lyme disease部分知识点

岛民A

-In USA, the white-footed mouse(Peromyscus leucopus) serves as the primary reservoir host for Borreliaburgdorferi, the causative agent of Lyme disease.

-The Ixodes tick is the primaryvector that transmits Borrelia burgdorferi, the pathogen responsible forLyme disease, to humans.

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Lyme Arthritis
Synovial fluid shows inflammation (leukocytes ~25,000/mm³) but Gram stain and culture are typically negative.

-3rd heart block caused by Lyme disease is reversible withappropriate treatment.

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Summary of CSF Findings in Lyme Disease

• Lymphocytic-predominant inflammation is common in     neuroborreliosis, characterized by elevated protein     levels and pleocytosis (increased cell count with     lymphocytes).
• Intrathecal Borrelia-specific IgG and IgM antibodies can     be detected via immunoblot, confirming the diagnosis of     neuroborreliosis.
  

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• Screening: ELISA is used for initial testing.
• Confirmatory testing: If ELISA is positive, perform Western     blot.
• PCR testing of synovial fluid can be used to confirm the     diagnosis in patients with suspected Lyme arthritis who are IgG     immunoblot-positive.
  

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• Tetracyclines: Contraindicated in children < 8 years old due     to potential inhibition of bone growth and permanent tooth discoloration.
• Doxycycline: Approved for short-term use (≤ 21 days) in children, including for Lyme disease.
  

• Early localized Lyme disease (e.g., erythema migrans):     First-line treatment is amoxicillin or doxycycline.
• Disseminated Lyme disease (e.g., Lyme arthritis, Lyme carditis,     or neuroborreliosis): First-line treatment is ceftriaxone or penicillin G.
• Pregnant or lactating women: Amoxicillin is preferred;     doxycycline should be avoided.
• Empiric treatment with a 14-day course of oral doxycycline is     curative in most patients
  

• Anaplasmosis and babesiosis are typically     transmitted soon after tick attachment. In contrast, Borrelia     burgdorferi, the pathogen causing Lyme disease, resides in the tick's gut     and requires 48-72 hours of feeding before migrating to the     salivary glands.
• Antimicrobial prophylaxis is not effective against     anaplasmosis and babesiosis but is recommended for preventing Lyme     disease.
  

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For tick  use small forceps to grasp the tick as close to the skin as possible. Pull upwards gently without twisting,and avoid squeezing or crushing the tick's body.

As for the criteria for antimicrobialprophylaxis, all five of the following conditions must be met:

• The tick must be Ixodes scapularis (deer tick).
• The tick has been attached for at least 36 hours or     is engorged.
• Prophylaxis must be started within 72 hours of tick     removal.
• The local Borrelia burgdorferi infection rate is ≥20% (e.g., New England).
• There are no contraindications to doxycycline (e.g.,     pregnancy).
  

If these criteria are met, a single-doseof doxycycline can be used for antimicrobial prophylaxis.

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