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ОглавлениеCHAPTER 2
How Do I Know I Have IBD?
CASE STUDY Jonathan
Jonathan is a 33-year-old police officer who has had several episodes of belly pain every 6 to 9 months during the past 5 years. Each time, these last between 2 and 6 weeks. Usually, the pain is crampy and tends to occur anywhere from 30 to 90 minutes after he eats. He feels bloated and uncomfortable. Jonathan also experiences watery diarrhea up to eight times a day during the pain episodes. The episodes subside on their own.
When the episodes occur, Jonathan’s appetite is poor, and he can lose up to 10 pounds (5 kg). In between the episodes, he has no pain and regains most of the weight that he lost. However, during the past 2 years, he has felt more tired than usual.
Jonathan doesn’t think much of these episodes. His wife has irritable bowel syndrome, a condition she has been told is related to diet and stress, and he figures that he has something similar. However, this year, Jonathan happens to have had his annual physical examination shortly after an episode of pain and diarrhea, and he mentions it in passing to his doctor.
After further questioning, his doctor is concerned that Jonathan may be suffering from something more serious than irritable bowel syndrome. He is concerned about the weight loss that occurs during the episodes and the fact that Jonathan wakes up from his sleep with pain and diarrhea. In addition, the doctor is able to feel a tender area of swelling in the lower right area of Jonathan’s abdomen.
Based on these findings, the doctor is concerned that Jonathan may have Crohn’s disease in the ileum (the last part of the small intestine). He decides to order tests to investigate further…
Recognizing Symptoms
Sometimes, people, particularly young people, delay seeking medical attention for inflammatory bowel disease because they believe that they will remain healthy and that any symptoms they experience are likely due to simple conditions that are probably not long-lasting. Although some people feel that the symptoms are suspicious, they may deny the possibility of having a serious chronic disease, especially if they already have a family history of IBD and do not wish to face the possibility that they, too, are going to have to live with this disease. In some cases, the delay in diagnosis may be due to a general lack of knowledge on the part of the individual about what constitutes abnormal or unacceptable symptoms or due to embarrassment that they may feel in discussing their symptoms.
Another feature of IBD that may lead to a delay in diagnosis is the fact that the symptoms may come and go without any treatment, so that someone with IBD may have symptoms that go on for days or weeks and then go away on their own, and the person may feel perfectly healthy again for many weeks or months until the symptoms come back. With this pattern of symptoms, people may dismiss the episodes when they occur, thinking they will go away again on their own, and will often not mention them to their doctor or primary care provider.
Very occasionally, a delay in diagnosis may occur when a physician discounts a patient’s description of symptoms or misses important clinical clues toward making the diagnosis.
For most people, any delay between the time symptoms begin and the time they ask their doctor for advice is due to the gradual change from a state of good health to a state of illness or disease. There are likely very few individuals with IBD who do not eventually undergo evaluation and have a diagnosis of Crohn’s disease or ulcerative colitis confirmed.
Good Health
Crohn’s disease and ulcerative colitis typically develop in people who previously were in good health and who had no prior bowel symptoms or digestive problems.
Common Symptoms
Inflammatory bowel disease — in particular, Crohn’s disease — can present with quite different symptoms from one person to the next, and these symptoms depend upon many different factors.
Some factors are not directly related to the disease. These include usual bowel habits before developing IBD, pain tolerance or threshold, and probably even mood. Although these individual factors may modify the symptom experience, the nature of the inflammation — its severity, extent, and location — is most important in determining the symptoms.
Flare Periods
Crohn’s disease and ulcerative colitis fluctuate in severity, and patients can experience flares and remissions. Symptoms are typically experienced primarily during these flare periods. When the disease is in remission, patients, particularly patients with ulcerative colitis, may have no symptoms whatsoever.
Crohn’s disease and ulcerative colitis tend to share a number of symptoms, such as abdominal pain and diarrhea, but they can be quite different with respect to the prominence of these symptoms and their course over time. The common symptoms of the two disorders and how they manifest are listed below.
Quick Guide to Ulcerative Colitis Symptoms
If you experience any one or combination of the following symptoms, be sure to consult with your doctor.
•Rectal bleeding (blood and mucus in the stool)
•Rectal urgency (frequent trips to the toilet and urgent need to move the bowels that often can’t be delayed)
•Severe abdominal cramps
•Frequent diarrhea
•Increased intestinal gas
•Persistent fatigue
•Weight loss
Ulcerative Colitis Symptoms
Because ulcerative colitis affects only the large intestine, the symptoms are due to inflammation, damage, and ulceration of the lining of the large intestine. The inflammation is usually contained within the most superficial inner linings of the large intestine. This determines the type of symptoms that a patient may experience. Because of these symptoms, patients with ulcerative colitis often feel they have to stay close to a bathroom when their disease is active.
