Disease Information for Lyme disease: Definition

  • An infectious disease caused by a spirochete, BORRELIA BURGDORFERI, which is transmitted chiefly by Ixodes dammini (see IXODES) and pacificus ticks in the United States and Ixodes ricinis (see IXODES) in Europe; It is a disease with early and late cutaneous manifestations plus involvement of the nervous system, heart, eye, and joints in variable combinations; The disease was formerly known as Lyme arthritis and first discovered at Old Lyme, Connecticut


    Lyme disease is caused by the bacterium Borrelia burgdorferi and is transmitted to humans by the bite of infected blacklegged ticks; Typical symptoms include fever, headache, fatigue, and a characteristic skin rash called erythema migrans; If left untreated, infection can spread to joints, the heart, and the nervous system; Lyme disease is diagnosed based on symptoms, physical findings (eg, rash), and the possibility of exposure to infected ticks; laboratory testing is helpful in the later stages of disease; Most cases of Lyme disease can be treated successfully with a few weeks of antibiotics; The ticks that transmit Lyme disease can occasionally transmit other tick-borne diseases as well; The Lyme disease bacterium can infect several parts of the body, producing different symptoms at different times;

    The first sign of infection is usually a circular rash called erythema migrans or EM; This rash occurs in approximately 70-80% of infected persons and begins at the site of a tick bite after a delay of 3-30 days; A distinctive feature of the rash is that it gradually expands over a period of several days, reaching up to 12 inches (30 cm) across; The center of the rash may clear as it enlarges, resulting in a bull’s-eye appearance; It may be warm but is not usually painful; Some patients develop additional EM lesions in other areas of the body after several days; Patients also experience symptoms of fatigue, chills, fever, headache, and muscle and joint aches, and swollen lymph nodes; In some cases, these may be the only symptoms of infection;

    Untreated, the infection may spread to other parts of the body within a few days to weeks, producing an array of discrete symptoms; These include loss of muscle tone on one or both sides of the face (called facial or "Bell’s palsy"), severe headaches and neck stiffness due to meningitis, shooting pains that may interfere with sleep, heart palpitations and dizziness due to changes in heartbeat, and pain that moves from joint to joint; Many of these symptoms will resolve, even without treatment; After several months, approximately 60% of patients with untreated infection will begin to have intermittent bouts of arthritis, with severe joint pain and swelling; Large joints are most often effected, particularly the knees; In addition, up to 5% of untreated patients may develop chronic neurological complaints months to years after infection; These include shooting pains, numbness or tingling in the hands or feet, and problems with concentration and short term memory

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