LYME DISEASE

What is it?

In the early 1970s, a mysterious clustering of arthritis occurred among children in Lyme, Connecticut, and surrounding towns. Medical researchers soon recognised the illness as a distinct disease, which they called Lyme disease. They subsequently described the clinical features of Lyme disease, established the usefulness of antibiotic therapy in its treatment, identified the deer tick as the key to its spread, and isolated the bacterium that caused it.

What are the symptoms?

Erythema migrans - In most people, the first symptom of Lyme disease is a red rash known as erythema migrans (EM). The tell-tale rash starts as a small red spot that expands over a period of days or weeks, forming a circular, triangular, or oval-shaped rash. Sometimes the rash resembles a bull's eye because it appears as a red ring surrounding a central clear area. The rash, which can range in size from that of a dime to the entire width of a person's back, appears within a few weeks of a tick bite and usually occurs at the site of a bite. As infection spreads, several rashes can appear at different sites on the body.

Erythema migrans is often accompanied by symptoms such as fever, headache, stiff neck, body aches, and fatigue. Although these flu-like symptoms may resemble those of common viral infections, Lyme disease symptoms tend to persist or may occur intermittently.

Arthritis - After several months of being infected by B. burgdorferi, slightly more than half of those people not treated with antibiotics develop recurrent attacks of painful and swollen joints that last from a few days to a few months. The arthritis can shift from one joint to another; the knee is most commonly affected. About 10 to 20 percent of untreated patients will go on to develop chronic arthritis.

Neurological symptoms - Lyme disease can also affect the nervous system, causing symptoms such as stiff neck and severe headache (meningitis), temporary paralysis of facial muscles (Bell's palsy), numbness, pain or weakness in the limbs, or poor motor co-ordination. More subtle changes such as memory loss, difficulty with concentration, and a change in mood or sleeping habits have also been associated with Lyme disease.

Nervous system abnormalities usually develop several weeks, months, or even years following an untreated infection. These symptoms often last for weeks or months and may recur.

Heart problems - Fewer than one out of ten Lyme disease patients develops heart problems, such as an irregular heartbeat, which can be signalled by dizziness or shortness of breath. These symptoms rarely last more than a few days or weeks. Such heart abnormalities generally surface several weeks after infection.

Other symptoms - Less commonly, Lyme disease can result in eye inflammation, hepatitis, and severe fatigue, although none of these problems is likely to appear without other Lyme disease symptoms being present.

What tests will the Doctor want to do?

Unfortunately, the Lyme disease microbe itself is difficult to isolate or culture from body tissues or fluids. Most physicians look for evidence of antibodies against B. burgdorferi in the blood to confirm the bacterium's role as the cause of a patient's symptoms. Antibodies are molecules or small substances tailor-made by the immune system to lock onto and destroy specific microbial invaders.

Some patients experiencing nervous system symptoms may also undergo a spinal tap. Through this procedure doctors can detect brain and spinal cord inflammation and can look for antibodies in the spinal fluid.

The inadequacies of the currently available antibody tests may prevent them from firmly establishing whether the Lyme disease bacterium is causing a patient's symptoms. In the first few weeks following infection, antibody tests are not reliable because a patient's immune system has not produced enough antibodies to be detected. Antibiotics given to a patient early during infection may also prevent antibodies from reaching detectable levels, even though the Lyme disease bacterium is the cause of the patient's symptoms. Because some tests cannot distinguish Lyme disease antibodies from antibodies to similar organisms, patients may test positive for Lyme disease when their symptoms actually stem from other bacterial infections. A lack of standardisation of antibody tests and poor quality control also contribute to inaccuracies in test results.

What is the treatment?

Nearly all Lyme disease patients can be effectively treated with an appropriate course of antibiotic therapy. In general, the sooner such therapy is begun following infection, the quicker and more complete the recovery.

Antibiotics, such as doxycycline or amoxicillin taken orally for a few weeks, can speed the healing of the erythema migrans rash and usually prevent subsequent symptoms such as arthritis or neurological problems.

Patients younger than 9 years old, or pregnant or lactating women with Lyme disease, are treated with amoxicillin or penicillin, because doxycycline can stain the permanent teeth developing in young children or unborn babies. Patients allergic to penicillin are given erythromycin.

Lyme disease patients with neurological symptoms are usually treated with the antibiotic ceftriaxone given intravenously once a day for a month or less. Most patients experience full recovery. Lyme arthritis may be treated with oral antibiotics.

Patients with severe arthritis may be treated with ceftriaxone or penicillin given intravenously. To ease these patients' discomfort and further their healing, the physician might also give anti-inflammatory drugs, draw fluid from affected joints, or surgically remove the inflamed lining of the joints.

Lyme arthritis resolves in most patients within a few weeks or months following antibiotic therapy, although it can take years to disappear completely in some people. Some Lyme disease patients who are untreated for several years may be cured of their arthritis with the proper antibiotic regimen. If the disease has persisted long enough, however, it may irreversibly damage the structure of the joints.

Physicians prefer to treat Lyme disease patients experiencing heart symptoms with antibiotics such as ceftriaxone or penicillin given intravenously for about 2 weeks. If these symptoms persist or are severe enough, patients may also be treated with corticosteroids or given a temporary internal cardiac pacemaker. People with Lyme disease rarely experience long-term heart damage.

Following treatment for Lyme disease, some people still have persistent fatigue and aches. This general malaise can take months to subside, although it generally does so spontaneously without requiring additional antibiotic therapy.

Researchers are currently conducting studies to assess the optimal duration of antibiotic therapy for the various manifestations of Lyme disease. Investigators are also testing newly developed antibiotics for their effectiveness in countering the Lyme disease bacterium.

Unfortunately, a bout with Lyme disease is no guarantee that the illness will be prevented in the future. The disease can strike more than once in the same individual if he or she is re-infected with the Lyme disease bacterium.