Distal Mononeuropathies

When it comes to identifying types of pain, there are two types: acute and chronic. Acute pain comes on quickly, can be severe but only lasts a relatively short time. It is typically experienced after an injury or trauma, and self-resolves.

Unlike acute pain, chronic pain is pain that lasts for a long time, and doesn't seem to get better or go away. This time period can vary but is typically defined as a three- to six-month period after symptoms begin. Chronic pain is often a debilitating symptom of many diseases and is considered a disease itself when it persists beyond recovery from an injury or illness. Chronic pain is a frequent component of many neurological disorders.

Pain warns you that something is not quite right in your body and can cause you to take certain actions and avoid others. Pain can significantly impact your quality of life—by adversely affecting your physical and emotional well-being; upsetting relationships with family, coworkers and friends; and limiting your mobility and participation in daily activities.

Hundreds of pain syndromes or disorders make up the spectrum of pain. One cause of pain are distal mononeuropathies. Distal mononeuropathies are progressive disorders that affect one nerve or one nerve group at a time, often the result of injury, trauma and inflammation. Two common distal mononeuropathies are carpal tunnel syndrome and ulnar neuropathy.

Two common distal mononeuropathies are carpal tunnel syndrome and ulnar neuropathy.

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, 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.

Damage to the ulnar nerve causes ulnar neuropathy. There are several possible compression sites along the length of the nerve—the wrist, fingers, forearm, upper arm and, most commonly, the elbow.

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

Damage to the ulnar nerve from long-term pressure on the elbow or base of the palm, or an injury such as a fracture or dislocation can cause ulnar neuropathy.

The risk of developing carpal tunnel syndrome (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 having worked at these types of jobs.

Injury and accidents are primary risk factors for ulnar neuropathy. However, causes like arthritis, bone spurs, complications following surgeries, diabetes, and tumors or cysts are conditions to monitor as they increase risk to damage or compression of the ulnar nerve.

By adjusting daily habits and reducing stress to hands and wrists, carpal tunnel syndrome can be avoided. Reduce repetitive hand movements and keep wrists in a neutral position to relieve pressure on the nerves. Take breaks between activities that have heavy hand and wrist use, stretch often and use equipment that relieves pressure, such as ergonomic, gel-filled wrist pads and rests.

Early detection is the most effective way to avoid the long-term symptoms and effects of ulnar neuropathy. Avoiding injury and accidents is a primary preventative measure, but causes like arthritis, bone spurs, complications following surgeries, diabetes, and tumors or cysts are conditions to monitor as they may result in damage or compression of the ulnar nerve.

Symptoms for carpal tunnel syndrome 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.

Damage or compression of the ulnar nerve can cause pain, numbness or tingling in the arm and fingers. Symptoms typically start slow as a result of overuse, unless there is an injury or trauma to the nerve. Other symptoms include:

• Tenderness in the elbow joint and/or hand
• Tingling in the palm and/or fingers
• Sensitivity to cold

Early diagnosis and treatment of carpal tunnel syndrome are important to avoid permanent damage to the median nerve. Talk to a medical professional, and request the following tests:

• 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 one 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.

Diagnosis traditionally relies on clinical history, physical examination and electrodiagnostic studies. A combination of electromyography (EMG) and nerve conduction velocity (NCV) tests can improve accuracy by mapping out the location of compression of the ulnar nerve, which would provide a relatively early diagnosis in patients who have symptoms suggestive of ulnar nerve lesions. Additionally, an ultrasound can detect the morphologic changes and the extent of the ulnar nerve lesion at the elbow.

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:

• Carpal tunnel release is one of the most common surgical procedures in the United States. 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 two 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 post-operative 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 a half-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.

The main treatment for ulnar neuropathy is reducing the frequency of external compression on the nerve and flexing of the elbow joint, thereby decreasing the stress placed on the ulnar nerve. The use of elbow splints, elbow pads or sleeves, and physical therapy can also reduce pain.

Injection procedures have also been proposed for the treatment of ulnar neuropathy at the elbow. Surgical treatment becomes a consideration for patients with persistent symptoms, with accompanying sensory changes and muscle atrophy. Several surgical methods include decompression, anterior transposition techniques and medial epicondylectomy.

There are a range of self-care and lifestyle changes that support recovery from the symptoms 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.

Relieving pressure on the ulnar nerve can reduce pain, as can avoiding activities that increase compression—such as putting pressure on your elbow, bending the elbow and wrist frequently (smoking, and sports like tennis).