Mechanical back pain, which occurs due to changes in the structure and functioning of your back, has symptoms similar to that of ankylosing spondylitis, but is caused by your body’s movements rather than by inflammation.

Ankylosing spondylitis (AS) is a form of arthritis that most often affects your lower back, causing pain, stiffness, and, in severe cases, fusion (joining together) of the bones in your spine. It occurs when the immune system attacks healthy cells in the body. This immune response leads to inflammation, and a pain medical professionals call “inflammatory..”

Mechanical back pain is another, unrelated type of back pain.

This type of pain occurs due to changes in the structure and functioning of the back. You may experience it frequently or rarely, and it can result from everyday tasks like lifting too much weight or poor sleep positions.

Let’s go over their differences, including symptoms, causes, and treatment.

Intermittent back pain and stiffness are the most common features of AS. The back pain experienced typically occurs in the mornings after you wake up, and at night. Other symptoms include:

  • poor posture or stooped shoulders
  • loss of appetite
  • low-grade fever
  • weight loss that you were not expecting
  • fatigue
  • anemia
  • reduced lung function
  • abdominal pain

AS can also cause inflammation in other parts of the body, such as your:

  • bowels (including diarrhea)
  • eyes (including vision changes and pain due to uveitis)
  • heart valves
  • other joints, such as in the shoulders, knees, feet, or ribs
  • skin rashes

Telling the difference between mechanical back pain and inflammatory back pain can be tricky.

According to CreakyJoints, you should ask yourself the following questions to help determine if you have mechanical or inflammatory back pain:

  • Does the pain feel worse when resting or sitting for long periods?
  • Did it start before age 40?
  • Can it get bad enough to wake you in the middle of night and prevent you from getting additional sleep?
  • Does moving and exercise generally make the pain feel better?
  • Will pain improve when taking a nonsteroidal anti-inflammatory drug (NSAID) like ibuprofen?
  • Do other symptoms occur with the back pain, such as inflammatory bowel disease, eye inflammation, pain in the joints of your arms or legs, or psoriasis?
  • Does it feel worse for the first 30 or so minutes from getting up?
  • Has it lasted intermittently for more than 3 months?

If you answered yes to the majority of these questions, you may have inflammatory pain.

The following table may help you determine if your back pain is likely mechanical or inflammatory:

SymptomsMechanicalInflammatory
Other symptoms are present.noyes
Pain improves during exercise.noyes
Pain improves with rest.yesno
Pain started after physical exertion or lying on a bad mattress.yesno
Pain and stiffness last a long time without gradual improvement.no (in most cases, with rest, your pain should start to improve gradually over time)yes (pain may go away but will typically come back or flare up)

Some factors can put you at greater risk of having mechanical or AS-associated back pain.

AS-associated back pain risk factors

Risk factors include:

  • Age: AS typically occurs in adults under age 45.
  • Gender: AS is more likely in men than women.
  • Genetics: A family history of the disease can put you at greater risk.
  • Other factors: Having inflammatory bowel disease or psoriasis puts you at greater risk.

Mechanical back pain risk factors

Mechanical back pain occurs as a result of the stress you put on your body, such as sleeping in an awkward position, or on repetitive actions, such as:

  • frequently bending over
  • lifting with your back instead of your legs
  • poor posture (including when seated at a desk)

Getting your back pain properly diagnosed can help with improving your treatment outlook.

Mechanical back pain treatment

Mechanical back pain will typically improve over time with rest. In moderate to severe cases, you may need additional treatment, but you should see improvement with treatments. These can include:

  • cold and heat therapy
  • massage
  • acupuncture
  • physical therapy
  • nonsteroidal anti-inflammatory drugs (NSAIDs)
  • muscle relaxants
  • steroid injections
  • biofeedback

Other things you can do to help decrease your symptoms include

AS-related back pain

If your back pain is inflammatory, most of the methods above will not work. This is because your immune system will still produce the inflammatory response and you will still experience pain. And since AS is a progressive disease, your symptoms may worsen over time, potentially causing more serious concerns.

Treatments for AS can include several different therapies to help ease symptoms and prevent or slow disease progression, including:

  • biologics
  • janus kinase (JAK) inhibitors
  • corticosteroids
  • NSAIDs
  • physical therapy

In severe cases, your doctor may recommend surgery to treat AS.

Mechanical back pain occurs either due to physical exertion, poor spinal alignment, or even sleeping in an odd position. Inflammatory back pain, such as from AS, occurs when the immune system creates inflammation and attacks the joints in the back.

Treatment for both types of pain varies. You will likely see your mechanical back pain improve with rest. Inflammatory back pain from AS will require ongoing monitoring and treatments to address the underlying inflammation to help improve symptoms and help slow disease progression.