Overview Of Lyme Disease
Lyme disease is a bacterial infection that is spread through the bite of one of several types of ticks.
Commonly Associated With
Borreliosis; Bannwarth syndrome
Causes Of Lyme Disease
Lyme disease is caused by bacteria called Borrelia burgdorferi (B burgdorferi). Blacklegged ticks (also called deer ticks) can carry these bacteria. Not all species of ticks can carry these bacteria. Immature ticks are called nymphs, and they are about the size of a pinhead. Nymphs pick up bacteria when they feed on small rodents, such as mice, infected with B burgdorferi. You can only get the disease if you are bitten by an infected tick. This disease was first reported in the United States in 1977 in the town of Old Lyme, Connecticut.
The same disease occurs in many parts of Europe and Asia.
In the United States, most infections occur in the following areas:
- Northeastern states, from Virginia to Maine
- North-central states, mostly in Wisconsin and Minnesota
- West Coast, mainly in the northwest
There are three stages of Lyme disease.
- Stage 1 is called early localized Lyme disease. The bacteria have not yet spread throughout the body.
- Stage 2 is called early disseminated Lyme disease. The bacteria have begun to spread throughout the body.
- Stage 3 is called late disseminated Lyme disease. The bacteria have spread throughout the body.
Risk factors for this disease include:
- Doing outside activities that increase tick exposure (for example, gardening, hunting, or hiking) in an area where Lyme disease occurs
- Having a pet that may carry infected ticks home
- Walking in high grasses in areas where Lyme disease occurs
Important facts about tick bites and Lyme disease:
- A tick must be attached to your body for 24 to 36 hours in order to spread the bacteria to your blood.
- Blacklegged ticks can be so small that they are almost impossible to see. Many people with Lyme disease never even see or feel a tick on their body.
- Most people who are bitten by a tick do not get the disease.
Symptoms of early localized Lyme disease (stage 1) begin days or weeks after infection.
They are similar to the flu and may include:
- Fever and chills
- General ill feeling
- Joint pain
- Muscle pain
- Stiff neck
- There may be a “bull’s eye” rash, a flat or slightly raised red spot at the site of the tick bite. Often there is a clear area in the center. It can be large and expanding in size. This rash is called erythema migrans. Without treatment, it can last 4 weeks or longer.
Symptoms may come and go. Untreated, the bacteria can spread to the brain, heart, and joints.
Symptoms of early disseminated Lyme disease (stage 2) may occur weeks to months after the tick bite, and may include:
- Numbness or pain in the nerve area
- Paralysis or weakness in the muscles of the face
- Heart problems, such as skipped heartbeats (palpitations), chest pain, or shortness of breath
- Symptoms of late disseminated Lyme disease (stage 3) can occur months or years after the infection.
The most common symptoms are muscle and joint pain. Other symptoms may include:
- Abnormal muscle movement
- Joint swelling
- Muscle weakness
- Numbness and tingling
- Speech problems
- Thinking (cognitive) problems
Exams & Tests
A blood test can be done to check for antibodies to the bacteria that cause Lyme disease. The most commonly used is the ELISA for Lyme disease test. An immunoblot test is done to confirm ELISA results. Be aware, though, in the early stage of infection, blood tests may be normal. Also, if you are treated with antibiotics in the early stage, your body may not make enough antibodies to be detected by blood tests.
In areas where the disease is more common, your health care provider may be able to diagnose early disseminated Lyme disease (Stage 2) without doing any lab tests.
Other tests that may be done when the infection has spread include:
- Echocardiogram to look at the heart
- MRI of the brain
- Spinal tap (lumbar puncture to examine spinal fluid)
Treatment Of Lyme Disease
People bitten by a tick should be watched closely for at least 30 days to see if a rash or symptoms develop. A single dose of the antibiotic doxycycline may be given to someone soon after being bitten by a tick when all of these conditions are true:
- The person has a tick that can carry Lyme disease attached to his or her body. This usually means that a nurse or doctor has looked at and identified the tick.
- The tick is thought to have been attached to the person for at least 36 hours.
- The person is able to start taking the antibiotic within 72 hours of removing the tick.
- The person is 8 years or older and is not pregnant or breastfeeding.
- The local rate of ticks carrying B burgdorferi is 20% or higher.
A 10-day to 4-week course of antibiotics is used to treat people who are diagnosed with Lyme disease, depending on the choice of the drug: