Brachial plexus injury is a loss of movement or weakness of the arm that occurs when the collection of nerves around the shoulder are damaged during birth.

This bundle of nerves is called the brachial plexus.

Klumpke paralysis; Erb-Duchenne paralysis; Erb's palsy; Brachial palsy

The nerves of the brachial plexus can be injured during a difficult delivery from:

• The infant's head and neck pulling toward the side as the shoulders pass through the birth canal
• Pulling on the infant's shoulders during a head-first delivery
• Pressure on the baby's raised arms during a breech (feet-first) delivery

There are different forms of brachial plexus injury in an infant. The type depends on the amount of arm paralysis:

• Brachial plexus injuries usually affect only the upper arm.
• Erb's paralysis affects the upper and lower arm.
• Klumpke paralysis affects the hand. The infant may also have an eyelid droop on the opposite side.

The following increase the risk of brachial plexus injury:

• Breech delivery
• Larger-than-average newborn (such as an infant of a diabetic mother)
• Difficulty delivering the baby's shoulder after the head has already come out (called shoulder dystocia)

Brachial plexus injury is less common now that delivery techniques have improved. Cesarean delivery is used more often when there are concerns about a difficult delivery. Although a c-section reduces the risk of injury it does not prevent it, and this delivery also has other risks.

Brachial plexus injury may be confused with a condition called pseudoparalysis, in which the infant has a fracture and is not moving the arm because of pain, but there is no damage to the nerves.

Symptoms can be seen immediately or soon after birth, and may include:

• Newborn is not moving the upper or lower arm or hand
• Absent Moro reflex on the affected side
• Arm flexed (bent) at elbow and held against body
• Decreased grip on the affected side

A physical exam usually shows that the infant is not moving the upper or lower arm or hand. The affected arm may flop when the infant is rolled from side to side.

The Moro reflex is absent on the side with the brachial plexus or nerve injury.

A careful examination of the clavicle or collarbone will be done to look for a fracture. Sometimes, the infant will need to have an x-ray of this bone.

Gentle massage of the arm and range-of-motion exercises are recommended for mild cases. More severe cases, or those that do not improve in the first few weeks of life may need to be evaluated by several specialists.

If some strength has not returned to the affected muscles by the time the baby is 3 - 6 months old, surgery may be considered.

Most babies will fully recover within 3 to 6 months, but those who do not recover have a poor outlook. In these cases there may be a separation of the nerve root from the spinal cord (avulsion).

It is not clear whether surgery to repair the nerves or fix the nerve problem can help. Nerve grafts and nerve transfers are sometimes tried.

In cases of pseudoparalysis, the child will begin to use the affected arm as the fracture heals. Fractures in infants usually heal very quickly and easily.

Complications include:

• Abnormal muscle contractions (contractures) or tightening of the muscles, which may be permanent
• Permanent, partial, or total loss of function of the affected nerves, causing paralysis of the arm or arm weakness

Call your health care provider if your newborn shows a lack of movement of either arm.

Taking measures to avoid a difficult delivery, whenever possible, reduces the risk of brachial plexus injury in newborn babies.

Fenichel GM. Trauma and vascular disorders. In: Fenichel GM, ed. Neonatal Neurology. 4th ed. Philadelphia, Pa: Elsevier Churchill Livingstone; 2006:chap 5.

Pham CB, Kratz JR, Jelin Ac, Gelfand AA. Child neurology: brachial plexus birth injury: what every neurologist needs to know. Neurology. 2011. 77:695-697.