Report of the Pathogenesis and Pathophysiology of Lyme Disease Subcommittee of the HHS Tick Borne Disease Working Group.

An understanding of the pathogenesis and pathophysiology of Lyme disease is key to the ultimate care of patients with Lyme disease. To better understand the various mechanisms underlying the infection caused by Borrelia burgdorferi, the Pathogenesis and Pathophysiology of Lyme Disease Subcommittee was formed to review what is currently known about the pathogenesis and pathophysiology of Lyme disease, from its inception, but also especially about its ability to persist in the host. To that end, the authors of this report were assembled to update our knowledge about the infectious process, identify the gaps that exist in our understanding of the process, and provide recommendations as to how to best approach solutions that could lead to a better means to manage patients with persistent Lyme disease.

What We Know and Don't Know About Lyme Disease.

We know the cause of Lyme disease. We know that the bacteria can be found in the initial rash, and occasionally in the blood in the subsequent 2-3 months, but after then, its subsequent location is unknown. Whereas diagnosis and treatment of early Lyme disease is generally straightforward, the etiology of relapsing or persisting symptoms is yet to be defined, and presents clinical challenges. There are no current tests to determine if the infection is still present or absent, thus complicating diagnosis and treatment. Presented here are approaches to the diagnosis and treatment of persisting Lyme disease, based on available published information, and the experience of the author.

Issues in the diagnosis and treatment of lyme disease.

Since the identification of the causative organism more than 30 years ago, there remain questions about the di-agnosis and treatment of Lyme Disease. In this article, what is known about the disease will be reviewed, and approaches to the successful diagnosis and treatment of Lyme disease described. In considering the diagnosis of Lyme disease, a major problem is the inability of documenting the existence and location of the bacteria. After the initial transfer of the bacteria from the Ixodes tick into the person, the spirochetes spread locally, but after an initial bacteremic phase, the organisms can no longer be reliably found in body fluids. The bacteria are proba-bly present in subcutaneous sites and intracellular loci. Currently, the use of circulating antibodies directed against spe-cific antigens of the Lyme borrelia are the standard means to diagnose the disease, but specific antibodies are not an ade-quate means to assess the presence or absence of the organism. What is needed is a more Lyme-specific antigen as a more definitive adjunct to the clinical diagnosis. As for the treatment of Lyme disease, the earliest phase is generally easily treated. But it is the more chronic form of the disease that is plagued with lack of information, frequently leading to erroneous recommendations about the type and du-ration of treatments. Hence, often cited recommendations about the duration of treatment, eg four weeks is adequate treatment, have no factual basis to support that recommendation, often leading to the conclusion that there is another, per-haps psychosomatic reason, for the continuing symptoms. B. burgdorferi is sensitive to various antibiotics, including pe-nicillins, tetracyclines, and macrolides, but there are a number of mitigating factors that affect the clinical efficacy of these antibiotics, and these factors are addressed. The successful treatment of Lyme disease appears to be dependent on the use of specific antibiotics over a sufficient period of time. Further treatment trials would be helpful in finding the best regimens and duration periods. At present, the diagnosis of Lyme disease is based primarily on the clinical picture. The pathophysiology of the disease remains to be determined, and the basis for the chronic illness in need of additional research. Whether there is continuing infection, auto-immunity to residual or persisting antigens, and whether a toxin or other bacterial-associated product(s) are responsible for the symptoms and signs remains to be delineated.

SPECT brain imaging in chronic Lyme disease.

OBJECTIVES: Lyme disease is an infectious disease that frequently involves the central nervous system, leading to cognitive and/or mood dysfunction. The basis for these symptoms remains to be defined but may be the result of a vasculitis or metabolic abnormality secondary to the infection. SPECT scans of the brain might provide an objective measure of abnormalities present in patients with otherwise difficult to objectify clinical findings. The objective of this study was to determine the frequency, location, and severity of abnormalities in SPECT scans of the brain of patients with chronic Lyme disease. METHODS: A total of 183 individuals who met the clinical definition of chronic Lyme disease underwent SPECT scanning of the brain using Tc and standard nuclear imagine techniques. Abnormalities of perfusion to affected areas of the brain were defined as mild, moderate, or severe. RESULTS: Of all patients, 75% demonstrated abnormalities in perfusion to various areas of the brain, most notably the frontal, temporal, and parietal lobes. Patients considered to be seropositive and those considered seronegative had similar rates, types, and severity of perfusion defects. Abnormalities of MRI of the brain were seen in 14% of patients. Treatment with antibiotics, especially those with intracellular-penetrating activity, resulted in resolution or improvement of abnormalities in 70% of patients over a 1- to 2-year period. CONCLUSIONS: Brain SPECT scans are abnormal in most patients with chronic Lyme disease, and these scans can be used to provide objective evidence in support of the clinical diagnosis. The use of certain antibiotic regimens seems to provide improvement in both clinical status and SPECT scans.

