Diagnosing the cause of back pain requires a medical history and a physical exam. If necessary, your doctor may also order medical tests, which may include x-rays.
During the medical history, your doctor will ask questions about the nature of your pain and about any health problems you and close family members have or have had. Questions might include the following:
- Have you fallen or injured your back recently?
- Does your back feel better – or hurt worse – when you lie down?
- Are there any activities or positions that ease or aggravate pain?
- Is your pain worse or better at a certain time of day?
- Do you or any family members have arthritis or other diseases that might affect the spine?
- Have you had back surgery or back pain before?
- Do you have pain, numbness or tingling down one or both legs?
During the physical exam, your doctor may:
- Watch you stand and walk.
- Check your reflexes to look for slowed or heightened reflexes.
- Examine your back for tender points, which are points on the body that are painful when pressure is applied to them.
- Check for muscle strength and sensation.
- Check for signs of nerve root irritation.
Often a doctor can find the cause of your pain with a physical and medical history alone. However, depending on what the history and exam show, your doctor may order medical tests to help find the cause.
Following are some tests your doctor may order:
X-rays: Traditional x-rays use low levels of radiation to project a picture onto a piece of film (some newer x-rays use electronic imaging techniques). They are often used to view the bones and bony structures in the body. Your doctor may order an x-ray if he or she suspects that you have a fracture or osteoarthritis or that your spine is not aligned properly.
Magnetic resonance imaging (MRI): MRI uses a strong magnetic force instead of radiation to create an image. Unlike an x-ray, which shows only bony structures, an MRI scan produces clear pictures of soft tissues, too, such as ligaments, tendons, and blood vessels. Your doctor may order an MRI scan if he or she suspects a problem such as an infection, tumor, inflammation, or pressure on a nerve. An MRI scan, in most instances, is not necessary during the early phases of low back pain unless your doctor identifies certain "red flags" in your history and physical exam. An MRI scan is needed if the pain persists for longer than 3 to 6 weeks or if your doctor feels there may be a need for surgical consultation. Because most low back pain goes away on its own, getting an MRI scan too early may sometimes create confusion for the patient and the doctor.
Computed tomography (CT) scan: A CT scan allows your doctor to see spinal structures that cannot be seen on traditional x-rays. A computer creates a three-dimensional image from a series of two-dimensional pictures that it takes of your back. Your doctor may order a CT scan to look for problems including herniated disks, tumors or spinal stenosis.
Blood tests: Although blood tests are not used generally in diagnosing the cause of back pain, your doctor may order them in some cases to check if there is an infection.
It is important to understand that medical tests alone may not diagnose the cause of back pain. Often, MRI scans of the spine show some type of abnormality, even in people without symptoms. Only with a medical history and exam – and sometimes medical tests – can a doctor diagnose the cause of back pain. Many times, the precise cause of back pain is never known. In these cases, it may be comforting to know that most back pain gets better whether or not you find out what is causing it.