Thoracic outlet syndrome: symptoms, causes, treatment and outlook

The NHS says thoracic outlet syndrome usually affects 1 arm and hand. Patient.info explains that the symptoms depend on what is being squashed in the thoracic outlet, and that in most cases it is the nerves of the brachial plexus rather than blood vessels, so symptoms are more likely to be nerve-related.

• Pins and needles, which can be worse at night and wake you up. Patient.info says these are often felt along the inside of the arm into the ring and little finger.

• An affected arm that gets tired easily or feels weak.

• Pain and swelling in the affected arm.

• A hand and arm that feel cold, especially in cold weather.

• Skin on the hand that turns blue, grey or pale. This can be harder to see on brown or black skin.

• Pain in the neck, ear, upper back, upper chest or outer arm, and sometimes headaches, if different nerves are involved (Patient.info).

The thoracic outlet is a space, or passageway, just above your first rib and behind your collarbone, running from the base of your neck to your armpit. Patient.info explains that several important structures pass through it, including the brachial plexus (a group of nerves running from the neck to the arm), and the subclavian artery and vein.

In thoracic outlet syndrome these nerves and blood vessels become squashed for some reason. The NHS describes it as nerves or blood vessels near the top of the ribs getting squashed. It usually affects one side of the body, although rarely both sides are affected.

The NHS says it can happen if the nerves or blood vessels running along the top of the rib cage become squashed, and lists several things that can lead to it. Patient.info adds that it is quite common for people to have a history of some kind of recent neck trauma such as whiplash, and that the cervical rib is a recognised cause: about 1 in 200 people are born with one, but only about 1 in 10 of them develop thoracic outlet syndrome.

• Being born with an extra rib (a cervical rib).

• Poor posture, including long hours at a computer with an incorrect desk position or chair (Patient.info).

• Having large breasts.

• An injury to the chest, neck or ribs, such as in a car accident.

• Jobs or activities with lots of repetitive arm movements, for example building or swimming.

• Gaining a lot of muscle, for example in body building.

• Other congenital features such as a fibrous band or extra muscles around the thoracic outlet (Patient.info).

The NHS says it is usually treated with physiotherapy and medicines. A physiotherapist can teach you stretching and strengthening exercises that reduce pressure on nerves and blood vessels. Medicines may be used to treat pain, relax muscles, improve circulation and reduce the risk of blood clots.

Patient.info says that for nerve compression there is not currently general agreement on the best treatment and that more trials are needed, so treatment is generally aimed at relieving symptoms. It lists physiotherapy (stretching, posture and strengthening exercises), occupational therapy to change work or sport activities and desk set-up, and anti-inflammatory painkillers such as ibuprofen, with other medicines tried occasionally. If a blood clot blocks a vessel, treatment with medicine is needed urgently to break down the clot, which may be followed by anticoagulants.

Surgery may sometimes be recommended if you are having serious problems, such as blood clots, and other treatments have not worked. The NHS gives the example of removing a cervical rib. Patient.info says surgery is best done only when there is really good evidence that the cervical rib or other structure is causing significant problems.

Neither the NHS nor Patient.info gives a fixed recovery time, because it depends on what is compressed and why. Patient.info says that in most people the outlook is generally good and symptoms often improve over time. If compression or blockage of the subclavian artery or vein is diagnosed quickly and treated, a good recovery is possible.

However, nerve compression symptoms can be difficult to treat in a few people. Persistent pain and weakness, with some loss of ability to use the affected arm, can sometimes be severe enough to affect quality of life. If symptoms are not improving, a GP can refer you to a specialist.

The NHS says a GP will usually check your arms, chest and neck for possible causes of your symptoms, and may refer you for an X-ray or other tests such as a CT or MRI scan.

Patient.info says the doctor may ask you to move your arms and shoulders into certain positions to try to bring on symptoms, and that the diagnosis is usually made after other conditions that cause arm pain or pins and needles have been excluded. A chest or neck X-ray can show a cervical rib, nerve conduction studies may be suggested, and if a blood vessel is suspected, tests such as angiography, venography or Doppler studies can look at blood flow.

Most cases are not an emergency, but the NHS lists two situations that are. The first suggests a blood clot caused by thoracic outlet syndrome, which can be life threatening if not treated quickly.

• Ask for an urgent GP appointment or call NHS 111 if you have throbbing or cramping pain, swelling, redness and warmth in 1 arm.

• Call 999 if you have sudden breathlessness, sharp chest pain (this may be worse when you breathe in) and a cough or coughing up blood.

• See a GP if you think you have thoracic outlet syndrome.

Arm pain and pins and needles have many causes, and thoracic outlet syndrome is usually diagnosed after others have been considered. Patient.info gives the example of arthritis in the neck compressing nerves in the neck. Related conditions on this site, such as carpal tunnel syndrome, cubital tunnel syndrome and cervical radiculopathy, can produce similar symptoms in the hand or arm and are worth discussing with a GP if your symptoms do not fit the pattern above.

On the NHS, thoracic outlet syndrome is usually assessed by a GP, with referral for physiotherapy, imaging or a specialist (for example vascular or neurological) if needed. In many areas you can refer yourself to NHS community MSK physiotherapy. Some people choose private physiotherapy or a private specialist opinion to be seen sooner. Whichever route, a clear diagnosis of which structure is compressed matters, because treatment differs between nerve and blood vessel compression.