Benefits and harms of doxycycline treatment for Gulf War veterans' illnesses: a randomized, double-blind, placebo-controlled trial.

BACKGROUND: It has been hypothesized that certain Mycoplasma species may cause Gulf War veterans' illnesses (GWVIs), chronic diseases characterized by pain, fatigue, and cognitive symptoms, and that affected patients may benefit from doxycycline treatment. OBJECTIVE: To determine whether a 12-month course of doxycycline improves functional status in Gulf War veterans with GWVIs. DESIGN: A randomized, double-blind, placebo-controlled clinical trial with 12 months of treatment and 6 additional months of follow-up. SETTING: 26 U.S. Department of Veterans Affairs and 2 U.S. Department of Defense medical centers. PARTICIPANTS: 491 deployed Gulf War veterans with GWVIs and detectable Mycoplasma DNA in the blood. INTERVENTION: Doxycycline, 200 mg, or matching placebo daily for 12 months. MEASUREMENTS: The primary outcome was the proportion of participants who improved more than 7 units on the Physical Component Summary score of the Veterans Short Form-36 General Health Survey 12 months after randomization. Secondary outcomes were measures of pain, fatigue, and cognitive function and change in positivity for Mycoplasma species at 6, 12, and 18 months after randomization. RESULTS: No statistically significant differences were found between the doxycycline and placebo groups for the primary outcome measure (43 of 238 participants [18.1%] vs. 42 of 243 participants [17.3%]; difference, 0.8 percentage point [95% CI, -6.5 to 8.0 percentage points]; P > 0.2) or for secondary outcome measures at 1 year. In addition, possible differences in outcomes at 3 and 6 months were not apparent at 9 or 18 months. Participants in the doxycycline group had a higher incidence of nausea and photosensitivity. LIMITATIONS: Adherence to treatment after 6 months was poor. CONCLUSION: Long-term treatment with doxycycline did not improve outcomes of GWVIs at 1 year.

Macrolide therapy of chronic Lyme Disease.

BACKGROUND: Macrolide antibiotics are highly active in vitro against B.burgdorferi, but have limited efficacy in the treatment of patients with Lyme Disease. As macrolides are less active at a low pH, their poor clinical activity might be due to localization of borrelia to an acidic endosome, and their activity improved by alkalinization of that compartment with hydroxychloroquine. MATERIAL/METHODS: 235 patients with a multi-symptom complex typical of chronic Lyme disease, ie fatigue, musculoskeletal pain, and neurocognitive dysfunction and with serologic reactivity against B.burgdorferi were treated with a macrolide antibiotic (eg clarithromycin) and hydroxychloroquine. RESULTS: Eighty % of patients had self-reported improvement of 50% or more at the end of 3 months. After 2 months of treatment, 20% of patients felt markedly improved (75-100% of normal); after 3 months of treatment, 45% were markedly improved. Improvement frequently did not begin until after several weeks of therapy. There were no differences among the three macrolide antibiotics used. Patients who had been on hydroxychloroquine or macrolide antibiotic alone had experienced little or no improvement. Compared to patients ill for less than 3 years, the onset of improvement was slower, and the failure rate higher in patients who were ill for longer time periods. CONCLUSIONS: These results support the hypothesis that the Lyme borrelia reside in an acidic endosome and that the use of a lysosomotropic agent augments the clinical activity of macrolide antibiotics in the treatment of patients with chronic Lyme Disease. In contrast, the efficacy of tetracycline in such patients is not affected by hydroxychloroquine.

Cognitive behavioral therapy and aerobic exercise for Gulf War veterans' illnesses: a randomized controlled trial.

CONTEXT: Gulf War veterans' illnesses (GWVI), multisymptom illnesses characterized by persistent pain, fatigue, and cognitive symptoms, have been reported by many Gulf War veterans. There are currently no effective therapies available to treat GWVI. OBJECTIVE: To compare the effectiveness of cognitive behavioral therapy (CBT), exercise, and the combination of both for improving physical functioning and reducing the symptoms of GWVI. DESIGN, SETTING, AND PATIENTS: Randomized controlled 2 x 2 factorial trial conducted from April 1999 to September 2001 among 1092 Gulf War veterans who reported at least 2 of 3 symptom types (fatigue, pain, and cognitive) for more than 6 months and at the time of screening. Treatment assignment was unmasked except for a masked assessor of study outcomes at each clinical site (18 Department of Veterans Affairs [VA] and 2 Department of Defense [DOD] medical centers). INTERVENTIONS: Veterans were randomly assigned to receive usual care (n = 271), consisting of any and all care received from inside or outside the VA or DOD health care systems; CBT plus usual care (n = 286); exercise plus usual care (n = 269); or CBT plus exercise plus usual care (n = 266). Exercise sessions were 60 minutes and CBT sessions were 60 to 90 minutes; both met weekly for 12 weeks. MAIN OUTCOME MEASURES: The primary end point was a 7-point or greater increase (improvement) on the Physical Component Summary scale of the Veterans Short Form 36-Item Health Survey at 12 months. Secondary outcomes were standardized measures of pain, fatigue, cognitive symptoms, distress, and mental health functioning. Participants were evaluated at baseline and at 3, 6, and 12 months. RESULTS: The percentage of veterans with improvement in physical function at 1 year was 11.5% for usual care, 11.7% for exercise alone, 18.4% for CBT plus exercise, and 18.5% for CBT alone. The adjusted odds ratios (OR) for improvement in exercise, CBT, and exercise plus CBT vs usual care were 1.07 (95% confidence interval [CI], 0.63-1.82), 1.72 (95% CI, 0.91-3.23), and 1.84 (95% CI, 0.95-3.55), respectively. The OR for the overall (marginal) effect of receiving CBT (n = 552) vs no CBT (n = 535) was 1.71 (95% CI, 1.15-2.53) and for exercise (n = 531) vs no exercise (n = 556) was 1.07 (95% CI, 0.76-1.50). For secondary outcomes, exercise alone or in combination with CBT significantly improved fatigue, distress, cognitive symptoms, and mental health functioning, while CBT alone significantly improved cognitive symptoms and mental health functioning. Neither treatment had a significant impact on pain. CONCLUSION: Our results suggest that CBT and/or exercise can provide modest relief for some of the symptoms of chronic multisymptom illnesses such as GWVI.

