Lyme disease is a systemic disease caused by a spirochete infection transmitted by the Ixodes tick which is endemic to the northeastern United States. Patients classically develop a bull's-eye rash with central clearing and can develop Bell's palsy, heart block, and arthropathies.
A spirochete is a spiral-shaped bacterium.
Spirochetes cannot be visualized on Gram stain and require Dark-field microscopy for visualization. This is one way a diagnosis can be made.
Giemsa stain is used to visualize the spirochete of Borrelia species.
Silver stain is used to visualize the spirochete of Borrelia species.
The white-footed mouse is the primary host for the lifecycle of the Ixodes tick. Therefore, these mice are necessary for the propagation of Lyme disease.
The Ixodes tick is the transmitting agent of the Borrelia burgdorferi. The Ixodes tick is considered the vector for Lyme disease, Babesia, and Anaplasma.
Babesia causes a protozoal infection in humans called babesiosis. Babesia, like Borrelia burgdorferi, is transmitted by the Ixodes tick. While babesiosis and malaria have similar clinical presentations, they do not share a common endemic region as babesiosis is primarily seen in the northeastern United States. There may be a coinfection of both Babesia and Borrelia burgdorferi since both infections are transmitted by the Ixodes tick.
Anaplasmosis is a disease caused by Anaplasma, a rickettsial parasite. Anaplasma is transmitted by the Ixodes tick, like Borrelia burgdorferi and Babesia. There may be a co-infection of both Anaplasma and Borrelia burgdorferi similar to the co-infection that may occur with Babesia and Borrelia burgdorferi. Anemia, diarrhea, tachycardia, skin rash (rare), fever, chills, headache and myalgias may be seen with anaplasmosis. Histologically, anaplasmosis can be diagnosed by the visualization of granulocytes with morulae in the cytoplasm of white blood cells.
Flu-like symptoms are common in the initial presentation of patients with Lyme disease.
Erythema migrans is a characteristic targetoid rash, which is the classic finding in Lyme disease and shows the site of the tick bite.
“Bull’s-eye” is the classic description of the rash seen in Lyme disease because of the typical target pattern with central clearing.
Bilateral Bell's palsy can be one of the presentations of Lyme disease. However, the palsy can present unilaterally.
Stage 2 Lyme disease can cause conduction defects of the heart, causing heart block and other cardiac findings. This typically happens weeks after the initial tick bite. Patients can present with first degree to complete heart block.
Arthropathy is the last of the characteristic symptoms seen in Lyme disease and is usually experienced weeks after the initial tick bite. The arthropathy is classically unilateral and can migrate from one joint to another.
If a patient has a tick bite and Lyme disease is suspected, the patient should be placed on doxycycline.
Ceftriaxone is used for late manifestations of Lyme disease after the patient has had the disease for a significant amount of time.
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