Lyme Borreliosis

Lyme borreliosis is the most common vectorborne infection in the temperate northern hemisphere. It is caused by Borrelia burgdorferi, a spirochaete transmitted by ixodid (hard-bodied) ticks. About 90% of patients with symptomatic infection have erythema migrans, a rash spreading slowly from the site of a tick bite, which responds well to antibiotic treatment. Multiple patches of erythema migrans can occur following bloodstream spread, and are usually accompanied by other systemic manifestations. Other uncommon skin presentations include borrelial lymphocytoma and acrodermatitis chronica atrophicans. Neurological complications include facial palsy, lymphocytic meningitis, radiculopathy and rarely encephalomyelitis. Musculoekeletal presentations include myalgias and arthralgias in the early stages and some untreated patients may develop large joint arthritis with marked synovitis, usually affecting the knee. The infection is treatable with antibiotics at any stage and the outcome is generally good, but the degree of recovery from very long-standing active infection will depend on the severity of tissue damage sustained prior to treatment.