How does ankylosing spondylitis affect your eyes. What are the symptoms of uveitis in AS patients. What treatments are available for AS-related eye problems. How can you manage eye inflammation caused by ankylosing spondylitis. Why do people with AS develop uveitis. What is the connection between AS and eye health. How can you protect your vision if you have ankylosing spondylitis.

What is Ankylosing Spondylitis and How Does It Affect the Eyes?

Ankylosing spondylitis (AS) is a form of inflammatory arthritis that primarily impacts the spine, causing pain and stiffness. However, its effects extend beyond the musculoskeletal system, with eye inflammation, known as uveitis, being a common complication. Understanding the relationship between AS and eye health is crucial for patients and healthcare providers alike.

Uveitis is an umbrella term for a group of inflammatory eye diseases that primarily affect the uvea, the middle layer of the eye. However, this inflammation can occur in various parts of the eye, leading to different classifications of uveitis.

Types of Uveitis Associated with Ankylosing Spondylitis

• Anterior uveitis (iritis): Affects the front part of the eye, including the iris
• Intermediate uveitis: Occurs in the vitreous, the fluid-filled space attached to the retina
• Posterior uveitis (choroiditis): Impacts the back of the eye, potentially affecting the retina and optic nerve
• Panuveitis: The most severe form, affecting all parts of the eye

Anterior uveitis is the most common type experienced by AS patients. If left untreated, it can lead to serious complications such as cataracts, glaucoma, or retinal edema.

The Link Between Ankylosing Spondylitis and Uveitis: Exploring the Causes

The exact mechanism linking AS and uveitis is not fully understood, but researchers have identified several potential factors contributing to this connection.

The Role of Inflammation

The same inflammatory processes that cause back pain in AS can also trigger inflammation in the eyes and other parts of the body. This systemic inflammation is a hallmark of autoimmune conditions like AS.

Genetic Factors

Many individuals with AS and anterior uveitis possess a gene called HLA-B27. This genetic marker significantly increases the likelihood of developing eye inflammation in AS patients.

The Gut-Eye Connection

Some experts propose that the inflammation may originate in an unexpected place: the gut. The trillions of microbes in our digestive system play a crucial role in regulating the immune system. When this delicate balance is disrupted, it can lead to immune system dysregulation, potentially triggering inflammation in various parts of the body, including the eyes.

Is there a direct link between gut health and uveitis in AS patients? While more research is needed, some studies suggest that gut bacteria may instruct immune cells called T cells to attack the eyes, contributing to the development of uveitis.

Recognizing the Symptoms of Uveitis in Ankylosing Spondylitis

Early detection and treatment of uveitis are crucial for preserving vision and preventing complications. AS patients should be vigilant for the following symptoms:

• Redness in one or both eyes
• Eye pain
• Blurred vision
• Increased sensitivity to bright light (photophobia)

These symptoms can develop rapidly and may affect one or both eyes. The frequency and duration of uveitis episodes can vary among individuals. Some may experience a single episode, while others may have recurring flares or chronic inflammation requiring ongoing management.

Treatment Options for Uveitis in Ankylosing Spondylitis Patients

The primary goal of uveitis treatment is to quickly reduce inflammation and prevent long-term damage to the eye. Treatment approaches may vary depending on the type and severity of uveitis.

Topical Treatments

For anterior uveitis, the most common form in AS patients, doctors typically prescribe two types of eye drops:

1. Steroid drops to reduce inflammation
2. Mydriatic drops to dilate the pupil and alleviate pain

Systemic Treatments

For more severe cases or other types of uveitis, additional treatments may be necessary:

• Oral steroid medications
• Steroid injections around the eye
• Implantation of a steroid-releasing device inside the eye

How long do patients typically use steroid treatments for uveitis? Due to the potential side effects of long-term steroid use, including an increased risk of glaucoma and cataracts, steroid treatments are usually limited to a maximum of three months. As patients taper off steroids, doctors may introduce alternative medications to manage inflammation.

The Potential of Gut Health in Managing Uveitis

Given the emerging understanding of the gut-eye connection in AS, some experts are exploring the potential of gut health interventions in managing uveitis. While more research is needed to establish definitive guidelines, some approaches being investigated include:

Probiotics and Prebiotics

Probiotics are live, beneficial bacteria that can be found in fermented foods like yogurt or taken as supplements. Prebiotics, on the other hand, are plant fibers that nourish healthy gut bacteria. Both may play a role in supporting a balanced gut microbiome and potentially reducing inflammation.