Rectal Bleeding
Blood in the stool occurs regardless of whether the inflammation is restricted to just the bottom end of the large intestine (rectum) or involves the entire large intestine. Mucus is often passed along with blood in the stool, but can sometimes occur on its own. In some cases, blood and mucus may be passed without any stool. Although this bleeding can happen with every bowel movement and can appear quite severe, it almost never results in a sudden fall in the hemoglobin (blood count), and, as a result, the bleeding is almost never an emergency situation. It is, however, an indication of the severity of the underlying inflammation and requires medical attention.
Other common conditions, such as hemorrhoids, can also cause blood with stools, so not all rectal bleeding is due to ulcerative colitis.
Blood in the Stool
The most obvious and consistent manifestation of ulcerative colitis is the presence of blood in the stool. This occurs in almost every individual with ulcerative colitis. In fact, if someone with IBD has never had blood in the stools, it is quite possible that the condition is Crohn’s disease rather than ulcerative colitis. Crohn’s disease is not always associated with blood in the stool.
Rectal Urgency
Inflammation of the rectum always occurs in ulcerative colitis and affects the normal ability to hold stool and gas. Patients with ulcerative colitis may experience frequent and very strong urges to move the bowels whenever there is the smallest amount of stool, blood, mucus, or gas in the rectum. This urgency is often accompanied by strong lower abdominal cramping that is probably due to contraction or spasm of the rectum and sigmoid colon.
When patients experience this type of urgency and are not close to a bathroom, they may not be able to control the urge long enough and may be incontinent. This loss of control can sometimes be the most troubling symptom for patients with ulcerative colitis. In many cases, individuals with active ulcerative colitis will plan their activities so that they always have easy and quick access to a bathroom.
The increased bowel activity usually occurs in the early-morning hours and soon after eating. As a result, patients will avoid going out in the morning until after bowel movements subside, or they will avoid eating before going out of the house. When the ulcerative colitis is more severe, the bowel activity may continue throughout the night and will make the patient wake up several times to go to the bathroom.
Unrelenting Pain
Between flares, patients usually do not feel any pain. If a patient with ulcerative colitis reports constant, unrelenting abdominal pain, it suggests the possibility of another diagnosis or a complication, such as bowel perforation. Be sure to consult with your doctor if abdominal pain has this characteristic.
False Urges
False urges are another troubling symptom that many patients with active ulcerative colitis experience. When the rectum becomes distended with gas or stool, it sends a signal to the brain indicating a need to move one’s bowels. When the rectum is inflamed, it becomes irritable and will send these signals to the brain with only the smallest amount of distension or even without any distension at all.
In that case, a person will feel a strong urge to move the bowels and will rush to the bathroom, only to find that nothing comes out or, at most, just a small amount of blood and mucus. As a result, people with ulcerative colitis may have to make countless trips to the bathroom every day, even though they may pass stool only a handful of times.
Typically, when stool is passed, it comes in only small amounts each time. Because patients will pass what is recognized as stool only very infrequently, they will sometimes feel as if they are constipated. When only the rectum is inflamed, the inflammation and spasm may actually block the normal stool that is present in the large intestine above the rectum from getting through and being excreted.
Abdominal Pain
The inflammation of the inner lining of the intestine can produce abdominal pain, but because the inner lining of the intestine does not have nerve endings that can detect painful stimuli, abdominal pain is not a constant feature in most cases of ulcerative colitis. When it does occur, pain tends to be crampy, occurring around the time of bowel movements, and is often associated with rectal urgency. This pain is probably due more to the contraction or spasm of the intestine than to the inflammation of the inner lining itself.
Diarrhea
When the inflammation of the large intestine extends above the rectum, it affects the normal fluid-absorptive function of the large intestine, resulting in loose or liquid stools, also known as diarrhea. The liquid stool may be mixed with variable amounts of blood and mucus.
Intestinal Gas
Some patients experiencing a flare of ulcerative colitis will feel that they have an increased amount of gas or that the odor of the gas changes. Some even say that they can tell when a flare is about to come on because of this change in the odor. The amount of gas produced during a flare of colitis has never actually been studied, but it is likely that, even if the amount of gas produced is not increased, the inflamed rectum and large intestine are more sensitive to the presence of gas and, therefore, will pass it more frequently.
Fatigue
When the inflammation in the colon is particularly bad or when it involves a large portion of the colon, patients with ulcerative colitis may suffer from fatigue and weight loss. The fatigue is most often due to the inflammation itself, but can also be due to anemia resulting from blood loss in the stool. Chronic blood loss can, over time, lead to iron-deficiency anemia. When a person is anemic, the blood is not able to carry oxygen to the tissues in the body as effectively, and, as a result, a person may experience fatigue and breathlessness with minimal amounts of exertion.
