What is Carpal Tunnel Syndrome? Causes, symptoms and treatment of this neurological disorder

By Cristiano Antonino On Jun 2, 2023

Carpal tunnel syndrome (CTS) is a common neurological disorder that occurs when the median nerve, which runs from your forearm into the palm of the hand, becomes pressed or squeezed at the wrist

You may feel numbness, weakness, pain in your hand and wrist, and your fingers may become swollen and useless. You might wake up and feel you need to “shake out” your hand or wrist.

The median nerve and the tendons that bend the fingers pass through the carpal tunnel—a narrow, rigid passageway of ligament and bones at the base of the hand.

The median nerve provides feeling to the thumb, index, and middle finger, and part of the ring finger (but not the little finger).

It also controls some small muscles at the base of the thumb.

Sometimes, thickening from the lining of irritated tendons or other swelling narrows the tunnel and compresses the median nerve.

CTS is the most common and widely known of the entrapment neuropathies, in which one of the body’s peripheral nerves is pressed on or squeezed.

You can sometimes treat carpal tunnel syndrome at home, but it may take months to heal. Your doctor can recommend treatments.

CTS rarely recurs following treatment and home care.

Symptoms of Carpal tunnel syndrome

Symptoms usually start gradually, with frequent numbness or tingling in the fingers, especially the thumb and the index and middle fingers.

Symptoms often first appear in one or both hands during the night.

The dominant hand is usually affected first and procures the most severe symptoms.

Early symptoms include:

Numbness, particularly at night
A feeling the fingers are useless or swollen
A tingling sensation or pain in the fingers.

As symptoms worsen, people might feel:

Tingling during the day, especially with certain activities such as talking on the phone, reading a book or newspaper, or driving
Mild to severe pain, sometimes worse at night
Some loss of movement in the hand
Hand weakness may make it difficult to grasp small objects or perform other manual tasks.

In chronic and/or untreated cases, the muscles at the base of the thumb may shrink and waste away.

Some people with very severe CTS cannot determine between hot and cold by touch and may burn their fingertips without knowing it.

Who is more likely to get carpal tunnel syndrome?

Carpal tunnel syndrome is often the result of a combination of factors that increase pressure on the median nerve and tendons in the carpal tunnel, rather than a problem with the nerve itself.

Sometimes no single cause can be identified.

Contributing factors may include:

Trauma or injury to the wrist that cause swelling, such as sprain or fracture
Imbalance of either the pituitary gland or the thyroid gland
Rheumatoid arthritis or other arthritic diseases
Mechanical problems in the wrist joint
Repeated use of vibrating hand tools
Fluid retention during pregnancy or menopause
Development of a cyst or tumor in the canal
Sex—women are three times more likely than men to develop CTS
Having diabetes or other metabolic disorders that directly affect the body’s nerves and make them more susceptible to compression
Repeated sleeping on a bent wrist
Increasing age—CTS usually occurs only in adults.

The risk of developing CTS is not confined to people in a single industry or job but may be more reported in those performing assembly line work—such as manufacturing, sewing, finishing, cleaning, and meatpacking—than it is among data-entry personnel.

Many people who have CTS report never have working at these types of jobs.

How is carpal tunnel syndrome diagnosed and treated?

Diagnosing CTS (Carpal tunnel syndrome)

Early diagnosis and treatment are important to avoid permanent damage to the median nerve.

Physical exam. Your doctor will examine your hands, arms, shoulders, and neck to determine if your complaints are related to daily activities or to an underlying disorder and to rule out other conditions that mimic carpal tunnel syndrome. Your wrist will be checked for tenderness, swelling, warmth, and discoloration. Your fingers will be tested for sensation, along with muscles at the base of the hand for strength and signs of atrophy.
Routine laboratory tests and X-rays can reveal fractures, arthritis, and nerve-damaging diseases such as diabetes.
Specific wrist tests may produce the symptoms of CTS.
In the Tinel test, the doctor taps on or presses on the median nerve in your wrist. The test is positive when tingling in the fingers or a resultant shock-like sensation occurs.
The Phalen, or wrist-flexion, test involves having you hold your forearms upright by pointing the fingers down and pressing the backs of the hands together. If you have CTS, you should feel tingling or increasing numbness in your fingers within 1 minute. Your doctor may also ask you to try to make a movement that brings on symptoms.

Electrodiagnostic tests may help confirm the diagnosis of CTSs.

