Lumbar Strain (“Mechanical” Low Back Pain, Sacroiliac Dysfunction), Acute

Presentation

Suddenly or gradually, after lifting, sneezing, bending, or other movement, the patient develops a steady pain in one or both sides of the lower back. At times, this pain can be severe and incapacitating. It is usually better when lying down, worse with movement, and will perhaps radiate around the abdomen or down the thigh but no farther. There is insufficient trauma to suspect bony injury (e.g., a fall or direct blow) and no evidence of systemic disease that would make bony disease likely (e.g., osteoporosis, metastatic carcinoma, multiple myeloma). On physical examination, there may be spasm in the paraspinous muscles (i.e., contraction that does not relax, even when the patient is supine or when the opposing muscle groups contract, as with walking in place), but there is no point tenderness over the spinous processes of lumbar vertebrae and no nerve root signs, such as pain or paresthesia in dermatomes below the knee (especially with straight-leg raising), no foot weakness, and no loss of the ankle jerk. There may be point tenderness to firm palpation or percussion over the sacroiliac joint (SIJ), especially if the patient complains of pain toward that side of the lower back.