Diagnosis And Treatment Of Lyme Disease
Microscopic Appearance of Borrelia burgdorferi
Diagnosis of Lyme Disease
Lyme disease has now become a very common vector borne infection. Persons of all ages and both sexes can suffer from the disease.
The increased incidence is due to the spread of tick vectors to new areas, and the encroachment of suburbs on once rural areas, bringing humans and ticks in close proximity.
According to the National Surveillance Case Definition, the criteria to label an illness as Lyme disease include the following :
- A person with exposure to a potential tick habitat developing Erythema migrans diagnosed by a physician.
- At least one late manifestation of the disease.
- Laboratory confirmation.
The serological tests may yield negative results during the first several weeks of infection, and are also unable to differentiate between active and inactive infection. Those with previous Lyme disease - particularly those progressing to late stages - often remain seropositive for years, even after receiving antibiotic treatment. In addition, some individuals show positive results because of asymptomatic infection.
On the other hand, a few people who receive inadequate antibiotic therapy during the initial weeks of infection develop subtle joint or neurological symptoms but are seronegative.
The better part is that , in most cases sero negative Lyme disease is a mild, attenuated illness.
For serological analysis, the CDC (Centers for Disease Control and Prevention) recommends a two step approach.
- Step - 1 : Samples are first tested by ELISA (Enzyme Linked Immunosorbent Assay).
- Step - 2 : Equivocal or positive results are tested by the Western Blot method.
Another approach is to use Indirect Immunoflorescence Assay as an initial test.
Western blot assay detects both IgM (early response) and IgG (late response) antibodies to the infection.
IgM antibody appears 2 to 4 weeks after the onset of skin rash, peaks at 6 to 8 weeks, and then declines to low levels after 4-6 months of infection. If the IgM antibody titres remain high more than six months after the initial infection, then it suggests either false positive test results, or constant re infections.
IgG antibodies occur later (appear 6-8 weeks after the onset of disease), peaks at 4-6 months, and may remain elevated at low levels indefinitely despite medication and resolution of symptoms as the infection may persist in a latent form.
Approximately 20-30% people test positive in acute phase samples (within the first one month of infection), whereas, the remaining 70-80% have a positive response during convalescence (2-4 weeks later).
If a person with suspected early Lyme disease has negative results on serological testing, then both acute and convalescent titres should be obtained. A four fold rise in the antibody titre as compared to the baseline is diagnostic of recent infection.
False positive reactions in the ELISA have been reported in cases of syphilis, infectious mononucleosis, and in persons with severe gum disease (due to cross reactivity with oral treponemes). In case of chronic persistent or late Lyme disease the immune system gets involved and autoimmunity and associated conditions begin to show.
False negative results are obtained if tests are performed in very early stages of infection, and when prompt antibiotic therapy is given during early stages, as it aborts seroconversion.
Other less commonly used tests for Lyme disease include the following :
- Antibody capture ELISA (sensitive for early disease)
- Detection of immune complexes.
Protect yourself from Lyme disease
What are the common preventive measures against Lyme disease?
Criteria For Laboratory Evaluation of Individuals With Suspected Lyme disease
Guidelines established by the American College of Physicians for laboratory evaluation of individuals with suspected Lyme disease include the following :
- Diagnosis of early Lyme disease is clinical (exposure to endemic areas, physician documented Erythema migrans), and does not require laboratory confirmation.
- Late disease requires objective evidence of signs and symptoms, consisting of recurrent and brief attacks of arthritis of large joints (single or a few joints affected at the same time), Lymphocytic meningitis, Bell's palsy, Peripheral neuropathy, Encephalomyelitis, Atrio ventricular conduction defects with or without myocarditis, and laboratory evidence of the disease (Two stage testing).
- Individuals with non-specific symptoms and without objective signs should not have serological tests done.
Other Tests To Detect Lyme disease
Other diagnostic tests for specific organ systems affected include the following :
- Culture - Borrelia burgdorferi may be cultured from skin lesions.
- PCR - Detection of Borrelia DNA by PCR (Polymerase Chain Reaction) is useful in case of Lyme arthritis. Whether a positive PCR indicates persistence of the microbe, or is a marker of residual DNA (and not active infection) still remains investigational.
Non-specific laboratory abnormalities include the following :
- Elevated ESR (>20mm/hour)
- Mildly abnormal liver function tests.
