Microscopic Colitis in Northern Virginia

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Microscopic colitis is a chronic inflammatory condition of the colon that causes ongoing watery diarrhea, even though the colon looks normal during a colonoscopy. The inflammation is real, but it can only be seen when small tissue samples are examined under a microscope, which is where the name comes from. It is one of the more common explanations when someone says, "my colonoscopy was normal, but the diarrhea is not." This guide explains what microscopic colitis is, who tends to develop it, which medications have been linked to it, why biopsies are the only way to confirm it, and how it is treated.

This article is general education, not medical advice. Persistent diarrhea should be evaluated by a physician who can consider your full history.

What microscopic colitis is

The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) describes microscopic colitis as a chronic disease in which abnormal reactions of the immune system cause inflammation on the inner lining of the colon. It is classified as a form of inflammatory bowel disease, alongside Crohn's disease and ulcerative colitis, but it behaves quite differently from those two. The NIDDK notes that, unlike the other types of inflammatory bowel disease, it does not increase the risk of colon cancer.

There are two main types, named for what the pathologist sees in the tissue:

• Lymphocytic colitis. The colon lining contains more white blood cells, called lymphocytes, than normal, while the collagen layer beneath the lining is normal or only slightly thickened.
• Collagenous colitis. The layer of collagen under the colon lining is thicker than normal, and the lining may also contain extra white blood cells.

The NIDDK notes that doctors call both types microscopic colitis because they cause the same symptoms and are treated the same way. For most patients, the distinction matters less than the diagnosis itself.

Symptoms of microscopic colitis

The hallmark symptom of microscopic colitis is chronic, watery, nonbloody diarrhea. The 2021 European guideline on microscopic colitis, developed by United European Gastroenterology and the European Microscopic Colitis Group, describes that diarrhea as frequently accompanied by urgency, bowel movements during the night, and fecal incontinence. The NIDDK lists these related symptoms as well:

• Diarrhea that wakes you at night
• An urgent need to reach a bathroom
• Accidents or leakage
• Abdominal pain
• Weight loss
• Fatigue

Symptoms may start suddenly or build gradually. According to the NIDDK, many people with the condition have four to nine bowel movements a day, and some have more than ten. The condition also tends to come and go, with periods of remission followed by relapses.

Nighttime bowel movements are worth mentioning to a physician specifically, because the European guideline lists them among the symptoms that frequently accompany the condition, and they help distinguish an inflammatory cause from everyday digestive upset. Visible blood in the stool is not a usual feature of this condition, so bleeding calls for its own workup. Our guide to blood in the stool explains why.

Who is most likely to develop it

Microscopic colitis is not rare. The NIDDK cites research estimating that about 700,000 people in the United States have it, and the European guideline estimates that it accounts for roughly 12.8 percent of cases of chronic watery diarrhea. Several factors make it more likely:

• Age. The NIDDK reports that the average age at diagnosis is 60 to 65, though it can occur at any age, including in children.
• Sex. Research cited by the NIDDK suggests the condition is three to nine times more common in women than in men.
• Smoking. The European guideline links both former and, especially, current smoking to a higher risk, and the NIDDK notes that people who smoke tend to develop it at a younger age.
• Other immune conditions. The NIDDK lists celiac disease, psoriasis, rheumatoid arthritis, thyroid disorders, and type 1 diabetes among the conditions that occur more often in people with microscopic colitis.

That profile matters in practice. A woman in her sixties who develops persistent watery diarrhea fits the typical profile, and so does anyone whose diarrhea began a few weeks or months after starting one of the medications listed below.

