Misdiagnosis Of Lyme Disease

We received such a positive response to our recent blog regarding Lyme disease (posted on May 25, 2011)  that we decided to further blog about the disease.

Lyme Disease Statistics

According to a report from the Centers for Disease Control and Prevention (CDC), from 1992 to 2006 there were a total of 248,074 cases of Lyme disease reported to the CDC by health departments in the 50 states, the District of Columbia, and U.S. territories. The annual cases of Lyme disease increased 101% from 9,908 cases in 1992 to 19,931 cases in 2006. During the same period, 93% of the cases of Lyme disease were reported from 10 states (Connecticut, Delaware, Massachusetts, Maryland, Minnesota, New Jersey, New York, Pennsylvania, Rhode Island, and Wisconsin). The greatest number of Lyme disease cases were in children between the ages of 5 and 14, and 53% of all reported cases occurred among males. More than 65% of patients with EM (the majority of patients with Lyme disease develop a characteristic rash called erythema migrans (EM))  had illness onset in June and July.

A Brief History Of Lyme Disease In The U.S.

Lyme disease was first described in 1977 following an investigation of a cluster of arthritis cases among children living near Lyme, Connecticut. Further study indicated that arthritis was a late manifestation of a multisystem, tick-transmitted disease. In 1981, a bacteria known as Borrelia burgdorferi (B. burgdorferi) was identified to be the cause of Lyme disease, which occurs naturally in mice, squirrels, shrews, and other small vertebrates. Deer ticks become infected with B. burgdorferi while feeding on the blood of mice, etc., and then can transmit the infection to humans (although deer are not infected with B. burgdorferi, they play a role in transporting ticks and maintaining tick populations).

In approximately 70%–80% of cases, patients develop a characteristic rash (EM) within 30 days of infection. EM is a red expanding rash, with or without central clearing, which often is accompanied by symptoms of fatigue, fever, headache, mild stiff neck, arthralgia, or myalgia. Within days or weeks, untreated infection can spread to other parts of the body, causing more serious neurological conditions (for instance, meningitis, radiculopathy, and facial palsy) or cardiac abnormalities. Over a period of months or years, untreated infection can lead to arthritis, peripheral neuropathy, or encephalopathy.

Diagnosis Of Lyme Disease

Lyme disease is diagnosed on the basis of physician-observed clinical symptoms and a history of probable exposure to infected ticks.  Laboratory tests are not required to confirm diagnosis for patients with recent onset (2–3 weeks) of a characteristic EM rash. However, positive results of recommended two-tiered serologic testing can provide confirmation of infection in patients with musculoskeletal, neurologic, or cardiac symptoms. 

Blood Tests For Lyme Disease

The CDC currently recommends a two-step process when testing blood for evidence of antibodies against the Lyme disease bacteria. The first step uses a testing procedure called “EIA” (enzyme immunoassay) or rarely, an “IFA” (indirect immunofluorescence assay).  If this first step is negative, no further testing of the specimen is recommended. If the first step is positive or indeterminate (sometimes called “equivocal”), the second step should be performed using a test called an immunoblot test (a “Western blot” test). Results are considered positive only if the EIA/IFA and the immunoblot tests are both positive. The two steps of Lyme disease testing are designed to be done together.  The CDC does not recommend skipping the first test and just doing the Western blot.  Doing so will increase the frequency of  false positive results and may lead to misdiagnosis and improper treatment.

The IgM Western Blot test result is only meaningful during the first 4 weeks of illness. If you have been infected for longer than 4-6 weeks and the IgG Western Blot is still negative, it is highly likely that the IgM result is incorrect (e.g., a false positive).

The accuracy of the blood tests depend upon the stage of disease. During the first few weeks of infection, such as when a patient has an erythema migrans rash, the test is expected to be negative. Several weeks after infection, currently available ELISA, EIA and IFA tests and two-tier testing have very good sensitivity. It is possible for someone who was infected with Lyme disease to test negative because  some people who receive antibiotics (e.g., doxycycline) early in disease (within the first few weeks after tick bite) may not develop antibodies or may only develop them at levels too low to be detected by the test. Also, antibodies against Lyme disease bacteria usually take a few weeks to develop, so tests performed before this time may be negative even if the person is infected. In this case, if the person is retested a few weeks later, they should have a positive test if they have Lyme disease. It is not until 4-6 weeks have passed that the test is likely to be positive. This does not mean that the test is bad, only that it needs to be used correctly.

Treatment For Lyme Disease

The majority of infections can be cured with use of recommended antimicrobials. Patients with physician-diagnosed EM can be treated with oral doxycycline, amoxicillin, or cefuroxime axetil. Patients with other manifestations of Lyme disease are treated with either oral or intravenous antimicrobials, depending on the specific clinical condition.

Approximately 10% to 20% of patients treated for Lyme disease with a recommended 2-4 week course of antibiotics will have lingering symptoms of fatigue, pain, or joint and muscle aches. In some cases, these can last for more than 6 months.  Although often called “chronic Lyme disease,” this condition is properly known as “Post-treatment Lyme disease Syndrome” (PTLDS).

The exact cause of PTLDS is not yet known. Most medical experts believe that lingering symptoms are due to residual damage to the tissues and the immune system that occurred during the infection. Similar complications and auto-immune responses are known to occur following other infectious diseases.

Sources: CDCCDC.

Although misdiagnosis or late diagnosis of Lyme disease can occur absent medical negligence, if you or a loved one had a missed or delayed diagnosis of Lyme disease that may be due to the negligence of a health care provider, please visit our website to be connected to medical malpractice lawyers in your local area who may be able to investigate whether you have a valid medical malpractice claim. You may also reach us toll free  800-295-3959.

This entry was posted on Thursday, June 2nd, 2011 at 10:00 am. Both comments and pings are currently closed.

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