Last reviewed: 31 Jun 2021
Last updated: 29 Sep 2020

Summary

Definition

History and exam

Key diagnostic factors

  • presence of risk factors
  • fever
  • fatigue
  • general malaise
  • headache
  • body pains
  • nausea
  • mild meningitis
  • severe encephalitis
  • altered mental state

Other diagnostic factors

  • cranial and spinal nerve palsies
  • vestibular/hearing defects
  • seizures
  • paresis
  • arms, shoulders, and head muscles paralysis

Risk factors

  • history of recent tick bite
  • summer months
  • occupational exposure
  • outdoors activities
  • recent consumption of raw (unpasteurised) milk or dairy products
  • age ≥50 years
  • bioterrorism

Diagnostic investigations

1st investigations to order

  • FBC
  • ESR
  • CRP
  • LFTs
  • CT brain
  • cerebrospinal fluid analysis
  • cerebrospinal fluid/serum serology

Investigations to consider

  • cerebrospinal fluid/serum reverse-transcription polymerase chain reaction
  • MRI head
  • EEG

Treatment algorithm

Contributors

Authors

Ashley M. Croft, MA, MBBS, MSc, DTM&H, FFPHM
Ashley M. Croft

School of Pharmacy and Biomedical Science

University of Portsmouth

Portsmouth

UK

Disclosures

AMC declares that he has no competing interests.

Peer reviewers

John Williams, MRCP, DTM&H, DipHIVMed

Consultant Infectious Diseases Physician

The James Cook University Hospital

Middlesbrough

UK

Disclosures

JW declares that he has no competing interests.

Charlie Easmon, MBBS, MRCP, MSc Public Health, DTM&H, DOccMed

Medical Director

Your Excellent Health Service

Honorary Lecturer

UCL

London

UK

Disclosures

CE runs a private travel clinic.

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