Medications linked to microscopic colitis

One of the most useful things to know about microscopic colitis is that several very common medications have been associated with it. The NIDDK lists:

• Nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen and naproxen
• Proton pump inhibitors (PPIs), the acid-reducing medications used for reflux
• Selective serotonin reuptake inhibitors (SSRIs), a type of antidepressant
• Hormone replacement therapy and oral contraceptives
• Beta blockers
• Statins

The European guideline adds two important cautions. First, while chronic or frequent use of PPIs, NSAIDs, or SSRIs is associated with a higher risk of the condition, that association does not prove the medication caused it. Second, the guideline suggests considering withdrawal of a drug when the timing fits, meaning the diarrhea began after the medication was started.

That second point is a conversation to have with your physicians, not a reason to stop a prescribed medication on your own. Many of these medications treat conditions that matter, and a gastroenterologist can coordinate with the prescribing doctor about whether a change or substitution is reasonable. If you take a PPI for reflux, our guide to GERD and acid reflux covers how that medication fits into long-term care.

How microscopic colitis is diagnosed

Microscopic colitis cannot be diagnosed from symptoms alone, from bloodwork, or from a stool test. It requires colon tissue. The NIDDK explains that doctors perform a colonoscopy with biopsies to diagnose it and to rule out other digestive conditions, and that the colon lining most often appears normal in people who have it.

Where those biopsies are taken matters. The European guideline recommends a colonoscopy with biopsies from at least the right and left sides of the colon, noting that when both sides are sampled, the characteristic changes appear on both in the large majority of cases. A pathologist then examines the tissue for the extra lymphocytes or the thickened collagen band that define the two types.

Evaluation usually includes a few other steps as well. The NIDDK notes that blood and stool tests help check for conditions with similar symptoms, including infections, other forms of inflammatory bowel disease, and celiac disease. The European guideline goes further on celiac disease specifically and recommends screening for it in everyone diagnosed with it, because the two conditions occur together more often than chance would predict. It also notes that fecal calprotectin, a stool marker often used for Crohn's disease and ulcerative colitis, is not useful for ruling microscopic colitis in or out.

Why a normal-looking colon does not rule out microscopic colitis

This is the single most important practical point about microscopic colitis. A colonoscopy report that says the colon looked normal is not the same as a report that says the biopsies were normal. If you had a colonoscopy to evaluate chronic diarrhea and no biopsies were taken, microscopic colitis has not been ruled out.

That is why a gastroenterologist evaluating diarrhea will usually take biopsies even when everything looks healthy on the screen, and why it is fair to ask about biopsies when you review a report. Our guide to colonoscopy results explained walks through how to read the pathology section.

The same logic applies to irritable bowel syndrome. Microscopic colitis and diarrhea-predominant IBS share symptoms and both leave the colon looking normal. The European guideline states that microscopic colitis should be ruled out in people who meet the criteria for a functional bowel disorder, especially when they have risk factors or when IBS treatment is not working. Two meta-analyses cited in the guideline found microscopic colitis in about 9 percent of people carrying a diarrhea-predominant functional diagnosis. If you were told you have IBS and the treatment has not helped, our guide to IBS in Northern Virginia explains how the two are told apart.

Treatment for microscopic colitis

The NIDDK notes that medicines most often treat the condition effectively, and that surgery is rarely needed. Treatment usually starts with the basics: quitting smoking, reviewing medications that may be contributing, and adjusting diet where it helps.

Budesonide as the first-line treatment

The American Gastroenterological Association (AGA) guideline on the medical management of microscopic colitis, published in 2015 and still its current guideline, recommends budesonide as the first treatment. Budesonide is a corticosteroid that acts mainly in the gut, with relatively little absorbed into the rest of the body compared with prednisone. The AGA guideline reports that people treated with 9 milligrams of budesonide daily were more than twice as likely to reach clinical remission as those who received no treatment. Because of its favorable balance of benefit and risk and its once-daily dosing, the AGA states that budesonide should be considered first-line therapy.

The 2021 European guideline reaches the same conclusion, recommending oral budesonide to induce remission in both collagenous and lymphocytic colitis. Neither guideline recommends a repeat colonoscopy simply to confirm that treatment worked. Response is judged by how you feel and how your bowel habits change.

