Lyme disease


  • Spirochete Borrelia burgdorferi infection via tick bite


  • Erythem migrans - macular erythematous rash with central clearing
  • Starts at bite site (3-21 days later) and spreads (spirochetes migrate from wound site)
  • Rash disappears after 1 month or may never be noticed
  • May have accociated "'flu" like fatigue, fever etc

Late symptoms seen in 2/3 if untreated:

  • Neuroborreliosis: mononeuritis multiplex (e.g. Bell's) or meningitis
  • Oligoarthralgia: (knees) - synovial ↑WCC and PCR +pos for spirochetes
  • Pancarditis: AV block, or myocarditis


  • Serology testing (ask labs) to confirm suspicious cases
  • IgG has lower false positive rate than IgM. IgM usually indicates more recent infection butmay saty positive even after treatment
  • ECG : typically AV block


  • If well with erythema migrans or strong suspicion for Lyme disease - treat with doxycycline then ask for serology testing
  • If significant ECG (beware block) or clinical signs of cardiac involvement, admit for ECG monitoring (±pacing) and iv CefTRIaxone. Later switch to po doxycycline
  • If neuroborrelleisos - admit neurology
  • If oligoarthritis get (sterile procedure) synovial aspirate
  • Please contact microbiology for antibiotic advice

Content by Dr Íomhar O' Sullivan. Last review Dr ÍOS 10/06/21.