Cytokines
Intestinal inflammation itself, even without producing anemia or iron deficiency, can also produce fatigue. This probably occurs as a result of certain proteins, called cytokines, that are released from inflamed tissues and that can produce symptoms such as fatigue, loss of appetite, and fever.
Weight Loss
Cytokines can also produce changes in metabolism that result in loss of body weight, even when food intake is at a level that should be sufficient to maintain a person’s healthy nutritional state.
Crohn’s Disease Symptoms
Crohn’s disease can affect any part of the gastrointestinal tract. As a result, the symptoms reported by patients with Crohn’s disease can be much more varied than those reported by patients with ulcerative colitis.
As with ulcerative colitis, the symptoms experienced in Crohn’s disease are highly dependent upon the location and severity of the inflammation within the gastrointestinal tract. However, the relative prominence of the symptoms may be different in Crohn’s disease than in ulcerative colitis. Because there are locations that are much more commonly affected than others, there are presenting symptoms that also tend to be more common than others. As a general rule, abdominal pain, diarrhea, fatigue, and weight loss tend to be the most common presenting symptoms in Crohn’s disease. In children, failure to grow normally, or “failure to thrive,” is a common presenting symptom.
Atypical Symptoms
Because the locations within the gut that are affected by the disease vary from person to person, there is no “typical” patient or “typical” symptom presentation in Crohn’s disease.
Quick Guide to Crohn’s Disease Symptoms
The symptoms of Crohn’s disease are similar to the symptoms of ulcerative colitis. However, a number of additional symptoms, not typically experienced in ulcerative colitis, may be experienced in patients with Crohn’s disease. One problem that is very uncommon in ulcerative colitis, but may be seen in Crohn’s disease, is the occurrence of fistulas and abscesses around the anus and ulcers within the anal canal. These complications occur because of the tendency of Crohn’s disease to penetrate more deeply into the bowel lining.
If you experience any one or combination of the following symptoms, be sure to consult with your doctor.
•Rectal bleeding (blood and mucus in the stool)
•Rectal urgency (frequent trips to the toilet and urgent need to move the bowels that often can’t be delayed)
•Severe abdominal cramps
•Frequent diarrhea
•Increased intestinal gas
•Persistent fatigue
•Weight loss
•Fistulas and abscesses around the anus and ulcers within the anal canal
•Failure to grow or thrive in children
Tips for Working with Your Doctor
Working with your doctor to diagnose your symptoms is the first step in understanding and treating inflammatory bowel disease. However, some patients find their initial meeting with their doctor somewhat unsatisfactory because they do not have enough time to ask all the questions they may have. While most doctors do have busy schedules, you can make the most of your appointments with them by being well prepared. To get the most out of your visit to your doctor, try the following tips:
Make sure there is enough time.
If you think that your problems and concerns are going to take longer than the time your doctor usually allocates for an appointment, ask for a longer meeting. You will find this much more satisfactory than trying to “find a moment” at the end of the appointment to raise what may be your most pressing questions and concerns. If you do come to the end of your allotted time, acknowledge to the doctor that you have run out of time and that you still have items to discuss. The doctor may sometimes ask you to continue or, in some cases, suggest that you schedule another appointment.
Keep your description of symptoms focused and factual.
The doctor wants to hear about what you are feeling, so just describe what you are experiencing without jumping to conclusions or making speculations. You might say to your doctor, “I’m here today because I keep getting episodes when I can’t move my bowels, my belly becomes distended like I’m 9 months pregnant, and I start vomiting. It feels exactly like it did when I had surgery for a bowel obstruction 4 years ago, but maybe a little less severe.” Although you may suspect this is caused by a bowel obstruction, you don’t need to interpret the experience or make a diagnosis. That is the doctor’s job — to determine if the symptoms are due to a bowel obstruction or due to some other cause or condition that could produce similar symptoms.
Bring a list of your medications and their doses.
The doctor will need to know if you are taking any medications and their dosage. Report if you have experienced any side effects and when they first started in relation to when you began taking the medications.
Make a list of your questions and issues.
Keep your list of questions short enough that it can be covered in the available time and try to make sure that the questions are specific and to the point rather than being overly general and difficult to answer concisely. For example, answering a question such as “What are the possible side effects of this medication?” may take up the entire appointment, whereas asking “What are the common and serious side effects of this drug?” will get the information you are really looking for in a relatively short time, allowing time for other questions.
Prioritize your list of questions from most important to the least important.
Take care of the questions that are causing you the most concern first so that you can feel more at ease and more comfortable asking other questions. Often your doctor’s answer to the most pressing question also answers other questions on your list.
