Exams and Tests

As with most illnesses, the diagnosis begins with a thorough history by a physician or health care practitioner. Since the presenting complaint is usually abdominal pain and diarrhea, it is important to learn about the onset and duration of symptoms and any other complaints the patient may have. Since most causes of diarrhea are relatively benign and self-limiting, questions may be asked to search for some of the causes listed above.

An important concern is whether there is blood in the bowel movement. While this may lead to the diagnosis of colitis, colon cancer is another important cause of blood in the stool, and this symptom should not be ignored.

Some questions asked of the patient may include:

1. the time of onset of symptoms,
   
   
2. the duration of pain,
   
   
3. the frequency of diarrhea, and
   
   
4. whether there are any other associated complaints.

These may be within the digestive tract, like nausea or vomiting, or may be more general such as fever, chills, or other complaints.

Other questions may ask about lifestyle, especially if an infectious cause is being considered. Recent travel, unusual diet, or the use of noncommercial water (for example, drinking from a well or river water on a camping trip) may direct the diagnosis to illnesses like Shigella, Campylobacter or Yersinia bacterial infections. Recent use of antibiotics will be helpful to know.

The past medical history is also important to assess the risk factors for peripheral vascular disease or narrowing of the arteries. These include smoking, high blood pressure, high cholesterol, and diabetes. This may give direction to explore ischemic bowel as the cause for colitis.

Physical examination will focus on the abdomen. The physician will palpate or feel for areas of tenderness, for masses, or abnormally enlarged organs like the liver, spleen, and kidney.

While unpleasant, the rectal examination is of utmost importance. Using a finger, the physician feels inside the rectum, trying to find a mass or tumor. As well, the color and consistency of stool can be evaluated and if it is not grossly bloody, can be tested for occult blood (blood that is present but unable to be seen with the naked eye).

Vital signs are an important part of the physical examination. Temperature, blood pressure, pulse, and respiratory rate will help guide the direction of testing. If the vital signs are not stable, that is the blood pressure is low or the pulse rate too fast, a crisis may be imminent. The physician may need to intervene acutely and delay some of the diagnostic evaluation until the patient is stabilized.

Laboratory

Blood testing will help assess the stability of the patient and look for potential issues associated with colitis.

• A complete blood count (CBC) will assess the red blood cell count, the white blood cell count, and the number of platelets. The red blood cell count will help define the amount of bleeding. White blood cell counts elevate when the body is undergoing stress including the stress of infection. Platelets help clot blood; it is useful to know that their number is normal in a patient with bleeding.
  
  
• Electrolyte abnormalities can occur with diarrhea. Low sodium and potassium levels may be seen and may cause symptoms far removed from the initial colitis complaints.
  
  
• Kidney function may be assessed by measuring the BUN (blood urea nitrogen) and creatinine levels.
  
  
• Stool samples will likely be collected for culture, looking for infection as the cause of colitis.

Colonoscopy

If the specific cause of colitis is not readily apparent, then colonoscopy may be considered. A gastroenterologist will insert a long flexible camera into the anus and examine the full length of the colon. The appearance of the colon by itself may be enough to make the diagnosis. Biopsies (small pieces of tissue) may be taken from the lining of the colon and examined by a pathologist (a medical doctor specializing in the diagnosis of tissues) to help confirm the diagnosis.

Colonoscopy is an essential cancer screening test and is especially important for those patients who have had blood in their stool that cannot be explained by another diagnosis.

Imaging

Computerized tomography (CT) may be used to image the colon and the rest of the abdomen. Different types of colitis have distinctive patterns that may help a radiologist recognize a specific diagnosis.

On occasion a barium enema or other imaging tests may be used to evaluate the anatomy of the colon.

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