This case was reported by a lawyer and described the occurrence of cognitive impairment in a male subject of unspecified age who was vaccinated with LYMErix for prophylaxis. A physician or other health care professional has not verified this report. On an unspecified date the subject received unspecified dose of LYMErix (unknown). An unspecified time after vaccination with LYMErix, the subject experienced cognitive impairment, fatigue, night sweat, sleep disturbance, visual problem, memory loss, heart problems, rheumatological symptoms, neurological impairment, autoimmune disease and decreased activity level. At the time of reporting the outcome of the events was unspecified. This information was received via a Statement of Injuries. Follow up information was received on 03 December 2007 via medical records. The patient reportedly developed confusion and disorientation after having "22 (sic) to 3 shots for Lyme disease". On 02 August 2000, the patient presented to an orthopaedist for evaluation of bilateral knee pain of "several weeks duration" which he was treating with aspirin. He reported a history of bilateral knee sprains after hiking in approximately 1998, which had resolved on their own. Examination revealed no bilateral effusions and no restriction in range of motion, and he was diagnosed with "mild" synovitis. A course of Naprosyn was recommended. Following x-rays of the knees on 23 August 2000, he was diagnosed with chondromalacia patella. He was treated with Naprosyn, but developed gastrointestinal upset. He was then switched to Vioxx and experienced bloody stools. He was noted to be intolerant to anti-inflammatory medications. On 01 September 2000, he was "significantly better" with respect to findings of both knees were "essentially normal". The subject was seen for orthopedic follow up of knee discomfort on 08 December 2000. He reported that he had switched to a "different floor at work and he has less discomfort". A four week course of twice weekly physical therapy was recommended. On an unspecified date, he was diagnosed with leukoencephalopathy. On 05 October 2002, Lyme antibody (IgG/IgM) results were 3.45 (positive 1.00 or greater), and on 29 October 2002 diagnostic findings included cervical disc herniations. Based on follow up information, this report was assessed to be medically significant. Follow up information was received on 03 December 2007 via medical records. In August 2001, the subject received his first LYMErix vaccination, and in September 2001 received the second LYMErix vaccine. He reportedly "did not experience any problems until about January 2002", at which he developed chronic fatigue manifested by feeling of persistent tiredness, and mental cloudiness with difficulty concentrating. The subject was 30 years old at the time of onset of the events. The subject also reportedly developed confusion and disorientation after having "22 (sic) to 3 shots for Lyme disease". He declined to undergo his third scheduled LYMErix vaccination in September 2002. On 19 September 2002, he presented to a neurologist with complaints of chronic fatigue with increased sleep during the weekends, mental "cloudiness", memory loss, and intermittent blurred vision. On 24 September 2002 magnetic resonance imaging (MRI) of the brain showed findings included multiple non-specific white matter abnormalities and a small arachnoid cyst. It was noted that the subject was experiencing difficulty with memory. On 05 October 2002, Lyme antibody (IgG/IgM) results were 3.45 (positive 1.00 or greater). On 28 October 2002, the subject underwent a neurological evaluation for chronic fatigue and memory difficulties. Lyme IgG Western blot results were described as "uninterpretable due to unknown interfering substance". Impression included 1) leukoencephalopathy, 2) left middle cranial fossae small arachnoid cyst, 3) chronic fatigue, and 4) status-post Lyme vaccination. On 29 October 2002 diagnostic findings included cervical disc herniations. A lumbar puncture was successfully performed on 19 November 2002 due to postural back pain. On 05 December 2002, the subject was seen for follow-up evaluation by his neurologist for ongoing problems with memory and fatigue which resulted in his withdrawal from graduate nursing courses. The neurologist commented that the etiology of the white matter abnormalities seen on the brain MRI remained unclear, and noted that "clinically his condition has not been progressive". Based upon follow up information, this report was assessed to be medically significant.