Ticks in certain regions, including the lands along the eastern Baltic Sea, also transmit viruses that cause tick-borne encephalitis.Coinfections complicate Lyme symptoms, especially diagnosis and treatment. It is possible for a tick to carry and transmit one of the coinfections and not Borrelia, making diagnosis difficult and often elusive. The Centers for Disease Control and Prevention studied 100 ticks in rural New Jersey and detected two pathogens in 10% of the ticks. Pathophysiology
B. burgdorferi can spread throughout the body during the course of the disease, and has been found in the skin, heart, joints, peripheral nervous system, and central nervous system. B. Burgdorferi does not produce toxins. Therefore, many of the signs and symptoms of Lyme disease are a consequence of the immune response to spirochete in those tissues.B. burgdorferi is injected into the skin by the bite of an infected Ixodes tick. Tick saliva, which accompanies the spirochete into the skin during the feeding process, contains substances that disrupt the immune response at the site of the bite. This provides a protective environment where the spirochete can establish infection. The spirochetes multiply and migrate outward within the dermis. The host inflammatory response to the bacteria in the skin causes the characteristic circular EM lesion. Neutrophils, however, which are necessary to eliminate the spirochetes from the skin, fail to appear in necessary numbers in the developing EM lesion because tick saliva inhibits neutrophil function.
People with Lyme arthritis treated with intravenous antibiotics or two months of oral antibiotics who continue to have joint swelling two months after treatment and have negative PCR test for Borrelia DNA in the synovial fluid are said to have antibiotic-refractory Lyme arthritis; this is more common after infection by certain Borrelia strains in people with certain genetic and immunologic characteristics. Antibiotic-refractory Lyme arthritis may be symptomatically treated with NSAIDs, disease-modifying antirheumatic drugs (DMARDs), or arthroscopic synovectomy. Physical therapy is recommended for adults after resolution of Lyme arthritis.People receiving treatment should be advised that reinfection is possible and how to prevent it. Prognosis
Lyme diseases typical first sign, the erythema migrans (EM) rash, resolves within several weeks even without treatment. However, in untreated people, the infection often disseminates to the nervous system, heart, or joints, possibly causing permanent damage to body tissues.People who receive recommended antibiotic treatment within several days of appearance of an initial EM rash have the best prospects. Recovery may not be total or immediate. The percentage of people achieving full recovery in the United States increases from about 64–71% at end of treatment for EM rash to about 84–90% after 30 months; higher percentages are reported in Europe. Treatment failure, i.e. persistence of original or appearance of new signs of the disease, occurs only in a few people. Remaining people are considered cured but continue to experience subjective symptoms, e.g. joint or muscle pains or fatigue.