Differential Diagnosis of Lyme Disease

Richard Krieger, MD, chairman of the Infection Control Committee at Chilton Medical Center, and infectious disease physician at ID care, discusses how symptoms associated with Lyme arthritis differ from those of rheumatoid arthritis.

Interview Transcript (slightly modified for readability)

“Chronic Lyme disease is a name that has been used kind of loosely and it’s been attached to various different collections of symptoms and syndromes and I personally don’t like the term because I think it’s abused too often; it’s given to people who probably don’t have Lyme disease at all. The question of ‘chronic Lyme disease’ or so-called chronic Lyme disease, and confusing it with rheumatoid arthritis, I think [that] I would rather call that Lyme arthritis because certainly arthritis is a very real part of Lyme disease, it was the first symptom that was recognized when the disease was recognized.

Like rheumatoid arthritis, people with Lyme arthritis can have long-standing arthritic symptoms, but some of the major differences are (assuming that we don’t have the predisposing factors, such as somebody who knows they had a tick bite sometime in the past that developed [into] a typical rash, or some other neurologic symptoms which might go along with Lyme disease, assuming that somebody has the arthritis in isolation, or isn’t very good at remembering things or whatever, for instance if it’s a child who may not be able to give much of a history) that rheumatoid arthritis is almost always bilaterally symmetrical; [meaning], if you come in with it in your left knee, usually you’re going to have it in your right knee, if you come in with it in your hands, it will be in both hands, whereas Lyme arthritis doesn’t have to be, in fact, it usually isn’t symmetrical. It usually only involves one or [a] few joints whereas rheumatoid can involve many. Usually, Lyme arthritis can involve almost any joint but it most often involves the large joints, whereas rheumatoid arthritis frequently involves the small joints. People with rheumatoid arthritis we know have the problems with their hands and their wrists and that type of thing; they will also have large joint involvement, but if there’s predominance of small joint involvement symmetrical[ly], it’s probably not Lyme. Those are some of the differentiating factors.

There are other lab tests; there’s something called a rheumatoid factor which people run as almost the first line thing when somebody comes in with arthritis, that should not be positive for Lyme disease—although it’s a fairly nonspecific test so I can’t say it would never be positive.”