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  • Lyme borreliosis should be considered in individuals who have a reasonable risk of exposure to Borrelia burgdorferi-infected ticks and who present with a characteristic complex of signs and symptoms.

  • Classic clinical features occur in stages:

    • Early localized infection (3–30 days after tick bite): a single hallmark skin lesion erythema migrans (EM), occasionally associated with fever, malaise, headache, arthralgias, and myalgias. These constitutional symptoms can occur in the absence of EM, but this is unusual.

    • Early disseminated infection (weeks to a few months after tick bite): signs include multiple EM lesions, often with associated fever, migratory arthralgias, and myalgias; carditis manifested primarily as AV nodal block; neurologic features, including cranial nerve palsies (especially involving the facial nerve), lymphocytic meningitis, and radiculoneuropathies.

    • Late infection (several months to years after tick bite): arthritis, including monoarticular and migratory pauciarticular arthritis; rarely neurologic features such as peripheral neuropathies or chronic mild encephalopathy.

    • Supporting serologic evidence of exposure to B burgdorferi is present in the majority of cases but can be absent in early infection.

General Considerations

Lyme disease is a multisystem disorder caused by infection with spirochetes of the genus Borrelia burgdorferi sensu lato (sl), most commonly B burgdorferi sensu stricto (ss), B garinii, and B afzelii species. Hard-shelled ticks of the Ixodidae family—Ixodes scapularis and I pacificus in the United States, I ricinus in Europe, and I persulcatus in Asia—serve as vectors for infection. In Europe and Asia, B garinii and B afzelii are the main etiologic agents of Lyme borreliosis, and cases due to B burgdorferi sensu stricto are less common. In contrast, B burgdorferi sensu stricto is responsible for virtually all cases of Lyme disease in the United States. The major exception to this rule is the small number of infections associated with a new species, B mayonii, recently identified in the upper Midwest (Minnesota, Wisconsin, and North Dakota). The specific B burgdorferi sl species causing infection influences the prevalence of certain disease manifestations. As examples, neurologic disease is more common with B garinii, late skin disease is more common with B afzelii, and arthritis is more common with B burgdorferi ss. B mayonii infection may exhibit atypical features described later.

Lyme borreliosis first came to medical attention in the United States in 1975, with the investigation of a clustering of childhood arthritis in the region around Lyme, Connecticut. Lyme arthritis, as it was initially termed, was soon found to be one manifestation of systemic infection with B burgdorferi. The earliest clinical sign reported by patients was a characteristic skin lesion erythema migrans (EM) at the site of a tick bite. In Europe, EM had been associated with I ricinus tick bites since the early twentieth century, and the skin disease was treated successfully with penicillin after spirochetes were visualized in biopsy specimens in the mid-1900s. Other systemic manifestations were occasionally ...

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