[] [CK] LYME DISEASE WORKUP IN NEW CARDIAC BLOCK(ARRHYTHMIA)

NEW ONSET OF CARDIOMYOPATHY(FUNCTIONAL BLOCK)

1. LYME?

2.AUTOIMMUNE?

3.VIRAL

SUMMARY AND RECOMMENDATIONS

●The diagnosis of early Lyme disease can be made solely on clinical grounds if the characteristic erythema migrans (EM) lesion is present in a patient who lives in or has recently traveled to an area that is endemic for Lyme disease (picture 1and picture 2). The patient with a characteristic EM lesion will likely be seronegative, since the lesion appears prior to development of a diagnostic, adaptive immune response. Laboratory testing is neither required nor recommended. (See 'Approach to diagnosis' above.)

●In contrast to the negative serology at the time of the appearance of the EM lesion, by the time the patient has findings of early disseminated extracutaneous disease (eg, lymphocytic meningitis, facial palsy, radiculoneuropathy, carditis with heart block), serologic tests are typically positive, as they are in patients with late Lyme disease. (See 'Approach to diagnosis' above.)

●Serologic testing should be performed in patients who meet all of the following criteria:

•A recent history of having resided in or traveled to an area endemic for Lyme disease

and

•A risk factor for exposure to ticks

and

•Symptoms consistent with early disseminated disease or late Lyme disease (eg, meningitis, radiculopathy, mononeuritis, cranial nerve palsy, arthritis, carditis) (see 'Indications for serologic testing' above)

●Serologic testing for Lyme disease should not be performed in the following settings:

•In patients with an EM rash. Patients with skin rashes consistent with EM who reside in or have recently traveled to an endemic area should be treated for Lyme disease. (See "Clinical manifestations of Lyme disease in adults", section on 'Erythema migrans' and "Lyme disease: Clinical manifestations in children", section on 'Erythema migrans' and "Treatment of Lyme disease", section on 'Early disease'.)

•For screening of asymptomatic patients living in endemic areas

•For patients with non-specific symptoms only (eg, fatigue, myalgias/arthralgias). The use of serologic testing in populations with a low pre-test probability of Lyme disease results in a greater likelihood of false-positive test results than true positive test results. (See 'Indications for serologic testing' above.)

●A skin lesion similar to EM can be seen in Southern tick-associated rash illness (STARI); however, the geographic distribution of Lyme disease and STARI are usually different (exceptions are Maryland, Delaware, and New Jersey). (See 'Distinction from STARI' above.)

●When serologic testing is indicated, two-tier testing is recommended. The traditional approach uses an whole cell-based enzyme-linked immunosorbent assay (ELISA) followed by a Western blot as the tests of choice. However, Western blot testing can be difficult to perform and interpret; thus, alternative algorithms that eliminate the need for Western blot testing are being tested (See 'Serologic testing' above.)

●Routine follow-up serologic testing is not recommended in assessing the patient who is cured or slowly improving. (See 'Persistence of antibodies' above.)

●The diagnosis of neurologic Lyme disease and Lyme arthritis are discussed separately. (See "Nervous system Lyme disease", section on 'Diagnosis' and "Musculoskeletal manifestations of Lyme disease", section on 'Laboratory testing'.)

●Polymerase chain reaction (PCR) testing of specimens of CSF or synovial fluid for Borrelia burgdorferi DNA in a reliable laboratory can add confirmatory information in seropositive patients. However, a positive PCR result by itself is likely to be a false-positive result, and a positive result does not prove that the patient has active infection, since spirochetal DNA may persist long after spirochetal killing has occurred. (See 'Polymerase chain reaction' above.)

●Use of laboratory tests other than those described above (ELISA, Western blot, and in limited cases, PCR), to support a diagnosis of Lyme disease is notrecommended. (See 'Special considerations' above.)