Clinical manifestations of Lyme disease.

Lyme disease typically begins with a unique skin lesion, erythema chronicum migrans (ECM) (stage 1). Patients with this lesion may also have headache, meningeal irritation, mild encephalopathy, multiple annular secondary lesions, malar or urticarial rash, generalized lymphadenopathy and splenomegaly, migratory musculoskeletal pain, hepatitis, sore throat, non-productive cough, conjunctivitis, periorbital edema, or testicular swelling. After a few weeks to months (stage 2), about 15% of patients develop frank neurologic abnormalities, including meningitis, encephalitis, cranial neuritis (including bilateral facial palsy), motor or sensory radiculoneuritis, mononeuritis multiplex, or myelitis. At this time, about 8% of patients develop cardiac involvement--AV block, acute myopericarditis, cardiomegaly, or pancarditis. Throughout this stage, many patients continue to experience migratory musculoskeletal pain in joints, tendons, bursae, muscle, or bone. Months to years after disease onset (stage 3), about 60% of patients develop frank arthritis, which may be intermittent or chronic. Recently evidence suggests that Lyme disease may also be associated with chronic neurologic or skin involvement. Thus, Lyme disease occurs in stages with different clinical manifestations at each stage, but the course of the illness in each patient is highly variable.