Diagnosing microscopic colitis involves a comprehensive approach to rule out other conditions and confirm the presence of this specific type of inflammatory bowel disease. If you’re experiencing persistent diarrhea and related symptoms, understanding the diagnostic process is crucial. Healthcare professionals utilize a combination of medical history review, physical examinations, and specific tests to accurately diagnose microscopic colitis.
Understanding Microscopic Colitis Diagnosis
The journey to a microscopic colitis diagnosis typically begins with a detailed review of your medical history and a thorough physical exam. Your healthcare provider will ask about your symptoms, paying close attention to the nature and frequency of your diarrhea. They will also inquire about any medications you are currently taking, as some drugs can contribute to microscopic colitis symptoms. To definitively diagnose this condition and exclude other potential causes of your symptoms, several tests are employed.
The Role of Colonoscopy in Diagnosis
Colonoscopy is a key procedure in diagnosing microscopic colitis. This examination allows your healthcare professional to visualize the entire colon using a colonoscope, a thin, flexible, lighted tube equipped with a camera. The colonoscope is gently inserted into the rectum, and the camera transmits real-time images of your colon lining to a monitor. This visual inspection helps to identify any macroscopic abnormalities, although in microscopic colitis, the colon often appears normal to the naked eye.
During a colonoscopy, beyond visual inspection, your healthcare professional can also perform biopsies. This involves passing instruments through the colonoscope to collect small tissue samples from the colon lining. These biopsies are essential for microscopic colitis diagnosis because the microscopic changes characteristic of this condition are not visible during a standard colonoscopy.
Flexible Sigmoidoscopy: An Alternative Examination
Flexible sigmoidoscopy is another procedure that may be used in the diagnostic process, particularly when the suspected inflammation is primarily in the lower part of the colon. Similar to a colonoscopy, a flexible sigmoidoscopy uses a slender, lighted tube called a sigmoidoscope. However, unlike a colonoscopy which examines the entire colon, a sigmoidoscopy focuses on the rectum and the sigmoid colon, which is the lower portion of the colon, approximately the last 1 to 2 feet.
During a flexible sigmoidoscopy, the sigmoidoscope is inserted into the rectum, allowing the healthcare professional to examine the lining of the rectum and sigmoid colon. Like colonoscopy, biopsies can be taken during a sigmoidoscopy. These tissue samples are then examined under a microscope to look for the cellular changes indicative of microscopic colitis. While sigmoidoscopy is less invasive than colonoscopy, colonoscopy is often preferred to examine the entire colon and ensure a comprehensive assessment.
Biopsies: The Key to Confirming Microscopic Colitis
For microscopic colitis diagnosis, biopsies are indispensable. In both collagenous colitis and lymphocytic colitis, the two subtypes of microscopic colitis, the colon tissue often appears visually normal during colonoscopy or sigmoidoscopy. Therefore, the diagnosis hinges on the microscopic examination of the biopsy samples.
After biopsies are taken during a colonoscopy or sigmoidoscopy, they are sent to a lab where a pathologist examines them under a microscope. The pathologist looks for specific cellular changes in the colon tissue that are characteristic of microscopic colitis, such as an increased number of lymphocytes (in lymphocytic colitis) or a thickened layer of collagen beneath the lining of the colon (in collagenous colitis). It is the identification of these microscopic features that confirms a diagnosis of microscopic colitis.
Other Tests to Rule Out Other Conditions
While colonoscopy and sigmoidoscopy with biopsies are crucial for diagnosing microscopic colitis, other tests may be conducted to exclude other conditions that can cause similar symptoms, such as chronic diarrhea. These tests help ensure an accurate diagnosis and appropriate treatment plan.
Stool Sample Study
A stool sample study is often performed to rule out infectious causes of diarrhea. This test analyzes your stool for the presence of bacteria, parasites, or viruses that could be responsible for your symptoms. By excluding infection, healthcare professionals can narrow down the possible causes of your diarrhea and strengthen the likelihood of a microscopic colitis diagnosis, especially when other tests are consistent.
Blood Test
Blood tests may be ordered to assess for signs of anemia or celiac disease, among other conditions. Anemia, a deficiency in red blood cells, can sometimes be associated with chronic inflammation. Testing for celiac disease is important as its symptoms can overlap with microscopic colitis. Blood tests can help screen for celiac disease and other systemic issues that might contribute to or mimic microscopic colitis symptoms.
Upper Endoscopy with Biopsy
In some cases, an upper endoscopy with biopsy may be recommended to further rule out celiac disease. This procedure involves inserting a thin, flexible tube with a camera through the mouth and into the upper digestive tract (esophagus, stomach, and duodenum). Similar to colonoscopy, biopsies can be taken during an upper endoscopy. These biopsies are examined to detect changes in the small intestine lining that are characteristic of celiac disease. This test is particularly useful when there is suspicion of celiac disease alongside symptoms suggestive of microscopic colitis, helping to provide a comprehensive diagnosis.
By utilizing a combination of these diagnostic procedures, healthcare professionals can effectively diagnose microscopic colitis and differentiate it from other conditions, paving the way for targeted treatment and symptom management.
