Lyme Disease Flashcards
What is Lyme disease?
A tick-borne illness caused by Borrelia species
Lyme disease is primarily transmitted through the bite of infected ticks, especially Ixodes ticks.
What is required for infection by Lyme disease?
Attachment of the tick for more than 48 hours
This duration is crucial for the transmission of the bacteria into the host.
What are the risk factors for Lyme disease?
- living in tick-dense regions
- outdoor activities
- tick attachment for more than 48 hours
These factors increase the likelihood of tick bites and subsequent infection.
What is erythema migrans?
A rash seen in 80% of Lyme disease cases
This rash typically presents with a characteristic bullseye appearance.
When does erythema migrans usually appear after a tick bite?
1-2 weeks post-bite
This timing is important for recognizing the condition early.
What are the early clinical features of Lyme disease?
- fatigue
- headache
- fever
- myalgia
- arthralgia
These symptoms may resemble other viral illnesses.
What are some features of disseminated Lyme disease?
- cardiac: AV block, myopericarditis
- neuro: facial nerve palsy, radiculopathy
- ocular: conjunctivitis, uveitis, keratitis
- skin: multiple discrete EM lesions (borrelial lymphocytoma)
These manifestations indicate a more severe progression of the disease.
What is borrelial lymphocytoma?
Painless blue-red swelling, most common in children with Lyme disease
It typically appears on the earlobe, nipple, or scrotum.
What investigations are used for Lyme disease?
- serology for Lyme-specific IgM and IgG
- enzyme immunoassay (EIA)
These tests help in confirming the diagnosis of Lyme disease.
How is Lyme disease diagnosed when erythema migrans is present?
Clinical diagnosis, no further investigations needed
The presence of the characteristic rash is sufficient for diagnosis.
What is the next step if erythema migrans is absent but EIA test is positive?
Western blot analysis
This test is used for further confirmation of Lyme disease.
What is the management strategy for post-exposure prophylaxis of Lyme disease?
Oral doxycycline given within 72 hours of the bite
This can prevent the onset of Lyme disease if administered promptly.
What antibiotics are used for localized Lyme disease?
- doxycycline
- amoxicillin
Treatment typically lasts for 21 days.
What is the Jarisch Herxheimer reaction?
An acute reaction within 24 hours of initiating antibiotic therapy
It is caused by the release of spirochetal lipoproteins into the bloodstream following organism death.
What symptoms present during the Jarisch Herxheimer reaction?
- fever
- rigors
- tachycardia
- hypotension
- nausea and vomiting
- headache
- flushing
This reaction is usually self-limiting.
