Diagnosis of Thoracic Outlet Syndrome
Each form of TOS presents in a different fashion. Thus, doctors need to be familiar with each type. Specifically, doctors need to diagnose venous TOS and arterial TOS promptly, as they require urgent initial treatment. Although neurogenic TOS does not require urgent surgical attention, prompt diagnosis improves treatment outcomes. The diagnosis of TOS is based on symptoms, clinical examination, laboratory tests, and imaging tests.
Symptoms of Thoracic Outlet Syndrome
It is important to remember that each type of TOS is caused by compression of a different structure. Thus, compression of the subclavian vein, subclavian artery, or brachial plexus causes different symptoms. In particular, patients suffer from abrupt blood flow changes when venous TOS or arterial TOS occurs. In contrast, neurogenic TOS often presents more slowly, with progressive or intermittent pain and numbness.
Clinical Diagnosis of Thoracic Outlet Syndrome
Each doctor needs to know the specialized examination for each type of TOS. In general, patients with abnormal blood flow present in a dramatic fashion. Thus, the examining doctor should evaluate for direct and indirect signs of arterial blockage or venous blood clot. On the other hand, standard neurological examination often appears normal in patients with neurogenic TOS. For this reason, doctors must know the specialized physical examination required in these patients.
Laboratory Diagnosis of Thoracic Outlet Syndrome
Unfortunately, laboratory tests are limited in the diagnosis of TOS. Specifically, there are no laboratory tests of value in the diagnosis of arterial TOS. There is one test of limited value in the diagnosis of venous TOS. In contrast, doctors frequently order one laboratory test for patients with neurogenic TOS. And this one test creates more confusion and controversy than any other diagnostic test used in the diagnosis of TOS.
Imaging Diagnosis of Thoracic Outlet Syndrome
Fortunately, imaging tests provide considerable value in the diagnosis of TOS. MRI and CT can create venograms or arteriograms, while MRI produces excellent images of soft tissues in patients with neurogenic TOS.