Lower back pain: Clinical

Back pain can originate from the spinal cord, the nerve roots, the vertebral column, the surrounding muscles and ligaments, or even extra-spinal structures such as abdominal organs.

Most lower back pain is considered non-specific musculoskeletal back pain, and is due to strained muscles and ligaments in the back. But sometimes it’s due to a specific disorder, and these can be categorized into 6 groups: degenerative disorders, mechanical disorders such as disk herniation and lumbar spinal stenosis, infections such as osteomyelitis and spinal epidural abscess, spinal epidural hematoma, inflammatory disorders such as ankylosing spondylitis, and cancers, such as multiple myeloma.

Specific disorders are often identified with a thorough history, and to help remember some common clues there’s the mnemonic: “TUNA FISH”.

“T” is for trauma. “U” is for unexplained weight loss, which may suggest a cancer. “N” is for neurological symptoms, like sensory loss, pain, or weakness in the legs, loss of sensation in the perineal area - which is called saddle anesthesia - as well as bowel, bladder, or sexual dysfunction.

“A” is for age over 50, which increases the risk of cancer.

“F” is for fever, which may indicate an infection.

“I” is for intravenous drug use or an immunocompromised state, both of which also increase the risk of infection.

“S” is for steroid use, which can cause secondary osteoporosis and vertebral fractures.

And finally, “H” is for a history of cancer.

On physical examination there might be some clues that suggest a specific disorder as well.

For example, erythema might be due to an underlying infection or and inflammatory process like psoriatic arthritis.

On palpation, if there’s a midline, point of focal tenderness then that could be due to an infection, cancer, or fracture.

Also, if there’s a problem with the straight leg test then that could be due to a radiculopathy.