Your small intestine is the longest part of your digestive system - about twenty feet long! It connects your stomach to your large intestine (or colon) and folds many times to fit inside your abdomen. Your small intestine does most of the digesting of the foods you eat. It has three areas called the duodenum, the ileum, and the jejunum.

Problems with the small intestine can include:

• Bleeding
• Celiac disease
• Crohn's disease
• Infections
• Intestinal cancer
• Intestinal obstruction
• Irritable bowel syndrome
• Ulcers, such as peptic ulcer

Treatment of disorders of the small intestine depends on the cause.

Celiac disease is an immune disease in which people can't eat gluten because it will damage their small intestine. If you have celiac disease and eat foods with gluten, your immune system responds by damaging the small intestine. Gluten is a protein found in wheat, rye, and barley. It may also be in other products like vitamins and supplements, hair and skin products, toothpastes, and lip balm.

Celiac disease affects each person differently. Symptoms may occur in the digestive system, or in other parts of the body. One person might have diarrhea and abdominal pain, while another person may be irritable or depressed. Irritability is one of the most common symptoms in children. Some people have no symptoms.

Celiac disease is genetic. Blood tests can help your doctor diagnose the disease. Your doctor may also need to examine a small piece of tissue from your small intestine. Treatment is a diet free of gluten.

Celiac disease is a condition in which the immune system is abnormally sensitive to gluten, a protein found in wheat, rye, and barley. Celiac disease is an autoimmune disorder; autoimmune disorders occur when the immune system malfunctions and attacks the body's own tissues and organs. Without a strict, lifelong gluten-free diet, inflammation resulting from immune system overactivity may cause a wide variety of signs and symptoms involving many parts of the body.

Celiac disease can develop at any age after an individual starts eating foods containing gluten. The classic symptoms of the condition result from inflammation affecting the gastrointestinal tract. This inflammation damages the villi, which are small, finger-like projections that line the small intestine and provide a greatly increased surface area to absorb nutrients. In celiac disease, the villi become shortened and eventually flatten out. Intestinal damage causes diarrhea and poor absorption of nutrients, which may lead to weight loss. Abdominal pain, swelling (distention), and food intolerances are common in celiac disease. Inflammation associated with celiac disease may lead to an increased risk of developing certain gastrointestinal cancers such as cancers of the small intestine or esophagus.

Inflammation and poor nutrient absorption may lead to problems affecting many other organs and systems of the body in affected individuals. These health problems may include iron deficiency that results in a low number of red blood cells (anemia), vitamin deficiencies, low bone mineral density (osteoporosis), itchy skin rashes (dermatitis herpetiformis), defects in the enamel of the teeth, chronic fatigue, joint pain, poor growth, delayed puberty, infertility, or repeated miscarriages. Neurological problems have also been associated with celiac disease; these include migraine headaches, depression, attention-deficit/hyperactivity disorder (ADHD), and recurrent seizures (epilepsy). Many people with celiac disease have one or more of these varied health problems but do not have gastrointestinal symptoms. This form of the condition is called nonclassic celiac disease. Researchers now believe that nonclassic celiac disease is actually more common than the classic form.

Celiac disease often goes undiagnosed because many of its signs and symptoms are nonspecific, which means they may occur in many disorders. Most people who have one or more of these nonspecific health problems do not have celiac disease. On average, a diagnosis of celiac disease is not made until 6 to 10 years after symptoms begin.

Some people have silent celiac disease, in which they have no symptoms of the disorder. However, people with silent celiac disease do have immune proteins in their blood (antibodies) that are common in celiac disease. They also have inflammatory damage to their small intestine that can be detected with a biopsy.

In a small number of cases, celiac disease does not improve with a gluten-free diet and progresses to a condition called refractory sprue. Refractory sprue is characterized by chronic inflammation of the gastrointestinal tract, poor absorption of nutrients, and an increased risk of developing a type of cancer of the immune cells called T-cell lymphoma.

