Diagnosing Back Pain
A primary doctor can evaluate and treat most cases of back pain. Health history, a physical exam and possibly diagnostic tests will be used to make a proper diagnosis.
Health History and Physical Exam
The doctor will collect information about your health history and symptoms and perform a physical exam. The answers to the questions below will help the diagnosis process:
When did the pain first begin?
What were you doing at the time?
Where is the pain?
What makes it better or worse?
How does it feel when you lie on your back with your knees bent?
What treatments, including over-the counter drugs and nutritional supplements, have you used?
Do you have any other health problems?
During the physical exam, the doctor will check your posture and look for problems such as curvature of the spine. He may ask you to stand and walk to determine if back pain is affecting your gait (the manner in which you walk) or if an awkward gait (perhaps due to leg-length discrepancy or arthritis in the knee or hip) may be contributing to your back pain. She may ask you to move, bend and change position to see if a particular activity or position makes your pain worse. Your doctor may also press on different parts of your body – even parts where you may not be aware of pain – to check for tender points (tender painful areas that are characteristic of fibromyalgia) and trigger points (areas of the body that, when pressed, cause pain elsewhere) to locate the source of your pain.
If the doctor needs more information, you may undergo one or more of the tests listed below. However, these tests are rarely needed for most routine cases of back pain.
For people with arthritis of the spine, a finding of a specific genetic marker called HLA-B27 in the blood can help the doctor identify a possible diagnosis of a spondylarthropathy, such as ankylosing spondylitis or reactive arthritis. Although the genetic marker is more common in people with these diseases, perfectly healthy people can have it. For that reason, a positive HLA-B27 test does not mean you have one of these diseases.
Tests of fluid drawn from the joint with a needle may reveal crystals of uric acid, confirming a diagnosis of gout, or a bacterium, suggesting that joint inflammation is caused by an infection.
Lower Body Nerve Evaluation
The doctor runs a device called a pinwheel along the skin, from hips to feet, to check for any areas that are either abnormally sensitive or insensitive to stimulus, which would suggest possible nerve involvement in the lower spine.
The doctor checks the strength of the different muscle groups in the lower body to detect possible nerve problems. Because different nerves supply different muscle groups, a weakened muscle group may suggest damage to the nerve that supplies that group of muscles.
Sciatic Nerve Stretch Test
The doctor determines whether stretching the sciatic nerve causes pain, suggesting possible nerve-root involvement.
For most cases of back pain of short duration, X-rays are not necessary. They are most helpful if your doctor suspects that your back pain is caused by arthritis, infection, inflammation or a tumor, or if symptoms are severe.
CT, MRI and Bone Scans
Computerized tomography (CT), magnetic resonance imaging (MRI) and bone scans are usually not necessary to diagnose acute low back pain, but are often very helpful in determining the cause of chronic back pain. The CT scan helps the doctor see if there is a ruptured or degenerated disc, spinal stenosis, tumors or infections of the spine. MRI can provide clear pictures of bone structures and soft tissues such as muscles, cartilage, ligaments, tendons and blood vessels. It is the best test for detecting whether there is pressure on a nerve or on the spinal cord. A bone scan is often used to detect infections or bone inflammation.
In a myelogram, a special dye is injected into the spinal canal and X-rays are then taken of the area. This test may give much more information about the cause of the back pain than a CT scan or MRI.
This is a nerve test used to determine whether the electrical activity of the nerves has been disrupted as a result of problems in the back.