Last reviewed: 6 Apr 2021
Last updated: 03 Sep 2020



History and exam

Key diagnostic factors

  • presence of risk factors
  • muscle weakness
  • respiratory distress
  • speech problems
  • paraesthesia
  • back/leg pain
  • areflexia/hyporeflexia
  • facial weakness
  • bulbar dysfunction causing oropharyngeal weakness
  • extra-ocular muscle weakness
  • facial droop
  • diplopia
  • dysarthria
  • dysphagia
  • dysautonomia
  • anisocoria
  • non-reactive pupil
  • ophthalmoplegia

Other diagnostic factors

  • ptosis
  • altered level of consciousness
  • ataxia

Risk factors

  • preceding viral illness
  • preceding bacterial infection
  • preceding mosquito-borne viral infection
  • hepatitis E infection
  • immunisation
  • cancer and lymphoma
  • older age
  • HIV infection
  • male

Diagnostic investigations

1st investigations to order

  • nerve conduction studies
  • lumbar puncture (LP)
  • LFTs
  • spirometry
  • antiganglioside antibody

Investigations to consider

  • serology
  • stool culture
  • HIV antibodies
  • spinal MRI
  • Borrelia burgdorferi serology
  • cerebrospinal fluid (CSF) meningococcal polymerase chain reaction
  • CSF cytology
  • CSF angiotensin-converting enzyme
  • chest x-ray
  • CSF West Nile polymerase chain reaction

Treatment algorithm


Consultant Neurologist

Queen Elizabeth Neurosciences Centre

University Hospital Birmingham




SJ is an Advisory Board member for Alexion Pharmaceuticals and Alnylam Pharmaceuticals. He lectures and is involved in other educational events for Terumo BCT and Eisai Ltd. He has attended clinical trial meetings as Chief/Principal Investigator for Argenx Ltd and Momenta Ltd.

Dr Saiju Jacob would like to gratefully acknowledge Dr John B. Winer, Dr Michael T. Torbey, Dr Dhruvil J. Pandya, and Dr Prem A. Kandiah, previous contributors to this topic.


JBW, MTT, DJP, and PAK declare that they have no competing interests.

Peer reviewersVIEW ALL

Division of Pediatric Neurology

Columbia University College of Physicians and Surgeons

New York



CA declares that he has no competing interests.

Consultant Neurologist

King's College Hospital




RH has been paid by Baxter Healthcare Ltd for membership of its neurology advisory board, and is a co-author of several studies referenced in this topic.

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