Understanding Carpal Tunnel Syndrome: symptoms, causes and treatment

What is Carpal Tunnel Syndrome? 

Carpal tunnel syndrome is a set of symptoms (e.g. “pins and needles”, numbness, weakness) that are caused by compression of the median nerve at the wrist. The median nerve supplies sensation to the thumb, index, middle and inner part of the ring finger. Early on, symptoms can often be relieved with simple measures like wearing a wrist splint or avoiding certain activities. If pressure on the median nerve continues, it can lead to nerve damage and worsening symptoms. To prevent permanent damage, surgery to take pressure off the median nerve may be recommended for some patients.

What are the symptoms of Carpal Tunnel Syndrome?

Symptoms usually begin slowly and can occur at any time. They may include:

• Numbness, tingling, burning, and pain—primarily in the thumb and index, middle, and ring fingers
• Tingling is often worse at night or first thing in the morning. It may be provoked by activities that involve gripping an object, for example a mobile telephone or newspaper, especially if the hand is elevated
• Occasional shock-like sensations that radiate to the thumb and index, middle, and ring fingers
• Pain or tingling that may travel up the forearm toward the shoulder
• Weakness and clumsiness in the hand—this may make it difficult to perform fine movements such as buttoning your clothes
• Dropping things—due to weakness, numbness, or a loss of proprioception (awareness of where your hand is in space)

What are the risk factors for Carpal Tunnel Syndrome?

In most cases it is not clear why carpal tunnel syndrome occurs. Most cases of carpal tunnel syndrome are caused by a combination of factors. It is often associated with:

• Older age
• Pregnancy – fluid retention and hormonal changes can cause swelling of the carpal tunnel, which usually disappears after childbirth
• Repetitive hand use-repeating the same hand and wrist motions or activities over a prolonged period may aggravate the tendons in the wrist, causing swelling that puts pressure on the nerve
• Hereditary- the carpal tunnel may be smaller in some people or there may be anatomic differences that change the amount of space for the nerve—and these traits can run in families
• Joint dislocations and fractures of the wrist – they can put pressure on the median nerve
• Bone or arthritic conditions of the wrist, such as rheumatoid arthritis – this can cause a thickening of the ligament that covers the carpal tunnel
• Other health conditions such as obesity, an underactive thyroid, diabetes, alcoholism and the menopause
• Side effects of some medicines – the combined oral contraceptive pill may disrupt the hormonal balance enough to cause carpal tunnel syndrome
• Cysts, growths and swellings coming from the tendons or blood vessels passing through the carpal tunnel – although this is rare

How is Carpal Tunnel Syndrome diagnosed?

Dr Mackenzie will take a detailed history including complete medical history, how the hands have been used, and any prior injuries.

That will be followed by examination of the hand and wrist. An x-ray may be taken to check for arthritis or a fracture.  In some cases, laboratory tests may be done.  Electrodiagnostic studies will be requested to confirm the diagnosis, check for other possible nerve problems and determine how well the median nerve itself is working and how well it controls muscle movement. 

What is the treatment?

Non-surgical treatment

Non-surgical treatments are usually tried first. Treatment begins with:

• Wearing a wrist splintat night- that helps relieve symptoms that may prevent sleep
• Taking nonsteroidal anti-inflammatory drugs, such as ibuprofen, to relieve pain
• Cortisone injections can be given though they provide only temporary relief of symptoms, but may provide evidence of confirmation of the diagnosis
• Changes to the work station can- raising or lowering the chair or the computer keyboard to bring the patient into proper alignment
• Changes in the hand/wrist positions used in jobs and other activities can also be tried, along with activity modification

Surgical treatment

When symptoms are severe or do not improve, surgery may be needed to make more room for the nerve. The goal of surgery is to increase the size of the tunnel to decrease pressure on the nerves and tendons that pass through the tunnel. 

This operation can be performed under local anaesthetic and involves a short incision at the base of the palm to release the ligament causing pressure on the nerve.

What are the risks of surgery?

Complications associated with this surgery are rare, but can include:

• Infection – this can be settled by taking antibiotics
• Swelling-may last for a few months
• Stiffness 4 in 100 patients and can last from weeks to 6 months. Hand physiotherapy may be required
• Painful scar
• Wound healing problems
• Bleeding/haematoma
• Damage to the median nerve or its branches-very rare
• Recurrence-2-3%
• Incomplete resolution of symptoms in severe nerve compression
• CRPS-complex regional pain syndrome-5%
• Exacerbation of finger triggering