Other options when budesonide is not an option

Here the two guidelines diverge somewhat, which is one reason treatment is a shared decision with a gastroenterologist. When budesonide is not feasible, the AGA suggests mesalamine, bismuth subsalicylate, or prednisone as alternatives over no treatment, while noting that budesonide outperformed mesalamine head to head. The European guideline is more cautious about mesalamine and bismuth and recommends against steroids other than budesonide. Both guidelines recommend against probiotics for treating it, and the AGA also suggests against Boswellia serrata, an herbal supplement that sometimes appears in online advice.

For milder symptoms, the European guideline notes that expert opinion favors the antidiarrheal loperamide, and it suggests bile acid binders for people who also have bile acid diarrhea. For the small group whose disease does not respond to budesonide, it supports immune-modifying medications such as thiopurines or biologic drugs in selected cases, with surgery as a last resort only after medical therapy has failed.

Relapse and maintenance treatment

Microscopic colitis is chronic, and relapse after stopping treatment is common. The AGA guideline says stopping budesonide can be considered after 8 weeks of treatment, and that about one-third of people remain symptom-free afterward and do not need ongoing therapy.

For those whose symptoms return, the AGA recommends budesonide for maintenance. In the trials it reviewed, maintenance at 6 milligrams daily over six months lowered the risk of relapse by about two-thirds, and in practice the dose is commonly tapered to the lowest amount that keeps symptoms controlled. The AGA suggests considering a stop after 6 to 12 months of maintenance. Because long-term use may contribute to bone loss, it also advises that people on maintenance therapy be considered for osteoporosis screening and prevention.

The European guideline recommends against routine repeat biopsies to monitor the condition, and it states that the condition does not require a special colonoscopy surveillance program, because it does not raise colorectal cancer risk. Standard colon cancer screening for your age and history still applies.

Diet, complications, and daily life

The NIDDK notes that no diet has been shown to heal the condition, but some changes can ease diarrhea. Depending on your symptoms, a physician may suggest limiting alcohol, caffeine, and artificial sweeteners. People who also have lactose intolerance may benefit from limiting dairy, and those who also have celiac disease need a gluten-free diet.

Complications are uncommon compared with other forms of inflammatory bowel disease. The NIDDK notes that severe diarrhea can lead to weight loss and dehydration, and that serious complications such as ulcers or perforation of the colon are rare. The bigger burden for most people is quality of life: urgency, nighttime trips to the bathroom, and worry about being far from a restroom. The European guideline recognizes that quality of life is meaningfully impaired during active disease, which is exactly why effective treatment is worth pursuing rather than simply adapting around the symptoms.

If you are sorting out a longer list of possible causes, our guide to chronic diarrhea in Northern Virginia covers the broader picture, and our guide to Crohn's disease and ulcerative colitis explains the other forms of inflammatory bowel disease. General patient information is also available from the NIDDK, and the American Gastroenterological Association publishes its guideline recommendations.

Care for microscopic colitis in Northern Virginia with GC of NoVA

Gastroenterology Center of Northern Virginia cares for patients across Arlington, Annandale, and the surrounding communities who are living with chronic watery diarrhea, including people who were told their colonoscopy was normal but still do not feel well. Our physicians can review your history and medication list, perform a colonoscopy with the right-sided and left-sided biopsies the diagnosis requires when it is appropriate, and work with you and your other physicians on a treatment plan. We see patients at our Arlington office, next to VHC Health, and our Annandale office, in the Woodburn Medical complex. If you are unsure whether your symptoms call for a specialist, our guide on when to see a gastroenterologist may help.

To schedule an evaluation, contact our Arlington office at (703) 522-7476 or our Annandale office at (703) 560-6106, or learn more at gcofnova.com.

This article is for general education and is not medical advice. Talk with a qualified gastroenterologist about your symptoms, diagnosis, and treatment options.