OVERVIEW

What is ankylosing spondylitis?

Ankylosing spondylitis is a common type of spondyloarthritis that primarily affects the axial joints, such as the spine, intervertebral discs, and sacroiliac joints above the pelvis. It may also be accompanied by extra-articular manifestations like conjunctivitis or uveitis. Patients experience severe pain, and normal walking may be affected. In severe cases, spinal deformity can occur, making the entire spine unable to bend normally, resembling a bamboo stick^[1].

Is ankylosing spondylitis common?

It is relatively common, with a prevalence rate of about 0.25% in China, meaning approximately 25 out of every 10,000 people are affected. The disease often shows familial clustering^[1].

Is ankylosing spondylitis a type of rheumatism?

Ankylosing spondylitis is a chronic inflammatory rheumatic disease^[1]. Since it can also affect peripheral joints and shares clinical, radiological, and pathological similarities with rheumatoid arthritis, it was long considered a variant of rheumatoid arthritis, referred to as "rheumatoid spondylitis."

Which department should patients with ankylosing spondylitis visit?

Rheumatology and immunology, orthopedics, or specialized clinics like spinal surgery or ankylosing spondylitis clinics in some hospitals. If rehabilitation is needed, they may also visit the sports rehabilitation department.

Patients with spine or hip pain as their main symptoms may first visit orthopedics. Orthopedic doctors can preliminarily diagnose ankylosing spondylitis through examinations and tests. After confirmation, some may refer patients to rheumatology for medical treatments like medication, which is the primary department for most patients.

For severe cases, such as spinal deformities, corrective surgery in orthopedics may be required, followed by rehabilitation training in sports rehabilitation.

Ankylosing spondylitis involves multiple disciplines, so the above departments are all viable options. However, if medical treatment is the focus, rheumatology should be prioritized.

SYMPTOMS

What are the characteristics of ankylosing spondylitis onset?

The disease often has an insidious onset (early stages may show no obvious symptoms), with the majority of cases occurring between ages 20–30. The male-to-female incidence ratio is approximately 2:1, and males tend to have more severe symptoms^[1]. The condition typically progresses upward (from the sacroiliac joints to the cervical spine) or downward, affecting bilateral hip and knee joints, while involvement of upper limb joints is rare.

It is often accompanied by various other conditions^[1] (e.g., peripheral arthritis, conjunctivitis, heart block, etc.).

What are the main early symptoms of ankylosing spondylitis?

Ankylosing spondylitis usually has a subtle onset^[1]. Early stages may lack clinical symptoms, though some patients exhibit mild systemic manifestations such as fatigue, weight loss, prolonged or intermittent low-grade fever, loss of appetite, or mild anemia.

Due to mild symptoms, most patients fail to detect the disease early, leading to delayed diagnosis and missed optimal treatment opportunities.

What are the joint manifestations of ankylosing spondylitis?

Most patients initially develop sacroiliitis, with early symptoms including pain and/or stiffness in the buttocks, hips, or lower back—particularly after prolonged lying (at night) or sitting—making it difficult to turn over. Morning stiffness or stiffness after prolonged sitting is pronounced^[1], but improves with activity. Some patients experience severe hip or buttock pain, occasionally radiating to surrounding areas.

Early pain is often unilateral and intermittent, but typically becomes bilateral and persistent within months. As the disease progresses, it spreads from the sacroiliac joints to the lumbar, thoracic, and cervical spine, causing pain, restricted mobility, or spinal deformities in affected areas.

Besides joint issues, what other manifestations occur in ankylosing spondylitis?

Extra-articular symptoms usually appear after spinal involvement, though occasionally they may precede musculoskeletal symptoms by months or years^[1].

