Wednesday, May 21, 2008

My test was negative: What makes you think its Lyme?

Lyme is a clinical diagnosis. No laboratory test can be absolutely relied upon. Even the CDC agrees with this. There are many studies to support this. Check out the ILADS website regarding this issue. I believe the diagnosis can be reliably made. Most of the diagnostic approach I used is unpublished. Some of it is published as fragments. What I try to present here is the whole, based on my experience and careful thought about this puzzling illness. The diagnosis must be suspected when patients live in regions where the disease is known to be endemic. Most patients present with an array of symptoms that are typical of the disease. Again, for the most part I am speaking of chronic Lyme disease, not the acute forms. Fatigue, pain, numbness and tingling are almost always present. Headaches and a loss of balance are very common. But it is the cognitive aspects of the illness which grab my attention. The online brochure available from the ILADS website entitled "What psychiatrists should know about Lyme disease," is very instructive. Lyme readily attacks the brain and central nervous system. The brain symptoms of Lyme disease are thought to be mediated by three effects: direct invasion by the bacteria, local inflammatory effects from the elaboration of neurotoxins, and autoimmune effects caused by the infection. Physicians call Lyme affecting the brain neuroborreliosis. A review of Lyme related medical literature might give one the impression that this is relatively rare. In my experience it is the rule, not the exception. The most consistent symptoms are problems with word retrieval, trouble with concentration, short term memory loss, brain fog, episodic confusion, a generalized slowing of cognitive processing necessary for critical thinking, analysis and problem solving. Frequently only the patient is aware of these symptoms and not observed by family members. Psychometric tests available at research institutions such as Columbia University can demonstrate these sometimes subtle changes.

Chronic Lyme patients with neuroborreliosis have abnormal physical exams. This appears to be universal. The abnormalities my be subtle and easily missed. Lyme does not effect only the brain; it affects all the parts of the nervous system, including the cranial nerves and the peripheral nerves. Cranial nerve abnormalities include some of these signs: A partial Bell's palsy may be present, which is drooping on one side of the face, the eyes may not move all the way laterally when the patient is asked to look all the way to the side, the tongue may deviated to one side.the uvula may be deviated to one side or the soft palate may move poorly and there may decreased sensation on one side of the face when tested with a sharp object. All of these findings are abnormal, common and frequently seen in Lyme patients. Abnormal reflexes including the Babinsky response and the Hoffman response may be frequently seen in Lyme patients.
A common finding is a decrease in sharp sensation seen in the distal arms and legs. This is referred to as a stocking and glove pattern of sensory loss. Many patients have a loss of vibratory sensation seen with a tuning fork test. History and physical findings can by themselves strongly suggest the diagnosis of chronic Lyme or a similar condition.

Abnormal lab findings may be more common than thought.. The expanded Western Blot test from labs like IgeneX is more accurate than results obtained through other labs. The C6 peptide antibody test for Lyme is a new test. I find this test helpful. I interpret the results differently from most physicians. The explanation for this is complex. The CD57 (Stricker panel) measures a subset of natural killer T cells which are typically depressed in chronic Lyme. Complement activation, an immunological response to infection and inflammation can be demonstrated with measures of C3a and C4a. Vitamin B12 and folic acid levels are frequently depressed. Vitamin D levels may show a reversal pattern. The inactive form is low and the active form is high. This may be due to a compex action of L-form, intracellular bacteria which suppresses normal immune responses. This is complex an will discussed elsewhere.

Imaging tests including a contrast brain MRI and a SPECT or SPECT scan may show abnormalities associated with Lyme involving the brain.
Diagnosing Lyme is complex, but can be reliable when a mix of tests and methods are combined.
The presence of co-infections is another important clue to this disease.

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