Bring a friend or relative to help you remember what you have discussed.
Many patients ask a spouse, relative, or friend to accompany them to the appointment, to help them remember the questions they planned to ask and make note of the answers given by the doctor. Their emotional support is also important.
Make notes about key points in the discussion.
You or your companion should make a record of what your doctor investigates and concludes so that you can follow any treatment program the doctor may prescribe. This is especially important if treatment options are presented to you for your decision. You may want to refer to your notes when making your decision.
| What is an abscess? | |
| The inflamed areas of the intestine may be tender to touch, so that any pressure applied to the abdomen may produce pain. When ulcers extend right through the intestinal wall, it can produce a reaction around the intestine, resulting in a swelling that can be felt by a physician examining the patient. Occasionally, this area can become infected by the bacteria from the intestine that are able to penetrate through the ulcer into the area of swelling. This is called an abscess. When this occurs, patients usually feel a constant pain over the affected area and may also have a fever. |
Abdominal Pain
Unlike ulcerative colitis, where the inflammation is limited to the innermost lining of the intestine, in Crohn’s disease, the inflammation and ulcers can penetrate through all the layers of the intestinal wall. Since there are nerves that can transmit pain signals in the deeper layers of the intestine, this means that pain may be a more consistent feature of Crohn’s disease.
Strictures and Blockages
If Crohn’s disease produces some narrowing of the intestine (most often in the small intestine), it can produce some degree of blockage, making it difficult for food and intestinal contents to get through the narrowed areas. This can be experienced as crampy abdominal pain that occurs within minutes to several hours after a meal, depending on the precise location of the narrowing. Bloating of the abdomen can occur along with this pain, and, when it is particularly severe, nausea and vomiting may also occur. More complete blockages can occur, and these will be associated with symptoms of abdominal pain, distension, nausea, and vomiting. During the episode, the person may not be able to pass any stool or gas.
Immediate Medical Attention
Episodes of abdominal pain that last more than 4 to 6 hours without passage of gas or stool require immediate medical attention and often require hospitalization.
Bowel Movements
As is the case in ulcerative colitis, patients with Crohn’s disease may have crampy abdominal pain around the time of bowel movements. This may be due to irritability of the intestine and the associated spasm that can occur as a result of inflammation.
Diarrhea
Diarrhea is a common, but not universal, symptom of Crohn’s disease. In fact, some patients with intestinal narrowing actually present with decreased bowel movements and constipation. The diarrhea that occurs in patients with Crohn’s disease is usually not bloody, but when the lower part of the large intestine is inflamed, bleeding can occur more often.
Fatigue
Fatigue is a very common symptom in Crohn’s disease and can be one of the most difficult symptoms to completely reverse with medical therapy. As in ulcerative colitis, it is probably due to the release of cytokines from the inflamed intestinal tissues.
Weight Loss
Weight loss may be due to the changes in metabolism caused by the cytokines, but it can also be caused by reduced nutrient intake as a result of pain that occurs after eating. In patients with small intestinal inflammation, there may be problems with absorption of nutrients, which can lead to weight loss.
Anal Problems
While patients with ulcerative colitis may describe irritation of the skin around the anus or may even develop hemorrhoids (swollen veins) because of the frequent bowel movements, patients with Crohn’s disease are at risk of developing certain specific problems that are more serious. They can develop anal fissures or ulcers (painful breaks in the skin inside the anus), abscesses (painful collections of pus), and fistulas (small openings to the skin around the anus that can drain stool, pus, or blood).
Nutrient Deficiencies
Depending on the part of the intestine involved in Crohn’s disease, patients can develop specific nutrient deficiencies. For example, the last part of the small intestine (terminal ileum) is commonly affected in Crohn’s disease; this is also where vitamin B12 is absorbed. As a result, vitamin B12 deficiency can develop in patients with Crohn’s disease of the terminal ileum.
Extra-Intestinal Symptoms
Both ulcerative colitis and Crohn’s disease can present with certain associated symptoms or conditions outside of the intestine. These are called extra-intestinal manifestations and are usually due to inflammation of other tissues outside of the bowel — joints, eyes, skin, and liver, for example. Joint manifestations (arthritis) are the most common. These extraintestinal manifestations can occur at the time of first diagnosis of IBD, or they can occur later on in the course of the disease. In occasional cases, they can first occur months or even years before the bowel symptoms first become apparent. The same major extra-intestinal manifestations and symptoms (joint, eye, skin, and liver) can occur in both disorders.
Onset of Symptoms
Inflammatory bowel disease usually first develops in one of three different patterns of symptom onset: gradual, sudden, and relapsing or remitting.
Gradual Onset
Most often, Crohn’s disease and ulcerative colitis develop very gradually so that it takes many weeks, months, or, in some cases, years before patients recognize the symptoms and mention them to their doctor for diagnosis.
