Is It IBS or Microscopic Colitis?
Does it seem like your IBS isn’t responding to treatments or strategies, but your test results all came back normal?
There are many reasons this can happen, but one condition I see come up that is often missed during the diagnostic process is microscopic colitis.
Microscopic colitis vs IBS
IBS is a functional disorder of the gut-brain interaction, characterized by changes in motility (constipation, diarrhea, or both) and pain. It is diagnosed via the Rome IV criteria, and exclusion of other conditions isn’t required unless red flags are present. Learn more about IBS in detail here.
Microscopic colitis is a form of inflammatory bowel disease (IBD) and is characterized by abnormal immune system reactions that lead to inflammation of the inner lining of the colon. The name “microscopic colitis” explains why it is commonly missed, because doctors can’t see the inflammation during a colonoscopy, without a microscope.
Microscopic colitis is broken down into 2 types:
Collagenous colitis: where the collagen bands of the colon are thickened, causing the elastin to become inflamed.
Lymphocytic colitis: where the intestinal mucosa has a high density of lymphocytes (type of white blood cell) that highlights inflammation.
What’s your poop personality? Find out here!
IBS is broken into 3 major types:
IBS-D: characterized by diarrhea as the predominant stool type
IBS-C: characterized by constipation as the predominant stool type
IBS-M: characterized by a mixed stool type of both constipation and diarrhea
All types will also have symptoms of pain and may have additional digestive symptoms, like bloating, gas, and cramping.
Symptoms of microscopic colitis include:
watery diarrhea
pain and cramping
bloating and distention
urgency
fatigue.
Sounds a lot like IBS-D…which is why many will be diagnosed with IBS first, even after a colonoscopy.
In severe cases of microscopic colitis, we also see symptoms of dehydration, nausea, vomiting, and weight loss. And may also see more defined symptoms of immune reactions, like joint or muscle pain, skin rashes, swollen lymph nodes, neurological problems, and more. These can be initial red flags to look further for someone that presents as IBS.
Causes, diagnosis, and treatment of microscopic colitis
Causes of microscopic colitis are very similar to IBS, including bacterial or viral infection, an autoimmune response, and genetics. These medications are also seen as possible causes:
NSAIDs (nonsteroidal anti-inflammatory drugs)
PPIs (proton pump inhibitors)
SSRIs (selective serotonin reuptake inhibitors
HRT (hormone replacement therapy)
Beta blockers
Statins
*full list pulled from the Cleveland clinic: https://my.clevelandclinic.org/health/diseases/17227-microscopic-colitis
There is also a link between microscopic colitis and celiac disease, so if you have one, make sure you are also ruling out the other.
Diagnosis starts with a thorough medical history, which should include evaluation of symptoms, potential causes, and medication use. During a colonoscopy, a biopsy of the intestinal lining will need to be taken, and then evaluated for microscopic colitis. If you’ve had a colonoscopy in the past, you can ask if they did this to see if it has been ruled out.
Treatment can be very similar to IBS-D, with a few additions for the inflammation and immune response side of microscopic colitis. Treatment may include the use of medications + diet and lifestyle changes. If you’re already treating your IBS-D and you’re not getting results, then this could be something to bring up with your doctor to explore.
Common medications used for microscopic colitis include:
Bulking agents, such as psyllium, to make your poop more solid and slow down its transit time.
Anti-diarrheals that slow down your bowel contractions, such as loperamide or diphenoxylate.
Bismuth Subsalicylate (Pepto Bismol®) for diarrhea, acid reflux, nausea and indigestion.
Budesonide, a corticosteroid that’s absorbed in your colon, where it reduces inflammation.
Mesalamine, a medication designed to treat ulcerative colitis, for inflammation and pain.
Bile acid sequestrants (colesevelam, colestipol), if you have bile acid malabsorption.
*Full list pulled from Cleveland Clinic: https://my.clevelandclinic.org/health/diseases/17227-microscopic-colitis
The goals for diet and lifestyle habits are to reduce triggers of symptoms, much like IBS, and reduce fiber and other things that may irritate the gut lining while inflammation is being reduced. Fiber may be reduced at first for this reason, but a low fiber diet does not need to be followed long term.
Dietary triggers may include alcohol, caffeine, dairy, artificial sweeteners, fats, and FODMAPs (read this for more info on these). Like with IBS, diet should be personalized based on your symptoms, state of your condition, and your other nutrition needs. This is why it’s important to work with a specialist dietitian, like our team, versus follow all of the information you may see online.
Sources:
https://www.niddk.nih.gov/health-information/digestive-diseases/microscopic-colitis#:~:text=Microscopic%20colitis%20is%20a%20chronic,older%20adults%20and%20in%20women.
https://my.clevelandclinic.org/health/diseases/17227-microscopic-colitis
https://www.crohnscolitisfoundation.org/what-is-microscopic-colitis
Are you frustrated with your IBS symptoms? Do you desire to be confident in your food choices? Do you want to have a healthier relationship with your body and diet? Are you ready to take control of your IBS?
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