APII243881241 - CME/CMLE - Lyme Disease-APII243881241

APII243881241 - Educational Activity

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This educational commentary by Dr. Xiaodong Cheng provides an overview of Lyme disease, focusing on clinical presentations, diagnosis, and laboratory testing. Lyme disease is a tick-borne illness caused mainly by Borrelia burgdorferi in the U.S., with additional pathogenic species in Europe and Asia. The disease progresses through early localized, early disseminated, and late stages, presenting with diverse symptoms.<br /><br />Early localized disease typically manifests 3-32 days after a tick bite as erythema migrans (EM), a characteristic expanding skin rash, sometimes accompanied by nonspecific flu-like symptoms. Early disseminated disease can involve neurological symptoms (e.g., Bell’s palsy, meningitis), multiple skin lesions, carditis (notably atrioventricular block), and musculoskeletal pains. Late-stage Lyme disease may develop months to years later and often presents as arthritis or neurologic issues like mild encephalopathy; in Europe, chronic skin conditions such as acrodermatitis chronica atrophicans have been reported.<br /><br />The primary vector in the eastern U.S. is Ixodes scapularis, with Ixodes pacificus predominant in the west. Environmental factors, including climate change and deer population increase, influence Lyme disease incidence by affecting tick populations.<br /><br />For diagnosis, the Centers for Disease Control and Prevention (CDC) stipulate that patients with EM in endemic areas can be diagnosed clinically without laboratory tests. Otherwise, diagnosis requires compatible clinical signs and laboratory confirmation. Serologic testing follows a two-tiered algorithm: an initial enzyme-linked immunosorbent assay (ELISA) screening followed by a confirmatory Western blot if positive or equivocal. Modified approaches using two sequential ELISAs targeting specific B. burgdorferi proteins also exist. PCR and culture tests have limited clinical utility due to false positives and technical complexity.<br /><br />The Infectious Diseases Society of America (IDSA) guidelines recommend against testing asymptomatic individuals after tick bites and emphasize using serology selectively based on symptoms. Testing is not advised for nonspecific symptoms alone.<br /><br />In summary, Lyme disease diagnosis relies on clinical presentation and targeted serologic testing, not routine screening, ensuring accurate identification and treatment.

Keywords

Lyme disease

Borrelia burgdorferi

Ixodes scapularis

Erythema migrans

Early disseminated Lyme

Late-stage Lyme disease

Two-tiered serologic testing

ELISA and Western blot

CDC diagnosis guidelines

IDSA testing recommendations