Lyme Disease Summary

Lyme Disease

Introduction

  • Lyme disease is the most common tick-borne illness in the US and Europe.
  • In the US, it is primarily transmitted through the bite of the Ixodes scapularis tick.
  • The causative agent in the US is the spirochete Borrelia burgdorferi.
  • In Europe, B. afzelii is a more common cause than B. burgdorferi.
  • Information mainly from “Early Lyme Disease” by Gary P. Wormsere, M.D.

Presentation: Erythema Migrans

  • Erythema migrans is an expanding red rash, typically round or oval but variable in size and appearance.
  • It appears 7 to 14 days after tick detachment (range: 3 to 30 days).
  • 75-80% of patients in the US have a single (primary) lesion.
  • Viral-type symptoms may occur, including:
    • Arthralgias
    • Fatigue
    • Headache
    • Neck pain
    • Fever (may or may not be present)
  • Without treatment, erythema migrans resolves spontaneously in approximately four weeks (median).
  • More serious sequelae can develop due to hematogenous spread of the spirochete to extracutaneous sites.
  • Spirochetemia is present in about 45% of patients with erythema migrans at presentation, regardless of the lesion's size or duration.
  • If untreated, approximately:
    • 60% of patients with erythema migrans will develop monoarticular or oligoarticular arthritis, usually involving the knee.
    • 10% will have neurologic manifestations, most commonly facial-nerve palsy.
    • 5% will develop cardiac complications, such as varying degrees of atrioventricular block.

Treatment

  • A 10- or 20-day course of doxycycline is usually effective for mild cases.
  • Parenteral therapy (e.g., with ceftriaxone) is more expensive and has a higher risk of serious adverse effects.
  • Parenteral therapy is typically reserved for:
    • Patients with advanced heart block from Lyme carditis
    • Neurologic manifestations of Lyme disease (excluding uncomplicated facial-nerve palsy).

Cardiovascular Involvement

  • Cardiovascular involvement occurs in fewer than 10% of untreated Lyme disease patients.
  • More common in males than females.
  • Manifestations may include:
    • Palpitations
    • Lightheadedness
    • Syncope (due to varying degrees of heart block, including complete heart block, which occurs in 50% of patients with cardiac involvement)
  • Lyme disease is a reversible cause of heart block.
  • Chest pain and dyspnea can occur with Lyme pericarditis, myocarditis, and myopericarditis.
  • Tamponade has been reported.
  • Physical exam findings:
    • Patients with complete heart block may have Canon A waves in the neck.
    • Possible slow or irregular pulse.
    • A cardiac rub, S3 and/or S4 may be auscultated in patients with myocarditis or pericarditis.
    • Signs of tamponade may rarely occur.
    • Patients with chronic cardiac involvement and congestive heart failure may have typical signs of congestive heart failure.
  • Occasional patients with Lyme disease-related heart block may require temporary cardiac pacing.
  • Indications for cardiac pacing are the same as for any other patient with varying degrees of heart block.
  • Permanent wires are rarely needed.