Walking Well: Lyme Disease

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Course
If you are bitten by an infected tick, in most cases on the thigh, buttocks or armpit, the earliest sign of infection is a red rash starting as a bump like a mosquito bite, which may become clear in the center and develop into a ring. This may appear 2 to 30 days after the bite. As soon as there is a rash or suggestive symptoms, you should consult a physician for diagnosis and treatment. About 75 percent of Lyme disease patients have a skin lesion and 25 percent remember the tick bite. The disease spreads from a local skin infection into the blood and may progress through 3 stages. Many patients recover completely in stage 1. Complications occur in those who do not. These start with the ring-shaped dermatitis in stage 1. This may feel like it is burning and may spread to additional areas. At the same time malaise, fatigue, chills, fever (up to 103 F), headache, backache and stiff neck may occur. Lymph glands may be swollen. Very few patients have arthritis during this period. This stage lasts 3-4 weeks and most patients recover.

More advanced Lyme disease primarily affects the nervous system, heart or joints. The neurological signs include meningitis (causing headache and neck stiffness), facial nerve paralysis and sensory nerve changes (resulting in pain or abnormal sensations). The heart problems are irregular heartbeat (causing palpitations and fainting), weakened heart pumping and heart enlargement. Frequently there is a recurrence of the skin lesions in different forms. Often fatigue and malaise persist for many weeks.

Arthritis is the major complication in 50 percent of patients who have had the rash and generally strikes large joints, especially the knees. A hiker reported to me that Lyme disease caused knee pain that was successfully treated. The joint changes come on within a few weeks to months but may be delayed up to 2 years. Knees are more swollen than painful in 10 percent of Lyme disease patients and, if untreated, this may last several years with some bone and cartilage damage. Lesions of all the affected systems become more severe in the last stage.

Diagnosis
Lyme disease can be readily detected early in the infection (3 to 4 weeks) by a blood test that measures the antibodies against the spriochetes. It is possible to culture spirochetes from skin or blood, but this is slower and more difficult. The VDRL test for syphilis is negative. The type of antibodies change and the titer rises later in the disease with the arthritis.

Although the disease was only described in the 1970's, we know that spirochete-bearing ticks lived on Long Island in 1940 thanks to PCR (O. J. Simpson type DNA testing) and that museum specimens of white-footed mice collected in Massachusetts in 1894 have evidence of infection.

Treatment
Antibiotic treatment of Lyme disease works in any of the stages but of course is best and most effective when given early. Doxycycline, tetracycline and amoxicillin are the main drugs used, but others are used in various regimens depending upon the site of the problem and its severity, including chronic arthritis or meningitis. Essentially all of the manifestations of Lyme disease can yield to treatment with a favorable outcome. Prophylactic antibiotic treatment is not a good idea, since the disease incidence is so low in an ongoing test.