What is Erb Palsy?
Erb palsy, also known as Erb-Duchenne paralysis, is a condition where the arm becomes paralyzed due to damage to a group of main nerves serving the arm, specifically nerves C5-C6 in the upper part of the brachial plexus, which is a network of nerves that sends signals from your spine to your shoulder, arm, and hand. This condition is one of the most frequent neurological birth injuries, most commonly, but not always, caused by force applied on the neck during a challenging childbirth.
While it’s often thought to be caused by the methods used during delivery, the two primary risk factors are shoulder dystocia (when the baby’s shoulder gets stuck inside the mother during birth) and a larger than average baby size. While most cases of Erb palsy get better over time, some infants may require physical therapy and possibly surgery to recover. Fortunately, permanent disability is rare in these cases.
What Causes Erb Palsy?
Erb palsy is a condition linked to an injury to the C5 and C6 spinal nerves in the neck. These nerves are part of a network called the brachial plexus, which includes other nerves from the neck (C5-C8) and upper back (T1) areas. This network stretches out from the spine, passing through a tunnel in the neck and the ribs before extending into the armpit area.
Most frequently, Erb palsy results from the neck being stretched during childbirth. It is especially common in larger than average babies who needed some extra help to be born, which can stretch and potentially harm the brachial plexus.
However, Erb palsy doesn’t always relate to birth difficulties. It can occur even without the baby’s shoulders getting stuck (shoulder dystocia) and in average weight babies as well. Various other factors can increase the risk of a brachial plexus injury, like breech birth (when a baby is born bottom or feet first), a very quick second stage of labor, a mother having given birth to multiple children, the mother being overweight or having diabetes, or the use of vacuum or forceps during delivery. Erb palsy can also sometimes happen even with cesarean section births.
Risk Factors and Frequency for Erb Palsy
Birth injuries are unfortunately common, with an estimated occurrence of about 0.9 to 2.6 injuries for every 1000 live births. One specific kind of birth injury results in significant arm weakness, affecting between 0.4 to 5 babies in every 10,000 births.
Signs and Symptoms of Erb Palsy
Erb’s palsy is a condition that often develops due to a birth injury. It’s highlighted by loss of feeling in the arm and paralysis and shrinking of the deltoid, biceps, and brachialis muscles, leading to a condition called “waiter’s tip hand”. This effect makes the newborn’s arm hang limply from the shoulder. The hand presents an appearance as if waiting for a tip, mainly due to restricted movement at the shoulder and the arm’s internal rotation. Because of the bicep muscle’s paralysis, the arm can’t be lifted from the side, and the elbow can’t be flexed. The affected side’s Moro reflex (startle reflex in babies) is typically absent whilst the grasp reflex (hand closing in response to a touch) remains present, distinguishing it from Klumpke’s palsy, another type of brachial nerve palsy. The newborn might suffer from reduced sensation on the arm’s outer side or a paralyzed diaphragm due to phrenic nerve palsy.
In some situations, there might be sensory loss on the upper arm’s outer side. In events where the C3 and C4 nerves are affected, the diaphragm may also get paralyzed, causing difficulty breathing. If the stellate ganglion (a collection of nerves in the neck) gets damaged, it can lead to Horner’s syndrome, a condition causing issues with the pupil size and eyelid position.
Testing for Erb Palsy
Erb palsy is a condition that is typically diagnosed based on symptoms, but certain tests can help confirm it if needed. One such test is an MRI (Magnetic Resonance Imaging) of the brachial plexus (a network of nerves that send signals from your spine to your shoulder, arm, and hand) and cervical cord (part of your spine located in the neck). Besides confirming Erb palsy, an MRI can also rule out any cancerous growths or tumors that might be impacting the brachial plexus.
An X-ray of the baby’s shoulder can be done to rule out any bone fractures or any issues with the shoulder or elbow joints. Another helpful test is an Electromyography (EMG). This test can estimate and record the electrical activity of the muscle. If there aren’t any fibrillations (irregular, rapid contractions of muscle fibers), it’s likely that neuropraxia (a type of nerve damage) is present. Nerve Conduction Studies (NCS) can measure how long it takes for an electrical stimulus to travel through a specific nerve.
A CT myelogram is another useful test. During this test, a contrast material (a type of dye that helps areas of the body show up more clearly on imaging scans) is injected to get a clear image of the baby’s spinal cord and nerve root (the part of the nerve that leaves the spinal cord). These tests can help get a detailed understanding of the condition of the spinal cord and nerves.
Treatment Options for Erb Palsy
Treatment for Erb’s palsy, a condition that affects the arm’s nerves, varies based on how severe the case is. Some instances might need surgery, while others can be handled just with physical therapy. The typical treatment plan starts with keeping the affected area still, then moving on to exercises that promote movement.
