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Snapshot
  • A 16-year-olPhotod boy presents to his primary care physician with fatigue, headache, and arthralgia. The doctor identifies a ring-shaped lesion on his lower back.
Introduction
  • Lyme Disease is caused by the spirochete Borrelia burgdorferi
  • Transmitted by the Ixodes tick on white-tailed deer and white-footed mice  
    • tick must attach 36-48 hours in order to trasmit B. burgdorferi
  • Most common vector-born disease in the USA
  • Usually observed in the summer months in the Northeast, northern midwest, and California
    • the disease occurs worldwide
  • Disease usually presents in three distinct stages, characterized by symptoms below
Presentation
  • Symptoms
    • prodrome symptoms include
      • fever
      • malaise
      • photophobia
      • erythema chronicum migrans
        • 7-14 days after tick bite
        • spreading circular red rash with central-clearing
    • secondary disease symptoms appear weeks after bite and include
      • weeks-months after tick bite
      • cardiac symptoms
        • myocarditis
        • conduction abnormalities
      • palsies (i.e. Bell's palsy) 
      • aseptic meningitis
      • joint pain (migratory polyarthropathies)
    • tertiary disease symptoms appears weeks to months after bite and include
      • months-years after tick bite
      • arthritis
      • subacute encephalitis
        • memory and mood changes
  • Physical exam
    • prodrome symptoms usually accompanied by identifiable rash
      • identified in areas difficult for patient to see (i.e. lower back, postauricular)
    • all other signs and symptoms identified as described
Evaluation
  • Diagnosis based primarily clinical and laboratory findings 
  • ELISA 
    • if positive, only denotes exposure
    • not specific for active disease
  • Western blot
    • used to confirm positive or indeterminate ELISA
  • Skin biopsy and/or tissue culture
    • of migrating rash may help identify pathogen
  • PCR
    • may aid in identification of Borrelia burgdorferi DNA
Differential
  •  Contact dermatitis, other tick-borne illness (Rocky Mountain Spotted Fever, etc),
Treatment
  • Medical management  
    • doxycycline
      • indicated for treatment of early disease
      • contraindicated in pregnant women and children <8yo
      • side effects include photosensitivity - must caustion patients to avoid sun exposure 
    • amoxicillin: first line treatment for children < 8 yo 
    • high-dose IV ceftriazone or penicillin 
      • indicated for treatment of more advanced or disseminated disease (i.e., cardiac, CNS)
      • given for period of 2-4 weeks
    • Macrolides (erythromycin, azithromycin)
      • third line agent if doxycycline contraindicated and allergic to penicillin
    • empiric therapy
      • indicated for patients with characteristic rash, arthralgias, or a tick bite in endemic areas but without confirmed diagnosis
Prognosis, Prevention, and Comlications
  • Prognosis
    • good to excellent if identified early and treated appropriately 
    • poor to fatal if left untreated
  • Prevention
    • take precautions in endemic areas (i.e. wear long clothes, apply DEET insect repellent)
    • examine body for tick bites after potential exposures
  • Complications
    • unidentified/untreated disease can progress to meningitis/encephalitis and death
 

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