Microscopic colitis (MC) is a chronic inflammatory condition of the colon that often presents a diagnostic challenge because the colon appears normal during a standard colonoscopy. The condition is defined by chronic, watery diarrhea and abdominal discomfort. The inflammation itself is only visible when a tissue sample is examined under a microscope. While a complete “cure” is complicated by the disease’s underlying nature, MC is highly treatable and manageable, with most patients achieving long-term symptomatic control. This condition is not linked to an increased risk of colorectal cancer, offering a favorable long-term outlook.
Understanding Microscopic Colitis
Microscopic colitis is categorized into two main subtypes, distinguished by what a pathologist observes in a biopsy of the colonic lining.
The first subtype, Lymphocytic Colitis (LC), is characterized by an increased number of white blood cells, specifically lymphocytes, within the surface layer of the colon tissue. The second subtype, Collagenous Colitis (CC), features the same increase in lymphocytes but is uniquely marked by a thickened band of collagen protein beneath the surface lining of the colon.
Despite these distinct microscopic differences, the clinical symptoms for both LC and CC are nearly identical. The distinction is relevant primarily for pathology rather than initial patient management. The main symptom across both types is persistent, non-bloody, watery diarrhea, often accompanied by abdominal pain, cramping, bloating, and a sense of urgency.
Remission Versus Permanent Resolution
Medical professionals generally avoid using the term “cure” for microscopic colitis because the condition is considered a chronic inflammatory disorder susceptible to recurrence. The goal of treatment is “remission,” meaning the patient experiences a significant, sustained reduction in symptoms, often to the point of being symptom-free.
Remission is broken down into clinical remission, where symptoms resolve, and histological remission, where the inflammatory changes in the tissue disappear. While some patients never relapse, the underlying disease mechanism often remains, meaning the potential for the immune system to launch another inflammatory response is always present. Therefore, MC is managed as a chronic condition where sustained remission is the measure of success, translating directly to a high quality of life.
Standard Approaches to Achieving Remission
The first-line therapy for inducing remission in microscopic colitis is a specialized corticosteroid medication called Budesonide. This drug is highly effective, with clinical remission rates ranging from 72% to 100% after an eight-week course of treatment, typically dosed at 9 mg daily. Budesonide works by delivering a topical anti-inflammatory effect directly to the colon lining where the inflammation is present.
A major advantage of Budesonide is its low systemic absorption because it is rapidly broken down by the liver after the first pass through the body. This minimizes the systemic side effects typically associated with traditional corticosteroids like Prednisone. Before starting any medical therapy, a crucial step involves identifying and discontinuing any medications that may be triggering the inflammation, such as non-steroidal anti-inflammatory drugs (NSAIDs) and proton pump inhibitors (PPIs). For patients whose disease is refractory, second-line options include immunosuppressants like Azathioprine or even biologic therapies, such as anti-tumor necrosis factor (TNF) agents.
Managing Life After Treatment
Once clinical remission is achieved, the focus shifts to maintaining that symptom-free state and preventing relapse, which is a common feature of the disease. A significant proportion of patients (30% to 50%) will experience a return of symptoms after discontinuing the initial induction therapy with Budesonide. To counteract this, a lower-dose maintenance regimen of Budesonide, often 6 mg or less daily, may be recommended for several months or even longer, which has been shown to sustain remission in a majority of patients.
Non-pharmacological strategies are also important for long-term management, centered on identifying and avoiding personal triggers. Dietary adjustments can significantly help manage symptoms, with many patients benefiting from:
- Reducing or eliminating known irritants like caffeine, alcohol, and lactose.
- Trying a low-FODMAP diet, which reduces fermentable carbohydrates that can contribute to diarrhea.
Continued monitoring with a healthcare provider is prudent, as the disease course is typically chronic or relapsing for many individuals.