Bilateral ulnar neuropathy is a condition characterized by damage to the ulnar nerve in both arms. The ulnar nerve runs from the neck to the hand, providing sensation to the little finger and the adjacent half of the ring finger. It also controls many small muscles in the hand responsible for fine movements and grip strength. Because the issue is present on both sides of the body, it points toward a symmetrical cause or a body-wide condition.
Symptoms of Bilateral Ulnar Neuropathy
Initial signs involve sensory changes in both hands, such as numbness, tingling, or a “pins and needles” sensation in the little and ring fingers. These sensations can be intermittent at first but may become constant as the condition progresses.
As the neuropathy advances, motor symptoms appear. A person might notice a progressive weakness in their grip, making it difficult to open jars or hold objects securely. Fine motor tasks that require dexterity, such as buttoning a shirt or writing, can become increasingly challenging as a result of diminished nerve signaling.
In severe cases, visible changes to the hand’s structure can occur. Muscle wasting, or atrophy, may become apparent in the hand, particularly in the fleshy area at the base of the thumb. A characteristic sign of advanced damage is the “ulnar claw,” where the fourth and fifth fingers involuntarily curl. This deformity happens because the muscles controlled by the ulnar nerve are too weak to straighten the fingers.
Underlying Causes
The causes of bilateral ulnar neuropathy fall into two groups: symmetrical external pressure and systemic medical conditions. Nerve damage can stem from prolonged compression of the ulnar nerve at the same point on both arms. The most common site for this is the cubital tunnel, a narrow passageway on the inner side of the elbow where the nerve is close to the surface.
Certain occupations or daily habits can lead to this symmetrical compression. Individuals with jobs that require leaning on their elbows for extended periods or those who perform repetitive elbow bending motions are at higher risk. This constant pressure or strain can damage the ulnar nerve on both sides.
Systemic conditions that affect the nervous system are the second major cause. These conditions can make the ulnar nerve more susceptible to injury or compression. Common examples include:
- Diabetes, due to widespread nerve damage from high blood sugar.
- Autoimmune disorders like rheumatoid arthritis, which can cause joint inflammation that compresses the nerves.
- Alcoholism, which has toxic effects on nerves.
- Certain vitamin deficiencies.
The Diagnostic Process
The diagnostic process begins with a clinical evaluation. A healthcare provider will discuss the patient’s medical history to identify risk factors like diabetes or repetitive occupational activities. The physical examination involves assessing sensation, muscle strength, and looking for signs of muscle atrophy in the hands and forearms.
During the physical exam, specific provocative tests may be performed to pinpoint nerve irritation. One common test is Tinel’s sign, where the physician gently taps over the ulnar nerve at the elbow; a tingling sensation suggests nerve sensitivity. Another is Froment’s sign, which tests for weakness in the pinch grip. If a patient must bend their thumb to maintain their grip on a piece of paper, it indicates weakness in a muscle controlled by the ulnar nerve.
For a more definitive diagnosis, electrodiagnostic studies are often ordered. A nerve conduction study (NCS) measures the speed and strength of electrical signals as they travel along the ulnar nerve; slower signal speeds can indicate nerve compression or damage. This is often paired with electromyography (EMG), which assesses the health of the muscles controlled by the nerve.
An EMG involves inserting a small needle electrode into the muscle to record its electrical activity. In some cases, imaging tests like an MRI or ultrasound may be used to look for physical sources of nerve compression, such as a cyst, bone spur, or inflammation.
Treatment Approaches
Treatment is tailored to symptom severity and the underlying cause, often starting with non-surgical methods. The goal of this conservative management is to reduce pressure on the ulnar nerves. This involves activity modification, such as avoiding leaning on the elbows or keeping the arms straight. Wearing a padded elbow brace or a splint at night can also be effective in preventing the elbow from bending during sleep.
Physical and occupational therapy are also part of conservative treatment. Therapists teach specific nerve gliding exercises to help the ulnar nerve move more freely within the cubital tunnel. If inflammation is a contributing factor, over-the-counter nonsteroidal anti-inflammatory drugs (NSAIDs) may be recommended to reduce pain and swelling.
If symptoms are severe or worsen despite conservative care, surgery may be considered to relieve pressure on the ulnar nerve. A common procedure is ulnar nerve decompression (neurolysis), where a surgeon cuts the ligament over the cubital tunnel to give the nerve more space.
In other cases, a surgeon may perform an ulnar nerve transposition. This procedure moves the ulnar nerve from its position behind the bony bump on the inside of the elbow to a new location in front of it. This prevents the nerve from being stretched or compressed when the elbow is bent. The choice of surgical technique depends on the cause of the nerve compression.