Lyme Disease

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Basics

Lyme disease is caused by the bacterium Borrelia burgdorferi.

Description

  • A multisystem infection caused by Borrelia spirochetes, transmitted primarily by ixodid ticks
    • Ixodes scapularis (deer ticks) in the Northeast and Great Lakes areas
    • Ixodes pacificus in the West (black-legged ticks and Western black-legged ticks)
    • Ixodes ricinus in Europe
    • Ixodes persulcatus in Asia and Russia
  • Early localized Lyme disease includes a characteristic expanding skin rash (erythema migrans [EM]) (80%) and constitutional flulike symptoms (headache, myalgias, fatigue, fever).
  • Early disseminated Lyme
    • Neurologic manifestations 15%: cranial nerve palsy, meningitis, acute radiculopathy, or mononeuropathy
    • Multiple EM lesions
  • Disseminated Lyme disease presents with involvement of ≥1 organ systems; most commonly neurologic, cardiac, and pauciarticular arthritis
    • Lyme carditis: AV block, myopericarditis 1%
    • Post–Lyme disease syndrome includes arthritis (50%) and chronic neurologic syndromes.
    • System(s) affected: hemic/lymphatic/immunologic; musculoskeletal; skin/exocrine; cardiac; neurologic
  • Synonym(s): Lyme arthritis; Lyme borreliosis

Epidemiology

  • Each year, approximately 30,000 cases of Lyme disease are reported to the CDC.
  • Recent estimates suggest that approximately 300,000 people may get Lyme disease each year in the United States.

Incidence
  • High incidence U.S. states: Wisconsin, West Virginia, Virginia, Vermont, Rhode Island, Pennsylvania, New York, New Jersey, New Hampshire, Minnesota, Massachusetts, Maryland, Maine, District of Columbia, Delaware, Connecticut
  • Around 475,000 Americans are diagnosed and treated for Lyme disease annually (1).
Prevalence
  • The most reported vector-borne illness in the United States
  • Predominant age: most common in children ages 5 to 14 years and in adults aged 55 to 70 years of age

Etiology and Pathophysiology

  • Infection with spirochete B. burgdorferi in the United States, or Borrelia afzelii or Borrelia garinii in Europe, transmitted by the bite of ixodid ticks
  • Approximately 90% of cases are transmitted during the nymph stage of the tick life cycle.
  • Average incubation period 7 to 10 days
  • Most transmissions occur in late May to September when nymphal tick activity is highest.
  • If a tick is infected, the chance of transmission increases with time attached: 12% at 48 hours, 79% at 72 hours, and 94% at 96 hours of attachment.
  • Primary animal reservoir is the white-footed mouse.
  • Spirochetes multiply and spread within dermis, resulting in characteristic (EM) rash. Hematogenous dissemination results in involvement of central nervous system (CNS), cardiovascular, or other organ systems.
  • Star ticks (Amblyomma americanum), the American dog tick (Dermacentor variabilis), the Rocky Mountain wood tick (Dermacentor andersoni), and the brown dog tick (Rhipicephalus sanguineus) are not known to transmit Lyme disease.

Genetics
Human leukocyte antigen haplotype DR4 or DR2 increases susceptibility to prolonged arthritis.

Risk Factors

Exposure in Lyme endemic area. Ixodid ticks are common on deer; hunters at increased risk

General Prevention

  • “Tick checks”: Examine skin after outdoor activities.
  • Remove ticks as soon as possible to limit transmission.
  • Wear clothing covering the ankles in endemic areas.
  • Apply 0.5% permethrin to clothes, shoes, and tents.
  • Prevention of tick bites N, N-diethyl-meta-toluamide (DEET), picaridin ethyl-3-(N-n-butyl-N-acetyl)aminopropionate (IR3535), oil of eucalyptus (OLE), p-menthane-3, 8-diol (PMD), 2-undecanone
  • Antibiotic prophylaxis is recommended for the prevention of Lyme disease in endemic areas following an Ixodes tick bite (depending on how long tick is attached). Prophylactic treatment with 1 dose of 200 mg of doxycycline within 72 hours of a tick that has been attached for at least 36 hours is indicated in endemic areas. Number needed to treat = 50 to 53. Contraindicated in pregnancy and in children; no prophylactic agent is approved for these groups.

Commonly Associated Conditions

  • Coinfection (e.g., babesiosis, ehrlichiosis, anaplasmosis) increasingly reported
  • Southern tick–associated rash illness may be mistaken for Lyme disease. It is seen in the Southeastern and South Central United States and is associated with the bite of the lone star tick, A. americanum.
  • Comorbid human granulocytic anaplasmosis and/or babesiosis in patients living in endemic regions

-- To view the remaining sections of this topic, please or --

Basics

Lyme disease is caused by the bacterium Borrelia burgdorferi.

