The brachial plexus is a bundle of nerves that connects the spinal cord and arms. It carries the signals that allow you to throw a ball or pick up a pen. When the brachial plexus is damaged, the functionality of the arm is affected. Brachial plexus injuries in adults are typically caused by trauma from car or sporting accidents, but babies may suffer brachial plexus injuries due to trauma during delivery.
Brachial plexus injuries range in severity; minor injuries may heal within a few months while more serious damage may cause permanent impairment of the arm. Let’s take a look at the symptoms associated with brachial plexus injuries.
Brachial Plexus Injury Symptoms
Mild brachial plexus injuries may cause numbness or tingling in all or part of the arm. It may be difficult to identify a mild brachial plexus injury in a newborn because they can’t tell you what they’re feeling.
Mild brachial plexus injuries can also cause weakness of the arm. Your doctor may be able to detect that weakness using the Apgar test administered to all babies after birth. Among other things, the Apgar test involves checking muscle tone. Weak muscle tone in one arm may indicate a brachial plexus injury. Your doctor may also be able to detect a brachial plexus injury with a Moro test. This is a standard test performed on all newborns to test the “Moro reflex.” It involves simulating a falling sensation to check whether the baby is startled and flexes its arms and hands in response. If the baby has no Moro reflex, a brachial plexus injury may be at fault.
More severe brachial plexus injuries will have more obvious symptoms. Brachial plexus injuries may prevent the baby from moving the affected arm and may cause a weakened grip in that hand. In some cases, the baby’s arm will turn inward and the elbow will flex, holding the arm against the baby’s body.
Your doctor may take x-rays of your baby’s shoulders to rule out the possibility of broken bones, which may cause similar symptoms. Your doctor may also use an electromyogram (EMG) to measure muscle damage related to the injury or perform a nerve conduction study (NCS) to measure the damage to the brachial plexus nerves.
Some types of nerve damage are painful. Your baby can’t tell you what hurts, so you’ll need to be alert to signs that your baby isn’t moving one arm or cries when that arm or shoulder is disturbed, as these may be signs of a brachial plexus injury.
Conditions Caused by Brachial Plexus Injury
The brachial plexus includes several different nerves. Brachial plexus injuries are categorized by which nerves and parts of the arm are affected. Different types of brachial plexus injuries cause different conditions with distinct symptoms. Conditions caused by brachial plexus injuries include global palsy, Klumpke’s palsy, and Erb’s palsy.
The symptoms and outcomes associated with each condition depend on the severity of the brachial plexus injury. The most serious types of damage are avulsion, where the nerves are torn from the spinal cord, and rupture, where the nerves are torn in a different area. This type of damage is typically irreversible. A neuroma is less severe and occurs where the nerve is compressed or scarred and can’t send signals efficiently. The least severe type of damage is a neuropraxia, which occurs when the nerve is stretched or compressed but not torn. Neuropraxias are often treatable and may even heal entirely.
Global palsy is caused by an injury to all five nerves of the brachial plexus. A child with global palsy will have no ability to move the affected arm or hand and may or may not have sensation in the affected arm.
Klumpke’s palsy (also known as Dejerine-Klumpke palsy or Klumpke’s paralysis) occurs as a result of damage to the eighth cervical (C8) and first thoracic (T1) nerves. These nerves control the hand, wrist, and forearm. Klumpke’s palsy may cause your baby’s hand to curl up into a claw. It may cause loss of feeling and weakness in the hand and lower arm.
Erb’s palsy (also known as Erb-Duchenne palsy) is caused by damage to the fifth and sixth cervical (C5 and C6) nerves. These nerves control the upper arm and shoulder. Erb’s palsy may cause your child’s arm to curl up against the body and turn inward in a pose called “waiter’s tip.” Depending on the severity of the damage, Erb’s palsy may stunt the growth of the affected arm and cause circulatory problems. Erb’s palsy may also cause a loss of sensation in the arm.
What To Look For
Brachial plexus injuries may range from minor damage that clears up in a few months to major injuries with lifelong consequences. Your doctor will do basic muscle and reflex tests shortly after your baby is born and may detect signs of a brachial plexus injury at that point. However, not all injuries are readily diagnosable so early. If you notice that your child isn’t moving one arm, has a weak grip with one hand, or is holding an arm in an unusual position, contact your doctor to ask whether your child may have a brachial plexus injury. You should also be alert for crying and other behavior that may indicate that your baby is in pain. Brachial plexus injuries may be treatable, so it’s important to act fast if you believe your baby may have suffered damage to the brachial plexus nerves.