Symptoms of Neurogenic TOS
Neurogenic TOS is the most common form of thoracic outlet syndrome. At the same time, neurogenic TOS is the most challenging form of thoracic outlet syndrome for a physician to diagnose. Symptoms of neurogenic TOS are often non-specific and confusing. A doctor may find a completely normal neurological examination if he doesn’t attempt specific tests for neurogenic TOS. Equally important, patients may not understand the confusing symptoms of neurogenic TOS that might cause them to seek a TOS specialist.
Symptoms of Neurogenic TOS
Compression and damage of the nerves of the brachial plexus cause the symptoms of neurogenic TOS. However, the brachial plexus is quite complex, comprising different nerve fibers, with multiple branches and divisions. Compression of different fibers or branches will cause different symptoms. Additionally, compression may only occur in certain positions of the arms and neck. As a result, patients may fail to understand why they are experiencing pain at certain times, in certain occupations or recreations. Nonetheless, patients suffer considerable pain of different types and causes.
Patients with neurogenic TOS may experience one or more of the following symptoms of the chest, arm, wrist, or hand:
Ill-defined, deep aching pain
Normal stimuli causing pain
Mild pain stimuli causing disproportionate pain
Decreased skin sensation
Cold or warm sensations
Color changes of the skin
Weakness or poor coordination of movement
Atrophy of muscles
Chest pain or tightness
Mechanisms of Pain
In general, doctors divide the mechanisms of pain into two broad categories: nociceptive pain and neuropathic pain.
Firstly, it is helpful to understand the normal pain pathway. Peripheral receptors of various types are located throughout the body. A peripheral receptor might be specialized for pressure, pain, position or temperature. A peripheral nerve typically connects peripheral receptors to the brain. When an appropriate stimulus triggers one of these receptors, the peripheral nerve transmits a signal from the receptor to the spinal cord, where it usually connects to another nerve, and then to the brain.
Second, we can broadly define the two basic mechanisms of pain:
- Nociceptive pain-A normal nerve transmits a pain signal from a normal peripheral receptor to the brain from a site of tissue damage, such as a burn or a cut in the skin.
- Neuropathic pain-A peripheral nerve is damaged somewhere along its course between the peripheral receptor and the brain. The peripheral receptor and overlying tissue are normal. In this case, the brain receives a signal from the abnormal, damaged peripheral nerve, but interprets the signal as coming from the peripheral receptors.
Third, neuropathic pain is a clinical descriptor, but not a specific diagnosis. Bear in mind that pain syndromes are complex. There are pain syndromes that are incompletely understood, and do not fall neatly into these two categories. Complex Regional Pain Syndrome (CRPS) represents one example of such a condition. Neuropathic pain may result from chronic diseases that affect the peripheral nerves, such as diabetes. Additionally, neuropathic pain may be acute or chronic. It can arise from the peripheral nerves, but also from the central nervous system (the brain and spinal cord).
Neurogenic TOS represents one example of neuropathic pain. The peripheral tissues and receptors are normal. However, entrapment and compression of the brachial plexus causes damage to its component nerves. These nerves send abnormal signals to the brain.
All of the different types of peripheral receptors of the arms send peripheral nerve fibers through the brachial plexus. The brachial plexus has a complex branching pattern. Given these facts, one can understand the complexity of symptoms that neurogenic TOS patients experience.
Course of Symptoms
The symptoms of neurogenic TOS may develop suddenly or gradually. Some patients develop the symptoms of neurogenic TOS suddenly following a motor vehicle accident. Others develop symptoms after longer periods spent at repetitive occupations. In particular, computer users carry significant risk for developing neurogenic TOS. Other occupations requiring physical activity may predispose workers to developing neurogenic TOS.
Symptoms of neurogenic TOS may occur in a progressive or intermittent fashion. Some patients may experience symptoms after a long work day, with symptoms resolving at night. If the disease is not diagnosed and treated, these patients may notice symptoms lasting into the evening or overnight. Eventually, symptoms may persist over the weekend. In other patients, the symptoms of neurogenic TOS begin, never resolve, even briefly, and continue to progress.
Additionally, symptoms may depend upon position and posture. Some patients are able to relieve or reduce their symptoms with certain arm or neck positions. Others find relief when laying down or sitting in a certain position. Unfortunately, symptoms often progress to the point where these measures fail to help.
Are these symptoms unique to neurogenic TOS?
Unfortunately, no. Patients with disease of the cervical spine (neck), such as disk herniations, may have similar symptoms. Other upper extremity nerve entrapment syndromes, such as carpal tunnel syndrome, may behave in a similar fashion. Nerve diseases such as complex regional pain syndrome (CRPS), may be confused with neurogenic TOS. An experienced TOS specialist is the best doctor to begin distinguishing these symptoms and their underlying causes. In many cases, advanced imaging provides critical information to confirm the diagnosis.
Diagnosis of Neurogenic TOS
Doctors typically find no focal abnormality on a standard neurologic examination. However, TOS specialists know how to perform a specialized examination for neurogenic TOS. Even so, the examination is often non-specific. Doctors are turning more frequently to modern imaging to confirm their clinical diagnosis of neurogenic TOS. Learn more about the diagnosis of neurogenic TOS here.
Treatment of Neurogenic TOS
Treatment of neurogenic TOS requires less urgency than treatment of venous or arterial TOS. Nonetheless, early diagnosis and treatment improves the chance of a good outcome. Doctors usually make their first treatment decision by selecting conservative or surgical treatment pathways. Learn more about the treatment of neurogenic TOS here.