Description

  • A multisystem infection caused by Borrelia spirochetes, transmitted primarily by ixodid ticks
    • Ixodes scapularis (deer ticks) in the Northeast and Great Lakes areas
    • Ixodes pacificus in the West (black-legged ticks and Western black-legged ticks)
    • Ixodes ricinus in Europe
    • Ixodes persulcatus in Asia and Russia
  • Early localized Lyme disease includes a characteristic expanding skin rash (erythema migrans [EM]) (80%) and constitutional flulike symptoms (headache, myalgias, fatigue, fever).
  • Early disseminated Lyme
    • Neurologic manifestations 15%: cranial nerve palsy, meningitis, acute radiculopathy, or mononeuropathy
    • Multiple EM lesions
  • Disseminated Lyme disease presents with involvement of ≥1 organ systems; most commonly neurologic, cardiac, and pauciarticular arthritis
    • Lyme carditis: AV block, myopericarditis 1%
    • Post–Lyme disease syndrome includes arthritis (50%) and chronic neurologic syndromes.
    • System(s) affected: hemic/lymphatic/immunologic; musculoskeletal; skin/exocrine; cardiac; neurologic
  • Synonym(s): Lyme arthritis; Lyme borreliosis

Epidemiology

  • Each year, approximately 30,000 cases of Lyme disease are reported to the CDC.
  • Recent estimates suggest that approximately 300,000 people may get Lyme disease each year in the United States.

Incidence
  • High incidence U.S. states: Wisconsin, West Virginia, Virginia, Vermont, Rhode Island, Pennsylvania, New York, New Jersey, New Hampshire, Minnesota, Massachusetts, Maryland, Maine, District of Columbia, Delaware, Connecticut
  • Around 475,000 Americans are diagnosed and treated for Lyme disease annually (1).
Prevalence
  • The most reported vector-borne illness in the United States
  • Predominant age: most common in children ages 5 to 14 years and in adults aged 55 to 70 years of age

Etiology and Pathophysiology

  • Infection with spirochete B. burgdorferi in the United States, or Borrelia afzelii or Borrelia garinii in Europe, transmitted by the bite of ixodid ticks
  • Approximately 90% of cases are transmitted during the nymph stage of the tick life cycle.
  • Average incubation period 7 to 10 days
  • Most transmissions occur in late May to September when nymphal tick activity is highest.
  • If a tick is infected, the chance of transmission increases with time attached: 12% at 48 hours, 79% at 72 hours, and 94% at 96 hours of attachment.
  • Primary animal reservoir is the white-footed mouse.
  • Spirochetes multiply and spread within dermis, resulting in characteristic (EM) rash. Hematogenous dissemination results in involvement of central nervous system (CNS), cardiovascular, or other organ systems.
  • Star ticks (Amblyomma americanum), the American dog tick (Dermacentor variabilis), the Rocky Mountain wood tick (Dermacentor andersoni), and the brown dog tick (Rhipicephalus sanguineus) are not known to transmit Lyme disease.

Genetics
Human leukocyte antigen haplotype DR4 or DR2 increases susceptibility to prolonged arthritis.

Risk Factors

Exposure in Lyme endemic area. Ixodid ticks are common on deer; hunters at increased risk

General Prevention

  • “Tick checks”: Examine skin after outdoor activities.
  • Remove ticks as soon as possible to limit transmission.
  • Wear clothing covering the ankles in endemic areas.
  • Apply 0.5% permethrin to clothes, shoes, and tents.
  • Prevention of tick bites N, N-diethyl-meta-toluamide (DEET), picaridin ethyl-3-(N-n-butyl-N-acetyl)aminopropionate (IR3535), oil of eucalyptus (OLE), p-menthane-3, 8-diol (PMD), 2-undecanone
  • Antibiotic prophylaxis is recommended for the prevention of Lyme disease in endemic areas following an Ixodes tick bite (depending on how long tick is attached). Prophylactic treatment with 1 dose of 200 mg of doxycycline within 72 hours of a tick that has been attached for at least 36 hours is indicated in endemic areas. Number needed to treat = 50 to 53. Contraindicated in pregnancy and in children; no prophylactic agent is approved for these groups.

Commonly Associated Conditions

  • Coinfection (e.g., babesiosis, ehrlichiosis, anaplasmosis) increasingly reported
  • Southern tick–associated rash illness may be mistaken for Lyme disease. It is seen in the Southeastern and South Central United States and is associated with the bite of the lone star tick, A. americanum.
  • Comorbid human granulocytic anaplasmosis and/or babesiosis in patients living in endemic regions

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