• Ocular lesions: 30% of patients develop conjunctivitis, iritis, or uveitis^[1], presenting with eye redness and itching. Ocular issues are often self-limiting but may require corticosteroids. Untreated cases can lead to glaucoma or blindness.
• Cardiac lesions: Aortic valve abnormalities are common, potentially causing angina. Rarely, aortic aneurysms, pericarditis, or myocarditis occur, manifesting as chest tightness or pain.
• Auditory lesions: Some patients develop chronic otitis media, leading to hearing loss or tinnitus.
• Neurological lesions: Spinal rigidity and osteoporosis increase risks of cervical dislocation or fractures, causing spinal cord compression symptoms like pain or sensory abnormalities (e.g., sudden cold/heat sensations or crawling skin sensations).
• Renal lesions: 10%–30% of patients experience kidney involvement, primarily secondary renal amyloidosis or IgA nephropathy, presenting with proteinuria, hematuria, or renal dysfunction.

Can ankylosing spondylitis cause disability and impair work ability?

Most patients develop joint lesions, primarily starting with sacroiliac joint involvement, which affects normal walking. The disease then ascends to the lumbar, thoracic, and cervical spine. Early symptoms include spinal and joint pain, while advanced stages lead to restricted mobility, muscle atrophy, and spinal deformities^[1], causing disability and severely impairing work capacity. Specific manifestations include:

• Lumbosacral involvement: May cause lumbar muscle atrophy.
• Thoracic involvement: Results in kyphosis and restricted chest expansion. Severe cases maintain an expiratory chest position, reducing expansion by >50% compared to normal, relying on diaphragmatic breathing^[1].
• Advanced cervical/thoracic progression: Causes pronounced kyphosis, with the head fixed in flexion, limiting upward gaze, lateral bending, or rotation.
• Shoulder involvement: Restricts joint movement, exacerbating pain and limiting activities like combing hair or raising arms.
• Knee involvement: Leads to compensatory flexion, further hindering walking, sitting, or daily tasks.

CAUSES

What are the common causes of ankylosing spondylitis?

Ankylosing spondylitis is a genetic disease caused by a combination of genetic and infectious factors^[1]:

• Genetic factors: The prevalence rate among first-degree relatives of ankylosing spondylitis patients is about 19%. Additionally, the susceptibility gene HLA-B27 is directly involved in the onset of ankylosing spondylitis. The prevalence rate increases to 32% among HLA-B27-positive first-degree relatives of patients^[2].
• Infectious factors: Ankylosing spondylitis is somewhat correlated with chronic infections. Chronic periodontal disease, intestinal infections, and other conditions can trigger the disease^[1].

Who is generally at risk for ankylosing spondylitis?

• Individuals with affected first-degree relatives: Ankylosing spondylitis tends to cluster in families, and those with a family history of the disease or positive susceptibility genes are more likely to develop it^[1].
• Young adults: Ankylosing spondylitis predominantly affects young adults, with a prevalence rate of approximately 0.1% to 1.6%^[2].
• Individuals with chronic infections: Those with chronic periodontal disease, intestinal infections, or chronic respiratory infections are more susceptible to the disease^[1].
• Long-term smokers: Compared to non-smokers, smokers have a higher probability of developing ankylosing spondylitis. Additionally, smoking patients exhibit lower disease activity (an indicator of disease severity; lower activity indicates more severe conditions) and more severe imaging findings on CT or X-rays^[3].

Is ankylosing spondylitis hereditary?

It may be hereditary, but it is not inevitable^[1]. In addition to genetic factors, the disease also results from the combined effects of infectious factors and other contributors.

DIAGNOSIS

What tests are needed for ankylosing spondylitis?

Doctors typically evaluate symptoms such as lower back pain, morning joint stiffness lasting over three months, symptom improvement with activity but not with rest, etc., and conduct the following tests^[1]:

1. Imaging tests:

   • X-ray: Helps identify joint lesions in affected areas. Doctors make a preliminary diagnosis based on X-ray results^[1].
   • CT scan: Detects changes in bone structure and density, aiding diagnosis^[1].
   • MRI: Assists in early diagnosis of ankylosing spondylitis.

2. Laboratory tests:

   • HLA-B27: Aids in diagnosis. About 90% of ankylosing spondylitis patients test positive for HLA-B27^[1].

