A Lyme disease case illustrating crucial differences between IDSA and ILADS guidelines

Townsend Letter for Doctors and Patients, May, 2007 by Marcus A. Cohen

A young urbanite living in the Northeastern US went for an outing in the country on one of those balmy days late last December. At a clearing in the trees, he lay down on a grassy spot and, taking his ease in the unusually warm winter sunlight, he probably gave no thought to the likelihood that the area might be prime habitat for Lyme ticks. Had the thought slipped into his mind, he still might not have worried since he was clothed from feet to neck, wearing shoes, socks, pants, a light sweater, and a jacket over his shirt.

Later that day, back in his city apartment, he felt an irritation on his back. Self-examination revealed a small dark tick embedded in his skin. Extracting as much as possible of the little blood-sucker, he wrapped the remnants of its body in tissue paper, intending to have the tick tested for Lyme disease; if it was carrying the bacteria that cause Lyme, he would immediately seek medical help. Years ago, he had been bitten by a tick, hadn't notice the bite, and had developed Lyme disease. Diagnosed and treated late, the infection persisted, with a number of prostrating symptoms. Now, the memory of his ordeal made him keep the tick. But as the days passed and the tick's body decomposed, the young man never got around to bringing it to a qualified lab.

Two weeks after the young man's country outing, he developed a rash on his chest, and he began to feel symptoms similar to those experienced during his first Lyme infection. Alarmed, he checked into the hospital, consulting the same doctor who had previously diagnosed and treated him. Mainly on the basis of the rash and the resemblance of past and current symptoms, the doctor prescribed oral antibiotics. Then the doctor ordered a Lyme antibody test to confirm that the man had been newly infected. The test was inconclusive. After a few weeks of treatment, the man's symptoms cleared up, and he has since remained symptom-free.

This case came to my attention in January, after I had submitted my column about the latest guidelines for Lyme disease published by the Infectious Diseases Society of America (IDSA) in 2006. (1) How would a physician adhering to the IDSA recommendations handle it?

A press release from the Lyme Disease Association (LDA), issued in October 2006 when IDSA published its revised guidelines, noted that the "new IDSA guidelines advise against clinical discretion in determining whether or not patients have Lyme disease. Instead, they advise that doctors either see a characteristic rash known to occur in about half the patients, or that patients register positive on the two tests recommended by the Centers for Disease Control & Prevention (CDC) tests known to miss up to half the patients." (2)

The LDA, representing more Lyme patients than any other organization in the US, particularly chronic patients, promotes guidelines published by the International Lyme and Associated Diseases Association (ILADS) in 2004. (3) These guidelines call for a clinical diagnosis, allowing physicians to weigh far more than the characteristic rash and antibody tests in determining whether to treat for Lyme disease. How would a physician belonging to the International Lyme and Associated Diseases Society (ILADS) handle the case described in the opening of this column?

An article cited in the October LDA press release (4) led me to phone Daniel Cameron, MD, acquaint him with this early case of Lyme disease (emphasis added), and ask for his opinion on the crucial differences in the IDSA and ILADS recommendations for diagnosis and care of the young man. Dr. Cameron, the sole author of the cited study, was also the lead author of the published ILADS treatment guidelines. He has been practicing in Mt. Kisco, New York (Westchester County) for 19 years. Much of his recent clinical research has focused on Lyme patients who fail antibiotic treatment. His findings to date suggest that the overwhelming reason is because they were diagnosed and treated late.

Here is Dr. Cameron's comparison:

The IDSA guidelines would not have recommended treatment for the tick bite. They suggest that a single dose of doxycycline (up to a maximum of 200 mg.) could be prescribed within 72 hours of the tick's removal, but under the following conditions:

(1) if the tick is readily identifiable as a deer tick in the adult or nymph stage and is estimated to have been attached for 36 hours or more, based on engorgement level or certainty of the time of exposure to the tick;

(2) if ecologic information indicates that the local tick infection rate with Lyme is at 20% or more;

(3) if doxycycline is not contraindicated.

In the case detailed above, even if the tick had been tested and confirmed as a carrier (note that such testing is not recommended by the IDSA guidelines), a physician sticking to the IDSA guidelines would wait for the characteristic rash to appear--and be larger than two inches--before prescribing treatment.

I quote from the IDSA recommendations concerning the rash: "Erythema migrans (EM, the characteristic rash) is the only manifestation of Lyme disease in the US that is sufficiently distinctive to allow clinical diagnosis in the absence of laboratory confirmation."