Dietary Modifications

Some studies suggest that a predominantly plant-based diet may help reduce inflammation and support gut health. Additionally, specific supplements like butyrate, which supports gut health, are being explored for their potential benefits.

While these approaches show promise, it’s essential to consult with a healthcare provider before making significant changes to your diet or starting new supplements, especially if you’re managing a chronic condition like AS.

Preventive Measures and Regular Monitoring for AS Patients

Given the increased risk of uveitis in AS patients, regular eye check-ups and preventive measures are crucial for maintaining eye health.

Regular Eye Examinations

AS patients should undergo regular comprehensive eye exams, even in the absence of symptoms. These check-ups can help detect early signs of inflammation or other eye problems associated with AS.

Prompt Reporting of Symptoms

Patients should be educated about the symptoms of uveitis and instructed to report any eye-related changes to their healthcare provider promptly. Early intervention can significantly improve outcomes and prevent complications.

Lifestyle Considerations

While lifestyle changes cannot prevent uveitis, maintaining overall health may help manage AS and potentially reduce the frequency or severity of flares. This includes regular exercise, stress management, and a balanced diet.

The Importance of a Multidisciplinary Approach in Managing AS-Related Eye Problems

Effective management of eye complications in AS often requires a collaborative approach involving multiple specialists.

Rheumatologist

As the primary manager of AS, the rheumatologist plays a crucial role in coordinating care and managing the overall inflammatory process.

Ophthalmologist

An eye specialist is essential for diagnosing and treating uveitis and other eye complications associated with AS.

Primary Care Physician

The primary care doctor can help manage overall health and coordinate care between specialists.

Gastroenterologist

Given the potential gut-eye connection, a gastroenterologist may be involved in managing gut health and exploring its impact on AS and uveitis.

How can patients ensure effective communication between their healthcare providers? Keeping a detailed health journal, including symptoms, medications, and questions, can help facilitate discussions and ensure all aspects of care are addressed.

Future Directions in Research and Treatment of AS-Related Eye Complications

As our understanding of the relationship between AS and eye health continues to evolve, researchers are exploring new avenues for treatment and prevention.

Targeted Therapies

Advances in understanding the molecular mechanisms underlying AS and uveitis may lead to more targeted therapies that can address inflammation with fewer side effects.

Microbiome Research

Further investigation into the gut-eye connection may yield new strategies for managing AS and its ocular complications through microbiome modulation.

Genetic Studies

Ongoing research into the genetic factors contributing to AS and uveitis may help identify individuals at higher risk and develop personalized prevention strategies.

What role can patients play in advancing research? Participating in clinical trials, when available and appropriate, can contribute to the development of new treatments and a better understanding of AS and its impact on eye health.

In conclusion, understanding the connection between ankylosing spondylitis and eye health is crucial for comprehensive patient care. By recognizing the symptoms of uveitis, pursuing appropriate treatment, and adopting a multidisciplinary approach to management, patients with AS can take proactive steps to protect their vision and overall well-being. As research continues to uncover new insights into the relationship between AS and eye health, we can look forward to more effective strategies for preventing and managing these challenging complications.

How It Can Affect Your Eyes

Written by Linda Rath

• What Is Uveitis?
• Why People With AS Get It
• Symptoms
• Treatments

Ankylosing spondylitis (AS) is a type of arthritis. It causes pain and stiffness, mainly in your spine. But it can also cause eye inflammation called uveitis. Left untreated, uveitis can harm your vision and, in some cases, lead to blindness.

Uveitis is a large group of inflammatory eye diseases. It gets its name from the fact that these diseases mostly strike the uvea, the middle part of your eye. But uveitis can show up almost anywhere inside the eye.

Doctors usually describe uveitis based on where you have it:

Anterior uveitis (also called iritis) happens in the front part of your eye. That includes the iris, the colored part. It’s the most common type of uveitis for people with AS. If it’s not treated, anterior uveitis can lead to cataracts, glaucoma, or a buildup of fluid called retinal edema.

Intermediate uveitis is in the vitreous. That’s the big, fluid-filled space in your eye attached to your retina, a layer of cells that sense light and send signals to your brain.

