Introduction
Microscopic colitis is a type of inflammatory bowel disease (IBD) characterized by chronic inflammation of the large intestine (colon) that can only be seen under a microscope. Unlike other forms of IBD, such as Crohn’s disease and ulcerative colitis, the colon appears normal during a colonoscopy. However, microscopic examination of tissue samples (biopsies) reveals inflammation. The main symptom of microscopic colitis is chronic, watery diarrhea.
Causes
The exact cause of microscopic colitis is not fully understood, but it is believed to involve a combination of genetic, environmental, and immune system factors. Possible contributing factors include:
- Immune system dysfunction: An abnormal immune response to bacteria or other substances in the colon.
- Medications: Certain medications, such as NSAIDs, proton pump inhibitors (PPIs), and selective serotonin reuptake inhibitors (SSRIs), have been linked to microscopic colitis.
- Infections: Previous gastrointestinal infections may trigger the condition.
- Autoimmune disorders: Microscopic colitis is more common in people with autoimmune conditions such as celiac disease, thyroid disease, or rheumatoid arthritis.
- Genetics: There may be a genetic predisposition to developing microscopic colitis.
Symptoms
The main symptom of microscopic colitis is chronic, watery diarrhea. Other symptoms may include:
- Abdominal pain or cramping
- Fecal incontinence (difficulty controlling bowel movements)
- Weight loss
- Fatigue
- Nausea
- Dehydration
Symptoms can come and go, with periods of remission and flare-ups.
Diagnosis
Diagnosis of microscopic colitis involves:
- Medical history and physical examination
- Colonoscopy to examine the colon (which usually appears normal)
- Biopsies of the colon lining to look for microscopic evidence of inflammation
- Stool tests to rule out other causes of diarrhea
There are two main types of microscopic colitis, which are distinguished by the specific findings on biopsy:
- Collagenous colitis: Characterized by a thickened layer of collagen in the colon lining.
- Lymphocytic colitis: Characterized by an increased number of lymphocytes (a type of white blood cell) in the colon lining.
Treatment Options
Treatment for microscopic colitis focuses on relieving symptoms and reducing inflammation:
- Medications:
- Anti-diarrheal medications (such as loperamide or bismuth subsalicylate)
- Anti-inflammatory drugs (such as budesonide, a corticosteroid)
- Immunomodulators (such as azathioprine or methotrexate) in severe cases
- Dietary changes:
- Avoiding trigger foods (such as caffeine, alcohol, dairy products, or artificial sweeteners)
- Eating a low-fat, low-lactose diet
- Probiotics: To help restore the balance of bacteria in the gut
- Discontinuing medications: If a medication is suspected to be contributing to the condition
In some cases, microscopic colitis may resolve on its own without treatment.
Prevention
There is no known way to prevent microscopic colitis, but you can reduce your risk of flare-ups by:
- Avoiding trigger foods and medications
- Managing stress
- Following your healthcare provider’s recommendations for medication and follow-up
When to Seek Medical Care
Seek medical attention if you experience:
- Chronic, watery diarrhea
- Abdominal pain or cramping
- Fecal incontinence
- Symptoms that worsen or do not improve with self-care
Takeaway
Microscopic colitis is a chronic inflammatory condition of the colon that causes watery diarrhea. Diagnosis requires colonoscopy with biopsy, and treatment focuses on relieving symptoms and reducing inflammation.