Could Your Pain Be Thoracic Outlet Syndrome?

It starts with numbness or tingling in your hand or arm. Your neck, shoulder and arm ache. You reach for a jar on the shelf and realize your grip is weak.

You might have developed a painful condition called thoracic outlet syndrome (TOS).

TOS is a rare disorder that occurs when certain nerves or blood vessels are pinched or compressed in a small area between your collarbone and first rib, called the thoracic outlet. However, that diagnosis might not be the first thing that comes to mind, even for your primary care doctor.

“It’s way underdiagnosed,” says UNC Health vascular surgeon Luigi Pascarella, MD. “But it is very disabling. People can lose their jobs because they cannot perform the tasks they need to.”

If you have shoulder pain and you’re not sure why, it could be helpful to learn about thoracic outlet syndrome. Below, Dr. Pascarella helps answer common questions.

What is thoracic outlet syndrome?

The most common type of TOS is neurogenic, meaning it stems from the nervous system. A network of nerves called the brachial plexus branches off from your spinal cord and controls the muscles and feeling in your hand, arm, neck and shoulder. If the brachial plexus becomes compressed or squeezed, you can feel pain, numbness and weakness. Your shoulder, arm, hand or fingers may swell, and your hands may turn red, purple or dark. Your hands may feel cold.

In other TOS cases, the blood vessels are compressed: Pinched veins can cause blood clots, and pinched arteries can bulge, creating a bubble called an aneurysm.

When a blood vessel is involved, you might feel numbness, tingling, aching and swelling in your arm and fingers, or weakness of your neck or arm. Your hands and fingers may change color and be sensitive to cold.

Who gets thoracic outlet syndrome?

Most people who develop TOS are young. Physical trauma, poor posture, and repetitive arm and shoulder movements are all risk factors.

“We don’t know for certain what causes it,” Dr. Pascarella says. “It could be a physical abnormality, scarring from some trauma, overstretching.”

Some patients he sees are athletes who develop pain or swelling after a particularly intense game or practice.

“Baseball players, tennis players, softball players,” he says. “The athletes I’ve treated have gone back to competitive life without any problems.”

How is thoracic outlet syndrome diagnosed?

Because the condition is rare (an estimated 3 in 100,000 people for cases involving nerves, even less common for blood vessels), other conditions often are considered first.

But when examining a patient with nerve-related TOS symptoms (including pain in the neck, shoulder, arm, chest or collarbone area), a doctor who suspects TOS will have the patient perform certain movements, including holding their arms at particular angles and positions, to see if the patient has limited range of motion.

Additional tests may be done, including electromyography (EMG) and nerve conduction studies, which measure how well certain muscles and nerves respond to electrical signals. A CT scan (computerized tomography), chest X-ray or MRI (magnetic resonance imaging) of nerves in the shoulder may be used.

Similar tests are used if swelling, discoloration and other symptoms of TOS involving blood vessels are involved. These include the physical exam with movements, a chest X-ray and a vascular ultrasound (also called a duplex ultrasound).

How is thoracic outlet syndrome treated?

Treatment usually starts with physical therapy, which is very specific and unlike physical therapy for many other conditions or injuries, Dr. Pascarella says. That is why having a diagnosis is important before physical therapy is started.

If physical therapy alone does not relieve the symptoms, surgery may be necessary to relieve pressure on the nerves. If there are blood clots, surgery can restore circulation in the arms and hands Recovery time is generally between two and 12 weeks.

Dr. Pascarella wants to increase the awareness of TOS with primary care physicians.

“People go first to their primary care physicians with complaints of pain and swelling in their shoulder,” he says. “If they don’t know what is causing it, they won’t know the best treatment. I would say that about 40 percent of patients I see have been prescribed an opioid for chronic pain at some point.”

Pain medicine will not cure TOS, he says, and may become addictive.

“Some people live with that pain for decades,” he says, “especially if it’s caused by compression of the nerves. It can be extremely frightening to be in pain for 10 to 25 years with no clear diagnosis.”

His advice to patients is not to live with pain. Keep looking for a solution.

If you have pain, numbness or swelling in an arm, see your doctor, or find one near you.