 |
| Image provided by www.cdc.gov/.../lyme/images/TickMaster4_12.jpg |
|
|
Lyme disease is a worldwide infectious disease caused by microscopic bacteria carried by deer ticks. There are several species of deer ticks across the US that become infected with Lyme bacteria, Borrelia burgdorferi. Unsuspecting humans and animals walking through woodlands and brushy areas may be bitten by a tick and never know it. The tiny ticks, some the size of poppy seeds, may stay on your body for hours to days. The tick engorges itself with blood, and the Lyme bacteria is transmitted to the bloodstream of the person or animal during the bite.
|
Suspect Exposure
Early recognition is important. If you find a tick attached to your skin, if you were in a known tick-infested area, or if your symptoms resemble those described below, see a physician with experience in treating Lyme disease.
Symptoms of Lyme Disease
A characteristic red "bulls-eye" rash (erythema migrans, or EM rash) at the site of the bite is present in 50% of patients. The rash may appear within days to weeks after the bite.
Some patients report flu-like symptoms, fever, aches, fatigue, neck stiffness, jaw discomfort, muscle pain and stiffness, swollen glands, and red eyes Symptoms may appear, disappear and reappear at various times.
Nervous system abnormalities including partial facial paralysis (Bell's Palsy), migratory joint pains and pains in the tendons, muscles and bones may occur later in the disease. Joint symptoms, if present, usually affect the large joints like the shoulder, hips and knees
|
Lyme Disease Diagnosis
Lyme disease is a clinical diagnosis. This means that your physician makes the diagnosis using your clinical history and symptoms. If you develop an EM rash following a tick bite, a diagnosis of Lyme disease can be made. If a rash is not seen by your physician, laboratory tests are needed in helping with the diagnosis.
Tests that are Available
A variety of tests are available. Many doctors who are unfamiliar with Lyme disease may only use the test available in their local laboratory. In may cases this is the Lyme ELISA (EIA) or IFA, often-called "Titer Test". These tests measure a patient's antibody, IgM and/or IgG, in response to exposure to Lyme bacteria. By today's standards, these tests are not very sensitive.
The Western Blot tests (IgG and/or IgM) are much more sensitive and specific than the above titer tests. With the Western Blot, the laboratory can actually visualize the exact antibodies you are making to the Lyme bacteria. In some cases the laboratory may be able to say that your "picture of Lyme antibodies" is consistent with early disease, with persistent/recurrent disease or maybe even with long-term disease. Not all patients have antibodies at all times when they are tested. Antibodies are more commonly detected within the first year after infection, although reinfection may cause a significant increase in antibodies. At most, only 70% of patients have antibodies that are detectable by Western Blot testing.
PCR (Polymerase Chain Reaction) test detects the presence of the DNA of Lyme bacteria. PCR tests have more sensitivity early in the disease before patients have received antibiotics. This is a relatively expensive test. The best specimen to test has not been defined. The test can be preformed on whole blood, serum, urine, synovial fluid and spinal fluid.
The Best Test
Physicians are often asked what is the best test for Lyme disease. That is a difficult question because there is no one best test. Lyme disease is complicated. It may mimic or masquerade as arthritis, muscle aches, flu, cardiac disease, chronic fatigue, fibromyalgia, multiple sclerosis, autoimmune diseases such as lupus and rheumatoid arthritis, or other illnesses. Some of these diseases require multiple tests and so does Lyme. At a minimum, the IgM and IgG Western Blots for B. burgdorferi need to be ordered. If your physician suspects and autoimmune disease (i.e., systemic lupus or rheumatoid arthritis), an ANA or rheumatoid factor test may be needed.
Patients with neurological symptoms of Lyme disease may need to have a spinal tap in order to study "the blood of the brain," the spinal fluid These patients may have negative blood tests and show positive results with spinal fluid. The Western Blot and PCR tests can be performed on spinal fluid.
Testing Ticks
Not all ticks are infected with the spiral bacteria B. burgdorferi. If the tick was saved, it can be identified and tested. Laboratories such as IGeneX (www.igenex.com) and MDL (www.mdlab.com) test ticks for the presence of the Lyme bacteria using the PCR test.
|
Preventing Lyme Disease
Wear long-sleeve shirts and long pants when going into tick country. Light colors are best - ticks can be seen easier. Tuck pants into socks and spray the clothes with a known tick repellent. After being in a tick area, check skin and hair areas completely. Promptly remove all ticks after being in an area known to harbor Lyme ticks. Check pets carefully, they are a source of entry for ticks entering the house. Deer hunters need to spend extra time checking their gear before bringing it into autos and home.
How to Remove a Tick
- Use tweezers of forceps.
- Grasp the tick mouthparts close to the skin.
- Use tissue to avoid touching the tick with fingers.
- Avoid squeezing the tick which may spread the infected body fluids.
- Pull the tick straight out. Do not twist. Do not attempt to burn the tick.
- Save the tick (you may want to have it tested for B.burgdorferi or other infectious agents).
- Wash your hands with soap and water.
- Apply antiseptic to bite site.
|
|