Most commons areas of AS inflammation

AS can cause a variety of different symptoms, but most people with AS have low back pain and stiffness. The stiffness is often worst in the morning and after you have been inactive for a while. The back pain and stiffness can prevent you from moving around comfortably and getting a good night's sleep. Most people with other kinds of low back pain feel better after a night's rest, but a hallmark of AS is that people usually feel worse and stiffer in the morning after sleeping.

 

Other joints can also become affected by AS, such as the hips, shoulders, heels, and knees. The involvement of the spine is called axial; involvement of other joints is termed peripheral. People with AS can experience fatigue, weight loss, and loss of appetite. The symptoms of AS tend to come and go, with periods of no symptoms followed by flare-ups.

 

AS can cause complications both in the joints and elsewhere in the body, including:

• bent-over or unusually straight posture
• limited mobility (ability to move around)
• eye inflammation (uveitis, which can cause eye pain, irritation, and sensitivity to light and requires immediate medical attention)
• breathing problems due to stiffness in the joints between the spine and the ribs
• sometimes significant damage to hip and shoulder joints (and occasionally to other joints)
• inflammation in places where ligaments and tendons attach to the bone (called enthesitis), such as the heel
• anemia
• spinal fractures 

Uncommon complications can include:

• inflammation of the aorta, a large blood vessel that brings blood from the heart to the rest of the body, and secondary aortic valve insufficiency (when the aortic valve is weakened, preventing the valve from closing properly)
• spinal cord injury due to fractures (breaks) in the spine
• cauda equina syndrome, where AS damages the nerves at the base of the spinal cord, leading to loss of sensation in the buttocks, rectum, thighs, and bladder; or loss of bowel or bladder control