Drop hand syndrome is caused by damage to the radial nerve of the arm
Drop hand syndrome, also known as wrist drop, is a condition caused by damage to the radial nerve of the arm, which carries signals from the brain down the arm to the hand. Damage may be caused by an injury or compression (radial neuropathy) due to conditions such as:
- Unrelieved pressure on the radial nerve (sleeping with the arm trapped under the body)
- Crutch palsy (persistent compression by the use of crutches may result in excess pressure on the nerve)
- Trauma or injuries
- Fracture of the humerus (upper arm bone)
- Long-term constriction of the wrist (from a tight watch or bracelet)
- Pressure caused by hanging the arm over the back of a chair (Saturday night palsy caused by excessive alcohol consumption and falling asleep in that position)
- Pressure to the upper arm from arm positions during sleep or coma
- Pinching of the nerve during deep sleep when a person is intoxicated
- External compression
- Systemic nutritional deficiencies
- Medical conditions such as diabetes and kidney disease, which can damage the nerves
Injury to the radial nerve results in the inability to properly use the extensor muscles. As a result, the hand hangs flaccidly in a flexion position when the person attempts to bring the arm to a horizontal position.
What are the symptoms of drop hand syndrome?
The radial nerve controls the movement of the triceps muscle at the back of the upper arm, ability to bend the wrist backward, and movement and sensation of the wrist and hand. Damage to the radial nerve leads to problems with movement or sensation of the back of the arm (triceps), forearm, or hand.
Symptoms of drop hand syndrome or wrist drop include:
- Weakness of the wrist and fingers
- Inability to straighten the wrist or fingers
- Numbness, burning, or tingling of the hand
- Pain in the wrist or hand
- Difficulty bending the hand back at the wrist
- Muscle shrinking in the wrist or hand
- Abnormal sensations in the:
- Hand or forearm (back of the hand)
- Thumb side (radial surface) of the hand
- Fingers nearest to the thumb (second and third fingers)
How is drop hand syndrome diagnosed?
After taking detailed history and evaluating current symptoms, your doctor may recommend certain tests including:
- Examination of the arm, hand, and wrist to check for:
- Decreased ability to extend the arm at the elbow
- Decreased ability to rotate the arm outward (supination)
- Difficulty lifting the wrist or fingers (extensor muscle weakness)
- Muscle loss (atrophy) in the forearm
- Weakness of the wrist and finger
- Wrist or finger drop
- Blood tests
- Electromyography
- Magnetic resonance imaging of the head, neck and shoulder to look for other causes
- Nerve biopsy (rarely needed)
- Nerve conduction study (to determine the extent of damage done to the radial nerve)
How is wrist drop treated?
The goal of treatment is to allow you to use your hand and arm as much as possible. The problem may go away once the pressure to the nerve is relieved.
Symptoms can be controlled with the following:
- Medications such as:
- Over-the-counter analgesics or prescription pain medications to control pain (neuralgia)
- Anticonvulsant medicines (phenytoin, carbamazepine, gabapentin, and pregabalin) or tricyclic antidepressants (amitriptyline) to reduce stabbing pain
- Steroid (prednisone) injections around the nerve to reduce swelling and pressure on the nerve
- Braces, splints, or other appliances to limit movement that may help with healing
- Physical therapy to help maintain muscle strength
- Occupational therapy and vocational therapy or counseling to suggest changes at the worksite
- Surgery to repair the nerve (may be needed for symptoms that do not respond to simpler treatments)
Home care measures include:
- Resting the wrist until normal feeling and strength returns
- Wearing a splint or sling as directed
- Taking medicines for pain or nerve sensations as prescribed
- Avoiding positions that may stretch or put pressure on the underarm
- Avoiding the activity that caused the problem (in some cases, repetitive motion is the cause)
Drop hand syndrome has a good chance of full recovery if the cause of the nerve dysfunction is found and successfully treated.
What are the complications of wrist drop?
Nerve pain caused by drop hand syndrome may be uncomfortable and ast for a long period with or without partial or complete loss of movement or sensation.
Other possible complications may include:
- Mild to severe deformity of the hand
- Partial or complete loss of sensations in the hand
- Partial or complete loss of wrist or hand movement
- Recurrent or unnoticed injury to the hand