Lyme Disease Diagnosis

Sample

1. Whole blood or citrated blood is needed.
2. Other samples are CSF and synovial fluids in the acute stage.

Precaution

• Spirochetal diseases like syphilis or leptospirosis can give a false-positive reaction.

Causative Agent

1. Lyme disease was first diagnosed in Lyme, Connecticut, in 1975.
2. Lyme disease is caused by the spirochete Borrelia burgdorferi.
   1. This is caused by the bite of a deer tick. (Ixodes dammini or pacificus).
      1. These ticks are the best vector for Lyme disease.
   2. This is difficult to grow in the culture.
   3. It takes a long time to grow.
   4. Cultural success is in 50% of the cases.
   5. The culture of blood and CSF has a poor result.
   6. Serological tests are more helpful.
   7. Its diagnosis was established in early 1980.
      

      Borrelia Organism Species

Reservoir

• Rodents and deer serve as the natural reservoir for these ticks. Other animals are sheep and cattle.

Morphology

• These are 0.18 to 0.25 X 4.3 μm. These are flexible helical spirochaete.
• These are a gram-negative organism.
• Culture: These are microaerophilic, growing at 34 °C in a special medium.

Lyme disease has the following presentation:

1. This is a chronic inflammatory disease which first shows a distinct skin lesion, Erythema migrans (erythema chronicum migrans).
   1. It starts at the site of the bite as a red macule.
   2. There is a central clearing at the site of the bite.
2. Erythema migrans.
3. Late Lyme disease.
4. Lyme arthritis.
5. Cardiovascular involvement.
6. Neurological involvement and presentation.

Signs and symptoms:

1. This disease was first time diagnosed in Lyme, Connecticut 1975.
2. This disease usually starts in summer with skin lesions called Erythema chronicum migrans.
3. This lesion usually appears at the site of the deer tick bite.
4. Characteristically there is:
   1. Fever.
   2. A headache and a stiff neck.
   3. There is fatigue.
   4. There are muscle and joint pain.
   5. These patients may develop arthritis and meningitis.
5. There are chronic meningoencephalitis and peripheral neuritis.
6. In CVS there are myocarditis, pericarditis, and conduction defects.
7. There is arthritis of large joints and often recurrent.

Diagnosis

1. The culture medium used in Kelly’s medium, and BSK II.
2. Antigen detection. Urine shows excreted  B. burgdorferi.
3. Polymerase chain reaction (PCR).
4. Antibody detection. This is the most common method.
   1. It is negative when there is a low level of IgM and IgG antibody.
   2. IgM titer peak is from 3 to 5th week of disease onset.
      1. Then it declines.
      2. A single high titer of specific IgM is diagnostic.
   3. IgG is low during the first few weeks of disease and reaches the maximum level by 4 to 6 months later on.
5. Indirect immunoassay.
6. Enzyme immune assay has replaced the indirect immunoassay.
7. Western Blot method is the confirmatory test.
8. Skin biopsy of the affected area surrounding the erythema migrans.
   1. Silver stain reveals spirochetes.
9. CDC criteria:
   1. Isolation of B.burgdorferi.
   2. The Positive IgM and IgG antibody in Blood or CSF.
   3. The positive antibody titer in the sera of convalescent or acute stage.

Treatment

1. Mostly this disease is treated with amoxicillin and doxycycline for 3 weeks.
2. Some time may need IV therapy.
3. These are also sensitive to penicillin and tetracycline.

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