Lyme Disease

Lyme disease is caused by Borrelia spirochete species. In North America, Borrelia burgdorferi is the primary pathogen. In Europe and Asia, Lyme disease has also been known to be caused by Borrelia afzelli, Borelia garinii, and Borellia burgdorferi 2. Spirochetes are transmitted by the Ixodes deer tick, found in wooded areas or fields

Source: CDC

Symptoms

Early Localized

  • Erythema migrans: The rash begins at the site of the tick bite. Over days to weeks, it matures from a small papule to a blanching erythematous patch with central clearing. The rash is typically > 5 cm in diameter. The time from tick bite to rash can range from 1 to 30 days, with most presenting 7 to 14 days after the bite. 
  • Low-grade fever
  • Myalgias
  • Arthralgias
  • Headache
  • Fatigue.

Early Disseminated

  • Erythema migrans
  • Peripheral facial nerve palsy (cranial nerve VII)
  • Meningitis
  • Papilledema, commonly associated with CSF infection.
  • Cardiac involvement: Uncommon in children. Lyme pericarditis, myocarditis, or atrioventricular block may present as fatigue, palpitations, chest pain, or syncope. Atrioventricular block is the most common cardiac manifestation of Lyme disease.

Late Lyme Disease

  • Monoarthritis or oligoarthritis, commonly involving the knee.  Lyme arthritis is more common in children than adults. “There have been no known cases of Lyme arthritis developing in patients who were previously treated for localized or early disseminated infections.”1

Diagnostics

The classic EM lesion ( > 5 cm) is diagnostic of Lyme disease, and no further testing is required prior to treatment. “Serologic testing for tick-borne illnesses has a high false-negative rate early in the disease course. If initial serologic test results are negative in high-risk patients, begin empiric treatment or consider repeat testing.”1


Treatment

Recommended Treatment Regimens for Lyme in Adults and Children

Medication*

Dosage

Route

Duration

Single or multiple erythema migrans lesions: first-line agents

Doxycycline

4.4 mg/kg/day (max 200 mg/day),
divided into 2 doses

PO

10 days

Amoxicillin

50 mg/kg/day (max 1.5 g/day),
divided into 3 doses

PO

14 days

Cefuroxime

30 mg/kg/day (max 1 g/day),
divided into 2 doses

PO

14 days

Single or multiple erythema migrans lesions: second-line agent

Azithromycin

10 mg/kg/day (max 500 mg/day),
once a day

PO

7 days

Doxycycline

4.4 mg/kg/day (max 200 mg/day),
divided into 2 doses

PO

14 days

Meningitis

Doxycycline

4.4 mg/kg/day (max 200 mg/day),
divided into 2 doses

PO

14 days

Ceftriaxone

50-75 mg/kg (max 2g/day), once a day

IV

14 days

Carditis (including heart block)

Doxycycline

4.4 mg/kg/day (max 200 mg/day),
divided into 2 doses

PO

14-21 days

Amoxicillin

50 mg/kg/day (max 1.5 g/day).
divided into 3 doses

PO

14-21 days

Cefuroxime

30 mg/kg/day (max 1 g/day),
divided into 2 doses

PO

14-21 days

Ceftriaxone

50-75 mg/kg (max 2g/day), once
a day

IV

14-21 days

Arthritis**

Doxycycline

4.4 mg/kg/day (max 200 mg/day),
divided into 2 doses

PO

28 days

Amoxicillin

50 mg/kg/day (max 1.5 g/day),
divided into 3 doses

PO

28 days

Cefuroxime

30 mg/kg/day (max 1 g/day),
divided into 2 doses

PO

28 days

Persistent arthritis (after oral antibiotics) or recurrence after initial episode

Re-treat with same oral regimen as initial episode**

Ceftriaxone

50-75 mg/kg (max 2 g/day), once
a day

IV

14-28 days

*Unless otherwise specified, the medications listed are options for first-line treatment, not to be used in combination.

**For children aged < 8 years, amoxicillin or cefuroxime is preferred, given the prolonged treatment.

  • In 2018, the American Academy of Pediatrics (AAP) and Infectious Diseases Society of America recommendations were updated to allow use of doxycycline for patients of any age for treatment of Lyme disease
  • Antibiotic choice is based on potential for co-infection, ability to avoid sun exposure, stage of disease, ease of dosing, and medication allergy.
  • Dental staining: A study of children in Arizona, where RMSF is prevalent, demonstrated lower rates of teeth-staining with doxycycline, compared to historical rates of older tetracyclines. This study also did not find evidence of teeth-staining in children treated with an average 1.8 courses of doxycycline (average of 7.3 days per course) when compared to children who did not receive doxycycline.
  • Doxycycline is preferred over other oral regimens for facial palsy or Lyme meningitis, due to lack of efficacy studies with amoxicillin or cefuroxime.
  • Corticosteroids are not indicated for facial nerve palsy, and treatment with doxycycline is primarily to prevent late complications and does not improve time to recovery of facial palsy. 
  • Carditis and meningitis can be treated with an oral regimen; however, if the patient requires hospitalization, a parenteral regimen should be started and transitioned to an oral regimen after the patient is stabilized.
  • Lyme arthritis is treated with a prolonged course of oral antibiotics. Given the limited safety data for prolonged courses of doxycycline in children aged < 8 years, amoxicillin or cefuroxime is preferred for children in this age group. Persistent arthritis after treatment or recurrence shortly after antibiotics can be retreated with oral antibiotics or parenteral antibiotics, if symptoms are worsening.

Source: EB Medicine Tick-Borne Illnesses: Identification and Management in the Emergency Department


Further Reading

Tick-Borne Illnesses: Identification and Management in the Emergency Department Date Release: Sep 2018This issue reviews the presentation of common tick-borne illnesses and provides recommendations for their diagnosis and management in the ED. Tick-borne illnesses discussed in this issue include: Lyme disease, Rocky Mountain spotted fever, ehrlichiosis, anaplasmosis, babesiosis, tularemia, tick-borne relapsing fever, Colorado tick fever, and tick paralysis.


References

  1. Bellis J, Tay ET. Tick-borne illnesses: identification and management in the emergency department. Pediatr Emerg Med Pract. 2018 Sep;15(9):1-24. Epub 2018 Sep 1. PubMed
  2. Shapiro ED. Clinical practice. Lyme disease. N Engl J Med. 2014 May 1;370(18):1724-31. doi: 10.1056/NEJMcp1314325. PMID: 24785207; PMCID: PubMed

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