Brachial Neuritis (Parsonage Turner Syndrome)


  • Painful weakness of shoulder muscles (with atrophy). Beware radiculopathy or cord pathology.
  • Brachial neuritis (BN) is a rare syndrome affecting LMN of brachial plexus.
  • Acute onset of excruciating unilateral shoulder pain, followed by flaccid paralysis of shoulder and parascapular muscles several days later.
  • The syndrome can vary greatly in presentation and nerve involvement.
  • Aetiology is unknown but probably immune-mediated inflammatory reaction against nerve fibres of the brachial plexus.
  • Wallerian degeneration and proximal conduction block are seen.

Incidence / Prevalence

  • In the US is over 1 case per 100,000 person-years
  • M: F = 3:1, any age (young adults especially)

Key Clinical Features

  • Sudden onset unremitting constant shoulder pain (right > left, occasionally bilateral)
  • Pain max at onset. No specific exacerbating factors. (? recent drugs / bugs as trigger)
  • Weakness, maximal at onset, several days after onset pain. Typically involves rotator cuff muscles and deltoid.
  • Muscle wasting early
  • Sometimes vague numbness of proximal area
  • Phrenic nerve or cranial nerve involvement very rare


  • Consider shoulder views to exclude calcific tendonitis
  • CXR to exclude sarcoidosis or mitotic disease
  • Consider MRI to exclude cervical radiculopathy
  • Consider referral to neurophysiologist for EMG studies (looking for denervation and proximal block)

Treatment and management

  • NSAIDS (± opiates in acute setting)
  • Physiotherapy


80% recover functionally by 2 years; 90% by 3 years.

Red flags and pitfalls

Differential Dx

  • Acute Poliomyelitis, Amyotrophic Lateral Sclerosis
  • Frozen shoulder
  • Biceps tendonitis or Rotator Cuff Disease
  • Cervical Disc Disease or Mononeuritis Multiplex


  • Human immunodeficiency virus (HIV)
  • Pack palsy
  • Polymyalgia rheumatica
  • Sarcoidosis and other granulomatous infiltration

Content by Dr Íomhar O' Sullivan 29/11/2004. Reviewed By Dr ÍOS 11/12/2007. Last review Dr IOS 6/12/18.