3. Other: Patients in the active phase may show increased erythrocyte sedimentation rate (ESR) and elevated C-reactive protein (CRP)^[1].

How is ankylosing spondylitis diagnosed?

The diagnosis often follows the 1984 revised New York criteria^[1]:

Clinical criteria:

• Lower back pain and morning stiffness lasting ≥3 months, improving with activity but not rest.
• Limited lumbar spine mobility in frontal and sagittal planes.
• Reduced chest expansion compared to age- and sex-matched healthy individuals.
• Radiological criteria: Bilateral grade ≥II or unilateral grade III–IV sacroiliitis.

Diagnosis:

• Definite ankylosing spondylitis: Meets radiological criteria plus ≥1 clinical criterion.
• Probable ankylosing spondylitis: Meets 3 clinical criteria or radiological criteria without clinical symptoms.

What diseases can ankylosing spondylitis be confused with?

Due to the lack of highly specific lab tests, ankylosing spondylitis may resemble other conditions. Doctors differentiate it through symptoms and tests, including^[1]:

• Rheumatoid arthritis: Shares symptoms like joint stiffness and pain but can be distinguished by negative rheumatoid factor.
• Tuberculous spondylitis: Causes spinal stiffness/deformity but results from tuberculosis infection (confirmed via lab tests).
• Osteoarthritis: Similar joint pain and stiffness but differentiated via X-rays and lab tests.
• Lumbosacral strain: Mimics lower back pain but distinguished by ESR and X-ray findings.

Why is HLA-B27 tested for ankylosing spondylitis?

HLA stands for Human Leukocyte Antigen, part of the major histocompatibility complex (MHC) that regulates immune responses. Ankylosing spondylitis is strongly linked to HLA-B27, with most patients testing positive^[1].

TREATMENT

What are the treatment methods for ankylosing spondylitis?

• Non-drug therapy: The foundation of non-drug treatment for ankylosing spondylitis is patient education about the condition and regular exercise targeting the spine, thorax, hip joints, and other areas. Late-stage patients should also pay attention to proper posture when standing, sitting, and lying down. It is recommended to use a firm mattress, a low pillow, avoid excessive weight-bearing, and refrain from intense physical activity^[1].
• Drug therapy:
  • Nonsteroidal anti-inflammatory drugs (NSAIDs): Currently the first-line treatment for ankylosing spondylitis^[1], they can quickly relieve back pain and improve morning stiffness and spinal mobility. Commonly used NSAIDs include celecoxib, diclofenac, and meloxicam. However, these drugs carry gastrointestinal and potential cardiovascular risks^[2]. Dosage and usage should follow medical advice.
  • Tumor necrosis factor (TNF) inhibitors: One of the key drugs for treating ankylosing spondylitis^[1]. For patients who do not respond adequately to NSAIDs or have extra-articular symptoms such as uveitis or inflammatory bowel disease, TNF inhibitors like etanercept, infliximab, and adalimumab may be used in combination.
  • Interleukin-17A (IL-17A) inhibitors: A newer class of biologics that can also be used for patients unresponsive to NSAIDs^[4], including secukinumab and ixekizumab.
  • Disease-modifying antirheumatic drugs (DMARDs): Suitable for patients with contraindications to TNF inhibitors and peripheral arthritis. Examples include sulfasalazine, methotrexate, leflunomide, and thalidomide^[5].
  • Corticosteroids: Local corticosteroid injections may be considered for acute uveitis or musculoskeletal inflammation^[1].
• Surgical treatment: For patients with refractory pain or joint disability due to hip involvement, total hip replacement should be considered regardless of age. Severe deformity or disability may require spinal corrective surgery^[1].

Can ankylosing spondylitis be cured?

Ankylosing spondylitis cannot be completely cured and often affects patients' daily life and work. A small number of patients may develop severe spinal or joint deformities, but the condition generally does not affect lifespan^[1]. With rapid advancements in biomedical technology, early diagnosis and comprehensive treatment during the "golden treatment period" can effectively control or slow disease progression and improve quality of life.

