Brachial Neuritis (Parsonage Turner Syndrome)



Background

  • 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.

Investigations

  • 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).

Prognosis

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.

Consider


Content by Dr Íomhar O' Sullivan 29/11/2004. Reviewed By Dr ÍOS 11/12/2007. Last review Dr IOS 6/01/21.