When Morning Back Stiffness Signals More Than Muscle Pain: Understanding Ankylosing Spondylitis

[medi K / HEALTH IN NEWS] A stiff lower back that makes rising from bed a chore is easy to dismiss as simple muscle soreness. But if the pain persists for more than 30 minutes and eases with movement, the explanation may lie elsewhere: ankylosing spondylitis, a progressive inflammatory disease that gradually fuses the spine.

The condition begins with chronic inflammation at the junctions between the spine and the sacroiliac joints, the paired structures that connect the spine to the pelvis. Over time, the inflammation prompts new bone formation, stiffening the vertebral column. It affects men somewhat more often than women and frequently emerges between ages 20 and 40. A hallmark feature—pain that improves with activity and worsens at rest—often leads to misdiagnosis as lumbar disk disease or muscular strain, delaying effective intervention.

“Recurring lower-back or pelvic pain during the night or early morning should raise suspicion of inflammatory back pain,” said Dr. Jae-min Kim, a rehabilitation medicine specialist at Incheon St. Mary’s Hospital of the Catholic University of Korea. “The longer the delay in diagnosis, the more rapidly spinal flexibility is lost.”

The Spark Within the Genes
Ankylosing spondylitis is not merely a disorder of bone or joint; it stems from immune-system misfiring. In affected individuals, the body’s defenses mistakenly target its own tissues, igniting inflammation that eventually spreads into bone and stiffens the spine.

The best-known risk factor is the HLA-B27 gene. A positive test increases disease likelihood 10- to 30-fold compared with the general population. Yet genetics alone do not trigger the illness; environmental cues, infections, or stress can ignite the aberrant immune response.

Early symptoms typically involve intermittent pain in the lower back or buttocks, often intensifying at night and disrupting sleep. As the disease advances, vertebral motion diminishes; severe cases reveal a “bamboo spine” on X-ray, in which the spine appears as a single, rigid column of fused bone.

“The inflammation can extend beyond the spine to the shoulders, knees, or costovertebral joints,” Dr. Kim said. “Systemic manifestations such as uveitis, inflammatory bowel disease, or psoriasis may accompany the spinal involvement.”

Movement as Medicine

Treatment combines anti-inflammatory medications with consistent physical activity to preserve joint range.

Nonsteroidal anti-inflammatory drugs are first-line therapy; when response is inadequate, biologic agents—TNF-α inhibitors or IL-17 inhibitors—are introduced. These targeted therapies block specific inflammatory pathways, alleviating pain and slowing structural damage.

Medication, however, is only part of the regimen. “Exercise is not an adjunct; it is essential,” Dr. Kim emphasized. “Stretching, swimming, and cycling help delay spinal stiffening.”

Gentle lumbar stretches and deep-breathing exercises performed immediately upon waking are particularly beneficial. Prolonged sitting exacerbates symptoms, so frequent posture changes during desk work are advisable.

Early Detection Preserves Mobility

Ankylosing spondylitis is managed rather than cured. Untreated, rigidity ascends the spine, eventually limiting the neck and chest. Timely diagnosis and sustained treatment, however, allow most patients to maintain normal daily function.

“This disease diminishes movement before it intensifies pain,” Dr. Kim noted. “Any subtle change warrants prompt specialist evaluation— the first step toward preserving a supple spine.”

Lim Hye Jung / press@themedik.kr

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