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 or mononeuritis
  • 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)
  • Acute onset of excruciating unilateral (R>L, 10% bilateral) shoulder pain, followed by flaccid paralysis and wasting of shoulder and parascapular muscles several days later
  • Check for scapular winging (early sign of muscle weakness), long thoracic nerve of Bell
  • Pain maximal at onset, atypical in nature, but often exacerbated (initially) by shoulder movement.Generally not pleuritic
  • Numbness (sometimes myotome and dermatome differ) not very prominent
  • Possible rtecent drugs / trauma / bugs as trigger
  • Weakness, maximal at onset, several days after onset pain. Typically involves rotator cuff muscles and deltoid
  • Phrenic nerve or cranial nerve involvement very rare


  • Consider shoulder views to exclude calcific tendonitis
  • CXR to exclude sarcoidosis or mitotic disease
  • FBC, ESR, inflam. markers & autoantibodies (connective tissue disease)?
  • HIV if at risk history
  • Consider MRI to exclude cervical radiculopathy
  • Consider EMG studies (looking for denervation and proximal block and exclude amyotrophic lateral sclerosis)

Treatment and management

  • NSAIDs (± opiates in acute setting)
  • Consider neuropathic pain medications (e.g. TCADs)
  • Physiotherapy (important to m,aintain shoulder ROM)


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
  • Thoracic outlet syndrome


Content by Dr Íomhar O' Sullivan. Last review Dr IOS 12/08/22.