The antibiotic treatment trial of Gulf War Veterans' Illnesses: issues, design, screening, and baseline characteristics.

Many veterans who were deployed to the Persian Gulf during the 1990-1991 Gulf War developed multiple unexplained symptoms such as pain, fatigue, and neurocognitive problems. This constellation of symptoms has been termed Gulf War Veterans' Illnesses (GWVI). Although there is no proven explanation for the cause of GWVI, one fairly widespread explanation is systemic Mycoplasma fermentans infection. The Antibiotic Treatment Trial of GWVI is a randomized placebo-controlled trial to determine whether a 1-year course of doxycycline treatment in deployed Gulf War veterans with GWVI and testing as Mycoplasma species positive will improve their overall functional status as measured by the Physical Component Summary of the SF-36V questionnaire. The study of a multisymptom illness such as GWVI is complicated by the nonspecific nature of the illness, the unknown etiology, and the lack of a widely accepted outcome measure. The presumption of mycoplasma infection raises concerns regarding the methodology for determination of mycoplasma infection, the choice of treatment, and the duration of treatment. However, such a presumption allows the formulation of a clear testable hypothesis that can be tested with treatments with known rates of adverse events and known activity against Mycoplasma species. This paper describes the major issues faced by the investigators during planning, the study design, the patient screening results, and the baseline characteristics of the study patients. There were 2712 patients screened for study entry at 26 Department of Veterans Affairs and two Department of Defense medical centers. Of these, 491 met all study entry criteria and were randomized to either 1 year of doxycycline (200 mg/day) or 1 year of placebo. All patients were seen monthly during treatment and at 6 months after the end of treatment. Study patients had a mean age of 41 years and were mostly male (86%), white (64%), married (68%), and employed full-time (71%).

Late and chronic Lyme disease.

This article reviews the late and chronic manifestations of Lyme disease. Special attention is given to the chronic manifestations of the disease, detailing its pathogenesis, clinical spectrum, and laboratory criteria for the diagnosis. Based on experimental evidence and experience, approaches to the successful treatment of the late and chronic disease are outlined. Much additional work is needed to improve the understanding of the underlying pathophysiology of the disease, its diagnosis and treatment.

Research on informed consent: investigator-developed versus focus group-developed consent documents, a VA cooperative study.

In the Department of Veterans Affairs Cooperative Study (VACSP) #470, A Randomized, Multicenter, Controlled Trial of Multi-Modal Therapy in Veterans with Gulf War Illnesses, a substudy was designed with the primary objective of comparing the utility of an informed consent document developed by a focus group of Gulf War veterans (focus group-developed) to an informed consent document developed by the standard process involving the study investigators (investigator-developed). In December 1998 a focus group of five Gulf War veterans convened at the coordinating center and developed a consent document during three sessions. The focus group used the investigator-developed consent document as a "starting point" and then modified it by consensus agreement. They also reviewed and modified the substudy's assessment questionnaire. Utility will be evaluated in 1092 veterans participating in the parent study, VACSP #470, by directly comparing selected patient-centered outcomes between those receiving the focus group-developed consent document versus those receiving the investigator-developed document. The primary outcomes to be evaluated over a 1-year follow-up period include measures of the informed consent process, such as patient recall, expectations about risks and benefits of participation, and understanding about the voluntariness of consent. Secondary outcomes will assess the impact of the substudy on the parent study with respect to recruitment and adherence. VACSP #470 was initiated in May 1999 in 20 sites that were randomly allocated to use either the focus group-developed or investigator-developed consent document. Sites are unaware of the type of consent document assigned. This article focuses on the rationale and design of the informed consent substudy and also discusses potential ethical issues.