What factors influence the prognosis of ankylosing spondylitis?

With timely diagnosis, proper treatment, and active rehabilitation, symptoms can be controlled and prognosis improved. However, poor prognosis is associated with younger age at onset, early hip involvement, HLA-B27 positivity, persistently elevated ESR and CRP^[1], recurrent uveitis, delayed diagnosis, inadequate or inappropriate treatment, and lack of long-term functional exercise.

What are the treatment goals for ankylosing spondylitis?

While ankylosing spondylitis cannot be cured, comprehensive treatment—including posture maintenance, medication, and surgery—can relieve pain and stiffness, control inflammation, prevent or correct deformities, and ultimately improve patients' quality of life.

Do ankylosing spondylitis patients need follow-up visits?

Yes, follow-up is necessary, but the frequency varies by individual and should follow medical advice. Stable patients may require check-ups every six months, while those with worsening symptoms should seek immediate medical attention.

What are the consequences of non-standardized treatment for ankylosing spondylitis?

Ankylosing spondylitis is a chronic condition requiring systematic and comprehensive treatment at a reputable hospital. Non-standardized treatment hinders recovery and may worsen disease persistence and disability rates. Personalized treatment plans, adjusted based on disease stability and spinal deformity, are essential to maximizing patients' quality of life.

DIET & LIFESTYLE

Does ankylosing spondylitis significantly impact daily life?

This disease often affects young adults, who are typically at a crucial stage of learning or working. Without proper treatment, it may lead to reduced academic or work performance, or even disability, significantly impacting patients.

The severity of clinical manifestations varies greatly. Some patients experience continuous progression, with noticeable spinal stiffness and kyphosis within 1–2 years. Severe hip joint involvement may even result in prolonged bed rest. Others may remain in a relatively stable condition without progression, allowing normal work and life^[1].

Can patients with ankylosing spondylitis conceive and have children?

Some medications for ankylosing spondylitis may affect the reproductive system. Patients are advised to discontinue these drugs for at least six months before planning pregnancy to ensure reproductive health. If symptoms worsen, low-dose hormone therapy may be used.

However, certain medications may increase miscarriage risk or cause fetal malformations, so patients must adjust their treatment under medical supervision.

What should patients with ankylosing spondylitis pay attention to in daily life?

• Develop a habit of daily exercise.
• Maintain good posture while standing or sitting^[1]. Perform regular deep breathing, chest expansion, and trunk-straightening exercises to strengthen back muscles and abdominal flexibility.
• Avoid excessive spinal stress or bending.
• Minimize prolonged spinal strain or bending to prevent worsening the condition. Avoid staying in one position for too long (e.g., lying on the sofa watching TV or prolonged computer use).
• For morning stiffness, a hot bath or compress can relieve symptoms.
• Recent studies suggest smoking worsens prognosis^[1], so patients should quit smoking and alcohol to avoid aggravating the disease.
• Maintain dietary hygiene, drink plenty of water, eat vegetables and fruits, and avoid urinary retention or constipation.

How can family members support patients with ankylosing spondylitis?

The disease has a prolonged course, and advanced cases may lead to loss of work ability, affecting career, family, and finances. Patients often feel burdensome, leading to increasing anxiety, pessimism, self-blame, or even loss of treatment confidence and life motivation.

Caregivers and family should understand the patient’s psychology, communicate frequently, alleviate stress, explain relapse causes, guide treatment and daily care, and offer encouragement to foster resilience.

Family should encourage active treatment compliance while advising on rest. They should also prepare patients for future social roles post-recovery, fostering a secure and stable environment to promote healing.

PREVENTION

What are the preventive measures for ankylosing spondylitis?

Since the onset of ankylosing spondylitis is related to genetics^[1], there is no effective prevention method for this disease. For individuals without a family history of the condition, there is no need to excessively worry about their risk of developing it.

If there is a family history of the disease, seeking medical attention promptly when related symptoms appear and starting standardized treatment early can help control disease progression and achieve the goal of maintaining a normal life.