Lyme disease is a tick-transmitted inflammatory disordercharacterized by an early focal skin lesion, and subsequently a growingred area on the skin (erythema chronicum migrans or ECM). The disordermay be followed weeks later by neurological, heart or jointabnormalities.SymptomatologyThe first symptom of Lyme disease is a skin lesion. Known aserythema chronicum migrans, or ECM, this usually begins as a reddiscoloration (macule) or as an elevated round spot (papule). The skinlesion usually appears on an extremity or on the trunk, especially thethigh, buttock or the under arm. This spot expands, often with centralclearing, to a diameter as large as 50 cm (c. 12 in.
). Approximately25% of patients with Lyme disease report having been bitten at thatsite by a tiny tick 3 to 32 days before onset of ECM. The lesion may bewarm to touch.
Soon after onset nearly half the patients developmultiple smaller lesions without hardened centers. ECM generally lastsfor a few weeks. Other types of lesions may subsequently appear duringresolution. Former skin lesions may reappear faintly, sometimes beforerecurrent attacks of arthritis. Lesions of the mucous membranes do notoccur in Lyme disease.The most common symptoms accompanying ECM, or preceding it by afew days, may include malaise, fatigue, chills, fever, headache andstiff neck. Less commonly, backache, muscle aches (myalgias), nausea,vomiting, sore throat, swollen lymph glands, and an enlarged spleen mayalso be present.Most symptoms are characteristically intermittent and changing,but malaise and fatigue may linger for weeks.
Arthritis is present in about half of the patients with ECM,occurring within weeks to months following onset and lasting as long as2 years. Early in the illness, migratory inflammation of many joints(polyarthritis) without joint swelling may occur. Later, longerattacks of swelling and pain in several large joints, especially theknees, typically recur for several years. The knees commonly are muchmore swollen than painful; they are often hot, but rarely red.
Baker’s cysts (a cyst in the knee) may form and rupture.Those symptoms accompanying ECM, especially malaise, fatigue andlow-grade fever, may also precede or accompany recurrent attacks ofarthritis. About 10% of patients develop chronic knee involvement(i.e.
unremittent for 6 months or longer).Neurological abnormalities may develop in about 15% of patientswith Lyme disease within weeks to months following onset of ECM, oftenbefore arthritis occurs. These abnormalities commonly last for months,and usually resolve completely. They include:1.
lymphocytic meningitis or meningoencephalitis2. jerky involuntary movements (chorea)3. failure of muscle coordination due to dysfunction of thecerebellum (cerebellar ataxia)4. cranial neuritis including Bell’s palsy (a form of facialparalysis)5. motor and sensory radiculo-neuritis (symmetric weakness, pain,strange sensations in the extremities, usually occurring firstin the legs)6.
injury to single nerves causing diminished nerve response(mononeuritis multiplex)7. inflammation of the spinal cord (myelitis).Abnormalities in the heart muscle (myocardium) occur inapproximately 8% of patients with Lyme disease within weeks of ECM.They may include fluctuating degrees of atrioventricular block and,less commonly, inflammation of the heart sack and heart muscle(myopericarditis) with reduced blood volume ejected from the leftventricle and an enlarged heart (cardiomegaly).When Lyme Disease is contracted during pregnancy, the fetus may ormay not be adversely affected, or may contract congenital Lyme Disease.In a study of nineteen pregnant women with Lyme Disease, fourteen hadnormal pregnancies and normal babies.
If Lyme Disease is contracted during pregnancy, possible fetalabnormalities and premature birth can occur.EtiologyLyme disease is caused by a spirochete bacterium (BorreliaBurgdorferi) transmitted by a small tick called Ixodes dammini. Thespirochete is probably injected into the victim’s skin or bloodstreamat the time of the insect bite. After an incubation period of 3 to 32days, the organism migrates outward in the skin, is spread through thelymphatic system or is disseminated by the blood to different bodyorgans or other skin sites.Lyme Disease was first described in 1909 in European medicaljournals. The first outbreak in the United States occurred in theearly 1970’s in Old lyme, Connecticut. An unusually high incidence ofjuvenile arthritis in the area led scientists to investigate andidentify the disorder. In 1981, Dr.
Willy Burgdorfer identified thebacterial spirochete organism (Borrelia Burgdorferi) which causes thisdisorder.Affected PopulationLyme Disease occurs in wooded areas with populations of mice anddeer which carry ticks, and can be contracted during any season of theyear.Related DisordersRheumatoid Arthritis is a disorder similar in appearance to Lymedisease. However, the pain in rheumatoid arthritis is usually morepronounced. Morning stiffness and symmetric joint swelling morecommonly occur in rheumatoid arthritis, and knotty lumps