Gluten is a protein found in wheat, rye, and barley. It is found mainly in foods but may also be in other products like medicines, vitamins, and supplements. People with gluten sensitivity have problems with gluten. It is different from celiac disease, an immune disease in which people can't eat gluten because it will damage their small intestine.

Some of the symptoms of gluten sensitivity are similar to celiac disease. They include tiredness and stomachaches. It can cause other symptoms too, including muscle cramps and leg numbness. But it does not damage the small intestine like celiac disease.

Researchers are still learning more about gluten sensitivity. If your health care provider thinks you have it, he or she may suggest that you stop eating gluten to see if your symptoms go away. However, you should first be tested to rule out celiac disease.

Many people who have celiac disease have not been diagnosed. However, experts estimate about 2 million people in the United States have celiac disease and about 1 percent of people around the world have celiac disease.

Experts have found that some people have both celiac disease and other disorders related to the immune system. These disorders include

• type 1 diabetes
• thyroid diseases, such as Hashimoto’s disease, Graves’ disease, Addison’s disease, and primary hyperparathyroidism
• selective immunoglobulin A (IgA) deficiency, a condition in which your body makes little or no IgA, an antibody that fights infections
• rheumatic diseases, such as Sjögren’s syndrome
• liver diseases, such as autoimmune hepatitis, primary sclerosing cholangitis, and primary biliary cholangitis

What is Crohn's disease?

Crohn's disease is a chronic disease that causes inflammation in your digestive tract. It can affect any part of your digestive tract, which runs from your mouth to your anus. But it usually affects your small intestine and the beginning of your large intestine.

Crohn's disease is an inflammatory bowel disease (IBD). Ulcerative colitis and microscopic colitis are other common types of IBD.

What causes Crohn's disease?

The cause of Crohn's disease is unknown. Researchers think that an autoimmune reaction may be one cause. An autoimmune reaction happens when your immune system attacks healthy cells in your body. Genetics may also play a role, since Crohn's disease can run in families.

Stress and eating certain foods don't cause the disease, but they can make your symptoms worse.

Who is at risk for Crohn's disease?

There are certain factors which can raise your risk of Crohn's disease:

• Family history of the disease. Having a parent, child, or sibling with the disease puts you at higher risk.
• Smoking. This may double your risk of developing Crohn's disease.
• Certain medicines, such as antibiotics, birth-control pills, and nonsteroidal anti-inflammatory drugs (NSAIDs) such as aspirin or ibuprofen. These may slightly increase your chance of developing Crohn's.
• A high-fat diet. This may also slightly increase your risk of Crohn's.

What are the symptoms of Crohn's disease?

The symptoms of Crohn's disease can vary, depending where and how severe your inflammation is. The most common symptoms include:

• Diarrhea
• Cramping and pain in your abdomen
• Weight loss

Some other possible symptoms are:

• Anemia, a condition in which you have fewer red blood cells than normal
• Eye redness or pain
• Fatigue
• Fever
• Joint pain or soreness
• Nausea or loss of appetite
• Skin changes that involve red, tender bumps under the skin

Stress and eating certain foods such as carbonated drinks and high-fiber foods may make some people's symptoms worse.

What other problems can Crohn's disease cause?

Crohn's disease can cause other problems, including:

• Intestinal obstruction, a blockage in the intestine
• Fistulas, abnormal connections between two parts inside of the body
• Abscesses, pus-filled pockets of infection
• Anal fissures, small tears in your anus that may cause itching, pain, or bleeding
• Ulcers, open sores in your mouth, intestines, anus, or perineum
• Malnutrition, when your body does not get the right amount of vitamins, minerals, and nutrients it needs
• Inflammation in other areas of your body, such as your joints, eyes, and skin

How is Crohn's disease diagnosed?

