NHE,
You have raised an important point when it comes the differential diagnosis with regard to Lyme and MS. Most people know that MS/Lyme can present exactly the same way---symptoms, spinal fluid analysis (presence of O-bands), lesions on brain and spine, abnormal evoked potentials, etc.
The question then becomes how do doctors diagnose MS and not Lyme?
In walks the Lyme test. The test is used to rule out lyme, but that can be dangerous. The problem is these tests are often very unreliable. Study after study has shown that the tests fail to detect lyme antibodies even in patients with KNOWN lyme disease( they had the definite "Bulls Eye" rash). Lyme is known to disrupt the immune system and many times the sickest patients (like those with neurological symptoms) are the ones LEAST likely to have a positive test.
Here's part of a postition paper produced by ILADS (International Lyme and Associated Disease Society) with included references discussing the fallibility of current Lyme tests. It follows:
The reason that most ELISA assays are inadequate as screening tests is that they were not designed by the manufacturers to be sensitive at the 95% confidence level, the level typically required for screening.5 In fact, Luger and Krause found up to a
56% false-negative rate (depending upon the commercial kit), when compared to their clinical diagnoses.7 Golightly et al. observed a lack of sensitivity (
over a 70% false-negative rate) with commercial kits in early Lyme disease and from 4 to 46% with late manifestations of Lyme disease.8 Thus, independent of the ELISA results, using both IgM and IgG Western blots may improve laboratory detection of LD.
Some studies show that it is common to miss patients if only the CDC serological criteria are used.3,4 Indeed, the CDC/ASPHLD criteria for a positive B. burgdorferi Western blot are very conservative.1 Five of ten antibody bands are required for IgG positivity. This cut-off is based on the assumption that all Lyme patients, even those without arthritis and neuroborreliosis, have similar immune systems and responses. The diversity of the immune response seen in other diseases is also disregarded. The CDC’s studies were problematic in that they primarily focused on patients with early Lyme disease (usually within four months of an EM). They also collected blood in most patients every few weeks during this four-month period and counted any positive event (five out of ten bands) as LD, even if the same patient had a negative test at a different time of the study.2
Engstrom et al.2 and Aguero-Rosenfeld et al.3,4 confirmed that almost one-third of all Lyme patients are IgG negative during the first year. Two years after a physician-diagnosed EM,
45% of the patients were negative by ELISA. In another study, Aguero-Rosenfeld et al. showed that the ELISA response declined much more rapidly than the Western blot response.4 Their study also demonstrated that the two-step protocol of the CDC/ASPHLD criteria would fail to confirm infection in some patients with culture-proven EM.
Furthermore, although a majority (89%) of patients with the EM rash developed IgG antibodies by Western blot sometime during disease, only 22% were positive by the criteria of the CDC/ASPHLD.4 The Engstrom et al. study did not use the IgG blot criteria of the CDC/ASPHLD.2 They found that 2 of 5 bands gave them a specificity of 93 to 96% and a sensitivity of 100% in the 70% of patients that produced antibody. This could imply an even lower sensitivity would be obtained had the more stringent CDC/ASPHLD criteria been used as a guideline for laboratory screening.
References
1.Association of State and Territorial Public Health Laboratory Directors (ASTPHLD). "Proceedings of the second national conference on the serological diagnosis of Lyme disease." 27-29 October, 1994, Dearborn, MI. Washington DC: ASTPHLD, 1995.
2.Engstrom, SM, Shoop, E, and RC Johnson. "Immunoblot interpretation criteria for serodiagnosis of early Lyme disease." Journal of Clinical Microbiology 33 (1995): 419-427.
3.Aguero-Rosenfeld, ME, Nowakowski, J, McKenna, DF, Carbonaro, CA, and GP Wormser. "Serodiagnosis in early Lyme disease." Journal of Clinical Microbiology 31 (1993): 3090-3095.
4.Aguero-Rosenfeld, ME, Nowakowski, J, McKenna, DF, Carbonaro, CA, and GP Wormser. "Evolution of the serologic response to Borrelia burgdorferi in treated patients with culture-confirmed erythema migrans." Journal of Clinical Microbiology 34 (1996): 1-9.
The full postition paper with many more references is available on the ILADS website.
Furthermore, here is a blurb from the NIAID website which states that Lyme should be a clincal diagnosis. The NIAID is the National Institute of Allergy and Infectious Diseases---the arm of the NIH that deals with Lyme:
Until better tests are available, the diagnosis of Lyme disease must be based on characteristic clinical findings in which the results of laboratory tests play a supportive role. Consequently, primary care physicians in endemic areas must be familiar with all aspects of this disease and understand both the characteristics and limitations of laboratory tests commonly used for the diagnosis of Lyme disease.
Here is the website:
http://www.niaid.nih.gov/dmid/lyme/diagnosis.htm
Given this information it is very difficult to say that a standard lyme diagnostic test is good enough to rule out Lyme in a person presenting with neurological symptoms. It simply isn't---not only according to ILADS, but according to the CDC. Say this, however, to most doctors and they would disagree. The lyme test is the only diagnostic tool that most use to rule out lyme. This is WRONG.
I would not want my MS diagnosis based on one (or even two) highly fallible tests.
Lexy