Sudden Onset
Unusually, though certainly not rarely, inflammatory bowel disease develops abruptly. Symptoms may come on suddenly, sometimes so quickly that the disease seems to develop virtually overnight, with the person going from a state of good health to a serious and severe illness without any obvious warning. This type of presentation is quite striking and can often make it very difficult for patients and their families. Important medical management decisions, including the choice of medications and the possibility of undergoing surgery, may be required before the patient has the chance to learn about the disease and its consequences, complications, and potential treatments.
Relapsing or Remitting Onset
Inflammatory bowel disease may also develop following a so-called relapsing or remitting course. Patients can present with mild episodes or flares that occur for days, weeks, or even months at a time. During these flares, symptoms get noticeably worse, but then seem to go away spontaneously (also called going into remission) so that the person goes back to a state of normal health with no symptoms for many weeks, months, or even years before another episode or flare occurs.
Because these flares often subside on their own, patients will sometimes not go to the doctor for investigation or treatment, until an episode is more severe, lasts longer than usual, or is more concerning in some way.
Diagnostic Methods
If you suspect you or a family member is experiencing any symptoms of inflammatory bowel disease, be sure to see your doctor as soon as possible. A medical history of symptoms and a physical examination are usually adequate for strongly suspecting a diagnosis of Crohn’s disease or ulcerative colitis, but further diagnostic testing is important in confirming the suspected diagnosis, determining the extent and severity of the disease, and screening for possible complications of the disease. These procedures include standard blood and stool tests, various imaging studies, endoscopies, and biopsy.
Not all tests or investigations are required in all patients. The tests chosen will depend on your specific symptoms, as well as the availability, potential risk, and discomfort of the specific investigation.
Diagnostic Tests for IBD
•Blood tests
•Stool tests
•Imaging studies
-X-ray
-Ultrasound
-CT scan
-MRI
•Endoscopy
-Gastroscopy
-Colonoscopy
-Wireless capsule endoscopy
-Enteroscopy
•Biopsies
Blood Tests
White blood cell or platelet count can increase in infections and inflammatory conditions and can be elevated in active IBD. Certain antibodies are found more frequently in the blood of patients with IBD. Antibodies are proteins produced by the immune system to defend against certain types of infection by binding to specific molecules found on the surface of viruses and bacteria. Some proteins, most commonly C-reactive protein, are found in higher levels in the blood of people with inflammatory conditions.
Screening
Although blood tests cannot replace more definitive diagnostic tests, such as imaging studies, endoscopy, or biopsy, and although they cannot yet be used to confirm a diagnosis, they may be helpful in screening out patients with possible IBD before proceeding to more definitive and often invasive diagnostic testing.
Antibody Patterns
The pattern of antibodies may help differentiate between ulcerative colitis and Crohn’s disease. The antibodies found in the blood in IBD include anti-ompC, anti-CBir1, and anti-fla-X, among others. These are antibodies that target certain proteins found on bacteria. They have been combined in a commercially available blood test panel with some other proteins and genetic markers found in blood; together, these markers provide a probability of a given individual having IBD. One of these antibodies, called perinuclear antineutrophil cytoplasmic antibody (pANCA), occurs more commonly in ulcerative colitis, whereas another antibody, anti-Saccharomyces cerevisiae antibody (ASCA), is fairly specific for Crohn’s disease.
There are several other antibody tests that are commercially available along with pANCA and ASCA. Although this panel of antibody tests cannot replace more definitive diagnostic tests, such as imaging studies, endoscopy, or biopsy, and although they cannot yet be used to confirm a diagnosis of IBD, they may be helpful in screening out patients with possible IBD before proceeding to more definitive and often invasive diagnostic testing. This may be particularly helpful in children, where invasive diagnostic testing is more difficult to justify and carry out, particularly when the suspicion of actually finding disease is relatively low. These antibody tests can be used to help determine who should undergo further testing, since it is very unlikely that a child with a negative pANCA and ASCA test will turn out to have IBD. It also appears that, in a patient with known Crohn’s disease or ulcerative colitis, certain patterns of the different antibodies, and the levels of antibodies present in the blood, may be associated with certain disease locations and with higher risk of developing certain complications of disease.
