT scans. There is no specific finding on these tests that can confirm the diagnosis of IBS, however, other problems can be ruled out by performing them.

肠易激syndrome test

Two relatively new blood tests may help diagnose irritable bowel syndrome. One test is for irritable bowel syndrome with diarrhea (IBS-D), and the other is for irritable bowel syndrome with both diarrhea and constipation (irritable bowel syndrome mixed IBS-M). Neither test is able to diagnose irritable bowel syndrome with constipation (IBS-C).

Both blood tests are for anti-CdtB and anti-vinculin antibodies. It is thought that these antibodies develop in some patients after an acute bout of gastroenteritis that is caused by several different, common types of bacteria. The overgrowth of these bacteria in the gut may trigger an immune attack on the patients’ own intestinal tissues (autoimmunity) with the ensuing inflammation and damage to the tissues causing the symptoms of IBS.

The tests may help distinguish between irritable bowel syndrome andinflammatory bowel disease或IBD, a different type of intestinal inflammatory disease that includes Crohn's disease andulcerative colitis.

成岩作用的抗体测试似乎是有用的osis of irritable bowel syndrome with diarrhea IBS-D, but not IBS with constipation (IBS-C). The tests also appear to be specific, and if the antibodies are present, it is highly likely that IBS is present. However, the tests are insensitive, meaning if the antibodies are not present, the patient still may have IBS. Thus, these irritable bowel syndrome tests may be identifying only a subset of patients with IBS, those with post-infectious IBS. Both IBS blood tests have not undergone rigorous testing, and have not yet been approved by the FDA. It is expected to be an expensive test costing $500 to over $1,000.

Other diagnostic tests

A doctor also may send the patient to a gastroenterologist (a specialist in the digestive system). Depending on the symptoms, anupper endoscopyand/orcolonoscopymay be performed.

Dietary modifications are the first treatments that should be tried to treat IBS. There are several types of foods in particular that often trigger characteristic symptoms and signs.

If dietary modifications and lifestyle changes do not adequately treat the symptoms and signs, a doctor may recommend medical therapies.

Medicine for diarrhea

• Antidiarrheal medicationssuch asloperamide(Imodium),attapulgite(Kaopectate), anddiphenoxylate and atropine(Lomotil) can be helpful if loose stools are one of the main signs. Eluxadoline (Viberzi) is a prescription for the treatment of irritable bowel syndrome with diarrhea (IBS-D).
• For females with IBS who experience severe diarrhea,alosetron(Lotronex) has been used.
• Rifaximin(Xifaxan) is an antibiotic for the treatment of irritable bowel syndrome with diarrhea (IBS-D) and IBS-related bloating.
• Bile acid bindersincludingcholestyramine( (Prevalite),colestipol(Colestid), orcolesevelam(Welchol) can help some patients with IBS-D, but can also cause bloating.

Medicine for constipation medication

• Over-the-counterlaxativessuch aspolyethylene glycol 3350( (MiraLax),bisacodyl(Dulcolax), and psyllium seed husks (Metamucil) can help relieve constipation and keep bowel movements regular.Sennalaxatives (Senokot, Ex-Lax Gentle Nature) may be taken short-term. Prescription laxatives such aslactulose(Constulose) may also be prescribed.
• Twodrugsspecifically used to treat IBS arelubiprostone(Amitiza), alaxative, andlinaclotide(Linzess), a constipation medication.
• SSRIantidepressantsfluoxetine(Prozac),citalopram(Celexa),sertraline(Zoloft),paroxetine(Paxil), andescitalopram(Lexapro) may be helpful for those with constipation (IBS-C), but they can trigger IBS attacks in patients with diarrhea (IBS-D).

• Antidepressantsin low doses, such astricyclic antidepressants(TCAs) and selective serotonin reuptake inhibitors (SSRIs), may help relieve symptoms associated with IBS.
• Bismuth subsalicylate (Pepto-Bismol) andmagnesium hydroxide(Milk of Magnesia).
• Antibioticsmay be used when small intestinal bacterial overgrowth (SIBO) is suspected.
• Antianxiety medicationssuch asdiazepam(Valium),lorazepam(Ativan), andclonazepam(Klonopin) are occasionally prescribed short-term for people whoseanxietyworsens theirirritable bowel syndrome symptoms.

• Antispasmodics, such asmetoclopramide(Reglan),dicyclomine(Bentyl), andhyoscyamine(Levsin), decrease symptoms of pain and cramping.
• Antidepressantssuch asamitriptyline(Elavil, Paregoric),doxepin( (Silenor),desipramine(Norpramin),nortriptyline(Pamelor), andimipramine(Tofranil) may help with abdominal pain but due to side effects are usually reserved for severe cases.

Some lifestyle changes that can also help relieve symptoms are as follows:

• Eat smaller, more frequent meals
• Quit smoking
• Exerciseregularly
• Takeprobiotics
• Avoidcaffeine
• Usestress managementand relaxation techniques
• Mindfulness training
• Gut-directed hypnosis
• Biofeedback
• Pain-management techniques
• Cognitive behavioral therapy或psychotherapy
• Regularexercisesuch aswalking或yoga
• Get an adequate amount ofsleep
• Tryginger或peppermint, which may helpdigestion
• Avoid laxatives unless prescribed by your health-care professional

In general, there are few complications associated with this functional disease other than the symptoms of the disease itself. If someone hashemorrhoids, the diarrhea and constipation associated with IBS may irritate them. Moreover, a diet that is too strict limits nutrients that could cause problems related to lack of propernutrition.

The biggest complication of IBS may be on the quality of life. Thestressandanxietyas well as the impact on daily activities the condition can cause may be troublesome for patients.

肠易激syndrome does not lead to:

• Colon cancer
• Rectal bleeding
• Inflammatory bowel diseases(Crohn's disease andulcerative colitis或UC

There is no known cure for IBS, but there are many treatment options to reduce or eliminate symptoms. Good communication with a doctor is important to help manage this condition.

肠易激syndrome is a chronic disease with symptoms that tend to come and go. The overall prognosis for patients with IBS depends on the severity and frequency of symptoms, and the patient's ability to control these symptoms, whether by diet, lifestyle changes, or medications.

它不可能阻止发展中肠易激综合症,but you can take steps to prevent symptoms for occurring or worsening. As discussed earlier, dietary and lifestyle changes can help you manage symptoms. To identify food triggers, your doctor may suggest that you keep a food diary and avoid foods that cause symptoms. Managestressandanxiety, and try cognitive therapy or psychotherapy if needed.

A primary-care provider or family-medicine specialist or a child's pediatrician may first diagnose irritable bowel syndrome. You will likely be referred to a gastroenterologist (a specialist in disorders of the digestive system) for further treatment.