Erb’s palsy or Erb-Duchenne palsy is one of the types of brachial plexus birth palsy (BPBP), where there is a paralysis of the arm caused by injury to the upper group of the arm’s main nerves, specifically the injury of the upper trunk C5-C6 nerves which is a part of the brachial plexus. These injuries arise most commonly, but not exclusively from shoulder dystocia during a difficult birth.

Etiology of Erb’s Palsy

Erb’s Palsy is commonly linked with lesions of cervical spinal nerves C5 and C6 of the brachial plexus, which is a complex formed by the ventral spinal nerve branches of cervical spinal nerves C5 to C8 and the extremity of the ventral ramus of the thoracic spinal nerve T1. These nerves arise from the spinal cord, run through the cervicoaxillary canal and the ribs and then come out into the axillary region.

A stretch on the neck is the leading cause of brachial plexus injury which occurs during delivery. It is common especially when a larger baby is being delivered and in the process the baby’s head must be pulled out through the birth canal which leads to stretching of the brachial plexus. Shoulder dystocia becomes an essential risk factor in these cases as it may trigger maneuvers that cause undue force on the baby’s neck.

However, the brachial plexus injuries can occur during labour with infants of average weight and more often it happens in cases when shoulder dystocia is not observed. Other factors associated with the risk include cases where a baby is born in breech presentation, a second stage of labour is short, the mother is a multipara, she is obese, diabetic, or underwent vacuum or forceps delivery. Erb’s Palsy can also appear after a caesarean section, therefore raising more possibilities of the causes for this affliction.

Thereby, knowing these risk factors can aid healthcare providers prevent or prepare for hazards that may cause Erb’s Palsy and or related injuries within delivery.

Fig. 1: A&B Erb’s Palsy

Clinical Presentation of Erb’s Palsy

• Characteristics position of the affected limb held close to the body rotated medially with elbow extended and pronated.
• Decreased movement of the affected limb can be elicited by asymmetric Moro’s response.
• Associated features of Horner’s syndrome (ptosis, miosis and anhidrosis).
• Respiratory distress, feeding difficulties as asymmetric chest rise due to diaphragmatic weakness or paralysis with phrenic nerve damage.
• Orthopedic injuries like humerus fracture or clavicular fracture to be looked.

Pathophysiology of Erb’s Palsy

The ventral rami of the cervical spinal nerves C5 and C6 contribute to form the upper trunk of brachial plexus. Both trunks are divided into anterior and posterior, which get subdivided into the cords. These cords branching regard several branches including the axillary nerve, the suprascapular nerve and the musculocutaneous nerve which innervate muscles of the upper limb.

Injuries to the brachial plexus can range from mild to severe, and their severity is classified into three categories: neuropraxic, axonotmetic and neurotmetic.

• Neuropraxic erosion of the peripheral nerve is the least severe. Most of them don’t cause complications and can be reversed with time.
• Axonotmetic trauma implies the damage of the axon with destruction of the myelin sheath. Curing of these injuries depends on the area of the body through which it has passed as well as the extent of the injury, this may take months after appropriate treatment has been administered, which may include physical therapy.
• Neurotmetic injuries are the more severe type where nerve roots are torn off the spinal cord. The type of injury that affects the axon, myelin sheath and the structures that support the nerve is irreversible. Sometimes, to regenerate, the proximal end of the nerve may from a neuroma although the prospects for the return of function are generally bleak.

Treatment Plan for Erb’s Palsy

The management of Erb’s Palsy includes a wide range of options aimed at the degree of the injury, as well as the age of the affected child. Speed is of essence when it comes to treating the injuries to avoid complications later in life. Here’s a comprehensive overview of the treatment options:

1. Observation & Physical Therapy

When the condition is classified as mild, or in some cases neuropraxia, the traditional treatment advice is to let the patient wait out the condition to improve the range of motion. This phase requires physical therapy to be effective. Mild procedures such as physiotherapy to encourage an improvement in the specific muscles and general muscle the child gradually regains their range of motion.

2. Occupational Therapy

Occupational therapist mainly deals with addressing children’s functional limitation regarding their daily living activities. Therapists endeavor to help children with respect to mobility, tonicity and coordination of upper and lower extremities. Examples of strategies can be those activities that involve the use of the affected arm with exercises such as passive movements, gentle stretching, massage or range of motion exercises.

3. Surgical Treatments

When the injury is severe, especially if the patient’s condition does not begin to improve within a few months, surgery might be required. Common surgical procedures include:

• Nerve repair: Operation can involve re-establishing the continuity of the severed nerve if a nerve is totally severed or transected.
• Nerve grafting: Nerve graft is an overview of another nerve from another section of the body can be applied to connect the missing link of the injured nerve.
• Tendon transfer: This procedure may be attempted if the child has shown signs of a serious weakness or paralysis. Muscles can be reconstructed by transplanting tendons from other muscles when healthy.

4. Supportive Care

Managing care is mandatory for Erb’s Palsy. This includes:

• Pain management: Analgesia can be rather important for a child’s comfort and may involve drug use or other options.
• Family education: To break the spirit of the parents this condition and the likely hood of each can be explained to them which will give them more confidence and prepare them to be actively involved in the recovery process for their child.
• Psychosocial support: It is suggested that families may be able to receive some counseling or support groups since they know other families that are struggling through similar challenges.

Frequently Asked Questions (FAQs)

Q1. What are brachial plexus nerves and how are they affected in brachial plexus palsy?

Ans. Brachial plexus nerves are a network of nerves formed from the ventral rami of cervical spinal nerves C5 to T1. They control the muscles and sensation in the upper limb. In brachial plexus palsy, these nerves can become damaged during difficult deliveries, such as those involving excessive pulling on the neck, leading to muscle weakness and loss of motion in the affected arm.

Q2. What is the role of nerve transfer in treating brachial plexus injuries?

Ans. Nerve transfer is a surgical procedure used as an effective treatment for severe brachial plexus injuries. This technique involves rerouting healthy nerves to restore function to damaged nerves. By connecting healthy nerve fibers to the affected areas, it can help improve muscle strength and regain lost motion in the arm.

Q3. What types of motion exercises are recommended for recovery from brachial plexus injuries?

Ans. Motion exercises are crucial for individuals recovering from brachial plexus injuries. These exercises help improve flexibility, strength, and coordination in the affected arm. A physical therapist can tailor a program that focuses on gentle stretching and strengthening to encourage the use of the arm, ultimately aiding in recovery from muscle weakness and loss of motion.

Q4. How does birth weight impact the risk of brachial plexus injury during delivery?

Ans. Higher birth weight, often seen in macrosomic infants, is a common type of risk factor for brachial plexus injuries during delivery. When the birth weight exceeds typical ranges, it increases the likelihood of difficult delivery situations, such as shoulder dystocia, which can stretch or damage the brachial plexus nerves.

Q5. Can brachial plexus injuries occur in breech births, and what are the implications?

Ans. Yes, brachial plexus injuries can occur during breech births. The positioning of the baby can complicate delivery, increasing the risk of damage to the cervical nerves and leading to muscle weakness or loss of motion in the arm. Early intervention and effective treatment strategies are essential for optimal recovery in such cases.