Your health care provider may use many tools to make a diagnosis:

• A medical history, which includes asking about your symptoms
• A family history
• A physical exam, including
  • Checking for bloating in your abdomen
  • Listening to sounds within your abdomen using a stethoscope
  • Tapping on your abdomen to check for tenderness and pain and to see if your liver or spleen is abnormal or enlarged
• Various tests, including
  • Blood and stool tests
  • A colonoscopy
  • An upper GI endoscopy, a procedure in which your provider uses a scope to look inside your mouth, esophagus, stomach, and small intestine
  • Diagnostic imaging tests, such as a CT scan or an upper GI series. An upper GI series uses a special liquid called barium and x-rays. Drinking the barium will make your upper GI tract more visible on an x-ray.

What are the treatments for Crohn's disease?

There is no cure for Crohn's disease, but treatments can decrease the inflammation in your intestines, relieve symptoms, and prevent complications. Treatments include medicines, bowel rest, and surgery. No single treatment works for everyone. You and your health care provider can work together to figure out which treatment is best for you:

• Medicines for Crohn's include various medicines that decrease the inflammation. Some of these medicines do this by reducing the activity of your immune system. Medicines can also help with symptoms or complications, such as nonsteroidal anti-inflammatory drugs and anti-diarrheal medicines. If your Crohn's causes an infection, you may need antibiotics.
• Bowel rest involves drinking only certain liquids or not eating or drinking anything. This allows your intestines to rest. You may need to do this if your Crohn's disease symptoms are severe. You get your nutrients through drinking a liquid, a feeding tube, or an intravenous (IV) tube. You may need to do bowel rest in the hospital, or you may be able to do it at home. It will last for a few days or up to several weeks.
• Surgery can treat complications and reduce symptoms when other treatments are not helping enough. The surgery will involve removing a damaged part of your digestive tract to treat
  • Fistulas
  • Bleeding that is life threatening
  • Intestinal obstructions
  • Side effects from medicines when they threaten your health
  • Symptoms when medicines do not improve your condition

Changing your diet can help reduce symptoms. Your provider may recommend that you make changes to your diet, such as:

• Avoiding carbonated drinks
• Avoiding popcorn, vegetable skins, nuts, and other high-fiber foods
• Drinking more liquids
• Eating smaller meals more often
• Keeping a food diary to help identify foods that cause problems

Some people also need go on special diet, such as a low-fiber diet.

What is diarrhea?

Diarrhea is loose, watery stools (bowel movements). You have diarrhea if you have loose stools three or more times in one day. Acute diarrhea is diarrhea that lasts a short time. It is a common problem. It usually lasts about one or two days, but it may last longer. Then it goes away on its own.

Diarrhea lasting more than a few days may be a sign of a more serious problem. Chronic diarrhea -- diarrhea that lasts at least four weeks -- can be a symptom of a chronic disease. Chronic diarrhea symptoms may be continual, or they may come and go.

What causes diarrhea?

The most common causes of diarrhea include:

• Bacteria from contaminated food or water
• Viruses such as the flu, norovirus, or rotavirus . Rotavirus is the most common cause of acute diarrhea in children.
• Parasites, which are tiny organisms found in contaminated food or water
• Medicines such as antibiotics, cancer drugs, and antacids that contain magnesium
• Food intolerances and sensitivities, which are problems digesting certain ingredients or foods. An example is lactose intolerance.
• Diseases that affect the stomach, small intestine, or colon, such as Crohn's disease
• Problems with how the colon functions, such as irritable bowel syndrome

Some people also get diarrhea after stomach surgery, because sometimes the surgeries can cause food to move through your digestive system more quickly.

Sometimes no cause can be found. If your diarrhea goes away within a few days, finding the cause is usually not necessary.

Who is at risk for diarrhea?

People of all ages can get diarrhea. On average, adults In the United States have acute diarrhea once a year. Young children have it an average of twice a year.

People who visit developing countries are at risk for traveler's diarrhea. It is caused by consuming contaminated food or water.

What other symptoms might I have with diarrhea?

Other possible symptoms of diarrhea include:

• Cramps or pain in the abdomen
• An urgent need to use the bathroom
• Loss of bowel control

If a virus or bacteria is the cause of your diarrhea, you may also have a fever, chills, and bloody stools.