Other blood tests indicate evidence of possible complications or nutritional deficiencies that may have occurred as a result of IBD. These include blood tests for anemia, liver disease, iron deficiency, vitamin B12 deficiency, and calcium deficiency.
| What tests will my doctor recommend? | |
| When recommending a specific test or series of tests, your doctor will take into account several factors. First, the choice of test is determined by your symptoms and what your doctor considers to be the likely diagnosis or possible site of disease. Second, the need to search for possible complications of IBD is considered when ordering tests. After taking these two factors into consideration, your doctor will then consider the accuracy of the diagnostic test, particularly if there are two or more possible tests that could provide similar information. In addition, some tests may have degrees of risk of complication or discomfort. The availability of the tests needs be taken into consideration since not all tests will be available in all communities or geographic areas. Third, the doctor will consider your special needs. Tests that would be ordered readily on adults might not be so appealing in children. Some patients may have had very bad experiences with certain tests or may be very afraid of other types of tests. |
Stool Tests
Stool samples may be sent for culture to rule out a bacterial infection as the cause for a patient’s symptoms. While the yield from this is quite low, particularly when symptoms have been going on for many weeks or even months, it is important to rule out infections before embarking on many types of therapy for Crohn’s disease and ulcerative colitis.
Stool may also be examined for parasites or the eggs of parasites. Occasionally, the laboratory will report that no parasites were seen, but that many white blood cells are present in the stool. The presence of white blood cells almost always indicates some type of inflammatory condition in the intestine. Stool can also be tested for certain proteins — calprotectin and lactoferrin — that are present in white blood cells that indicate the presence of active intestinal inflammation. The calprotectin level in stool has proven to be quite useful in people who present with symptoms that are not clearly or highly likely to be due to IBD. In that situation, an elevated calprotectin level is very suggestive of an underlying inflammatory condition such as IBD, and would support going ahead with other testing, such as endoscopy and biopsy, that can confirm the diagnosis.
Disease Activity
Stool tests can be used to monitor disease activity and response to treatment. These tests, when combined with blood tests, help make decisions regarding changes in treatment strategies.
X-Rays
Since the intestine does not appear in sufficient detail on plain X-rays, a contrast agent, usually barium, is used to fill the intestine so that the intestinal lining and wall can be seen in contrast to the barium. The barium is administered in several ways, depending on the area of bowel under examination. Because of the two-dimensional limitation of these techniques, they have been largely replaced by cross-sectional imaging studies, such as ultrasound, CT scan, and MRI.
Upper GI Series and Small Bowel Follow-Through
When examining the small intestine, the barium can be given by having the person drink it. X-rays are taken every few minutes as the barium passes out of the stomach and through the small intestine. This type of X-ray can also detect problems in the esophagus, stomach, and duodenum. It requires no preparation on the part of the patient other than having to fast on the day of the examination.
Small-Bowel Enema, or Enteroclysis
In some cases, a small-bowel follow-through X-ray doesn’t provide enough detail because of problems with the movement of barium through the small intestine or because the images are captured only every few minutes and important information can be missed. To solve this problem, the barium is administered directly into the small intestine by means of a tube placed through the nose into the esophagus, stomach, and duodenum. The radiologist can watch continuously as the barium flows through the entire small intestine. This examination also requires only fasting prior to the procedure.
Barium Enema
Barium enema provides images of the large intestine (colon). Liquid barium solution and air are pumped into the large intestine. A barium enema is rarely performed, however, having been replaced by colonoscopy and CT scan. Conversely, a normal calprotectin level makes the likelihood of IBD much lower, and the doctor and patient or family may then decide against further testing. This decision can be of value when it comes to children, for whom a test such as endoscopy is more difficult to do.
X-Ray Risk
All X-rays involve some degree of exposure to radiation, but, as long as the tests are not repeated frequently, the amount of radiation exposure is relatively small compared to the amount that one is exposed to every day from background sources.
Imaging Studies
Imaging studies provide “pictures” of the intestines and other internal organs without having to open up the abdomen by performing surgery. Imaging studies have been the mainstay of IBD diagnosis for many years. X-rays provide two-dimensional pictures of the intestine, while other types of imaging studies also provide information about surrounding structures within the abdomen, something which conventional X-ray studies cannot do. These include ultrasounds, computer-assisted tomography (CT, or CAT) scans, and magnetic resonance imaging (MRI). They provide multiple images of the abdomen in “slices” that can be positioned crosswise or lengthwise through the abdomen. In this way, it is possible to provide a three-dimensional representation of the intestines, other abdominal organs, and even blood vessels. Because of this capability, these imaging studies can provide improved diagnostic information compared with conventional X-ray studies.
Ultrasound
Ultrasound examinations are very safe and widely available. A probe that transmits a high-frequency sound wave is moved over the abdominal wall. That sound wave is reflected off structures within the abdomen and back to the probe, which has a sensor to detect the reflected sound waves, or echoes. These echoes are then converted into an image. Patients must fast before an abdominal ultrasound study. There are certain modifications of the ultrasound technique that can allow the radiologist to determine the rate of blood flow within the intestine. An increased blood flow may give an indication that the bowel is inflamed.