Posterior uveitis (also called choroiditis) attacks the back of your eye. It may affect your retina and your optic nerve, which connects your eye to your brain.

Panuveitis affects all parts of your eye. It’s the most severe type. It can cause blindness if it’s not treated.

About half of people with ankylosing spondylitis have uveitis at least once. It’s one of the most common complications of that form of arthritis.

Your eye doctor could actually be the first to figure out you have AS. That’s because the same inflammation that makes your back hurt can also cause inflammation in your eyes and other parts of your body.

Some experts think the inflammation starts in a place you might not think of: your gut.

It’s home to trillions of tiny organisms called microbes. They perform so many vital functions that you can’t live without them. One of their main jobs is to control your immune system. When the microbes get out of whack, your immune system does, too.

Uveitis may start when gut bacteria tell immune cells called T cells to attack your eyes. But that’s probably not the whole story. Many people with AS and anterior uveitis have a gene called HLA-B27. This gene makes eye inflammation much more likely.

Keep an eye out for:

• Redness
• Pain
• Blurred vision
• Sensitivity to bright light

These symptoms can come on quickly in one or both eyes. Sometimes uveitis is a one-time thing. In other cases, you may go years between flares. In still others, it can also be long-lasting and need ongoing treatment.

The goal of uveitis treatment is to ease inflammation fast. For anterior uveitis, doctors usually prescribe two types of eye drops:

• Steroid drops to lower inflammation
• Drops that widen your pupil to ease pain

For other types of uveitis, you may need steroid pills or shots around your eyes. Sometimes doctors implant a steroid capsule inside your eye.

Steroids can cause serious side effects, including eye diseases like glaucoma and cataracts. Usually, you won’t use steroids for more than 3 months. As you taper off them, your doctor may start you on another medicine.

Some experts think a change in gut bacteria can ease uveitis. You might try:

Probiotics. These are live, friendly bacteria. You find them in yogurt and other fermented foods. They’re in supplements, too.

Prebiotics. These plant fibers feed healthy bacteria in your gut and make them stronger. You can find them in foods like bananas and onions.

Supplements for gut health like butyrate are another option. A diet that’s mostly plant-based could also help.

Talk with your doctor to find out which treatment might work best for you.

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Why Ankylosing Spondylitis Causes Eye Pain – Cleveland Clinic

Ankylosing spondylitis (AS) is a type of inflammatory arthritis that typically affects your lower back.

While those who have AS may experience stiffness, fatigue and pain, the autoimmune condition can also cause eye inflammation known as uveitis.

Rheumatologist Ahmed Elghawy, DO, explains why you may experience eye problems and what treatments are available.

Why does AS cause eye pain?

The short answer is: Doctors aren’t entirely sure.

“With autoimmune conditions like ankylosing spondylitis, your body is acting inappropriately against its own tissue,” explains Dr. Elghawy. “We think this is also the case when it comes to uveitis. There may have been some sort of pathogen that could have led to the body recognizing a self-antigen instead of the pathogen. The body makes the mistake of attacking itself.”

There may also be a link between a certain gene known as HLA-B27 that’s common in both ankylosing spondylitis and uveitis.

Between 25% to 35% of individuals with ankylosing spondylitis will go on to develop some sort of uveitis.

There are different types of uveitis:

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• Anterior uveitis. This affects the front part of your eye, including your iris. About 90% of people with AS will develop this type.
• Posterior uveitis. The back part of your eye is affected, including your retina and optic nerve.
• Intermediate uveitis. This type attacks your vitreous, the clear fluid between your lens and retina.
• Panuveitis. This type affects every part of your eye. It’s the most severe type.

“The longer the patient has ankylosing spondylitis, the more likely they are to develop uveitis,” says Dr. Elghawy.

Uveitis symptoms

Uveitis typically only affects one eye at a time; though, it’s possible to have symptoms in both eyes at once.

If you have uveitis, you may experience the following symptoms:

• Redness.
• Swelling.
• Inflammation.
• Pain.
• Blurred vision.
• Sensitivity to light.
• Increased floaters or spots in your vision.
• Decreased vision.

“In people who are older, uveitis increases the risk of developing cataracts or glaucoma or making those conditions worse,” says Dr. Elghawy.

