Lyme borreliosis

Lyme borreliosis is caused by the spirochaete Borrelia burgdorferi, which affects the skin and other tissues, including the nervous system, joints and heart. It is transmitted by ixodid ticks and is the most common arthropod-borne infection in the temperate northern hemisphere. Ixodes spp. are common in woodland, heath and moorland, and may be found in semi-rural or suburban areas, particularly if there has been intrusion by deer. Peak feeding periods for ticks are late spring, early summer and autumn. An infected tick is unlikely to transmit spirochaetes within the first 24 hours of its feed, so awareness of risk and prompt removal of attached ticks are important preventive measures. Erythema migrans is the most common clinical manifestation. It is not usually itchy or painful, but there may be systemic flu-like symptoms. Spirochaetes can spread to other tissues, causing disseminated infection, which may become chronic if untreated. In the UK, the most common complications are neurological, including isolated or bilateral facial palsy, other cranial nerve palsies, lymphocytic meningitis, painful radiculopathy and, rarely, chronic encephalomyelitis or encephalopathy. Patients may also present with myalgia, arthralgia, and occasionally frank arthritis, but chronic large joint arthritis is uncommon in UK-acquired infections. Other complications include carditis, uveitus and hepatitis. Doxycycline or amoxillin given orally for 2-4 weeks is the first-line antibiotic for non-neurological presentations. Parenteral antibiotics, usually ceftriaxone, are recommended for patients with neuroborreliosis. Response to treatment is usually excellent, particularly when it given early.