Synonyms: Erb-Duchenne paralysis

Erb's palsy is caused by damage to the brachial plexus during delivery of the neonate. This is mostly limited to the 5th and 6th cervical nerves.

Epidemiology

• Rare; in the United States the incidence has ben quoted as 1.6-2.9 per 1,000 live births¹
• Upper plexus palsies are more common than lower plexus palsies
• 50% of cases are associated with shoulder dystocia

Risk factors

Raised maternal BMI at term and presence of gestational diabetes mellitus have also been reported as risk factors.² The same study reported high birthweight, long second stage of labour, Afro-Caribbean background and long deceleration phase of labour as other prominent risk factors.²

Presentation

Infant is unable to:

1. abduct the arm from the shoulder
2. rotate the arm externally from the shoulder
3. supinate the forearm

This results in the classic 'porter's tip' or 'waiter's tip' appearance¹

Clinical signs

• Characteristic position - adduction and internal rotation of the arm with forearm pronated
• Forearm extension normal
• Biceps reflex absent
• Moro reflex absent on affected side
• Sensory impairment on outer aspect of arm (unusual)
• Power of the forearm is normal (if impaired, suggests injury to lower part of plexus)
• Hand grasp normal unless lower part of plexus is also damaged

Investigations

• MRI shows nerve root damage
• EMG and nerve root studies are not helpful in determining the extent of the damage severity,¹ although this has been opposed.³

Management

• Intermittent immobilisation and positioning to prevent contractures
• Positioning such that arm is abducted to 90°, externally rotated at the shoulder, supination of forearm, extension at wrist with the palm turned toward the face
• Gentle massage
• Physiotherapy with active and passive movement exercises by end of first week
• Electrical stimulation may prove to be beneficial⁵
• Referral to neurosurgeon if paralysis persists beyond three months or more proximal damage to plexus¹
• Surgery can involve direct neurorrhaphy after neuroma resection, neurolysis to remove any scar tissue, nerve grafting with transplant of another nerve or nerve transfer from a local functioning nerve; however, results are mixed and pain, along with functional disability, persist in significant numbers³

Prognosis

• Depends upon degree of damage
• Effective hand grasp throughout is associated with a good prognosis
• Function may return within a few months
• Some may have been left with permanent damage

History

Named after Wilhelm Heinrich Erb (1840-1921) a German neurologist who described a case in 1874, although an earlier case was described by Duchenne in 1872. However Erb was also a pioneer in a description of the electrophysiological nature of tetany, characterisation of the physiological response to stimulation of the superior root of the brachial plexus, and describing the deep tendon reflex.⁶

Document references

1. Hemady N, Noble C; Newborn with abnormal arm posture. Am Fam Physician. 2006 Jun 1;73(11):2015-6.
2. Weizsaecker K, Deaver JE, Cohen WR; Labour characteristics and neonatal Erb's palsy. BJOG. 2007 Aug;114(8):1003-9. Epub 2007 Jun 12. [abstract]
3. Kirjavainen M, Remes V, Peltonen J, et al; Long-term results of surgery for brachial plexus birth palsy. J Bone Joint Surg Am. 2007 Jan;89(1):18-26. [abstract]
4. Birch R, Ahad N, Kono H, et al; Repair of obstetric brachial plexus palsy: results in 100 children. J Bone Joint Surg Br. 2005 Aug;87(8):1089-95. [abstract]
5. Okafor UA, Akinbo SR, Sokunbi OG, et al; Comparison of electrical stimulation and conventional physiotherapy in functional rehabilitation in Erb's palsy. Nig Q J Hosp Med. 2008 Oct-Dec;18(4):202-5. [abstract]
6. Watt AJ, Niederbichler AD, Yang LJ, et al; Wilhelm Heinrich Erb, M.D. (1840 to 1921): a historical perspective on Erb's palsy. Plast Reconstr Surg. 2007 Jun;119(7):2161-6. [abstract]

Acknowledgements