Collagenous colitis/lymphocytic colitis

Definition

Collagenous colitis and lymphocytic colitis are inflammatory conditions of the colon that cause chronic watery diarrhea as the most common symptom. Some researchers believe that collagenous colitis and lymphocytic colitis are different phases of the same condition rather than two separate conditions.

In some people, the inflammation tends to occur in patches along the lining of the colon. In other people, it's present along the entire length of the bowel.

Collagenous colitis is so named because of the thickened layer of connective tissue (collagen) in the colon's lining. Lymphocytic colitis gets its name because of the increased level of specialized white blood cells (lymphocytes) found in the colon.

Both collagenous colitis and lymphocytic colitis are sometimes referred to collectively as "microscopic colitis" — because the diagnosis is confirmed by microscopic examination of the colon's cells. They're rare — occurring much less commonly than other, better known gastrointestinal diseases such as ulcerative colitis and Crohn's disease. Collagenous colitis and lymphocytic colitis are more prevalent in older adults, ages 60 to 80 years.

Treatment involves a phased approach beginning with lifestyle changes and progressing to medications and (rarely) surgery if necessary.

Symptoms

In both collagenous colitis and lymphocytic colitis, the signs and symptoms are virtually identical.

Chronic diarrhea is the most common sign. This diarrhea is watery and nonbloody, and often starts quite suddenly. The diarrhea may become constant, or in some people, it's intermittent, with symptoms improving and then worsening again in a repeated cycle. Some people may have from three to 20 bowel movements a day. Signs and symptoms often are present for months before a proper diagnosis is made.

People with collagenous colitis and lymphocytic colitis may also experience:

• Abdominal pain or cramps
• Abdominal bloating (distention)
• Modest weight loss
• Nausea
• Fecal incontinence
• Dehydration

Causes

The cause of collagenous colitis and lymphocytic colitis has not been identified. Some researchers believe that bacteria and the toxins they produce or a virus may trigger the inflammation associated with these conditions.

Other investigators have theorized that these disorders are autoimmune problems, meaning that the body's own immune system is overactive and actually attacks and damages healthy cells, mistakenly recognizing them as foreign invaders. In fact, people with collagenous colitis or lymphocytic colitis often have one or more additional autoimmune disorders as well, such as:

• Celiac disease, a digestive system disorder associated with the intake of the protein gluten, and which may have the same signs and symptoms as microscopic colitis
• Diabetes mellitus
• Rheumatoid arthritis
• Thyroid disorders
• Pernicious anemia, a condition that results in low red blood cell counts
• Scleroderma, a disease of the skin and connective tissue
• Sjogren's syndrome, an immune system dysfunction causing inflammation of the connective tissue
• CREST syndrome, a connective tissue disorder affecting the skin and blood vessels

There have been some reports of collagenous colitis and lymphocytic colitis occurring in families, suggesting a possible genetic component in some cases.

Collagenous colitis and lymphocytic colitis are inflammatory disorders of the colon. In some people, the inflammation tends to occur in patches along the lining of the colon. In other people, it's present along the entire length of the bowel.

Risk factors

The use of certain medications has been linked to a higher risk of collagenous colitis and lymphocytic colitis in some people, but this association is unproved. The implicated medications include nonsteroidal anti-inflammatory drugs (NSAIDs) such as aspirin and ibuprofen (Advil, Motrin, others). Be sure to tell your doctor about all the medications that you're taking, especially any you began taking in the months before the onset of your diarrhea.

When to seek medical advice

If you have watery and nonbloody diarrhea that lasts more than a few days, contact your doctor so that the condition can be diagnosed and properly treated.

Tests and diagnosis

Your doctor will likely start the diagnostic process by culturing your stool to rule out an infectious cause of the watery diarrhea.

Your doctor may also refer you to a specialist to perform either a colonoscopy or a flexible sigmoidoscopy. Both of these tests involve threading a tube through your rectum and into your colon, allowing your doctor to view the interior of your large intestine with the help of a small camera on the tip of the instrument. Because the colonoscopy tube is inserted into the entire length of the colon, rather than simply the first one-third of the colon as in a sigmoidoscopy, a colonoscopy is more thorough.

These tests may be as important in ruling out other conditions as in making a definitive diagnosis of collagenous colitis or lymphocytic colitis. In fact, if either disorder is present, the inflammation that results won't be visible during an examination of the colon's lining; the colon looks normal during these exams. However, when these diseases are suspected, biopsies of the colon can be performed as part of the colonoscopy or sigmoidoscopy.