Diarrhea can cause dehydration, which means that your body does not have enough fluid to work properly. Dehydration can be serious, especially for children, older adults, and people with weakened immune systems.

When do I need to see a health care provider for diarrhea?

Although it is usually not harmful, diarrhea can become dangerous or signal a more serious problem. Contact your health care provider if you have:

• Signs of dehydration
• Diarrhea for more than 2 days, if you are an adult. For children, contact the provider if it lasts more than 24 hours.
• Severe pain in your abdomen or rectum (for adults)
• A fever of 102 degrees or higher
• Stools containing blood or pus
• Stools that are black and tarry

If children have diarrhea, parents or caregivers should not hesitate to call a health care provider. Diarrhea can be especially dangerous in newborns and infants.

How is the cause of diarrhea diagnosed?

To find the cause of diarrhea, your health care provider may:

• Do a physical exam
• Ask about any medicines you are taking
• Test your stool or blood to look for bacteria, parasites, or other signs of disease or infection
• Ask you to stop eating certain foods to see whether your diarrhea goes away

If you have chronic diarrhea, your health care provider may perform other tests to look for signs of disease.

What are the treatments for diarrhea?

Diarrhea is treated by replacing lost fluids and electrolytes to prevent dehydration. Depending on the cause of the problem, you may need medicines to stop the diarrhea or treat an infection.

Adults with diarrhea should drink water, fruit juices, sports drinks, sodas without caffeine, and salty broths. As your symptoms improve, you can eat soft, bland food.

Children with diarrhea should be given oral rehydration solutions to replace lost fluids and electrolytes.

Can diarrhea be prevented?

Two types of diarrhea can be prevented - rotavirus diarrhea and traveler's diarrhea. There are vaccines for rotavirus. They are given to babies in two or three doses.

You can help prevent traveler's diarrhea by being careful about what you eat and drink when you are in developing countries:

• Use only bottled or purified water for drinking, making ice cubes, and brushing your teeth
• If you do use tap water, boil it or use iodine tablets
• Make sure that the cooked food you eat is fully cooked and served hot
• Avoid unwashed or unpeeled raw fruits and vegetables

When you eat, your body breaks food down to a form it can use to build and nourish cells and provide energy. This process is called digestion.

Your digestive system is a series of hollow organs joined in a long, twisting tube. It runs from your mouth to your anus and includes your esophagus, stomach, and small and large intestines. Your liver, gallbladder and pancreas are also involved. They produce juices to help digestion.

There are many types of digestive disorders. The symptoms vary widely depending on the problem. In general, you should see your doctor if you have

• Blood in your stool
• Changes in bowel habits
• Severe abdominal pain
• Unintentional weight loss
• Heartburn not relieved by antacids

Have you ever had the "stomach flu?" What you probably had was gastroenteritis - not a type of flu at all. Gastroenteritis is an inflammation of the lining of the intestines caused by a virus, bacteria or parasites. Viral gastroenteritis is the second most common illness in the U.S. The cause is often a norovirus infection. It spreads through contaminated food or water, and contact with an infected person. The best prevention is frequent hand washing.

Symptoms of gastroenteritis include diarrhea, abdominal pain, vomiting, headache, fever and chills. Most people recover with no treatment.

The most common problem with gastroenteritis is dehydration. This happens if you do not drink enough fluids to replace what you lose through vomiting and diarrhea. Dehydration is most common in babies, young children, the elderly and people with weak immune systems.

Viral gastroenteritis is an infection of your intestines that typically causes watery diarrhea, pain or cramping in your abdomen, nausea or vomiting, and sometimes fever.

Viral gastroenteritis is caused by viruses. Viruses invade normal cells in your body. Many viruses cause infections that can be spread from person to person.

People commonly call viral gastroenteritis “stomach flu,” but the term is not medically correct. Viral gastroenteritis is an infection of the intestines, not the stomach, and it is not caused by influenza (flu) viruses. The flu vaccine does not protect against viral gastroenteritis.

