Lyme Disease Diagnosis and Treatment: A Q&A with David J. Herman, MD, FACP

APRIL 11, 2014
Internal Medicine World Report Editor-in-Chief Simon Douglas Murray, MD, consulted with David J. Herman, MD, FACP, Senior Partner at ID Care, the largest network of infectious disease specialists in New Jersey, on the treatment of Lyme disease and other tick-borne infections.
 
Despite the fact that Lyme disease is relatively common, there still seems to be a great deal of confusion about its diagnosis, treatment, and prognosis. Practicing physicians in the Northeast see many cases of suspected Lyme disease and are often not clear about the actual diagnosis.

What tools are available for diagnosing Lyme disease beyond a good history and physical exam? Specifically, what is the value of Western blot testing, and are there any other tests of value?

The recommended testing for Lyme disease is to screen with an antibody test using the enzyme-linked immunosorbent assay (ELISA) method. If the result is positive or equivocal, then perform a confirmatory test with a Western blot. Both forms of testing should be performed by a laboratory that has been accredited by the College of American Pathologists (CAP).
 
Lyme disease testing should only be performed if all of the following criteria are met: (1) The patient resides or has traveled to an area endemic for Lyme disease; (2) the patient has risk factors for exposure to ticks; and (3) the patient has symptoms compatible with early disseminated Lyme disease or late-stage Lyme disease, including meningitis, arthritis, carditis, or cranial nerve palsy. The testing should not be ordered on asymptomatic patients living in an endemic area or those with nonspecific symptoms.
 
The serologic tests are not very sensitive in very early Lyme disease infection, as there are many false negative tests in the first few weeks following infection. Therefore, patients who present with an erythema migrans rash do not need serologic testing; instead, those patients should just be treated. 
 
The Western blot is not intended to be used as a screening test. Rather, it should be used as a confirmatory test, since it is more specific than the ELISA test, and thus produces fewer false positive results. Nonetheless, neither of these serologic tests should be ordered on synovial fluid.
 
Although neither of these serologic tests should be ordered on synovial fluid, the polymerase chain reaction (PCR) test may be useful to help confirm the diagnosis of Lyme disease on synovial fluid, and perhaps on cerebrospinal fluid (CSF). However, it should not be ordered if the serum tests are negative, because a positive PCR test on synovial fluid or CSF in the setting of a negative serum antibody test likely represents a false positive result.
 
PCR testing is most useful in a patient with a positive Lyme disease antibody with a confirmatory Western blot and a joint effusion that recurs after treatment. If the PCR test on the synovial fluid is positive after treatment, it suggests the possibility of ongoing infection, instead of immunologic reasons for the recurrent joint effusion.
 
What are the stages of Lyme disease and what is the best treatment based upon stage?
Lyme disease may be divided into 3 stages:  (1) Early localized disease, such as erythema migrans rash; (2) early disseminated disease, such as Lyme carditis, meningitis, and cranial nerve palsies; and (3) late-stage disease, such as Lyme arthritis and Lyme encephalopathy.
 
The recommended treatment for early localized disease is twice-daily oral doxycycline 100 mg for 10-21 days or thrice-daily oral amoxicillin 500 mg for 14-21 days. Although other antibiotics such as azithromycin, clarithromycin, and cefuroxime axetil have been used, none are more effective than doxycycline or amoxicillin, and some are much more expensive. In fact, some trials have shown azithromycin to be less effective than amoxicillin.
 
The recommended therapy for early disseminated Lyme disease without meningitis is twice-daily doxycycline 100 mg for 21 days. In patients who are unable to take doxycycline, amoxicillin may be used.
 
Other recommended therapies for early disseminated and late-stage Lyme disease are as follows:
  • Lyme meningitis: Daily intravenous (IV) ceftriaxone 2 grams for 14-28 days.
  • Lyme arthritis: Twice-daily doxycycline 100 mg or thrice-daily amoxicillin 500 mg for 30 days.
  • Lyme encephalopathy: Daily ceftriaxone 2 grams for 28 days.
  • Lyme carditis
    • First-degree atrioventricular (AV) block with PR interval <0.3 seconds: Twice-daily doxycycline 100 mg for 14-21 days
    • First-degree AV block with PR interval >0.3 seconds, or a second- or third-degree AV block: IV ceftriaxone for 14 -21 days, although there is no data to show that it is superior to oral doxycycline.
What is the role of IV therapy in the treatment of Lyme disease?
IV therapy is only used for central nervous system Lyme disease, Lyme carditis with a PR interval >0.3 seconds, or for proven Lyme arthritis that is unresponsive to oral antibiotics. There is no data to support IV antibiotic therapy in excess of 30 days.
 
There is a great deal of hysteria surrounding Lyme disease. Many patients are frightened the disease is easily missed by doctors and will go on to become very serious and life-threatening. I had a patient who went as far as replacing all the grass in the yard with Astroturf before allowing the children play outside. In the summer months, patients are exposed to deer ticks on a daily basis. At the same time, I don't see hospitals and offices filled with people with crippling arthritis and neuropsychiatric symptoms attributable to Lyme disease.

Is it possible that only a minority of patients will develop long-term complications, even if left untreated?

The best data I can find on this subject revolves around the diagnosis of Lyme arthritis. In the late 1970s, before the cause of Lyme disease and the role of antibiotics were known, the natural history of Lyme arthritis was described in a cohort of 55 patients followed prospectively from the onset of the disease with erythema migrans through later manifestations of the disease. Months after the onset of infection, about 60% of the untreated patients developed joint swelling and pain.
 
Is it advisable to treat patients prophylactically for tick bites?
It is generally not advisable to treat patients prophylactically for tick bites. Many patients do not know what bit them. Even if they knew it was a tick, they may not know what type.

However, if the patient was bitten by a deer tick, and if the tick fed for >36 hours, and if the treatment can be started within 72 hours of the tick bite, then a single dose of doxycycline 200 mg has been shown to decrease the occurrence of Lyme disease from 0.4% in the doxycycline treated patients to 3.2% in the placebo treated patients. But if a known tick bite occurred and the patient is observed for signs and symptoms, then treatment may be initiated at that time with an approximate 90% cure rate from a 14-day course of doxycycline or amoxicillin.

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