Overview of Lyme Disease With a Focus on Clinical Progression and DiagnosisDr. Jorge Parada
- National Pest Management Association
Wednesday, June 18, 2014
Lyme disease is caused by bacteria called Borrelia burgdorferi
(B. burgdorferi), which is typically carried by blacklegged
(deer) ticks. The ticks pick up the bacteria when they bite
mice or deer that are infected with B. burgdorferi and then
transmit these bacteria to humans as well as dogs, horses and
cattle in some cases, thereby causing infection.
In most cases a tick must be attached to a person's body for
24-36 hours to spread the bacteria into the bloodstream. Because
blacklegged deer ticks are very small (the size of a poppy seed)
and can be difficult to detect, many people who are diagnosed with
Lyme disease may have never even noticed a tick on their body.
Fortunately, most people who are bitten by a tick do not get Lyme
disease, as most ticks are not blacklegged ticks and do not
transmit B. burgdoreri. Additionally, not all blacklegged ticks are
infected with the Lyme bacteria or may not be on the body long
enough to transmit infection. The somewhat lengthy period that a
tick must be on a body before infection takes hold, underscores the
necessity of performing a thorough tick check after spending any
Lyme disease was first reported in the United States in 1977 in
the town of Old Lyme, Connecticut, and New England continues to be
the area with the greatest amount of Lyme disease. In fact, 95
percent of Lyme cases occur in 15 states - most heavily
concentrated in New England and the Mid-Atlantic states. Another
high risk area for Lyme infections are the North-central states,
mostly in Wisconsin and Minnesota. The third area of highest Lyme
transmission is along the Northwest coast, including northern
California and the Pacific Northwest.
Lyme disease can progress through three stages and may cause
different symptoms, depending on how long the patient has been
infected and which body parts have been affected by the
The first stage of the disease is early localized Lyme disease
(the infection has not yet spread throughout the body). The second
stage is early disseminated Lyme disease (here the bacteria have
begun to spread throughout the body). The third stage is late
disseminated Lyme disease (where the bacteria have spread
throughout the body and may establish chronic infection).
Stage 1: Early
Localized Infection (One to four weeks post-tick bite)
The most classic sign of Lyme infection is an expanding,
circular red rash called erythema migrans (EM). The early localized
EM rash is a flat or slightly raised expanding red spot at the site
of the tick bite with a clear area in the center giving it a
"bull's eye" appearance. Typically it is > 5 cm (2 inches) in
size, but can be much larger. Without treatment, EM can last 4
weeks or longer. Other times the rash may present as a homogenous
ovoid rash (lacking central clearing). Atypical rashes have also
been reported (blisters or a necrotic lesion that may be mistaken
for a spider bite or Staph infection). On the other hand, some
people may get a small bump or redness at the site of a tick bite
that goes away in 1-2 days, like a mosquito bite. This is not a
sign of Lyme infection.
Other signs and symptoms of early Lyme infection are
non-specific and may include flu-like
symptoms. People may complain of a general ill feeling and lack of
energy. Often there are headaches
and stiff neck. Many people complain of joint pain.
Fever and chills, swollen lymph nodes and muscle pains are also
Some people may not develop (or notice) a rash. Others may lack
the generalized signs and symptoms of infection. Yet others may
have these findings, but not seek medical attention. Unfortunately,
untreated Lyme disease can progress and spread to the brain, heart
Stage 2: Early
Disseminated Infection (One to four months post-tick
Untreated, B. borgdorferi may spread from the site of the bite
to other parts of the body, typically affecting the
skin, joints, nervous system and the heart. The infection may
produce a mix of symptoms that may wax and wane. Often multiple EM
lesions appear in additional areas of the body. These typically are
a paler shade of red, and may be smaller than the EM of early
Other signs and symptoms of infection include not being able to
use the muscles of the face. Loss of muscle tone or paralysis on
one or both sides of the face is called facial or "Bell's" palsy.
Many patients present with severe headaches and neck stiffness due
to meningitis (inflammation of the spinal cord). Others may
complain of other neurologic problems such as pain, weakness, or
numbness in the arms or legs, and poor memory and reduced ability
to concentrate. Arthritis is another leading symptom with episodes
of pain, redness and swelling in the large joints, most typically
the knees. Others may suffer heart palpitations and dizziness due
to changes in heartbeat.
Many of these symptoms will resolve over a period of weeks to
months, even without treatment. However, in other cases that are
left untreated, Lyme disease will progress and can result in
Stage 3: Late
Disseminated Infection (Months to years post-tick bite)
A small number of persons with untreated infections may go on to
develop chronic conditions that can occur months or years after the
infections first occur. The most common are recurrent bouts of
arthritis, with severe joint pain and swelling (Lyme arthritis).
Large joints - especially the knees - are most often affected.
Arthritis caused by Lyme disease manifests itself differently than
other causes of arthritis and must be distinguished from
arthralgias (pain, but not swelling, in joints).
