Lyme Disease

Lyme disease facts

• Lyme disease is a bacterial illness that is spread by tick bites.
• Lyme disease can affect the skin, joints, heart, and the nervous system.
• Lyme disease occurs in phases -- the early phase beginning at the site of the tick bite with an expanding ring of redness.
• Lyme disease is diagnosed based on the patient's clinical signs of illness and the detection of Lyme antibodies in the blood.
• Lyme disease is treated with antibiotics.

What is Lyme disease? What causes Lyme disease?

Lyme disease is a bacterial illness caused by a bacterium called a "spirochete." In the United States, the actual name of the bacterium is Borrelia burgdorferi. In Europe, another bacterium, Borrelia afzelii, also causes Lyme disease. Certain ticks found on deer harbor the bacterium in their stomachs. Lyme disease is spread by these ticks when they bite the skin, which permits the bacterium to infect the body. Lyme disease is not contagious from an affected person to someone else. Lyme disease can cause abnormalities in the skin, joints, heart, and nervous system.

What is the history of Lyme disease?

Interestingly, the disease only became apparent in 1975 when mothers of a group of children who lived near each other in Lyme, Connecticut, made researchers aware that their children had all been diagnosed with rheumatoid arthritis. This unusual grouping of illness that appeared "rheumatoid" eventually led researchers to the identification of the bacterial cause of the children's condition, what was then called "Lyme disease" in 1982.
Ticks are carriers of the Lyme bacterium in their stomachs. The ticks then are vectors that can transmit the bacterium to humans with a tick bite. The number of cases of the disease in an area depends on the number of ticks present and how often the ticks are infected with the bacteria. In certain areas of New York, where Lyme disease is common, over half of the ticks are infected. Lyme disease has been reported most often in the northeastern United States, but it has been reported in all 50 states, as well as China, Europe, Japan, Australia, and parts of the former Soviet Union. In the United States, it is primarily contracted in the Northeast from the states of Maine to Maryland, in the Midwest in Minnesota and Wisconsin, and in the West in Oregon and Northern California.

Picture of a deer tick

What are symptoms and signs of Lyme disease?

Lyme disease affects different areas of the body in varying degrees as it progresses. The site where the tick bites the body is where the bacteria enter through the skin. As the bacteria spread in the skin away from the initial tick bite, the infection causes an expanding reddish rash that is often associated with "flu-like" symptoms. Later, it can produce abnormalities in the joints, heart, and nervous system.
Lyme disease is medically described in three phases as: (1) early localized disease with skin inflammation; (2) early disseminated disease with heart and nervous system involvement, including palsies and meningitis; and (3) late disease featuring motor and sensory nerve damage and brain inflammation as well as arthritis.
In the early phase of the illness, within days to weeks of the tick bite, the skin around the bite develops an expanding ring of unraised redness. There may be an outer ring of brighter redness and a central area of clearing, leading to a "bull's-eye" appearance. This classic initial rash is called "erythema migrans" (formerly called erythema chronicum migrans). Patients often can't recall the tick bite (the ticks can be as small as the periods in this paragraph). Also, they may not have the identifying rash to signal the doctor. More than one in four patients never even develop a rash. The redness of the skin is often accompanied by generalized fatigue, muscle and joint stiffness, swollen lymph nodes ("swollen glands"), and headache, resembling symptoms of a virus infection.
The redness resolves, without treatment, in about a month. Weeks to months after the initial redness of the skin the bacteria and their effects spread throughout the body. Subsequently, disease in the joints, heart, and nervous system can occur.
The later phases of Lyme disease can affect the heart, causing inflammation of the heart muscle. This can result in abnormal heart rhythms and heart failure. The nervous system can develop facial muscle paralysis (Bell's palsy), abnormal sensation due to disease of peripheral nerves (peripheral neuropathy), meningitis, and confusion. Arthritis, or inflammation in the joints, begins with swelling, stiffness, and pain. Usually, only one or a few joints become affected, most commonly the knees. The arthritis of Lyme disease can look like many other types of inflammatory arthritis and can become chronic.
Researchers have also found that anxiety and depression occur with an increased rate in people with Lyme disease. This is another important aspect of the evaluation and management of this condition.

How is Lyme disease diagnosed?