Treating eye pain and AS

If not treated, uveitis can harm your vision and could potentially lead to blindness.

“We recommend that those who have eye issues at all, especially who already carry a diagnosis of ankylosing spondylitis, that they let their doctor know immediately because it needs to be it needs to be addressed quickly,” emphasizes Dr. Elghawy.

Your doctor will not only treat uveitis, but will also treat your ankylosing spondylitis. In many cases, your rheumatologist may suggest you see an ophthalmologist, too.

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Treatment options for uveitis may include anti-inflammatory eye drops or eye drops with corticosteroids.

Treatments options for AS can include:

• Nonsteroidal anti-inflammatory drugs (NSAIDs). Either an over-the-counter or prescription NSAID can work as an anti-inflammatory and help with other symptoms as well.
• Disease-modifying anti-rheumatic drugs (DMARDs). This type of drug can also help control your overactive immune system and help with symptoms.
• Corticosteroids. To help temporarily ease joint pain and inflammation, your doctor may recommend an injection of corticosteroids.

Often, the biologic therapies used for ankylosing spondylitis also address uveitis.

“A common scenario would be a person who has low back pain and was treated with prescription or over-the-counter NSAIDs. They’re doing well, but later they develop eye issues, and then, that’s what kind of prompts us to start the biologic therapy,” explains Dr. Elghawy. “There are other individuals who are on biologic therapy who never go on to develop uveitis and that’s probably because they’re already being treated with the biologic therapy.”

And don’t overlook the importance of regular eye exams, says Dr. Elghawy.

“Sometimes, you may find evidence of uveitis during a typical eye exam, even before you have symptoms,” he adds. “So, it’s important if you do have evidence of uveitis, it’s treated properly to prevent the long-term consequences.”

Ankylosing spondylitis – what is it

The official international name of the disease is ankylosing spondylitis. The term Bechterew’s disease is used only in Russia and until recently was used in Germany.

Ankylosing spondylitis is a systemic inflammatory disease, a type of spondyloarthritis that affects the joints, spine, and entheses (attachments of ligaments and tendons to bones). The difference between the disease and other spondyloarthritis lies in the fact that ankylosing (fusion) of the vertebrae among themselves occurs, as a result, the spine can turn into a single bone and deform. The quality of life in this disease is significantly reduced. The second severe complication of Bechterew’s disease is damage to the hip joints, up to a complete loss of mobility and disability.

Why does this disease occur?

The exact cause of the disease is unknown. According to one hypothesis, certain intestinal microbes can trigger pathological inflammation in entheses and joints. For the appearance of a disease, it is not enough to get a certain infection into the body, a certain state of the body’s immune system is necessary, in which self-sustaining inflammation is possible. Scientifically proven risk factors for the development of ankylosing spondylitis are heredity and smoking.

Symptoms

Ankylosing spondylitis usually begins at a young age. The most common symptom of Bechterew’s disease is back pain. This pain has a number of characteristic features (the so-called “inflammatory back pain”). It increases with prolonged immobility, including during nocturnal sleep, and decreases with motor activity. Pain of an inflammatory nature is often accompanied by a feeling of stiffness, especially in the morning when the patient wakes up. The presence of this symptom is a reason for an immediate appeal to a specialist to clarify the diagnosis. Young people often have pain in the calcaneus or Achilles tendon attachments.

Most often, the disease begins with sacroiliitis, which is manifested by pain in the lower back (lumbar region). But in some cases, the patient may feel pain in the neck or at the level of the thoracic spine. In the later stages, there is a restriction of movements, in especially severe cases, a “posture of the supplicant” is formed.

Often, patients report pain, limited mobility and swelling in peripheral joints, such as the shoulder, hip, small joints of the hands and feet, temporomandibular.

The disease can also cause extra-articular manifestations – damage to organs: heart, kidneys, eyes. The latter is the most common and is manifested by uveitis (pain, photophobia, redness of the eye).

Associated conditions include the presence of psoriasis, inflammatory bowel disease, intestinal or genitourinary infections.

Depending on the area where inflammation develops, central and peripheral forms of the disease are distinguished.

Diagnostics

The diagnosis is confirmed using instrumental and laboratory diagnostic methods. X-ray and MRI in the diagnosis of ankylosing spondylitis are used as complementary methods. Often, ultrasound or MRI of the hands and feet can effectively detect enthesitis (inflammatory lesions of enthesis).