A nerve conduction study measures how quickly impulses are transmitted along a nerve.

Electrodes are placed on your hand and wrist and a small electric shock is applied and the speed with which nerves transmit impulses is measured

In electromyography, a fine needle is inserted into a muscle and electrical activity is viewed on a screen to determine the severity of damage to the median nerve.

Diagnostic imaging also can help diagnose CTS or show problems.

Ultrasound imaging can show an abnormal size of the median nerve.

Magnetic resonance imaging (MRI) can show the anatomy of the wrist but to date has not been especially useful in diagnosing carpal tunnel syndrome.

Treating CTS

Treatments for carpal tunnel syndrome should begin as early as possible, under a doctor’s direction.

Underlying causes such as diabetes or arthritis should be treated first.

Non-surgical treatments

Splinting. Initial treatment is usually a splint worn at night.
Avoiding daytime activities that may provoke symptoms. If you have slight discomfort you may wish to take frequent breaks from tasks, to rest the hand. If the wrist is red, warm and swollen, applying cool packs can help.
Over-the-counter drugs. In special circumstances, various medications can ease the pain and swelling associated with carpal tunnel syndrome. Nonsteroidal anti-inflammatory drugs (NSAIDs), such as aspirin, ibuprofen, and other nonprescription pain relievers, may provide some short-term relief from discomfort but haven’t been shown to treat CTS.
Prescription medicines. Corticosteroids (such as prednisone) or the drug lidocaine can be injected directly into your wrist or taken by mouth (in the case of prednisone) to relieve pressure on the median nerve if you have mild or intermittent symptoms. (Check first with your doctor if you have diabetes or may be predisposed to it, as prolonged use of corticosteroids can make it difficult to regulate insulin levels.)
Exercise. Ask your doctor about hand exercises that might help with pain.
Alternative therapies. Yoga has been shown to reduce pain and improve grip strength among those with CTS. Other alternative therapies, such as acupuncture and chiropractic care, have benefited some people with CTS but their effectiveness remains unproved.
Vocational or occupational therapy. You may need to learn new ways to perform certain tasks or job skills that will not complicate or worsen your CTS.

Surgery with Carpal Tunnel Syndrome

Carpal tunnel release is one of the most common surgical procedures.

It may be recommended when non-surgical treatments are ineffective or if the disorder has become severe.

Carpal tunnel surgery involves cutting a ligament to relieve the pressure on the nerve.

Surgery is usually done under local or regional anesthesia (involving some sedation) and does not require an overnight hospital stay.

Many people require surgery on both hands.

Open release surgery is the traditional procedure used to correct carpal tunnel syndrome.

It consists of making an incision up to 2 inches in your wrist and then cutting the carpal ligament to enlarge the carpal tunnel.

The procedure is generally done under local anesthesia on an outpatient basis, unless there are unusual medical conditions.

Endoscopic surgery may allow somewhat faster functional recovery and less postoperative discomfort than traditional open release surgery but it may also have a higher risk of complications and the need for additional surgery.

The surgeon makes one or two incisions (about ½ inch each) in your wrist and palm, inserts a camera attached to a tube, observes the nerve, ligament, and tendons on a monitor, and cuts the carpal ligament (the tissue that holds joints together) with a small knife that is inserted through the tube.

Following the surgery, the ligaments usually grow back together and allow more space than before.

Your symptoms may be relieved immediately after surgery, but full recovery can take months.

You may have infections, nerve damage, stiffness, and pain at the scar.

Almost always there is a decrease in grip strength, which improves over time.

You may need to modify work activity for several weeks following surgery or need to adjust job duties or even change jobs after recovery from surgery.

Recurrence of carpal tunnel syndrome following treatment is rare.

Less than half of individuals report their hand(s) feeling completely normal following surgery. Some residual numbness or weakness is common.

How can self-care or lifestyle changes support a treatment plan for carpal tunnel syndrome?

At night, keep your wrist straight while resting or asleep to prevent pressing on the nerve and carpal tunnel.

Tasks at home or work, along with workstations, tools, and tool handles, can be redesigned to help your wrist maintain a natural position during work.

Wearing fingerless gloves can help keep hands warm and flexible.

At the workplace, workers can do on-the-job conditioning, perform stretching exercises, take frequent rest breaks, and use correct posture and wrist position.

Jobs can be rotated among workers.

Employers can develop ergonomic programs to adapt workplace conditions and job demands to the capabilities of workers.

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