One treatment option is hydrotherapy, which is a type of physical therapy that is done in water. The water provides an environment where there’s less stress on the body’s skeletal structure. This makes it easier for the infant to move with minimal discomfort while making their muscles stronger and reducing muscle spasms. Hydrotherapy can help stimulate coordinated movement in the arm that’s affected by Erb’s palsy.
Physiotherapy, or physical therapy, often goes alongside hydrotherapy, but sometimes it’s done independently. It’s important to note that different patients respond to therapy differently; some may heal sooner than others. For severe cases of Erb’s palsy, physical therapy might be used in addition to surgery, while milder cases could just involve therapy to strengthen the muscles and foster natural healing. Various kinds of exercises, like gentle stretches and stimulation techniques, can promote greater flexibility and strength.
Occupational therapy is another form of treatment for Erb’s palsy. This therapy focuses on helping those who’ve had the condition long-term or have had surgery to manage daily activities, such as eating, playing, drawing, or tying shoelaces.
Surgery is generally seen as a last resort for treating Erb’s palsy and is usually only considered if physical therapy gains aren’t observed. The surgery may involve nerve grafts or nerve decompression, which both have the potential for good outcomes.
Medically, injections of the toxin named Botulinum are sometimes used to alleviate muscle contractions. This could be a part of a treatment plan for those with Erb’s palsy.
What else can Erb Palsy be?
It’s vital to distinguish Erb’s palsy from other similar conditions, such as Klumpke’s injury, clavicle fracture, cervical ribs, humerus or clavicle osteomyelitis, and shoulder septic arthritis. Here’s a brief description of the each of these conditions:
- Klumpke’s injury results in forearm and hand muscle paralysis due to damage to the C7, C8, and T1 nerves. The newborn might present with a “claw hand” due to injury to the wrist, fingers, and forearm pronator flexor muscles. This also impacts the intrinsic muscles. Sometimes, it could be linked with Horner’s syndrome due to T1 being affected, influencing the iris dilators and eyelid elevators.
- A clavicular fracture might cause pseudoparalysis, mistaken for a brachial plexus injury.
- Cervical ribs may predispose to Erb’s palsy by stretching the nerves around the cervical rib or through concentrated pressure when the shoulder is pushed against the cervical spine.
- Osteomyelitis of the humerus or clavicle and septic arthritis of the shoulder can occasionally lead to a brachial plexus injury. This is probably due to the vasa vasorum’s thrombophlebitis or an arterial embolism causing ischemic nerve damage.
What to expect with Erb Palsy
Erb palsy, a condition that affects the nerves in the arm causing weakness and loss of motion, usually has a good outlook. If treatment starts within the first four weeks of life, the condition can often be fully resolved before the child’s first birthday. However, if the muscle remains disconnected from nervous system control, and no efforts are made to restore this connection, the damage turns permanent after about 18 to 24 months.
This timeframe is why doctors urge for early treatment of Erb palsy. If not addressed in time, the changes in the muscle and nerves become irreversible, making it critical to start managing the condition as soon as possible.
Possible Complications When Diagnosed with Erb Palsy
If left untreated, there’s a risk of 20% to 30% lasting nerve damage. This could affect the child’s quality of life and self-esteem due to persistent Erb palsy, which is a type of paralysis involving the arm. The complications of Erb’s palsy can be long-term, and include:
- Decreased strength and endurance
- Abnormal movement and joint function
- Muscle breakdown or decline
- Hindered bone growth
- Osteoarthritis, a type of joint disease
- Differences in limb length
- Impaired balance, and coordination
Recovery from Erb Palsy
There’s some debate about when the best time to start rehabilitation is. To gauge how the timing of rehabilitation can affect a patient’s recovery, a tool called the Modified Mallet Scale (MMS) can be used. If the patient has a mild to moderate condition, getting started with rehabilitative treatment before any surgical procedures is often the best way forward, no matter how old they are.
Preventing Erb Palsy
It’s crucial to diagnose and treat Erb palsy as early as possible for the best results. Erb palsy is a condition that affects the arm’s nerves, causing weakness or paralysis. For expecting mothers with diabetes, it’s especially important to maintain balanced blood sugar levels, as this can lower the risk of their baby developing Erb palsy. This is because babies who are significantly larger at birth (a condition known as macrosomia), or who experience difficulties during delivery (shoulder dystocia), are at a higher risk of Erb palsy.
Parents with a child affected by Erb palsy need to know the importance of early physiotherapy. Physiotherapy involves exercises and treatments that help improve the child’s arm function. In some cases, if the injury to the arm nerves is long-lasting, surgery might also be needed. Informing parents about these necessary steps can help ensure the child’s best possible recovery.
