Definition

A dull, insidious ache localized deep in the lower back and gluteal region.

Clinical Details

The autoimmune attack severely inflames the sacroiliac joints connecting the base of the spine to the pelvis. Unlike mechanical back injuries, this unique pain significantly worsens with rest and is most excruciating during the second half of the night. It forces the patient to wake up and physically move around to briefly alleviate the deep, aching stiffness.