Laboratory diagnostics plays a significant role. 90% of patients with ankylosing spondylitis are carriers of the HLA B-27 gene. This is a genetically determined leukocyte antigen, which is associated with the possibility of developing an autoinflammatory reaction. However, the presence of HLA B-27 does not mean the development of the disease, this gene only indicates an increased risk of ankylosing spondylitis.

Early diagnosis is the key to successful treatment of Bechterew’s disease, but it is not easy to recognize the disease. Much depends on the qualifications of the rheumatologist.

Treatment of ankylosing spondylitis

Drug treatment

Non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen, diclofenac, naproxen, nimesulide, etoricoxib, ketoprofen, aceclofenac, meloxicam, etc. are the mainstay of treatment. They can inhibit ankylosing of the spine , reduce the inflammatory response , improve the prognosis of the development of the disease, increase the range of motion and at the same time can be used as painkillers. The drugs block the self-sustaining autoinflammatory process and block the disease mechanism. Patients with peripheral involvement, in whom arthritis prevails, are recommended to take basic anti-inflammatory drugs (sulfasalazine, leflunomide, methotrexate). In the absence of the effect of taking non-steroidal anti-inflammatory drugs, patients are prescribed genetically engineered drugs from the group of inhibitors of tumor necrosis factor

Surgical treatment

Surgical treatment may be required to correct conditions associated with a complication of the course of the disease, such as severe spinal deformities, vertebral fractures, destruction of the hip joints, and heart damage.

Physiotherapy

Physiotherapeutic methods can be used to relieve pain: massage, acupuncture and other methods. Their disadvantage is that they do not give a long-term sustainable effect. Physiotherapy is not included in the official recommendations for the treatment of Bechterew’s disease.

Exercise therapy

Regular physical exercise in addition to the main therapy helps to maintain mobility in the joints. Especially recommended exercises to strengthen the muscles of the back.

Prevention

The causes of the development of the disease have not been reliably established, therefore, special prevention has not been developed.

General recommendations would be to maintain an active lifestyle while trying to avoid spinal and joint injuries, refraining from smoking, eating a Mediterranean diet is preferable..

Diagnosis and treatment at EMC

Thanks to a wide range of diagnostic methods and modern technologies, the majority of patients with this disease can achieve a good effect in treatment. At the European Medical Center (Moscow), comprehensive care is provided according to the protocols adopted by international rheumatological organizations (ASAS, EULAR, ACR). For patients who cannot come to the clinic, it is possible to arrange a remote consultation.

Bechterew’s disease: possible complications | Clinical Diagnostic Center

“Bekhterev’s disease”: possible complications / Interview with Anna Okhotnikova, 24-hour hospital rheumatologist at the BUZOO “CDC” dorsal joints, which can proceed simultaneously with the defeat of peripheral joints, entheses and internal organs. Anna Okhotnikova, a rheumatologist at the CDC round-the-clock hospital, talks about the symptoms of the disease and its various consequences for the body:

Clinical manifestations of spondyloarthritis are varied, they appear gradually, sometimes imperceptibly for the patient, long spontaneous remissions are often observed at the onset of the disease. Ankylosing spondylitis most often begins with inflammatory back pain (in 75-85% of cases) and peripheral arthritis (in 15-25% of cases)

The following symptoms are characteristic of the onset of ankylosing spondylitis:

Deep-seated pain in the spine associated with restriction of movement in the lumbar

Morning stiffness of the spine that disappears during the day.

The central place in the clinical picture is occupied by the lesion of the axial skeleton (spine, pelvis, hip, shoulder and mandibular joints).

Criteria for inflammatory back pain are:

slow (creeping) onset extending over weeks

nocturnal pain better on waking

better with exercise

worse during sleep and at rest .

Inflammatory pain reflexively causes muscle spasm, which contributes to the development of stiffness of the spine. In the early stages of the disease, the restriction of movements in the spine is due to inflammation and painful spasm of the muscles of the back, in the later stages – mainly ossification of the spine.

If the thoracic spine, costovertebral joints are affected, there is pain in the chest, sometimes encircling, aggravated by coughing, deep breathing, turning the torso. As a result of damage to the costovertebral joints, the respiratory excursion of the chest decreases, while the respiratory function is compensated by the diaphragm.

