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Ankylosing Spondylitis and the Digestive System

Updated: Jul 5, 2021

April 14th, 2021

Gastrointestinal complications with Ankylosing Spondylitis

Ankylosing Spondylitis (AS) is one of several similar chronic diseases that falls under the more broad term ‘Axial Spondyloarthritis.’ The conditions under the Axial Spondyloarthritis (AxSpA) umbrella are fairly similar--they’re characterized by sacroiliac joint involvement, spinal pain and inflammation, and often exhibit extra-axial manifestations due to they’re systemic nature.

Gastrointestinal issues are some of the more common complications of Axial Spondyloarthritis that occur outside of the spine. GI involvement may come in the form of Irritable Bowel Disease (IBD), whether that be Crohn’s Disease or Ulcerative Colitis, Irritable Bowel Syndrome (IBS), or simply gut inflammation. Not only are GI symptoms common with AxSpA, but one study shows that higher disease activity is “associated with inflammatory gut lesions.”

The Prevalence of Digestive Symptoms in Axial Spondyloarthritis

While there’s not much information on the cause of gastrointestinal manifestations with AxSpA, there are many recent studies that document how frequently digestive involvement occurs.

Managing digestive issues in Ankylosing Spondylitis

One study from 2015 shows that Irritable Bowel Syndrome occurs in 30.1% of patients with Ankylosing Spondylitis. This study also found prevalence to be higher in females over males.

Furthermore, the National Axial Spondyloarthritis Association estimates that 7% of people with AS will go on to develop Irritable Bowel Disease.

The link between IBS/IBD and Axial Spondyloarthritis isn’t a one way street either. On the flip side, one study confirms that Spondyloarthritis is “the most frequent extraintestinal manifestation in patients with IBD,” with frequency ranging from 17 to 39%.

Clearly there’s a larger correlation between Irritable Bowel Diseases and Spondyloarthritis, though no study indicates that the correlation is causal in nature. In other words, one disease does not cause the other and vice versa.

But there seems to be a genetic component, as people with AxSpA are more likely to have close relatives who develop IBD, and people with IBD are more likely to have close relatives who develop AxSpA (this is true for me, since IBD runs strong in my mother's side of the family). More research is needed to determine the nature of the relationship and the root cause.

Symptoms of Possible GI Involvement

In my experience, it’s difficult to identify what symptoms may be related to my Ankylosing Spondylitis and which ones are not. But the main symptoms of GI involvement are what you might expect:

  • Abdominal Pain - in my experience, this occurs during stressful times and is at its worst not long after I eat a meal.

  • Diarrhea - for me, this symptom is so consistent that I can count on it day in and day out. I go through periods where this symptom seems to flare-up just as my AS joint pain and fatigue does, and then periods where the symptom is more mild.

  • Loss of Appetite and Weight Loss - this isn’t a symptom that I deal with necessarily. That being said, when other symptoms do flare up, I tend to not want to eat to avoid the stomach pain.

  • Tiredness and Fatigue - this is also a common symptom of Ankylosing Spondylitis, so for me it’s hard to distinguish what’s causing the fatigue.

  • Passing Blood - I’ve suspected this symptom occasionally, but a doctor’s office has not confirmed it.

These seem to be the most common symptoms, and in my experience they can be difficult to figure out and are not always consistent. If you experience more severe symptoms, or are passing a significant amount of blood, it’s crucial to get checked out immediately.

Ankylosing Spondylitis and Irritable Bowel Disease

My Experience with Digestive Issues

My first notable experience with ongoing digestive system issues occurred during the winter of 2019. It was a stressful time for me as my wife and I were considering moving and changing jobs, and I’m confident that stress helped my symptoms flare. During a particular 5-day stretch I ate very little because every meal I ate would be followed by intense abdominal pain and the urge to run to the bathroom.

Eventually the stomach pain subsided, but since that winter I have been managing chronic loose stool and occasional abdominal pain. While this is not a pleasant conversation to have with a doctor, the symptoms were so consistent that I brought it up to my rheumatologist during my next visit the following October.

Clearly there’s a larger correlation between Irritable Bowel Diseases and Spondyloarthritis, though no study indicates that the correlation is causal in nature.

I recently underwent an upper and lower endoscopy, which would allow the gastrointestinal specialist to actually see what’s going on and take biopsies. As it turns out, I have multiple stomach ulcers, a medium-sized hiatal hernia, and severe inflammation in the stomach (along with acid reflux, which was no surprise). What’s unclear is whether I have microscopic inflammation in my intestines, or microscopic colitis. Biopsies may show this. What’s also unclear, at this point, is what’s causing my symptoms and if there’s a specific diagnosis associated with the findings.

In the meantime, I wait. I wait to hear something definitive from my healthcare team. I wait for my symptoms to resolve or for a treatment plan. Mostly, I wait for answers and hope that they come.


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