Lyme disease in Canada: Focus on children Flashcards Preview

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Flashcards in Lyme disease in Canada: Focus on children Deck (18):

What causes Lyme disease?

Borrelia burgdorferi


How is Lyme disease transmitted?

Bite of infected black legged deer tick


What are the primary hosts (carriers) for the black-legged tick?

1. Mice
2. Other small rodents
3. Small mammals
4. Birds (reservoirs)
5. White tailed deer


What is the peak incidence of Lyme disease?

Children 5-9yo
Adults 55-59yo


When must a tick be removed after starting feeding to prevent LD?

Within 24-36h


What is the prevalence of LD?

>500 cases in 2013


What is early localized disease?

1. Erythema migrans (7-14d), resolves within 4wk without treatment
2. Fever
3. Malaise
4. Headache
5. Mild neck stiffness
6. Myalgia
7. Arthralgia


What is early disseminated disease?

~20% of children present
1. Multiple EM lesions (usu. several weeks post tick bite) = spirochetemia w/ cutaneous dissemination
2. Acute neurological signs i.e. facial nerve palsy, papilledema, lymphocytic meningitis
3. Lyme carditis causing heart block rare


What is late disease?

Rare if treated with antimicrobials early in disease
Weeks to months post bite
1. Pauciarticular arthritis affecting large joints esp. knees
2. Peripheral neuropathy
3. CNS manifestations


How to diagnosis LD?

1. Early localized disease --> diagnose if history of potential tick exposure and symptoms in an area with LD
Antibodies are undetectable until 4weeks after infection

Early disseminated disease or late LD: ELISA screening test (may yield false positive test) with confirmatory Western blot test

If travel history to Europe require European IgG Western blot as well.
If arthritis present ~97% positive antibodies, if neurological involvement ~80% positive antibodies, if acute EM ~30-50% positive antibodies, if EM late 75-80% positive for antibodies


What is the recommended antibiotic therapy for LD?

1. >8yo: Doxycycline 4mg/kg/day PO BID
2. <8yo: Amoxicillin 50mg/kg/day PO TID

Alternative: Cefuroxime 30mg/kg/day PO BID

IV: Ceftriaxone 50-75mg/kg IV daily
Pen G 200 000-400 000U/kg/day IV q4h


What is the recommended route/duration of antibiotic therapy for LD?

1. Erythema migrans 14-21d PO
2. Isolated facial palsy 14-21d PO
3. Multiple erythema migrans 21d PO
4. Arthritis 28d PO
5. Recurrent or persistent arthritis 28d PO/IV
6. Heart block or carditis 14-21d IV
7. Meningitis 10-28d (14d) IV
8. Encephalitis or late neurological disease 14-28d IV


What is the Jarisch-Herxheimer reaction?

Fever, headache, myalgia, and an aggravated clinical picture lasting <24h after initiation of antimicrobials.

Treat with NSAID and continue antimicrobials


What is post treatment Lyme disease syndrome?

10-20% of cases experience lingering fatigue, joint and muscle ache >6m
Likely residual damage to tissue and immune system. Do not retreat with antimicrobials


How to remove a tick?

1. Use fine-tipped tweezers to grasp the tick close to the skin surface

2. Pull upward with steady, even pressure. Try not to twist or jerk, which can cause the mouthpart of the tick to break off and remain in the skin. If this happens and you are unable to remove the mouthpart easily with clean tweezers, leave it alone and let the skin heal.

3. Clean the bite area and your hands with rubbing alcohol, an iodine scrub, or soap and water


What does the Public Health Agency of Canada advise?

1. Keep any ticks they remove themselves in a resealable plastic bag or pill vial and note the location and date of the bite.

2. Watch for symptoms and see a health care professional immediately should symptoms appear.

3. Take the tick with them to their medical appointment, to verify species and test as needed


How can LD be prevented?

1. Where play spaces adjoin wooded areas, landscaping can reduce contact with ticks

2. Apply 20% to 30% DEET or icaridin repellents. Repellents can be applied to clothing as well as to exposed skin. Always read and follow label directions

3. Do a ‘full body’ check every day for ticks. Promptly remove ticks found on yourself, children and pets. Shower or bathe within two hours of being outdoors to wash off unattached ticks


What is the recommendations on post-exposure antibiotic therapy?

Consider doxycycline 4mg/kg (max 200mg) PO x 1 dose for children >8yo after a tick bite within 72h of removing a tick even if its been attached for >36h
Insufficient evidence for amoxicillin prophylaxis in younger children

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