Nervous system Lyme disease, chronic Lyme disease, and none of the above.

Lyme borreliosis, infection with the tick-borne spirochete Borrelia burgdorferi sensu lato, causes nervous system involvement in 10-15 % of identified infected individuals. Not unlike the other well-known spirochetosis, syphilis, infection can be protracted, but is microbiologically curable in virtually all patients, regardless of disease duration. Diagnosis relies on 2-tier serologic testing, which after the first 4-6 weeks of infection is both highly sensitive and specific. After this early, acute phase, serologic testing should rely only on IgG reactivity. Nervous system involvement most commonly presents with meningitis, cranial neuritis and radiculoneuritis, but can also present with a broader array of peripheral nervous system manifestations. Central nervous system infection typically elicits a cerebrospinal fluid pleocytosis and, often, intrathecal production of specific antibody, findings that should not be expected in disease not affecting the CNS. Treatment with recommended courses of oral or, when necessary, parenteral antibiotics is highly effective. The attribution of chronic, non-specific symptoms to "chronic Lyme disease", in the absence of specific evidence of ongoing B. burgdorferi infection, is inappropriate and unfortunate, leading not only to unneeded treatment and its associated complications, but also to missed opportunities for more appropriate management of patients' often disabling symptoms.