What are the symptoms of ankylosing spondylitis?

Generally, common symptoms of ankylosing spondylitis include lower back pain, morning stiffness, joint swelling and pain, restricted spinal mobility, and nocturnal aching. If any of these symptoms occur, it is advisable to seek timely medical evaluation and treatment at a reputable hospital. A detailed analysis follows:

1. Lower Back Pain

Lower back pain is typically localized to the lumbosacral region and often presents as chronic, dull, or insidious pain. Immune dysregulation triggers inflammation in the sacroiliac joints of the spine; persistent inflammatory infiltration of surrounding soft tissues stimulates local nerve endings, resulting in continuous pain. Discomfort tends to worsen after prolonged sitting or standing.

2. Morning Stiffness

Morning stiffness manifests as tightness and rigidity in the lumbar back and trunk joints upon waking, impairing mobility. During sleep, the body remains immobile for extended periods, allowing inflammatory metabolites to accumulate within joints and cause local tissue adhesions. With gentle movement, blood circulation accelerates, facilitating clearance of these metabolites and gradually relieving stiffness.

3. Joint Swelling and Pain

Joint swelling and pain commonly affect large lower-limb joints—such as the hip, knee, and ankle—and may occur unilaterally or bilaterally. Aberrant immune activation targets periarticular tissues systemically, inducing sterile inflammation that leads to synovial hyperemia and edema, accompanied by mild swelling and pain, thereby compromising normal flexion and extension of affected limbs.

4. Restricted Spinal Mobility

Restricted spinal mobility is evident in diminished range of motion during activities such as forward bending, neck rotation, or chest expansion. Recurrent inflammation damages vertebral bodies and adjacent ligaments, promoting progressive fibrosis and calcification of soft tissues. Consequently, spinal flexibility declines progressively, intervertebral space narrows, and functional limitations intensify as the disease advances.

5. Nocturnal Aching

Nocturnal aching typically occurs during late-night or early-morning hours, disrupting sleep quality. During nighttime, heightened activity of pro-inflammatory cytokines combined with reduced joint perfusion exacerbates inflammatory stasis, provoking aching discomfort. In some individuals, symptoms may ease following positional changes or light physical activity upon awakening.

Additionally, ankylosing spondylitis may present with systemic manifestations such as fatigue and low-grade fever. In daily life, patients should maintain regular, moderate exercise, practice proper posture, undergo periodic specialist evaluations, and initiate early intervention to prevent irreversible damage to spinal and articular structures.