Lyme Disease Diagnosis

Sample for Lyme Disease Diagnosis

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

Precaution for Lyme Disease Diagnosis

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

Definition of Lyme disease

1. Lyme disease is caused by spirochete Borrelia burgdorferi by several tick vectors.
2. The most common vector deer in the Northeast and North-central United States of America is deer tick Ixodes dammini.
3. The pacific coast states have Ixodes pacificus, the western black-legged tick, morphologically called hard tick.

Causative Agent of Lyme Disease

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.

Epidemiology of Lyme disease

1. The three major affected areas are:
   1. Northeastern states like New Jersey to Connecticut.
   2. Far eastern states.
   3. Upper midwestern states.
   4. Cases are reported in Canada, Europe, and Australia.

The reservoir of Lyme Disease

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

Morphology of Lyme Disease

1. These are 0.18 to 0.25 X 4.3 μm. These are flexible helical spirochaete.
2. These are gram-negative organisms.
3. Culture: These are microaerophilic, growing at 34 °C in a special medium.
   1. Ixodes dammini has 2 years, three-form life cycle.
4. Larval stage: The very young tick is called the larval stage.
   1. The larval ticks are very small and have only 3 pairs of legs like insects.
5. Nymph stage: These ticks have 4 pairs of legs in the following years, like in the adult stage.
6. Adult stage: These ticks are 4 legged.

Lyme disease has the following presentation:

1. In 50% to 80% of the patients, after one week of the bite by ticks (range 3 to 68 days), a reddish macular spreading lesion with central clearing appears (erythema chronicum migrans).
2. This chronic inflammatory disease 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.
3. This lesion usually fades within 2 to 3 weeks and is usually accompanied by low-grade fever, weakness, fatigue, and regional lymphadenopathy.
   1. This characteristic skin lesion should strongly suggest Lyme disease.
4. 10% of patients develop anicteric hepatitis.
5. 7% of the patients develop transitory ECG abnormality or myocardial inflammation after about 5 weeks of the tick bites.
6. In the second stage of illness, there is aseptic meningitis, or peripheral nervous system abnormalities like Bell’s palsy or Bannwarth’s polyneuritis syndrome occur after about 4 weeks of the tick bites.
7. Erythema migrans.
8. Late Lyme disease.
9. Lyme arthritis. There is migratory arthralgia, and myalgia is frequently present.
10. Cardiovascular involvement.
11. Neurological involvement and presentation.
12. In the third stage of the disease, about 40% of the patients develop recurrent arthritis.
    1. This is the most common involvement of one or more of the joints. The most common site is the knee.
    2. The joint involvement starts after6 weeks to 6 months after the tick bites.

Signs and symptoms of Lyme Disease:

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 are:
   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.

Lyme Disease Diagnosis

1. There are raised ESR in 50% of the cases.
2. WBCs are raised in about 10% of the cases.
3. Aspiration of the joint synovial fluid has similar findings to rheumatoid arthritis.
4. CSF:
   1. When there are meningeal or peripheral nerves, symptoms usually show;
   2. Increased WBCs predominantly lymphocytes.
   3. Normal glucose.
   4. Mildly increased protein.
   5. An oligoclonal band like multiple sclerosis.
   6. CSF IgM antibodies are present.
5. The culture:
   1. Biopsy of the erythema migrans skin lesion can be used for culture.
   2. The transport medium used is a special medium, BSK.
   3. The culture medium used in Kelly’s medium and BSK II.
6. Antigen detection. Urine shows excreted  B. burgdorferi.
7. Polymerase chain reaction (PCR).
8. Antibody detection. This is the most common method.
   1. It is negative when there is a low level of IgM and IgG antibodies.
   2. IgM titer peak is from the 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 the disease and reaches the maximum level by 4 to 6 months later on.
9. Indirect immunoassay.
10. Enzyme immune assay has replaced the indirect immunoassay.
11. The western Blot method is the confirmatory test.
12. Skin biopsy of the affected area surrounding the erythema migrans.
    1. Silver stain reveals spirochetes.
    2. The special stain used is Warthin-Starry silver stains for a skin biopsy.
13. 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 of Lyme Disease

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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