- Mild anemia
- Raised white blood cell count (11,000-18,000/micro liter)
- Microscopically detected blood in urine.
The most common conditions that resemble late Lyme disease are chronic fatigue syndrome and fibromyalgia. Some people develop these chronic conditions in association with, or after Lyme disease. Compared with Lyme disease, these conditions lead to more disabling symptoms that include marked fatigue, severe headache, diffuse muscle and bone pains, multiple symmetric tender points in characteristic locations, pain and stiffness in many joints, and difficulty in concentration. They lack joint swelling and inflammation; and have normal results on neurological testing.
Treatment of Lyme disease
Drug and Dosage
Doxycycline, 100 mg twice daily for 3-4 weeks; or amoxicillin, 500mg three times daily for 3-4 weeks; or cefuroxime axetil, 500 mg twice daily for 3-4 weeks
Neurological disease (Bell's palsy)
Doxycycline, or amoxicillin as above for 3-4 weeks
Other central nervous system disease
Ceftriaxone, 2 g IV once daily for 2-4 weeks; or penicillin G, 20 million units daily IV in 6 divided doses for 2-4 weeks; or cefotaxime, 2 g IV every 8 hours for 2-4 weeks
Cardiac disease (First-degree block)
Doxycycline oe amoxicillin as above for 3-4 weeks
High degree atrioventricular blocks
Ceftriaxone or penicillin G as above for 2-4 weeks
Arthritis oral dosage
Doxycycline, or amoxicillin as above for 4 weeks
Arthritis intravenous dosage
Ceftriaxone or penicillin G as above for 2-4 weeks
Acrodermatitis chronica atrophicans
Doxycycline or amoxicillin as above for 4 weeks
The best preventive measure is to avoid being bitten by the Borrelia vector
Prevention of Lyme disease
Simple preventive measures to check the spread of Lyme infection include the following :
- Avoid tick-infested areas.
- Cover exposed skin with long-sleeved shirts and wear long trousers tucked into socks.
- Use tick repellents (such as DEET)
- Inspect for ticks after exposure
- Take a shower after returning from the woods.
These measures are especially essential for pregnant women and children below the age of 8 years, in whom the drug of choice Doxycycline use should be avoided, as can cause serious side effects.
Prophylactic antibiotic therapy may be given in situations where follow-up is uncertain; the person is a pregnant woman (antibiotic amoxicillin preferred), or the tick was engorged when removed.
Lyme disease - a vector borne multi organ disease
- This illness is commonly caused by the spirochete Borrelia burgdorferi, and is characterized by erythema migrans skin rash, progressing into arthritis of large joints, meningitis, Bell's palsy, heart blocks, and peripheral neuropathy.
- Common laboratory tests to diagnose the disease include ELISA, Western blot, Indirect Immunoflorescence test, PCR, bacterial culture, and detection of immune complexes.
- Preventive measures to avoid being bitten by the Borrelia vector include use of repellents, protective clothing, and inspecting for ticks after exposure.
- At present there is no immunization available, but a vaccine against bacterial Osp (Outer surface protein) is undergoing clinical trials.
Prospects of a Lyme disease Vaccine
In 1998 the FDA approved a vaccine for Lyme disease prevention, called LYMErix which was later withdrawn from the markets in year 2002. Protection provided by this vaccine diminished over time. So a person who has been vaccinated against this disease before 2002, is no longer protected against the disease
According to the Lancet Infectious Disease, a new vaccine is undergoing phase-1&2 clinical trials at the Stony Brook University School of Medicine and National Laboratory, that has been aimed at the outer surface protein of the bacteria. By using the scaffold of this protein Osp A, the experts have developed a set of specific proteins that do not normally exist in nature. These new proteins, better known as Chimeras contain components from different species of Borrelia. Thus it is being expected, that after completing the Phase - 3 clinical trials, this vaccine should have a protective effect against all the possible species of Borrelia that are causing the disease in the entire Northern hemisphere.
Mixed infections are a cause of treatment failure
Most areas endemic for Lyme disease are also endemic for babesiosis and ehrlichiosis. Coinfection with the microbes causing these infections may be associated with more severe symptoms than with either agent alone and is another possible explanation for failure to respond to therapy directed at Lyme disease
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Disclaimer: This Hub has information meant for educational purposes. It in no way intends to replace or substitute the advice of your doctor or health care provider.