Updated Guidelines on Diagnosis, Treatment of Lyme Disease

Alexandria, Va., Oct. 2, 2006—In response to growing concern and confusion about Lyme disease, the Infectious Diseases Society of America (IDSA) has updated its Clinical Practice Guidelines on the disease, in order to provide guidance to physicians and patients based on the latest scientific evidence.  The guidelines were originally published in 2000.  The most significant changes in the updated version include:

• The addition of information on human granulocytic anaplasmosis (HGA) and babesiosis, two diseases transmitted by the same tick that transmits Lyme disease;
• Recommendations of a single dose of an antibiotic for certain high-risk patients who have been bitten by a tick but do not have symptoms of Lyme disease;
• Expanded discussion and definition of so-called “chronic” or post-Lyme syndromes.

The Guidelines, developed by an expert panel according to widely accepted criteria for evidence-based medicine, contain updated information on the epidemiology, clinical features and diagnosis of Lyme disease, according to Gary P. Wormser, Chief, Division of Infectious Diseases and Vice Chairman of the Department of Medicine, New York Medical College.  Dr. Wormser is lead author of IDSA’s 2006 Lyme disease guidelines and chair of the expert panel that developed the guidelines.

“We worked to make the guidelines as comprehensive as possible based on a thorough review of all credible scientific literature,” said Dr. Wormser.  The guidelines are now available on the IDSA Web site and will be published in the Nov. 1 edition of the journal, Clinical Infectious Diseases.

Lyme disease is caused by an infection with the bacteria Borrelia burgdorferi. This infection is principally transmitted by the black-legged deer tick (Ixodesscapularis) that typically feeds on small mammals, birds and deer but may also feed on cats, dogs and humans.  Although the disease has been reported in nearly all states, the majority of cases are concentrated in the Mid-Atlantic and northeast states.  Other regions in the United States with significant numbers of cases include Wisconsin, Minnesota and northern California.

“Most people who are infected with Lyme disease have a circular, red rash surrounding the site of a tick bite, that may be accompanied by muscle and joint aches and less commonly, facial paralysis,” said Lyme disease expert Paul Auwaerter, M.D., M.B.A., who was a reviewer of the IDSA guidelines.  Dr. Auwaerter is the Clinical Director of the Division of Infectious Diseases, Johns Hopkins University School of Medicine, Baltimore, and managing editor of the Johns Hopkins Antibiotic Guide.

“The symptoms are sometimes alarming, but with proper diagnosis and antibiotic treatment almost all will go away within a few weeks.”

HGA and Babesiosis

Although Lyme disease is the most common tick-borne infection in North America and Europe, the updated guidelines now contain information on two other tick-related diseases, HGA and babesiosis.  HGA is a tick-associated disease caused by a species of bacteria called Anaplasma phagocytophilum. The most common symptoms are headache, fever, chills, muscle pain and fatigue.  Babesiosis is a parasitic infection which affects the red blood cells, resembling malaria; it is also transmitted through the bite of a deer tick.  In the United States, the disease usually does not cause symptoms in healthy individuals and is most likely to affect those who are elderly or have compromised immune systems.

Treatment for Lyme Disease

Although routine preventive antibiotic administration is not recommended for individuals with tick bites and no symptoms of disease, one substantive change in IDSA’s treatment recommendations is that some selected, high-risk tick bites may be treated with a single dose of the antibiotic doxycycline for people who are eligible for the drug, according to Dr. Wormser.  Eligibility criteria for preventive Lyme disease treatment with doxycycline include:

• the attached tick can be reliably identified as an Ixodes scapularis tick that is estimated to have been attached for 36hours or longer;
• preventive treatment can be started within 72 hours of the time the tick was removed;
• ecologic information indicates that the local rate of infection of these ticks with B. burgdorferi bacteria is 20 percent or greater.

Whether use of antibiotic prevention after a tick bite will reduce the incidence of HGA or babesiosis is not known, Dr. Wormser said.

In general, doxycycline is not recommended in pregnant women and in children under the age of eight, he said.

Most patients who develop Lyme disease are cured with a single course of 10-28 days of antibiotics, depending on the stage of their illness.  Occasionally a second course of treatment is necessary.   More prolonged antibiotic therapy is not recommended and may be dangerous, according to Dr. Wormser.

“Nearly all people – more than 95 percent – who do get sick with Lyme disease and are treated with the recommended course of antibiotics get better and go on with their lives,” he said.

“Chronic” or Post -Lyme Disease Syndromes

A small number of patients report a variety of non-specific symptoms such as generalized pain, joint pain or fatigue following an episode of Lyme disease that has been appropriately treated with antibiotics. The updated IDSA guidelines contain greater detail in the discussion of post-Lyme disease syndromes, and conclude that objective evidence of prior B. burgdorferi infection must be part of any acceptable definition of these syndromes.

As in the past, the guidelines do not recommend ongoing antibiotic therapy for those with chronic symptoms who have completed the recommended initial course of treatment for Lyme disease.

“After a thorough review of the literature, the panel concluded there is no convincing biologic evidence for symptomatic, chronic Borrelia burgdorferi infection after completion of the recommended treatment for Lyme disease,” the guidelines state.

Furthermore, long-term antibiotic therapy may be dangerous and it also can lead to complications for the patient such as blood stream catheter infection (for those on intravenous antibiotics) and Clostridium difficile colitis (a potentially severe infection of the bowel). Long-term antibiotic therapy may also foster the development of drug-resistant superbugs that are difficult to treat, Dr. Auwaerter added.

“IDSA and its expert panel do not doubt that patients with symptoms that persist for weeks, months or longer are suffering, but many report non-specific symptoms that also are associated with a number of other medical conditions,” Dr. Wormser said. “People who continue to have symptoms that persist after appropriate antibiotic treatment for Lyme disease should talk to their physicians about whether the diagnosis was accurate or if they may have a different or new illness to be certain they get the proper medical care.”

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