A case revealing the natural history of untreated Lyme disease.

BACKGROUND: A 71-year-old woman presented to a rheumatologist with what she believed to be a 2-year history of Lyme disease, progressing from erythema migrans to Lyme arthritis. INVESTIGATIONS: History, physical examination and serologic testing confirmed the diagnosis of Lyme disease. DIAGNOSIS: Lyme disease. MANAGEMENT: The patient refused antibiotic therapy during the first 2 years of her illness. During the next 2 years, she consulted a rheumatologist, but declined antibiotic therapy. She continued to have recurrent episodes of arthritis, following which she was successfully treated with doxycycline, given initially for 2 weeks, with a second, 4-week cycle administered 2 months later. This case illustrates the natural history of untreated Lyme disease, which is rarely observed in most patients since diagnosis almost always leads to successful antibiotic treatment. Furthermore, this case also demonstrates that infection with Borrelia burgdorferi can persist for years in untreated patients; however, antibiotic therapy is still likely to be effective, despite long-term infection.