Erb’s palsy is a condition that affects the brachial plexus and weakens the muscles in the arm or the shoulder. We will look at the causes, symptoms, and diagnosis of this condition, along with possible treatment options.
What Is Erb’s Palsy?
The brachial plexus, located near the neck, consists of five nerves responsible for movement, flexibility, and sensations in the arms, hands, and fingers. These nerves contain thousands of fibers that act as the network of communication between the brain and the muscles in your arm. Injury to this group of nerves impacts this communication, causing muscle weakness and, in some cases, even paralysis.
Erb’s palsy is a specific nerve condition that leads to weak muscles in the arms and shoulders. This occurs when the upper two brachial nerves (called C5 and C6) are affected, leading to limited movements and sensation.
This palsy typically occurs due to an injury at birth or later on in life. Erb’s palsy is often reported in infants when, after the baby’s head has come out of their mother’s vagina, their shoulders remain trapped in the mother’s pelvis. In such cases, the baby’s head is tilted to the opposite side, which can sometimes stretch the nerves in the brachial plexus. Erb’s palsy may also occur due to the baby’s position inside the uterus or, in rare cases, during a C-section.
Research indicates that Erb’s palsy occurs in roughly 0.9 to 2.6 births out of 1,000 live births. It’s more common in larger infants who need to be pulled out during vaginal childbirth after getting stuck due to their size.
Types of Erb’s Palsy
There are four types of Erb’s palsy, depending on the seriousness of the condition.
- Neuropraxia. This is the least painful and most widely reported form of Erb’s palsy. In this scenario, the brachial nerves undergo shock and are extended but not entirely torn away from the spinal cord. It takes roughly three months to heal completely and can cause a child intense pain.
- Neuroma. This type of injury damages the nerve fibers, leaving scar tissue once the injury has healed. The scar tissue may put pressure on the existing healthy nerves and cause complications. This type of Erb’s palsy is not considered to be as serious, but it takes longer to heal.
- Rupture. Rupture involves a nerve tear (though not from the spine) that, in most cases, requires surgical treatment. This surgery includes removing a healthy nerve from another part of the body and implanting it in the affected area, which allows functions like movements and sensations to return. In most cases, though, there may still be some challenges even after surgery.
- Neurometric Erb’s palsy. This is the most severe condition. Nerves that branch out of the spinal cord are severed (a process called avulsion) from their roots. This causes irreparable damage to the myelin sheath (the layer that protects the nerves) and other nerve structures. In some cases, the nerve ending close to the spinal cord may start to grow again, but in most cases, your child will not be able to move their arm. Surgery may restore movement, though.
Erb’s Palsy Causes
Erb’s palsy usually occurs when the brachial plexus nerves stretch and the head and shoulder move in opposite directions.
Some risk factors include:
- Large size as an infant
- A petite mother
- Assisted delivery procedures such as vacuum extraction that could apply increased force and lead to a tear in the muscle
- Unusually long second-stage delivery that lasts for more than 60 minutes
- A previous child with Erb’s palsy
Contact sport injuries are the most common cause of Erb’s palsy in adults.
Erb’s Palsy Symptoms
Erb’s palsy generally affects the shoulders, arms, and elbows. Some of the symptoms include:
- Paralysis in the shoulders, arms, and elbows, including an inability to move your arm away from your body or bend your elbows
- Numbness coupled with a tingling sensation in your arms and hands
- A peculiar hand position known as the “waiter’s tip” position, in which the palms point backward and the fingers curl
Erb’s Palsy Diagnosis
Doctors typically carry out a physical examination to identify any possible symptoms of Erb’s palsy. Sometimes, they may use electromyography or other imaging tests to help with the diagnosis.
Electromyography (EMG) helps the doctor understand whether your nerves and muscles are working properly. This usually involves inserting thin needles in the skin to measure muscle activity.
Other imaging tests such as x-rays, magnetic resonance imaging (MRI) scans, and computed tomography (CT) scans can also take pictures of your body and allow your doctor to pinpoint nerve and muscle damage.
Erb’s Palsy Treatment
Erb’s palsy treatment depends on the severity of the condition. While occurrences of neuropraxia usually heal without any medical interference, more serious cases may require treatment, such as:
- Physical therapy for babies who are older than three weeks
- Stretching exercises that improve range of motion and prevent stiffness in the wrists, arms, and hands
- Hydrotherapy exercises that could make movements easier
Some doctors may also suggest botulinum toxin injections that paralyze specific muscles, thus forcing other, weaker muscles to improve their function. This could also prevent you or your baby’s hands from curling.
Nerve repair may take time, but if your baby’s condition hasn’t improved by the time they are six months old, your doctor may recommend surgery.