Brachial plexus injury (BPI) is a generic term used to describe several conditions that limit or disrupt the network of nerves that carries neuroelectric signals from the spinal cord. Most BPI injries suffered by babies are caused by trauma, including injuries before or during delivery. Brachial plexus injuries that affect babies are often referred to as birth related brachial plexus palsy or obstetric brachial palsy. Since there are several types of BPIs and related conditions, they cause a wide spectrum of symptoms which vary in severity from one patient to another.
Brachial plexus injuries vary in type and severity, depending on the specific location and cause of the injury. Symptoms range from mild side effects to severe limitations, including total loss of motion and feeling of the shoulder or hand. According to the Mayo Clinic, brachial plexus injuries and related conditions such as Erb’s palsy only affect one arm, but can happen to either arm.
In cases in which the brachial plexus injury is minor, such as when the nerves are compressed or stretched, signs and symptoms are slight and generally do not last a long time. While newborns typically experience a brachial plexus injury after a difficult labor and delivery period, children and adults can sustain brachial plexus injuries that result in stretching or compression of the brachial plexus nerves after participating in strenuous sports or other physical activities. This type of injury is known as neuropraxia, the most common type of brachial plexus injury due to overexertion.
The most typical minor symptoms associated with neuropraxia are:
- A sudden burning sensation that resembles an electric shock that travels down the nerves of the arm. These sensations are often referred to as “zingers” or “stingers.”.
- A temporary lack of sensitivity or sudden weakness in the affected arm.
Minor symptoms associated neuropraxia normally vanish within a short time after the initial injury. However, in some people, stingers and temporary numbness of the affected arm may last as long as several days.
Brachial plexus injuries are not limited to neuropraxia. Per the John Hopkins Medicine Peripheral Nerve Surgery Center, there are five other types of injuries that can cause damage to the nerves leading from the spinal cord to the upper body and limbs, including:
- Avulsion, or total disconnection of a nerve from the spinal cord
- Rupture, or partial tearing of the nerve at a location other than the spinal cord
- Axonotmesis, a disruption of a nerve’s axons
- Neurotmesis, a serious condition in which the nerve is completely cut in two
- Neuroma, a growth or tumor of nerve tissue which did not regenerate properly
Since the severity of the injury depends on its cause, location, and amount of nerve damage suffered, symptoms will vary from one person to another. Generally, however, serious BPIs have the following signs and symptoms:
- Loss of feeling in the affected arm, hand, or extremities
- Muscle weakness
- Intense pain
- Muscle paralysis in the shoulder or upper arm (may be partial or total)
- Erb’s palsy
- Klumpke’s palsy
- Horner’s syndrome, which combines a drooping of one eyelid and constriction of the pupil
In severe cases of brachial plexus injuries, infants may experience avulsion pain. Avulsion symptoms are marked by a burning or crushing type of pain centered in the area where the most serious nerve damage is done.
Outlook for Infants with Brachial Plexus Injuries
In cases of obstetric brachial plexus palsy, most of the minor symptoms either go away on their own or respond well to physical therapy. However, brachial plexus injuries which cause severe damage to a baby’s nerves may require surgery and medication.
According to the National Institutes of Health (NIH), mild brachial plexus injuries usually clear up within three to six months. For infants who still haven’t recovered after this time period, the prognosis is generally poor. Even with surgery, there is no guarantee that it will treat severe injuries.