Damage to the joints of the anterior chest wall (sternoclavicular, sternocostal, manubrium and body of the sternum) can be observed at any stage of the disease. Arthritis of the joints of the anterior chest wall occurs in ankylosing spondylitis in 17% of cases. Symptoms can range from mild soreness to severe, firm swelling.

Involvement of the cervical spine occurs at a later stage of the disease. Initially, pain appears, the range of motion of the neck gradually decreases: rotation and inclinations are limited. In some cases, complete ankylosis of the cervical spine occurs with absolute immobility of the head and neck. Spondylitis of the cervical spine may result in dyscirculatory encephalopathy, accompanied by dizziness, nausea, and headache.

Peripheral joint involvement can occur at any stage of the disease and is sometimes one of the first symptoms. In more than 50% of patients, peripheral joints are involved in the process, including the hip and shoulder joints. Peripheral arthritis can be either a temporary manifestation of the disease and pass without a trace, or a frequently recurring manifestation leading to a permanent dysfunction of the joint. Large and medium joints of the lower extremities (hip, knee, ankle) are predominantly involved, arthritis of individual joints of the toes is possible, temporomandibular joints may be affected.

A special variant of arthritis in this disease is damage to the hip joint (coxitis). It develops in about 1/3 of patients with ankylosing spondylitis; in adults, coxitis develops in the first 10 years of the disease. It is manifested by pain in the inguinal region, which can radiate along the anterior and lateral surface of the thigh, to the buttocks, and the anterior surface of the lower leg. It is possible to identify asymptomatic x-ray changes in the hip joints.

In addition to pain in the joints, there are also pains in the bones. We are talking about inflammation of those places where the tendons are attached to the bones. The very first symptoms of Bechterew’s disease are sometimes pains in the heels, which make standing on a hard floor very unpleasant. Inflammation of the attachment of the tendons at the ischium makes sitting on hard chairs unpleasant. Other tendon attachments may also be affected. Inflammation of the tendon attachments is so characteristic of Bechterew’s disease that, together with other characteristic signs, they can even be considered as a diagnostic criterion.

Bechterew’s disease is a “systemic disease”. The erroneous functioning of the immune system can also manifest itself in other organs, not only in the spine. General clinical manifestations of the disease:

fever in the evening not higher than 37.5 C, lethargy, weight loss with preserved appetite, fatigue.

EYES. Approximately 40% of patients develop eye inflammation at one or more times in their lives. We are talking about iritis (inflammation of the iris). If, in addition to the iris, the adjacent areas of the eye also become inflamed, the doctor speaks of iridocyclitis or uveitis. The eye hurts (especially with large changes in brightness, at which the pupil should constrict), becomes sensitive to pressure and reddens.

HEART. Pathology from the side of the heart occurs more often, the longer the disease lasts and the more severe it is. After a 15-year duration of the disease, 3.5%, and after a 30-year duration, 8-10%. Inflammatory changes in the heart caused by Bechterew’s disease develop where the aorta exits the heart. They can lead to heart valve failure (the valve no longer closes properly and blood flows back into the heart with every heartbeat). But inflammation can also block nerve regulation between the atrium and the main chamber and lead to abnormal heart rhythms. To avoid these unpleasant complications, it is important for patients to eliminate or reduce risk factors such as smoking, high blood pressure, being overweight, and lack of exercise.

LIGHT. Lung function is maintained through abdominal breathing, even with complete ossification of the costal joints. But the volume of breathing can be severely limited. In about 15% of patients, this results in upper lung fibrosis (an overgrowth of the connective tissue in the lung), which makes it easier for bacteria and fungi to infect the lungs. The countermeasure against this side effect (along with stopping smoking as a risk factor) is to maintain as much breathing volume as possible, which can be achieved with the help of breathing exercises and physical training.

KIDNEYS and LIVER. Due to inflammatory processes in almost all organs, there is a deposition of protein molecules, which is called amyloid. In the late stage, the lack of volume of the kidneys and liver can limit the function of these organs. Then they talk about amyloidosis. It is treated with diet and cortisone-containing drugs. Amyloidosis is a compelling reason to use these drugs despite their side effects.

NERVOUS SYSTEM. Rarely, but still, complications in the nervous system occur in the late stage of ankylosing spondylitis.