Viral gastroenteritis is acute, meaning it happens suddenly and lasts a short time. Most cases of viral gastroenteritis last less than a week, and most people get better on their own without medical treatment. In some cases, viral gastroenteritis may cause severe symptoms or may lead to dehydration.

Viral gastroenteritis is very common. Norovirus is the most common cause of viral gastroenteritis. In the United States, norovirus causes 19 to 21 million cases of viral gastroenteritis each year. Other viruses that cause gastroenteritis are less common.

Your digestive or gastrointestinal (GI) tract includes the esophagus, stomach, small intestine, large intestine or colon, rectum, and anus. Bleeding can come from any of these areas. The amount of bleeding can be so small that only a lab test can find it.

Signs of bleeding in the digestive tract depend where it is and how much bleeding there is.

Signs of bleeding in the upper digestive tract include

• Bright red blood in vomit
• Vomit that looks like coffee grounds
• Black or tarry stool
• Dark blood mixed with stool

Signs of bleeding in the lower digestive tract include

• Black or tarry stool
• Dark blood mixed with stool
• Stool mixed or coated with bright red blood

GI bleeding is not a disease, but a symptom of a disease. There are many possible causes of GI bleeding, including hemorrhoids, peptic ulcers, tears or inflammation in the esophagus, diverticulosis and diverticulitis, ulcerative colitis and Crohn's disease, colonic polyps, or cancer in the colon, stomach or esophagus.

The test used most often to look for the cause of GI bleeding is called endoscopy. It uses a flexible instrument inserted through the mouth or rectum to view the inside of the GI tract. A type of endoscopy called colonoscopy looks at the large intestine.

What is GI bleeding?

Gastrointestinal (GI) bleeding is any type of bleeding that starts in your GI tract, also called your digestive tract. GI bleeding is a symptom of a disease or condition, rather than a disease or condition itself.

Acute GI bleeding is sudden and can sometimes be severe. Chronic GI bleeding is slight bleeding that can last a long time or may come and go.

Does GI bleeding have another name?

GI bleeding is also called bleeding in the digestive tract, upper GI bleeding, or lower GI bleeding. The upper GI tract and lower GI tract are different areas of your GI tract.

How common is GI bleeding?

Every year, about 100,000 people in the United States go to the hospital for upper GI bleeding. About 20 to 33 percent of GI bleeding episodes in Western countries are in the lower GI tract.

Who is more likely to have GI bleeding?

Men are twice as likely as women to have upper GI bleeding.

Your small intestine is part of your digestive system. It is a long tube that connects your stomach to your large intestine. Intestinal cancer is rare, but eating a high-fat diet or having Crohn's disease, celiac disease, or a history of colonic polyps can increase your risk.

Possible signs of small intestine cancer include:

• Abdominal pain
• Weight loss for no reason
• Blood in the stool
• A lump in the abdomen

Imaging tests that create pictures of the small intestine and the area around it can help diagnose intestinal cancer and show whether it has spread.

Surgery is the most common treatment. Additional options include chemotherapy, radiation therapy, or a combination.

KEY POINTS

• Small intestine cancer is a rare disease in which malignant (cancer) cells form in the tissues of the small intestine.
• There are five types of small intestine cancer.
• Diet and health history can affect the risk of developing small intestine cancer.
• Signs and symptoms of small intestine cancer include unexplained weight loss and abdominal pain.
• Tests that examine the small intestine are used to diagnose and stage small intestine cancer.
• Certain factors affect prognosis (chance of recovery) and treatment options.

Small intestine cancer is a rare disease in which malignant (cancer) cells form in the tissues of the small intestine.

The small intestine is part of the body’s digestive system, which also includes the esophagus, stomach, and large intestine. The digestive system removes and processes nutrients (vitamins, minerals, carbohydrates, fats, proteins, and water) from foods and helps pass waste material out of the body. The small intestine is a long tube that connects the stomach to the large intestine. It folds many times to fit inside the abdomen.