In early Lyme disease, doctors can sometimes make a diagnosis simply by finding the classic red rash (described above), particularly in people who have recently been in regions in which Lyme disease is common. The doctor might review the patient's history and examine the patient in order to exclude diseases with similar findings in the joints, heart, and nervous system. Blood testing for antibodies to Lyme bacteria is generally not necessary or helpful in early stage disease, but it can help in diagnosis in later stages. (Antibodies are produced by the body to attack the bacteria and can be evidence of exposure to the bacteria. These antibodies can be detected using a laboratory method called an enzyme-linked immunosorbent assay [ELISA].) Antibodies, however, can be false indicators of disease, since they can persist for years after the disease is cured. Moreover, false-positive tests in patients with nonspecific findings (those that are not specifically suggestive of Lyme disease) can lead to confusion. Currently, the confirmatory test that is most reliable is the Western Blot assay antibody test. More accurate tests are being developed.
Generally, Lyme blood testing is helpful in a patient who has symptoms compatible with Lyme disease, who has a history of a tick bite at least a month prior, or who has unexplained disorders of the heart, joints, or nervous system that are characteristic of Lyme disease.

What is the treatment for Lyme disease, and what is its prognosis?

Most cases of Lyme disease are curable with antibiotics. This is so true that some authors of Lyme disease research have stated that the most common cause of lack of response of Lyme disease to antibiotics is a lack of Lyme disease to begin with! The type of antibiotic depends on the stage of the disease (early or late) and what areas of the body are affected. Early illness is usually treated with medicines taken by mouth, for example, doxycycline (Vibramycin), amoxicillin (Amoxil), or cefuroxime axetil (Ceftin). Of note, doxycycline should not be used in pregnancy or in children under 8 years of age.
Therefore, if a person finds a typical bull's-eye skin rash (described above) developing in an area of a tick bite, they should seek medical attention as soon as possible. Generally, antibiotic treatment resolves the rash within one or two weeks with no long-term consequences. Later illness such as nervous-system disease might require intravenous drugs; examples are ceftriaxone (Rocephin) and penicillin G.
For the relief of symptoms, pain-relieving medicines might be added. Swollen joints can be reduced by the doctor removing fluid from them (arthrocentesis). An arthrocentesis is a procedure whereby fluid is removed from a joint using a needle and syringe under sterile conditions. It is usually performed in a doctor's office. Rarely, even with appropriate antibiotics, the arthritis continues. It has been suggested by researchers that sometimes joint inflammation can persist even after eradication of the Lyme bacteria. This has been explained as an ongoing autoimmune response causing inflammation of the joint that was initially stimulated by the original bacterial infection. The doctor also can use oral medications such as ibuprofen (Motrin, Nuprin) to reduce inflammation and improve function.

How can Lyme disease be prevented? Is there a vaccine?

Avoiding known tick-infested areas obviously can prevent transmission of Lyme disease. Because Lyme disease is transmitted by ticks attaching to the body, it is important to use tick-bite avoidance techniques when visiting known tick-infested areas. Spraying insect repellant containing DEET onto exposed skin can help. Wearing long pants tucked into boots and long sleeves can protect the skin. Clothing, children, and pets should be examined for ticks. Ticks can be removed gently with tweezers and saved in a jar for later identification. Bathing the skin and scalp and washing clothing upon returning home might prevent the bite and transmission of the disease.
If a person is bitten by the classic deer tick (Ixodes) that has been attached for at least 36 hours, a single dose of doxycycline (200 mg) can be helpful for prevention of Lyme disease. This therapy is not recommended if the tick is acquired in an area where these ticks are not commonly infested (infection rate less than 20%) with the bacterium (Borrelia) that causes Lyme disease. Also, doxycycline should not be used in pregnancy or in children under 8 years of age.
Vaccines were formerly on the market; however, as of Feb. 25, 2002, the manufacturer announced that the LYMErix Lyme disease vaccine would no longer be commercially available. Further studies of vaccines are needed. For now, ideal prevention focuses on the recommendations of the preceding paragraph.

For more information about Lyme disease, please visit the following site:
American Lyme Disease Foundation (http://www.aldf.com)
American Lyme Disease Foundation, Inc.
Mill Pond Offices
293 Route 100, Suite 204
Somers, New York 10589
800-876-LYME
Alternatively, you may contact the CDC:
U.S. Centers for Disease Control and Prevention (CDC)
404-332-4555

REFERENCES:

Klippel, John H., et al., eds. Primer on the Rheumatic Diseases. 13th ed. New York: Springer and Arthritis Foundation, 2008.

Koopman, William, et al., eds. Clinical Primer of Rheumatology. Philadelphia: Lippincott Williams & Wilkins, 2003.

Ruddy, Shaun, et al., eds. Kelley's Textbook of Rheumatology. Philadelphia: W.B. Saunders Co., 2000.

Medical Author:

William C. Shiel Jr., MD, FACP, FACR

Medical Editor:

Melissa Conrad Stöppler, MD

Source:Medicinenet.com.