Chronic Lyme disease: misconceptions and challenges for patient management.

Lyme disease, infection with the tick-borne spirochete Borrelia burgdorferi, causes both specific and nonspecific symptoms. In untreated chronic infection, specific manifestations such as a relapsing large-joint oligoarthritis can persist for years, yet subside with appropriate antimicrobial therapy. Nervous system involvement occurs in 10%-15% of untreated patients and typically involves lymphocytic meningitis, cranial neuritis, and/or mononeuritis multiplex; in some rare cases, patients have parenchymal inflammation in the brain or spinal cord. Nervous system infection is similarly highly responsive to antimicrobial therapy, including oral doxycycline. Nonspecific symptoms such as fatigue, perceived cognitive slowing, headache, and others occur in patients with Lyme disease and are indistinguishable from comparable symptoms occurring in innumerable other inflammatory states. There is no evidence that these nonspecific symptoms reflect nervous system infection or damage, or that they are in any way specific to or diagnostic of this or other tick-borne infections. When these symptoms occur in patients with Lyme disease, they typically also subside after antimicrobial treatment, although this may take time. Chronic fatigue states have been reported to occur following any number of infections, including Lyme disease. The mechanism underlying this association is unclear, although there is no evidence in any of these infections that these chronic posttreatment symptoms are attributable to ongoing infection with B. burgdorferi or any other identified organism. Available appropriately controlled studies indicate that additional or prolonged courses of antimicrobial therapy do not benefit patients with a chronic fatigue-like state after appropriately treated Lyme disease.