One particular type of ultrasound, a transanal ultrasound, is used to evaluate patients for possible anal abscesses and fistulas. This involves putting a special ultrasound probe into the anus in order to obtain images of the surrounding tissues. Although this may provide excellent detail, the procedure may be very difficult or impossible for patients with painful anal conditions associated with Crohn’s disease.
Detecting Complications
Ultrasound may be helpful in detecting complications of IBD, such as abscesses, but it is not the most sensitive imaging study, particularly when the intestines are to be evaluated.
Computer-Assisted Tomography (CAT scan, or CT scan)
Computer-assisted tomography is a very safe and widely used imaging technique. This technology, along with MRI, has virtually replaced the small bowel follow-through and small-bowel enema procedures.
During a CT scan, the patient lies on a table, which is surrounded by a large donut-shaped structure that produces and detects X-rays. These X-rays are converted into very detailed images when processed in the machine’s computer.
Patients undergoing CT scans of the abdomen are often given a contrast solution to drink 1 to 2 hours before the scan to provide better diagnostic images or an intravenous injection of another contrast material to show blood supply to the intestine and other tissues.
CT scans are generally not needed for routine follow-up of a patient’s clinical disease activity. If an abscess is detected by CT scan, the images can be used by the radiologist to insert a needle or plastic tube through the skin and into the abscess in order to allow it to drain properly.
CT scans involve radiation exposure, which is always a concern, particularly in young people. However, newer “low-dose” CT scans expose patients to a fraction of the radiation that they would be exposed to with a standard CT scan, without losing much of the important diagnostic information.
Sensitive Test
CT scans are very sensitive at detecting IBD complications, such as abscesses and intestinal obstructions. They do involve some radiation exposure and so should not be repeated too frequently or unnecessarily.
Magnetic Resonance Imaging (MRI)
Magnetic resonance imaging is relatively new in IBD diagnosis. It uses a large magnet to create images based on the different water content and molecular makeup of different tissues. A patient undergoing an MRI scan lies on a table that slides into the machine. The patient lies very still during the procedure, which can last up to 20 or 30 minutes. Like a CT scan, the MRI provides cross-sectional images, but because the intestines are continuously contracting in the abdomen during the procedure, the images of the intestines may not be as clear as they are in CT scans, where the image is obtained in a fraction of a second. Some studies are done after patients are administered an injection of a contrast agent into the vein. Because it does not involve any exposure to radiation, MRI may become the investigation of choice once the technology has advanced to the point where it provides images that are comparable in quality to CT scans.
Assessing the Anus
MRI is particularly useful for assessing the anus and the surrounding tissue for complications, such as fistulas and abscesses, in Crohn’s disease.
MRI is particularly useful for assessing the anus and the surrounding tissue for complications, such as fistulas and abscesses, in Crohn’s disease. MRI is also useful in determining whether areas of the intestine are inflamed or whether the changes seen are due to scarring. This is a particularly helpful distinction because tissue that is inflamed may respond to therapy with medication, whereas areas of scarring will likely not improve with medical therapy.
Endoscopy
In endoscopy, a long, narrow tube with a light and a camera on its tip is passed into the gastrointestinal tract. The endoscope can be steered in the desired direction to provide very detailed images of the inner lining of the gastrointestinal tract on a video monitor. When the procedure examines the esophagus, stomach, and duodenum, it is called an upper gastrointestinal endoscopy or, more commonly, a gastroscopy. When the instrument is inserted through the anus into the rectum and colon, it is called a colonoscopy. When doing a colonoscopy, the physician can often also examine the ileum (last part of the small intestine). This is one of the areas most commonly involved in Crohn’s disease.
Gastroscopy
Gastroscopy is a relatively straightforward procedure, but is done much less commonly in IBD than is colonoscopy, with the possible exception of individuals first diagnosed in childhood. In that case, gastroscopy is frequently carried out at the time of diagnosis. Gastroscopy is usually carried out following an overnight fast so that the stomach is empty. The back of the throat is sprayed with a local anesthetic so that the gag reflex is reduced, and, in some cases, a mild sedative is given intravenously to relax the patient. The whole procedure usually takes no more than 10 to 15 minutes and is typically not painful. In young children, it may be necessary to administer heavier sedation or general anesthetic in order to carry out the procedure.
Colonoscopy
Colonoscopy requires preparation of the bowel with a special diet (usually clear liquids) and a special laxative for one or more days prior to the procedure. This is important because the presence of feces can interfere with visibility and make the procedure almost useless. In some cases, the physician may not order a special laxative for the patient. Usually this is when the IBD is very active, but even in these instances, a smaller or more gentle preparation is probably still advisable and safe.
