Nervous system lyme disease.

Lyme disease, a multisystem spirochetal infection, continues to be the subject of considerable debate, but not controversy. Recent years have seen improvements in diagnostic tools, better understanding of pathophysiology, and increasing evidence of efficacy of standard treatment regimens. Nervous system involvement is particularly confusing to patients and many physicians. A rational approach based on objective findings can clarify the cause and dictate the best treatment of patients' difficulties. Diagnosis for all but the earliest cases rests on the combination of likely contact with infected Ixodes ticks and laboratory confirmation of exposure to the causative organism, Borrelia burgdorferi (two-tier serology, combining ELISA with a confirmatory Western blot). Treatment is generally with oral antimicrobials such as doxycycline. Parenteral regimens are usually necessary only for the most severe cases.