Complications of Severe Ankylosing Spondylitis

In rare cases, people with severe ankylosing spondylitis may develop serious complications, including:

Left untreated, ankylosing spondylitis can cause changes to the spine that result in a hunched posture.

A hunched posture. A curled forward, chin-to-chest stance can occur if the spine fuses together in a hunched forward position. People who develop this deformity have a permanent downward gaze. The heart, lungs, and other organs can be affected.

Bone fractures. Bones may lose mineral density (osteopenia and osteoporosis) making them brittle and prone to fractures.


Cauda equina syndrome. This rare condition involves extreme pressure and swelling of the nerves at the end of the spinal cord. The condition can cause weakness, tingling, or numbness in the legs, and/or feet on one or both sides of the body. It also causes bowel or bladder dysfunction. This condition is considered a medical emergency.

Spondylodiscitis. In this condition, one or more intervertebral discs or disc spaces become infected. One study estimates that 8% of people with ankylosing spondylitis develop spondylodiscitis.1

Bamboo spine. The spine is a series of joints that provide a high degree of movement and flexibility in all directions. In severe, advanced cases of ankylosing spondylitis there is a complete fusion of the bones of the spine, turning the spinal column into one long bone, which some people say resembles a bamboo stalk. It is quite rare for complete spinal fusion to occur in patients receiving treatment.


See 5 Unusual Ankylosing Spondylitis Symptoms


Most patients receiving treatment for ankylosing spondylitis will not experience these symptoms.


  • 1.Kabasakal Y, Garrett SL, Calin A. The epidemiology of spondylodiscitis in ankylosing spondylitis--a controlled study. Br J Rheumatol. 1996;35(7):660-3.