Upper Gastrointestinal Endoscopy
Colonoscopy
The colonoscopy procedure itself is usually performed with a sedative and an analgesic (pain medication). It typically takes 15 to 45 minutes to complete. It is generally quite a safe procedure, with a very small risk of serious complications, but some degree of abdominal pain and cramping is not unusual at times during the procedure. In most cases, the medication given before the procedure helps to minimize the discomfort.
Extremely Useful
Colonoscopy is an extremely useful diagnostic test in IBD. It will always detect ulcerative colitis if it is present, and will detect Crohn’s disease in 80% to 90% of cases. In 10% to 20% of cases of Crohn’s disease, the procedure is not able to examine the areas of disease because of technical factors or because the disease is beyond the reach of the colonoscope.
Wireless Capsule Endoscopy
Standard gastroscopy and colonoscopy are not able to reach large segments of the small intestine that may be affected in Crohn’s disease. The imaging studies that can take pictures of those areas of the small intestine are improving, but do not always provide the detailed images required by the physician to make management recommendations. Wireless capsule endoscopy (WCE), or PillCam technology, was developed to provide the types of high-quality visual images of the inner lining of the small intestine that are provided by gastroscopy in the stomach and duodenum and by colonoscopy in the colon and ileum. In most cases, the procedure allows examination of the entire length of small intestine.
A capsule — about the size of a large vitamin pill or capsule — that contains a battery, light source, and a tiny lens and camera chip is swallowed by the patient and begins taking two pictures every second during an 8-hour period. It is propelled through the esophagus, stomach, and small bowel by the normal muscular movements of the gastrointestinal tract in the same way food is passed down along the gastrointestinal tract. The patient wears a recording device, much like a cellular telephone, and can go about daily activities. Once the procedure is over, images are downloaded from the recorder to a computer. The physician can then look for signs of Crohn’s disease.
Despite the fact that the WCE can provide excellent images of the entire small intestine, it is not commonly used in IBD diagnosis. In ulcerative colitis, the small intestine is not involved and does not require this type of detailed evaluation. In Crohn’s disease, care must be taken because the capsule could produce a blockage or bowel obstruction in any strictures of the intestine. Nevertheless, the capsule may be helpful in diagnosing subtle degrees of Crohn’s disease in the small intestine, where the other imaging techniques do not provide a full answer to the patient’s symptoms.
Enteroscopy
A number of innovations have been developed in the area of endoscopy to allow examination of areas of the small intestine that are beyond the reach of the standard gastroscope and colonoscope.
•Push enteroscopy uses a longer-than-normal gastroscope to get farther into the small intestine, but the success of this procedure is limited because of the floppiness and many twists and turns of the small intestine.
•Double balloon enteroscopy (DBE) generally allows more extensive examination of the small intestine through sequential inflation and deflation of two balloons near the tip of the instrument. This inflation and deflation helps to propel the tip of the instrument along the small intestine. The technique can be performed through the mouth, esophagus, and stomach into the first part of the small intestine, or it can be performed through the colon into the last part of the small intestine. It tends to be a longer procedure than standard endoscopy and typically requires general anesthetic or propofol for deep sedation. Using this technique, it is often possible to examine the entire length of small intestine that cannot be examined by gastroscopy or colonoscopy. Biopsies can be obtained of the inner lining of the small intestine, and the rate of progress through the small intestine is under the control of the physician, as opposed to the wireless capsule endoscopy, where the progress through the intestinal tract is largely determined by contractions of the small intestine.
Biopsies
Endoscopy also allows the operator to perform biopsies of the inner lining of the gastrointestinal tract. Small samples are taken with a tiny instrument with small jaws that can cut or pull off pieces of the inner lining. This part of the procedure is not painful; usually, the patient is not aware that it is happening. The biopsy process is very safe; complications, such as serious bleeding, are extremely uncommon.
In some instances, biopsies are done to screen for precancerous changes. Some patients with IBD involving the large intestine for more than 8 to 10 years are at increased risk of colon cancer, and their physicians may recommend a surveillance program that involves regular colonoscopy with many biopsies taken throughout the colon.
Rule Out Other Conditions
Biopsies are usually taken to confirm the suspected diagnosis of IBD and to help rule out other conditions, such as infection. As surprising as it may seem, biopsies do not always provide 100% certainty about the diagnosis, particularly when distinguishing between Crohn’s disease and ulcerative colitis. Other information, such as the location of the inflammation or other associated features, provides more assistance in diagnosis.
Prognosis
Once the diagnosis of IBD has been confirmed using one or more of the available investigations, some of that information can be used to help the physician determine the severity and prognosis of a patient’s particular IBD. However, even with the most complete diagnostic staging, the ultimate prognosis can be unpredictable, varying from person to person with the same disorder. Patients naturally have many pressing questions about the course of their disease, which are asked and answered in the next chapter.