Brain and nervous system problems may develop chronic months to
years after infection. These include shooting pains, numbness or
tingling in the hands or feet, and problems with memory, mood or sleep,
and sometimes problems speaking or with vision may occur. Heart
problems are rare, but can become present long after one is bitten
by an infected tick. These may include problems with heart rhythm,
or inflammation of the structures surrounding the heart.
after treatment (post-treatment Lyme disease syndrome)
Some patients with Lyme disease have persistent subjective
symptoms that last months to years after treatment with
antibiotics. These symptoms can include muscle and joint pains,
cognitive defects, sleep disturbance, or fatigue. The cause of
these symptoms is not known, but there is no evidence that these
symptoms are due to ongoing infection with B. burgdorferi. There is
some evidence that these lingering symptoms are caused by an
autoimmune response, in which a person's immune system continues to
respond, doing damage to the body's tissues, even after the
infection has been cleared. Studies have shown that continuing antibiotic therapy is not helpful
and can actually be harmful, Management of these patients can be
quite challenging as often they seek additional, repeated courses
of therapy for their persistent symptoms.
Early Localized Lyme
Diagnosis can be made on clinical criteria alone. In areas where
Lyme is known to occur, a history of outdoor activities, with or
without a known tick bite in the presence of an EM rash is enough
to warrant treatment. Typically, no special testing will be
performed as it usually takes four to six weeks for antibodies
against B. borgdorferi to develop. Thus, blood tests may be
negative in 60-80 percent of the cases of early Lyme infection.
Diagnosis is made using a combination of clinical suspicion and
laboratory testing. In areas where Lyme is common and there is a
risk factor for exposure to ticks, signs and symptoms that are
strongly associated with Lyme infection (such as "Bell's" palsy or
an EM rash) are enough to justify laboratory testing for Lyme
infection. If no palsy or EM is noted, then other symptoms
consistent with early Lyme infection are needed.
Typically, doctors order two-step testing which consists of a
highly sensitive, but less specific screening blood tests using
enzyme-linked immunosorbent assay (ELISA)for antibodies directed
against B. borgdorferi. If the screening test returns negative, the
patient is considered negative and no further testing is performed.
If the ELISA is positive, then the more specific Western Blot (WB)
confirmatory test is performed. The Centers for Disease Control and
Prevention (CDC) has developed evidence-based criteria for Western
blot interpretation to determine if the test is positive, negative
Newer testing methods have been developed, but have not yet been
recommended for general use in the Infectious Diseases Society of
America (IDSA) Clinical Practice Guidelines for Lyme.
Like in early disseminated infection, diagnosis is made using a
combination of clinical suspicion and laboratory testing. In late
disease laboratory tests are nearly universally positive. The
absence of seroreactivity (reactivity of blood serum, especially to
a virus) in such a patient excludes the diagnosis of Lyme disease.
However, a positive Lyme test result does not prove a patient's
current symptoms are due to Lyme. Persons who were treated for Lyme
disease previously will often continue to test positive after
In patients where Lyme infection of the brain or nervous system
is suspected, a comparison of cerebral spinal fluid (CSF) Lyme
antibody levels compared to blood levels may be helpful, with
higher levels in the CSF than the blood supporting neuro-Lyme
It's best to avoid indiscriminant laboratory testing, especially
in areas without high concentrations of Lyme infection. Subjective
symptoms alone, such as fatigue, neurocognitive symptoms and
fibromyalgia-like symptoms are not regarded as an indication for
Lyme testing, as these symptoms are too vague to strongly support
Lyme infection. Indiscriminant testing, even using a highly
sensitive and specific test, will inevitably lead to many false
positive diagnosis. This in turn will lead many people to be
inappropriately treated for a Lyme infection that they do not have,
as well as delaying the workup for the true underlying cause of the
patient's signs and symptoms.
During the summer months, it's best to take
precautions against ticks whenever outdoors, especially in
areas known for tick populations.
- Wear long pants, long-sleeved shirts and closed-toe shoes when
outdoors, especially in wooded areas or tall grasses.
- Wear light colored clothing, which makes it easier to spot
ticks and other insects.
- Wear a bug spray containing at least 20% DEET when outdoors,
and reapply as directed on the label.
- When hiking, stay in the center of trails, away from
- Take steps to keep your own yard tick-free. Keep grass cut low
and remove weeds, woodpiles and debris, which can attract ticks and
- Inspect your pets for ticks on a routine basis. Just like
humans, pets can contract Lyme disease from ticks.
- Inspect yourself and your family members carefully for ticks
after being outdoors.
- If you find a tick on yourself or a family member, remove it
with a slow, steady pull so as not to break off the mouthparts and
leave them in the skin. Then, wash your hands and the bite site
thoroughly with soap and water. Ticks should be flushed down a
toilet or wrapped in tissue before disposing in a closed
- Be on the lookout for signs of tick bites, such as a telltale
red bull's eye rash around a bite. If you suspect a tick has bitten
you, seek medical attention.
- Learn the symptoms of Lyme disease and consult with your doctor
immediately if you believe you have contracted it.
- If you find a tick in your home or suspect you have ticks on
your property, contact a licensed pest professional who can inspect
and recommend a course of action to reduce or eliminate ticks on
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