Low back stiffness

Low back stiffness is a sensation of tightness and reduced movement in the lumbar spine, often felt most on waking or after sitting still. Most low back stiffness is mechanical — from muscle strain, poor posture, degenerative changes of the discs and joints (spondylosis), or osteoarthritis — and this kind typically worsens with activity and heavy use and eases with rest, may follow an obvious strain, and improves over days. A different and important pattern is inflammatory back stiffness, the hallmark of axial spondyloarthritis such as ankylosing spondylitis. Inflammatory stiffness has a recognisable profile: it usually begins gradually before the age of 45, is worst in the early morning and after periods of rest with prolonged morning stiffness, wakes the person in the second half of the night, and characteristically improves with exercise and movement rather than rest. It is often felt in the buttocks as well as the lower back, sometimes alternating sides, and responds well to anti-inflammatory medication. This distinction is clinically valuable because inflammatory back disease is treatable and benefits from early diagnosis, yet is often mistaken for ordinary back pain for years. Accompanying clues — heel or tendon pain, a painful red eye, psoriasis, or inflammatory bowel disease — strengthen the suspicion of a spondyloarthritis.

• Mechanical strain and poor posture — worse with activity, better with rest; the commonest cause.
• Degenerative spine changes and osteoarthritis — stiffness with age, brief in the morning.
• Ankylosing spondylitis (axial spondyloarthritis) — inflammatory stiffness: gradual onset before 45, worse with rest, better with movement, night waking.
• Psoriatic arthritis — inflammatory back stiffness, often with psoriasis or nail changes.
• Prolonged inactivity or sitting — transient, non-inflammatory stiffness.

The pattern of stiffness guides testing. Mechanical low back stiffness usually needs no blood tests. When the picture is inflammatory — gradual onset in a younger adult, prolonged morning stiffness, night pain, and improvement with movement — inflammatory markers ESR and CRP are checked, though they are often normal and a normal result does not rule out spondyloarthritis. Imaging (MRI or X-ray of the sacroiliac joints) is central to the diagnosis, and the genetic marker HLA-B27 supports it, so blood tests are only one part of the assessment. Mediora.AI surfaces raised inflammatory markers that fit an inflammatory cause from your results, but because they are frequently normal in spondyloarthritis, the diagnosis rests on the symptom pattern and imaging, assessed by your doctor.