Differential diagnostic aspects of lower back pain

1. Big picture

Lower back pain is one of the most common neurological and general medical complaints. Most cases are benign mechanical pain, but the exam danger is missing the small group of patients with radiculopathy, spinal cord/cauda compression, infection, tumor, fracture, vascular catastrophe, or visceral referred pain.

For the state exam, the question is not simply “does the patient have back pain?” The correct approach is:

1. Is it local mechanical lumbar pain?
2. Is it radicular pain from a nerve root?
3. Is there cauda equina or conus syndrome?
4. Is there spinal canal stenosis?
5. Is it actually non-spinal referred pain from aorta, kidney, pelvis, hip, prostate, or retroperitoneum?
6. Are there red flags suggesting infection, malignancy, fracture, or inflammatory disease?

The key clinical principle:

Lower back pain must be separated into benign local pain, radicular pain, emergency neurological compression, and non-neurological referred pain.

---