Erb’s palsy is a condition most often caused during childbirth because of injury to certain nerves. This injury causes muscle weakness and paralysis in one arm. Many children recover, but not all will and some will have to live with the damage for life.
What is Erb’s Palsy?
Erb’s palsy is a type of palsy, or a weakness or paralysis of muscles, that occurs sometimes in infants due to injuries to nerves during childbirth. It is also sometimes called brachial plexus palsy, after the name of the bundle of nerves damaged, but there are actually a few types of palsy that can result from damage to the brachial plexus. Erb’s palsy is characterized by the paralysis, weakness, or loss of movement in one arm at birth. The condition improves or completely goes away for most infants, but some live with it for life.
The Brachial Plexus
The bundle of nerves that can be damaged and cause Erb’s palsy are called the brachial plexus. This network of nerves runs from the spine, through the bones of the neck, down either side, and out to the arm. These nerves allow the arm, hand, and fingers to move and give them sensation. The nerves that run lower provide movement and sensation to the hands and fingers, and those that are higher go to the shoulder.
Where within the brachial plexus the damage occurs determines which part of the arm is affected. Erb’s palsy typically affects both the lower and upper arm. Some injuries that occur higher up in the brachial plexus only affect the upper arm and shoulder, while those occurring lower down affect the hand. This latter type of injury is sometimes called Klumpke paralysis.
Symptoms of Erb’s Palsy
The injury that causes Erb’s palsy occurs at childbirth, so it is usually detected right away. The signs of damage or injury include a lack of reflexes on the affected side, no movement in the arm or a part of the arm, minimal grip strength in the affected hand, and an arm bent at the elbow and held tightly to the side of the infant. If somehow the condition is not detected until later, the child may experience weakness, loss of feeling, or partial or total paralysis in the arm.
Types of Injuries to the Brachial Plexus
The severity of the symptoms seen in a child with Erb’s palsy depends on the extent of the injury to the brachial plexus. The most common type of injury seen is called neurapraxia. This means that the nerves have been stretched too far and shocked, but not torn or damaged. This can actually happen to adults too, and is painful, but not serious. For the infant, recovery occurs usually within three months.
A neuroma injury is when the nerves have been stretched enough to cause some damage. This can lead to the formation of scar tissue that presses on healthy nerves. Infants with a neuroma may take longer to recover, but most still do. A rupture occurs when some of the nerves tear and cannot heal on their own. The most severe injury to the brachial plexus is called an avulsion. This means the nerves have been torn and separated from the spinal cord. Both ruptures and avulsions are serious. Some repair may be possible through surgery, but full recover is not likely.
Causes of Erb’s Palsy
The overwhelmingly most common cause of Erb’s palsy in infants is a difficult childbirth. The damage is more likely to occur if the child is unusually large, the birth is breech, or labor goes on for a long time. The actual physical motions that can cause the injury include pulling on the shoulders if the infant comes out head first, pressure on the arms in a breech position, or pulling to the side of the infant’s head as it comes out of the birth canal.
Sometimes the injury is unexpected and unavoidable, but too often it is caused by whoever is delivering the baby. The doctor, midwife, or other medical professional may pull too hard or in one direction too much and cause the injury to the brachial plexus. This is most likely to occur if the delivery is complicated and long or if the head has already emerged and the shoulder comes out only with difficulty.
Fortunately, for most children born with Erb’s palsy, recovery occurs within three to six months. Recovery of damaged nerves is slow but possible for many infants. Most children with this condition will receive treatment such as physical therapy to help stimulate healing and to prevent permanent stiffness in the joints of the arm.
In more severe cases of Erb’s palsy, surgical treatments may be necessary. For torn nerves, a graft using a donor nerve may be possible and can restore feeling and movement. A full replacement of a nerve with a donor nerve may also work, but these are complicated surgeries and they are not always successful at restoring complete movement and sensation. Nerve surgery is not done until the infant is at least six months and the nerves are not healing.