How is Erb's Palsy diagnosed?

Erb's Palsy is primarily diagnosed through a comprehensive clinical physical examination that assesses the newborn’s arm movement, muscle tone, and specific reflex patterns immediately following birth. While imaging and electrodiagnostic tests can help determine the severity of the nerve damage, the diagnosis of Erb's Palsy is predominantly based on the physical presentation of a paralyzed or weak limb following a difficult delivery.

How is Erb's Palsy diagnosed?

The diagnostic process for Erb's Palsy usually begins in the delivery room or the neonatal nursery. A pediatrician or neonatologist will observe the infant for "waiter's tip" positioning, where the arm hangs at the side with the palm facing backward. Because Erb's Palsy involves injury to the brachial plexus nerves (typically C5-C6), doctors assess the Moro reflex, which will appear asymmetrical in affected infants.

What tests confirm the extent of nerve injury?

While the initial diagnosis is clinical, further testing may be required to monitor recovery or determine if surgical intervention is necessary. Common assessments include:

• Physical Examination: Serial assessments of range of motion and muscle strength over the first few months of life.


• Electromyography (EMG) and Nerve Conduction Studies: These help evaluate electrical activity in muscles, though they are often delayed until the infant is 3-6 months old to allow for natural nerve healing.


• Magnetic Resonance Imaging (MRI): Used in complex cases to visualize the brachial plexus roots and rule out nerve root avulsions.


• Ultrasound: Sometimes used to evaluate the diaphragm for potential phrenic nerve involvement.

What conditions are in the differential diagnosis?

It is common for families to feel frustrated if the initial diagnosis is delayed or unclear. Clinicians must differentiate Erb's Palsy from other conditions that cause limb weakness, such as congenital fractures of the clavicle or humerus, septic arthritis, or rare congenital neurological conditions. Seeking a pediatric orthopedist or a brachial plexus specialist is crucial, as they have the expertise to distinguish Erb's Palsy from these mimics and provide an accurate prognosis.

Next steps

• Consult a pediatric orthopedist or a plastic surgeon specializing in brachial plexus injuries.


• Begin early intervention physical therapy to prevent joint contractures.


• Connect with the Erb's Palsy community at DiseaseMaps.org to share experiences with others navigating similar challenges.

Medical disclaimer: This content is for informational purposes only and does not substitute professional medical advice, diagnosis, or treatment.

References

• NIH Genetic and Rare Diseases Information Center (GARD): Brachial Plexus Birth Palsy


• Orphanet: Erb-Duchenne palsy


• American Academy of Orthopaedic Surgeons (AAOS): Brachial Plexus Birth Palsy


• United Brachial Plexus Network (UBPN)