What Is Erb's Palsy?
Erb’s palsy, also called brachial plexus palsy, is a type of birth injury that may develop when an infant’s neck is stretched to one side during a difficult delivery, causing temporary or permanent nerve damage.
The brachial plexus is a network of nerves that run down the spine and give feeling to the nerves in the arm. These nerves control the muscles in the shoulders, elbows, wrists, and hands, as well as providing movement and feeling. When the upper nerves are damaged during a difficult birth, this can delay a child’s development or result in paralysis or permanent damage.
Since Erb's palsy is caused by nerve damage during delivery, the symptoms will most likely be recognizable at birth. That said, determining the severity of the nerve damage and limited mobility may not be possible until the child is three to six months of age.
Other Types of Brachial Plexus Birth Injuries
When the paralysis affects voluntary movement in the upper arm and range of motion in the lower arm, it is considered Erb’s palsy.
Klumpke’s palsy refers to paralysis of the lower brachial plexus. This typically affects only the muscles in the hand and is not common in babies. Total plexus involvement includes damage to all five nerves of the brachial plexus C5-T1. This can cause a child to have no movement in the shoulder, arm, wrist, and hand.
Types of Erb's Palsy Injuries
Diagnosing the type of Erb’s palsy can be challenging, as it mostly depends on the degree of damage to the brachial plexus nerve. The four main types of nerve injuries that occur in Erb’s palsy are discussed below.
Also known as “burners” or “stingers,” neuropraxia is the most common type of neural injury. This condition occurs when a nerve is stretched or “shocked” but does not tear. These injuries typically heal on their own within 3 months.
A neuroma is a more serious stretch injury that damages some of the nerve fibers. A neuroma can cause scar tissue to form as it heals, which presses on the remaining healthy nerve and creates discomfort. As a result, long-term recovery from neuroma is typically only partial, not complete.
A rupture is a stretch injury that occurs when the nerve itself is torn. Rupture injuries require surgery to splice and graft the nerve back together. This type of injury will not be able to heal on its own.
An avulsion occurs when a nerve is totally torn from the spinal cord. It is the most severe type of nerve injury. Surgery may help to repair avulsions, but the affected nerve cannot be reattached to the spinal cord. Sometimes this can affect the nerves of the diaphragm causing difficulty breathing.
Avulsions may cause Horner’s Syndrome, causing drooping eyelids and small pupils.
Causes and Risk Factors
The most common cause of Erb’s palsy is excessive pulling or stretching of an infant’s head and shoulders during vaginal birth. This typically occurs when the baby is “stuck” in the birth canal, requiring the caretaker to pull harder to get the baby out.
Erb’s palsy can develop if an infant’s head and neck are pulled to the side at the same time as the shoulders pass through the birth canal.
Erb’s palsy can also develop based on the positioning of the infant in the birth canal. This is common in larger babies with broad shoulders. What typically happens is that the infant’s head drops into the birth canal, but one shoulder is held back by the mother’s pubic bone. As the baby’s head is pushed lower into the birth canal, the nerves stretch, resulting in Erb’s palsy.
The risk of a child developing Erb’s palsy nearly triples if they develop shoulder dystocia during birth. This is when the infant’s head is delivered, but both of their shoulders get stuck inside the mother’s womb.
Risk factors of Erb’s palsy include:
- Breech delivery
- Excessive maternal weight gain
- Large infant size or high birth weight
- Maternal diabetes
- Second stage of labor lasting over an hour
- Small or abnormal maternal pelvis shape
- Using extraction tools like forceps during delivery
- Other forms of improper pediatric health care
Signs and Symptoms of Erb's Palsy
The symptoms of Erb’s palsy vary depending on the type and severity of paralysis. Signs range from weakness or soreness to total paralysis of the affected arm.
The most common symptoms of Erb’s palsy are:
- Arm hangs by the side and rotated inward
- Decreased grip strength in hand of the affected side
- Impaired circulatory, muscular and nervous development
- Limited motion in the shoulder, bicep, elbow, forearm, wrist, or hand causing the “waiter’s tip”
- Numbness in arm
- Partial or total paralysis of the arm
- Weakness in one arm
A child’s paralysis can range from partial to complete immobility, and nerve damage can be minor bruising to full tears or avulsions. In the case of a mild stretch or tear, most children will recover on their own within three to six months after birth.
Erb’s Palsy Treatment
Paralysis can resolve on its own within a few months, but more severe cases require more in-depth treatment such as therapy or surgery. Your child may require more treatment if their range of movement and development is still delayed after six months.
This is one of the first methods used to treat mild cases of Erb’s palsy. Physical therapy can help improve any stiffness or immobility in a child’s arms or shoulders. A physical therapist will use massage techniques and motion exercises to improve movement in the muscles and nerves. Therapists also use exercise balls and weights to strengthen a child's grip.
Occupational therapy is often used in cases of Erb’s palsy that have not improved on their own after two to four months.
Occupational therapy can help a child develop the strength to perform everyday activities, such as picking up a toy or bottle. An occupational therapist will use a range of movement exercises to improve joint function and muscle tone.
Children with severe cases of Erb’s palsy will usually require surgery to repair nerve damage and paralysis in the arm, hand, elbow, or shoulder. It is important to perform surgery as soon as possible since postponing Erb's palsy surgery can lower the chance of complete recovery.
The main type of surgery used to treat this condition is a nerve transfer. This is when a healthy nerve is removed from another area of the body and stitched to the disrupted nerve. Surgery combined with physical and/or occupational therapy allows children to develop arm motion.
In some cases, a tendon transfer may also be performed on those with Erb’s palsy or other forms of brachial plexus palsy. This is when a tendon from another part of the body is moved to the arm or shoulder, according to the American Academy of Orthopaedic Surgeons (AAOS).
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