This was on the immunne support email today. 11-01-2006 Journal: Journal of Chronic Fatigue Syndrome. Vol. 13(4) 2006 pp. 73-82. [Published online ahead of print. Article copies are available for a fee from The Haworth Document Delivery Service: 1-800-HAWORTH. E-mail address: firstname.lastname@example.org ; Website: http://www.HaworthPress.com.] Author and affiliation: Samuel Shor. George Washington University Health Care Sciences, Reston, VA. [E-mail: email@example.com) DOI: 10.1300/J092v13n04_06 Objective: Chronic Fatigue Syndrome (CFS) by definition represents a diagnosis of exclusion. Late stage or "Chronic Lyme" infection with or without "co-infections" is a difficult diagnosis to establish. The symptom complex of both conditions can be very similar. This case study represents an attempt to support serious consideration for a subpopulation of patients otherwise diagnosed with "CFS," as actually representing chronic Lyme disease. Method: A case study is presented of a 33-year-old man, who for two years, was being managed as having CFS. However, after ~2 years of utilizing multiple modalities of management with limited success, the diagnosis of Lyme was reconsidered. Historical exposure risks to Lyme in this individual were high. He had prolonged exposure in the highly tick-infested mountains of North Carolina for 18 months, several years prior to becoming ill. More aggressive investigation confirmed the diagnosis of Lyme. Appropriate changes in management were associated with an improved level of functioning that was far in excess of what maximal management of CFS was able to achieve. The features of CFS and chronic Lyme can be very similar and include the following: Profound fatigue often associated with cognitive impairment. Other common symptoms related to both of these conditions include sleep disturbances, fibromyalgia, and dysautonomias. In pursuing clarification of this diagnosis, the author was exposed to a contrast in medical opinion regarding diagnostic tools and criteria that were perceived as creating potential barriers to the management of patients presenting with these symptoms. Conclusion: Acceptance and awareness of the possibility that Lyme disease can present as CFS has important therapeutic and prognostic implications. Keywords: Lyme disease, chronic Lyme, chronic fatigue syndrome, CFS, fatigue.