Lyme Disease: Making a Diagnosis
Lyme disease is an infectious disease caused by four different species of bacteria. In Europe and Asia, it spreads through Borrelia afzelii and Borrelia garinii, while in the USA, it spreads through Borrelia burgdorferi and Borrelia mayonii. The disease is transmitted to humans via a common tick, which is also known as the deer tick and can be usually seen in people who live in the woods or those who have pets, especially dogs, which have ticks breeding inside their hairy coat.
Lyme disease is a treatable disease, which is not contagious and is short-lived. Sometimes, just a red rash might appear on the skin, which is the site of the tick bite. The rash should, however, disappear within a few days. If the disease is not treated properly, then the Lyme disease-causing bacteria can continue to grow in your blood and become a chronic progressive disease, which could be life-threatening.
Therefore, it is important for doctors to make an early diagnosis of Lyme disease so treatment can be started at the earliest. If you have any signs of Lyme disease, consult a doctor as soon as possible.
On consulting a doctor…
When you first visit the doctor, he or she will take a detailed history and carry out a quick physical examination.
The presence of a “bull’s-eye rash” or a rash that has expanded from the center of your skin, which resembles a bull’s-eye pattern, is an early important clinical sign that you have Lyme disease. If this sign is present, your doctor can make a quick clinical diagnosis and will start treatment immediately. Unfortunately, this rash only appears 30 percent of the time, even in confirmed cases of Lyme disease. In addition, only 17 percent of the confirmed cases recall a history of a tick bite. Other common symptoms might be fever, joint pain, and fatigue, which if not assessed early, might lead to other severe health problems.
Therefore, a clinical diagnosis is not always a reliable method to diagnose Lyme disease. There are several blood tests available that can help in the diagnosis of Lyme disease. These tests are reliable only a few weeks after contracting the infection because most of these tests are antibody tests. In some cases, these tests do not measure the level of infection caused by the disease, but the antibodies that are produced to fight the infection. It also takes a few weeks for our bodies to produce such antibodies.
Enzyme-Linked Immunosorbent Assay (ELISA)
ELISA is a screening test that checks for antibodies against the Lyme-causing bacteria B. burgdorferi. Unfortunately, there is a possibility that only 3.5 percent of 1,000 patients show correct positive results after this test. This test cannot be solely relied upon. Even if the test result is negative, one cannot be sure if the Lyme disease has spread to the other areas of the body or not. Thus, other confirmatory tests become necessary.
Western Blot
The next most common test for Lyme disease after ELISA is the Western blot test. This test is used to detect the IgM and IgG antibodies for the specific bacteria, B. burgdorferi. Although this test is better than ELISA, there are chances that only 50-70 percent of the test results are accurate for the confirmation of Lyme disease. The antigens, which are responsible for inducing the Lyme disease antibodies, are separated by electricity into bands, which look similar to a barcode, and is used as a template to measure the antibodies in your blood. If the band is positioned in the same manner as in the template, the result is said to be positive.
Even though the Western blot technique is an excellent test, there is still a distinct possibility of a missed Lyme disease diagnosis. One of the reasons behind this inaccuracy is that the Lyme bacteria that affects the body profoundly weakens the immune system to such an extent that the body fails to produce the much-needed antibodies.
Borrelia Culture Testing
Borrelia culture is a newer test, which is now the most preferred test for Lyme disease in the past several years. This test involves culturing of the Lyme disease-causing bacteria. A blood sample is collected from the patient and then sent to the laboratory. The sample is then cultured in a medium providing all the optimum conditions that are required for the bacteria to grow. After about one or two weeks, the culture media is observed under a dark field microscope. If there is a growth of bacteria, then the test is said to be positive. This test is 93 percent accurate. Although the test is not perfect, it is much better than ELISA and Western blot testing.
Cerebrospinal Fluid (CSF) Test
Lyme disease usually affects the person’s heart and nervous system if the bacteria had already spread in the body. Therefore, when ELISA and Western blot tests show negative results for Lyme disease and the person is still experiencing neurological symptoms such as Bell's palsy (facial paralysis), the person's cerebrospinal fluid is tested to confirm the disease.
Cerebrospinal fluid surrounds our brain and spinal cord. This test makes use of a small portion of the spinal fluid, which is extracted from the spinal cord using a needle. A local anesthesia is injected in the same area before the extraction, which causes numbness for a while. In this procedure, the patient will feel a slight pressure in the extraction area. The fluid is then tested in the laboratory.
When a person faces serious health conditions such as meningitis due to Lyme disease, an intravenous therapy is provided. A heart block or an inflammation of the spinal cord lining need to be observed carefully with the administration of antibiotics as there are risks involved in intravenous treatments.
Although there is no exact or proper test available to make a definitive diagnosis of Lyme disease, a person's clinical history, examination, and the currently available blood tests allow the doctors to make an accurate diagnosis of Lyme disease. Therefore, if you think that you were bitten by a tick, feel that you are having flu-like symptoms, has a red rash, or any other serious symptoms, consult a doctor immediately and get the appropriate tests done.
