Thoracic Outlet Syndrome
Diagnosis
Diagnosing TOS can be difficult. Symptoms vary in type and severity among people with the condition. In addition, some other medical conditions have symptoms similar to those of TOS (for example, rotator cuff injuries, cervical disorders that cause compression of the nerve roots in the neck and complex regional pain syndrome).
[pop-up bubbles: rotator cuff : group of muscles and tendons surrounding the shoulder joint; cervical disc: spongy cushion between the vertebrae; complex regional pain syndrome: a chronic pain disorder, usually arising from injury, in which pain is worse than expected for the injury and continues long after the injury should have healed. ]
There are several tests and procedures that are specific for diagnosing TOS. Your health care provider can begin by gathering important information from talking to you and doing a physical examination. Your health care provider may ask about your general health, medical history, occupation and symptoms. He or she may check your shoulder, arm and hand for outward signs of TOS, such as swelling or color changes, or limited range of motion.
During the physical examination, your health care provider may perform procedures designed to reproduce your symptoms (provocation tests). These tests may help determine the cause of your symptoms and rule out other conditions with similar symptoms. During these tests, your health care provider will check pulse and blood pressure in your affected arm while it is in various positions. If your arm pulse and/or blood pressure are diminished or if you have symptoms during the tests (a positive result), you may have TOS. However, since provocation tests often produce false-positive results, your health care provider may repeat the tests on your unaffected arm.
Health care providers usually recommend imaging studies, nerve conduction studies or electromyography to confirm a diagnosis of TOS and rule out other conditions. Your health care provider may order one or more of the following tests:
[pop-up bubbles: rotator cuff : group of muscles and tendons surrounding the shoulder joint; cervical disc: spongy cushion between the vertebrae; complex regional pain syndrome: a chronic pain disorder, usually arising from injury, in which pain is worse than expected for the injury and continues long after the injury should have healed. ]
Medical History and Physical Exam
There are several tests and procedures that are specific for diagnosing TOS. Your health care provider can begin by gathering important information from talking to you and doing a physical examination. Your health care provider may ask about your general health, medical history, occupation and symptoms. He or she may check your shoulder, arm and hand for outward signs of TOS, such as swelling or color changes, or limited range of motion.
Tests You May Have
During the physical examination, your health care provider may perform procedures designed to reproduce your symptoms (provocation tests). These tests may help determine the cause of your symptoms and rule out other conditions with similar symptoms. During these tests, your health care provider will check pulse and blood pressure in your affected arm while it is in various positions. If your arm pulse and/or blood pressure are diminished or if you have symptoms during the tests (a positive result), you may have TOS. However, since provocation tests often produce false-positive results, your health care provider may repeat the tests on your unaffected arm.
Health care providers usually recommend imaging studies, nerve conduction studies or electromyography to confirm a diagnosis of TOS and rule out other conditions. Your health care provider may order one or more of the following tests:
- Electromyogram (EMG) – An EMG can check how your nerves and muscles are working. Small electrode needles are inserted into the muscle where you are having symptoms. The electrodes measure the electrical response of the muscle to specific nerves or nerve roots. An abnormal muscle response can give your health care provider information about the status of the nerve going to that muscle.
- Nerve conduction velocity (NCV) testing – NVC measures the speed at which impulses travel through a nerve. Tiny amounts of electrical current are sent to your nerve through electrode patches placed on the skin. The test records nerve activity and measures how long it takes the electrical impulses to travel between the electrodes. This helps your health care provider check how well the nerve sends messages to the brain.
- X-ray – X-rays may be used to view bones in and around the thoracic outlet area, and to check for the presence of an extra (cervical) rib.
- General laboratory tests – Tests to measure thyroid function and blood sugar may be helpful in diagnosing TOS.
- Magnetic resonance imaging (MRI) – An MRI scan creates computerized images of the body’s soft tissues. MRI images may help determine the location and cause of nerve or vessel compression in the thoracic outlet area.
- Computerized tomography (CT) – Sometimes also called computerized axial tomography (CAT), CT scans are sensitive to the hardness of body tissues and can be used to find bone problems.
- Ultrasound – Ultrasound uses sound waves to make images of body tissues. It may be used to check for problems such as blood clots, vessel narrowing or blockage, and nerve compression.
- Angiography – Angiography is an X-ray of the arteries and veins used to diagnose blockages and other blood vessel problems.
- Arteriography; venography – For these tests, a special dye is injected into the bloodstream to make the arteries and veins visible. Then, X-rays are taken to look for blood vessel damage.