There are five types of small intestine cancer.

The types of cancer found in the small intestine are adenocarcinoma, sarcoma, neuroendocrine tumors, gastrointestinal stromal tumor, and lymphoma. This summary discusses adenocarcinoma and leiomyosarcoma (a type of sarcoma).

Adenocarcinoma starts in glandular cells in the lining of the small intestine and is the most common type of small intestine cancer. Most of these tumors occur in the part of the small intestine near the stomach. They may grow and block the intestine.

Leiomyosarcoma starts in the smooth muscle cells of the small intestine. Most of these tumors occur in the part of the small intestine near the large intestine.

An intestinal obstruction occurs when food or stool cannot move through the intestines. The obstruction can be complete or partial. There are many causes. The most common are adhesions, hernias, cancers, and certain medicines.

Symptoms include

• Severe abdominal pain or cramping
• Vomiting
• Bloating
• Loud bowel sounds
• Swelling of the abdomen
• Inability to pass gas
• Constipation

A complete intestinal obstruction is a medical emergency. It often requires surgery.

Your abdomen extends from below your chest to your groin. Some people call it the stomach, but your abdomen contains many other important organs. Pain in the abdomen can come from any one of them. The pain may start somewhere else, such as your chest. Severe pain doesn't always mean a serious problem. Nor does mild pain mean a problem is not serious.

Call your health care provider if mild pain lasts a week or more or if you have pain with other symptoms. Get medical help immediately if

• You have abdominal pain that is sudden and sharp
• You also have pain in your chest, neck or shoulder
• You're vomiting blood or have blood in your stool
• Your abdomen is stiff, hard and tender to touch
• You can't move your bowels, especially if you're also vomiting

Irritable bowel syndrome (IBS) is a problem that affects the large intestine. It can cause abdominal cramping, bloating, and a change in bowel habits. Some people with the disorder have constipation. Some have diarrhea. Others go back and forth between the two. Although IBS can cause a great deal of discomfort, it does not harm the intestines.

IBS is common. It affects about twice as many women as men and is most often found in people younger than 45 years. No one knows the exact cause of IBS. There is no specific test for it. Your doctor may run tests to be sure you don't have other diseases. These tests may include stool sampling tests, blood tests, and x-rays. Your doctor may also do a test called a sigmoidoscopy or colonoscopy. Most people diagnosed with IBS can control their symptoms with diet, stress management, probiotics, and medicine.

Irritable bowel syndrome (IBS) is a group of symptoms that occur together, including repeated pain in your abdomen and changes in your bowel movements, which may be diarrhea, constipation, or both. With IBS, you have these symptoms without any visible signs of damage or disease in your digestive tract.

IBS is a functional gastrointestinal (GI) disorder. Functional GI disorders, which doctors now call disorders of gut-brain interactions, are related to problems with how your brain and your gut work together. These problems can cause your gut to be more sensitive and change how the muscles in your bowel contract. If your gut is more sensitive, you may feel more abdominal pain and bloating. Changes in how the muscles in your bowel contract lead to diarrhea, constipation, or both.

Does IBS have another name?

In the past, doctors called IBS colitis, mucous colitis, spastic colon, nervous colon, and spastic bowel.

How common is IBS?

Studies suggest that about 12 percent of people in the United States have IBS.

Your small intestine does most of the digesting of the foods you eat. If you have a malabsorption syndrome, your small intestine cannot absorb nutrients from foods.

Causes of malabsorption syndromes include

• Celiac disease
• Lactose intolerance
• Short bowel syndrome. This happens after surgery to remove half or more of the small intestine. You might need the surgery if you have a problem with the small intestine from a disease, injury, or birth defect.
• Whipple disease, a rare bacterial infection
• Genetic diseases
• Certain medicines

Symptoms of different malabsorption syndromes can vary. They often include chronic diarrhea, abnormal stools, weight loss, and gas. Your doctor may use lab, imaging, or other tests to make a diagnosis.

Treatment of malabsorption syndromes depends on the cause.