Ankylosing Spondylitis and IBS: What Is the Relationship?

Some studies have shown that people with ankylosing spondylitis are more likely to have irritable bowel syndrome (IBS) symptoms. This article will discuss the connection between ankylosing spondylitis and IBS, how having one may influence the risk of having the other, and how each condition is managed.

Connection Between Ankylosing Spondylitis and IBS 

Ankylosing spondylitis is a disease that causes inflammation. It is a form of arthritis that primarily affects the spine. However, it also affects other body systems and can produce digestive symptoms.

Research is putting some evidence behind what people living with ankylosing spondylitis have already experienced in regard to their digestive symptoms. One study showed that 40% of people with ankylosing spondylitis also had digestive problems that were severe enough to classify as a functional bowel disorder (such as IBS). 

The reasons for this connection aren’t clear and may be quite complex. A flare-up of ankylosing spondylitis might also lead to more digestive symptoms.

Nonsteroidal anti-inflammatory drugs (NSAIDs) might frequently treat ankylosing spondylitis pain and inflammation and could make digestive symptoms worse for some people, though research on this conflicts.

But for now, why the two seem to go together is not exactly understood, and in fact, the answer might be one or more of many factors. 

Risks

People with ankylosing spondylitis have higher rates of IBS than people who don't live with the condition. Having ankylosing spondylitis might mean that there's an increased risk of developing IBS. 

One study showed that people with ankylosing spondylitis who receive a type of drug called a tumor necrosis factor (TNF) inhibitor might have more IBS symptoms. Another study showed that this was not the case. However, the authors say it's worth considering a diagnosis of IBS in people taking a TNF inhibitor who also have digestive problems.

Ankylosing spondylitis is also connected to inflammatory bowel disease (IBD). IBD causes inflammation in the body, while IBS does not. It's important to understand the difference between the two and get the right diagnosis when there are symptoms in the gut because the treatments for each condition are different. 

Treatment and Management of Ankylosing Spondylitis With IBS

The treatments for ankylosing spondylitis and IBS don’t overlap much. Ankylosing spondylitis causes inflammation and is progressive. IBS is a gut-brain disorder, is not progressive, and does not lead to inflammation.

Ankylosing Spondylitis Treatments

Treatments for ankylosing spondylitis will work to tamp down the inflammation (sometimes by affecting the immune system or the immune response) as well as slow down the progression of the disease.

Treatment can include NSAIDs, which treat both pain and inflammation. Other medications may prove necessary if NSAIDs are ineffective.

Disease-modifying antirheumatic drugs (DMARDs) are a common treatment for several forms of arthritis but not for ankylosing spondylitis. Azulfidine (sulfasalazine) or methotrexate are only recommended in cases of prominent peripheral arthritis for which TNF inhibitors are not available.

Some biologic TNF inhibitor medications include:

• Cimzia (certolizumab pegol)
• Enbrel (etanercept)
• Humira (adalimumab)
• Remicade (infliximab)
• Simponi (golimumab)
  

Another class of medication that works to dampen the immune system in targeted ways is the interleukin (IL) inhibitor. Cosentyx (secukinumab) or Taltz (ixekizumab) may treat ankylosing spondylitis if TNF inhibitors are not working.

The Janus kinase (JAK) inhibitors are the latest class of medications for treating inflammatory conditions such as ankylosing spondylitis. The JAK inhibitor Rinvoq (upadacitinib) treats ankylosing spondylitis after other forms of treatment (such as TNF inhibitors) haven’t worked.

Exercise is one of the non-medication treatments that may treat ankylosing spondylitis. A regular exercise program may help with pain and mobility because the condition may lead to stiff joints. A physical therapist can help develop one.

IBS Treatments

Treatment for IBS may include diet and lifestyle changes for most people and over-the-counter or prescription medication for some people. Whether diarrhea, constipation, or pain is the most prevalent symptom may also play a role in which treatment to try first.

Diet is a difficult puzzle to solve with IBS. In some cases, a dietitian or other healthcare provider might recommend a particular diet. This might include a diet that focuses on adding more soluble fiber or the low fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAP) diet.

Healthcare providers might recommend over-the-counter medications or supplements such as those that can slow down diarrhea (such as Imodium) or relieve constipation (laxatives). Though the research is far from complete and all the angles aren’t yet understood, some healthcare providers might suggest trying probiotics.

Prescription drugs that may treat diarrhea-predominant IBS include:

• Amitiza (lubiprostone)
• Linzess, Constella (linaclotide)
• Trulance (plecanatide)
• Motegrity (prucalopride)
• Zelnorm (tegaserod, which is only for use in select patients)

Viberzi (eluxadoline) is a drug that might be recommended to treat constipation-predominant IBS. Xifaxan (rifaximin) is an antibiotic that can treat IBS or small intestine bacterial overgrowth. 

Because IBS may cause muscle spasms or pain, a healthcare provider may prescribe an antispasmodic such as Bentyl (dicyclomine), although the 2021 clinical guidelines for IBS from the American College of Gastroenterology recommends against them.

Another type of drug that may treat IBS is the antidepressant. These drugs are usually prescribed for IBS in lower dosage amounts than they are for depression:

• Tricyclic antidepressants (TCAs)
• Selective serotonin reuptake inhibitors (SSRIs)
• Serotonin-norepinephrine reuptake inhibitors (SNRIs)
  

Non-drug therapies and lifestyle changes that might treat IBS include cognitive behavioral therapy (CBT), hypnotherapy, stress management, and relaxation exercises. These therapies might also help in coping with ankylosing spondylitis because they are useful for overall wellness, but there’s no research that looks at how well they work in people who live with both conditions. 

Prevention

Ankylosing spondylitis and IBS are not preventable conditions. However, for people diagnosed with ankylosing spondylitis, it’s important to make that connection with the digestive symptoms.

They may be thought of as two separate problems, but the research is showing that there is indeed an overlap, and the symptoms in the gut should be taken seriously and investigated by a healthcare provider.

Summary

Ankylosing spondylitis is an inflammatory form of arthritis that primarily affects the spine. It’s increasingly being understood that anywhere from 30% to 40% of people with ankylosing spondylitis meet the criteria for having a disorder of brain-gut interaction, such as IBS. The two conditions are treated in different ways.

A Word From Verywell

A diagnosis of ankylosing spondylitis is upsetting and disruptive. How this form of arthritis affects the digestive system is still not well understood, though its connection to IBD (Crohn’s disease or ulcerative colitis) is well known.

However, there’s more evidence coming to light that people with ankylosing spondylitis may also have a disorder of gut-brain interaction. Healthcare providers should take digestive symptoms seriously and work toward making a diagnosis. Advocate for yourself to ensure you receive the right treatment.