During the biopsy, small samples of tissue from your colon are removed and sent to a laboratory for evaluation under a microscope — hence, the umbrella term "microscopic colitis."  Because the inflammation tends to occur in patches rather than along the entire length of the large intestine, tissue in several areas of the colon needs to be evaluated. The findings of the lab examination can differentiate between the two conditions:

• If you have collagenous colitis, the doctor evaluating the biopsy (pathologist) will see an increase in the thickness of a nonelastic, protein band of connective tissue (collagen) inside the colon lining.
• If you have lymphocytic colitis, the laboratory analysis will reveal an increased level in the number of specialized white blood cells (lymphocytes) found between the cells that line the large intestine. However, unlike with collagenous colitis, there are no apparent changes in the collagen.

Without biopsies, these conditions can be misdiagnosed as other digestive conditions such as irritable bowel syndrome (IBS). In most cases, IBS has a long-term course of alternating constipation and diarrhea, while collagenous colitis and lymphocytic colitis are characterized primarily by diarrhea.

Blood tests aren't usually helpful in diagnosing collagenous colitis and lymphocytic colitis, because findings tend to be normal. The same is true with tests of urine and stool samples. 

Because the treatment for collagenous colitis and lymphocytic colitis are the same, many doctors believe it's not crucial to differentiate between them as part of the diagnostic process. However, your doctor will want to eliminate other conditions affecting the colon as a possible diagnosis.

Complications

Although other inflammatory diseases of the large intestine such as Crohn's disease and ulcerative colitis increase your likelihood of developing cancer of the colon, there's no evidence that either collagenous colitis or lymphocytic colitis increases the risk of colon cancer or death.

Treatments and drugs

Many cases of collagenous colitis and lymphocytic colitis get better on their own without treatment, usually within weeks. However, when the signs and symptoms are serious, doctors generally regard treatment as necessary.

The therapy is the same for both collagenous colitis and lymphocytic colitis. Doctors usually recommend a stepwise approach, starting with the simplest, most easily tolerated treatments. The goal is to produce the relief of symptoms.

• Lifestyle changes. As a first step, you'll need to make adjustments to your diet. By decreasing the amount of fat you consume, your signs and symptoms may ease. Also, remove caffeine from your diet (found in coffee, tea and soft drinks), as well as foods containing lactose (milk sugar found in dairy products). Avoid spicy foods and alcohol. Staying away from foods that may lead to gas and diarrhea — including carbonated beverages, caffeine, raw fruits, and vegetables such as beans, cauliflower, broccoli and cabbage — may help.

  If you take over-the-counter nonsteroidal anti-inflammatory drugs — such as aspirin, ibuprofen and naproxen (Aleve) — talk to your doctor about switching to other types of pain relievers. These NSAIDs can worsen the diarrhea associated with collagenous colitis and lymphocytic colitis.

• Medications. If problems persist despite adjustments in lifestyle, the next step is to take medications. Before your doctor recommends medications, however, he or she will want to exclude other possible causes for your symptoms, such as celiac disease.

  Doctors often advise starting with antidiarrheal preparations such as loperamide (Imodium) or the combination drug diphenoxylate and atropine (Lomotil). These drugs slow the contractions that propel the bowel contents through your colon. They're effective treatment for many people, particularly those whose diarrhea is mild to moderate, and they're well tolerated in most cases. However, if signs and symptoms don't subside with these drugs, your doctor may suggest a different medication such as bismuth subsalicylate (Pepto-Bismol).

  If your problems are more serious, your doctor may recommend anti-inflammatory prescription drugs such as mesalamine (Asacol, Pentasa), balsalazide disodium (Colazal) or sulfasalazine (Azulfidine), which can minimize swelling and inflammation in the colon. A cholesterol-lowering medication called cholestyramine (Questran) has also demonstrated some effectiveness.

  In severe cases, you may need to take a short course of corticosteroids to improve your symptoms and your quality of life. One of these potent anti-inflammatory drugs, budesonide (Entocort), is usually taken for a relatively brief period of time — six to eight weeks — and side effects are uncommon. However, once you discontinue using this drug, there's a chance of a relapse.

  Other drugs, such as the immunosuppressive agents methotrexate (Rheumatrex) and azathioprine (Imuran), are more powerful medications that may be associated with increased side effects. These medications are often used only as a last resort when corticosteroids have not reduced inflammation and symptoms.

  More studies of many of these drugs are needed to fine-tune their role in the management of collagenous colitis and lymphocytic colitis.

• Surgery. When the symptoms of collagenous colitis and lymphocytic colitis are severe, and medications aren't effective, your doctor may recommend surgery to remove inflamed portions of your colon, which tends to eliminate diarrhea. Surgery is rare for these conditions.

In many people with collagenous colitis or lymphocytic colitis, persistent symptoms can interfere with quality of life. But with proper treatment, the prognosis for most people is good, and symptoms gradually resolve completely.

Prevention

There are no proven techniques for preventing collagenous colitis and lymphocytic colitis. However, once the disease has occurred and has been successfully treated, you may be able to prevent symptoms from recurring by adopting important lifestyle measures — dietary changes and avoidance of certain medications.