Lyme Disease

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What is Lyme Disease?

Lyme Disease, also known as Lyme Borreliosis, is an inflammatory disorder that is transmitted by minute ticks of the Izodes ricinus complex, and the infection is caused by a spirochete, Borrelia burgdorferi. The primary reservoir (carrier) for B. burgdorferi in the United States is the white-footed mouse, and the preferred host for the adult tick is the deer, but in Europe it is the sheep.

How common is Lyme Disease?

First recognized in 1975 in a cluster of cases in Lyme, Connecticut, this tick-borne illness has been reported in 49 states in the United States, with 17,730 cases in year 2000 alone. Majority (more than 90%) of these were in Massachusetts, Maryland, Wisconsin, Minnesota, California and Oregon. This disease is also found in Europe, across the former Soviet Union, in Japan and in China.

Who are the usual victims?

The incidence is highest in young children (5-10) and in adults (50-59) living in heavily wooded areas. The onset is usually summer and early fall. Very few of these patients recall the tick bite. The infection rate following the tick bite is about 1.4%. Although this rate is not high, it is obviously important that one prevents tick bites because the complications can be serious.

How is the disease transmitted?

Deer ticks are very small and hard to see. When the ticks in their nymphal stage attack humans, they attach themselves to the skin and engorge on blood for days. B. burgdorferi is becomes infective only after it has been in place for 36-48 hours, the reason why screening for ticks after exposure and removing them can aid in avoiding Lyme Disease. When the B. burgorferi enters the skin at the site of the tick bite, it spreads to the lymph glands and also circulates with the blood to various organs.

What are the signs and symptoms?

The best clinical indicator (obvious sign) of Lyme Disease is erythema migrans, which begins as a red macule or papule on the skin of the proximal (nearest the body) portion of the arm or leg, especially the thigh, buttocks and axilla (arm pit), between 3 to 32 days after a tick bite. This usually lasts for a few weeks. A flu-like muscle and bone syndrome frequently accompanies erythema migrans, manifesting as fatigue, chills, fever, malaise, headache, bones aches, muscle pains and stiff neck. The symptoms are usually changing and intermittent. Fatigue and malaise may linger for a month or longer.

What are the possible complications?

About 15% of cases develop neurologic (brain and nerve) abnormalities, which last for months but which recover completely. Cardiac findings, like heart block leading to very slow heart beat, and inflammation of the heart muscles occur in 8% of patients within weeks of the erythema migrans, most of which usually recover. Arthritis happens in 60% of cases, with painful and swollen joints, especially the knees, which could last up to more than 6 months in 10% of patients.

How is the diagnosis made?

When the patient is in an endemic area and the classical erythema migrans is noted, no laboratory confirmation is needed. The clinical acumen (knowledge and experience) of the attending physician is enough to make the diagnosis and start the appropriate treatment. ELISA serum test has a sensitivity of 98% and specificity of 72%, and reserved for those cases where the index of suspicion is high. Identification of B.burgdorferi takes weeks and difficult. Although testing the fluids from the joints of untreated patients for spirochetal DNA could be useful, the test is not generally available yet. Examination of the synovial fluids/membrane, and other blood and immune system indicators could also be helpful in ruling out other diseases that could mimic Lyme Disease and arrive at the correct diagnosis.

What diseases may be confused with Lyme Disease?

Illnesses that can present like Lyme Disease include juvenile rheumatoid arthritis in children, Reiter's syndrome and atypical rheumatoid arthritis in adults, Ehrlichiosis (an emerging infection transmitted by the same tick), idiopathic (cause unknown) Bell's Palsy, as well as lymphocytic meningitis, chronic fatigue syndrome, peripheral neuropathies and other central nervous system disorders.

How can Lyme Disease be prevented?

Just like almost all maladies afflicting the human race, prevention is always best in dealing with Lyme Disease. Those who live in endemic areas or persons high at risk must be educated about tick habitat, the disease in particular, and about tick-borne illnesses in general. Those with occupational exposure can be protected by insect repellant spray on their clothing and appropriate repellant for the exposed skin. After being in the wooded areas, individuals must routinely examine themselves for ticks, using a magnifying lens is necessary. Arbitrarily taking antibiotics "to prevent Lyme Disease" is not recommended because of potential adverse side effects.

Is there a vaccine for Lyme Disease?

New vaccines, based on recombinant outer surface protein specific to B. bugdorferi, are being clinically tested. Thus far, they have been found effective and safe among adults in the study.

What is the treatment for Lyme Disease? Appropriate antibiotic regimen is the treatment of choice for Lyme Disease. The attendant symptoms are managed accordingly. Complications like heart block may require a cardiac pacemaker and effusion in the knees may need to be tapped, etc. Each stage of the illness is treated respectively, and the prognosis is generally good for most patients. The standard of care is outlined in the guidelines drafted by the Infectious Diseases Society of America. As we have stated earlier, routinely treating all persons exposed to, or bitten by, the tick with antiobiotics is not recommended, because only less than one percent of the totally asymptomatic (symptoms-free) patients eventually develop the disease. Persons with tick bites should be closely monitored for skin rash and fever for one whole month following exposure. Each patient must be individually evaluated, because a shot-gun approach will cause more harm than good.
©2003Raoul R. Diez, M.A.O.D.