Diagnosing lower back pain:
Most cases of low back pain are due to strained muscles and need no further investigations. Your doctor will listen to your complaint and if nothing alerts them to another cause, they will diagnose it as a simple muscle strain. If, however, they suspect another cause to be the problem, they may order a number of investigations including some lab tests and imaging studies. Laboratory tests that may be ordered include:
- A complete blood count: A complete blood count may not reveal the cause, but it helps give a general look at the patient’s condition as in cases of infection in pelvic inflammatory disease or anemia.
- Inflammatory markers: Inflammatory markers are certain substances secreted when the tissues are inflamed. The most commonly measured are the CRP and ESR. They are elevated in cases of arthritis and infection.
- Tumor markers: Tumor markers are chemical substances that a tumor produces by itself or produces when it destroys normal tissue. Not all cancers have tumor markers, but for low back pain, prostatic cancer can be screened by using a tumor marker called prostatic specific antigen or PSA. Elevated PSA is not a sure sign that prostatic cancer is present, and further, more specific investigations would be needed.
Imaging studies are more specific in back pain and can be ordered routinely. They include:
- Plain X-rays: A plain X-ray doesn’t show much, but it can exclude fractures and, sometimes, kidney stones.
- CT scans: CT stands for computerized tomography and is an advanced form of X-rays that produces high-resolution images of bones and organs. They are most useful in kidney stones, fractures, and cancer.
- MRI: MRI stands for Magnetic Resonance Tomography. It is a form of imaging that uses magnets to see body tissue. It doesn’t involve radiation and is safe in most patients. MRI is especially useful to see the spinal cord and any disc bulge or herniation.
- Ultrasonography: Ultrasound imaging is rarely used in back pain except in gynecological conditions like endometriosis or pelvic inflammatory disease. Prostatic cancer can be seen by a special type of ultrasound called endorectal ultrasound, and a sample can be taken.