Lyme Disease
Lyme Arthritis

Lyme disease is a tick-transmitted inflammatory disorder
characterized by an early focal skin lesion, and subsequently a growing
red area on the skin (erythema chronicum migrans or ECM). The disorder
may be followed weeks later by neurological, heart or joint
abnormalities.


Symptomatology

The first symptom of Lyme disease is a skin lesion. Known as
erythema chronicum migrans, or ECM, this usually begins as a red
discoloration (macule) or as an elevated round spot (papule). The skin
lesion usually appears on an extremity or on the trunk, especially the
thigh, buttock or the under arm. This spot expands, often with central
clearing, to a diameter as large as 50 cm (c. 12 in.). Approximately
25% of patients with Lyme disease report having been bitten at that
site by a tiny tick 3 to 32 days before onset of ECM. The lesion may be
warm to touch. Soon after onset nearly half the patients develop
multiple smaller lesions without hardened centers. ECM generally lasts
for a few weeks. Other types of lesions may subsequently appear during
resolution. Former skin lesions may reappear faintly, sometimes before
recurrent attacks of arthritis. Lesions of the mucous membranes do not
occur in Lyme disease.

The most common symptoms accompanying ECM, or preceding it by a
few days, may include malaise, fatigue, chills, fever, headache and
stiff neck. Less commonly, backache, muscle aches (myalgias), nausea,
vomiting, sore throat, swollen lymph glands, and an enlarged spleen may
also 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 as
2 years. Early in the illness, migratory inflammation of many joints
(polyarthritis) without joint swelling may occur. Later, longer
attacks of swelling and pain in several large joints, especially the
knees, typically recur for several years. The knees commonly are much
more 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 and
low-grade fever, may also precede or accompany recurrent attacks of
arthritis. About 10% of patients develop chronic knee involvement
(i.e. unremittent for 6 months or longer).

Neurological abnormalities may develop in about 15% of patients
with Lyme disease within weeks to months following onset of ECM, often
before arthritis occurs. These abnormalities commonly last for months,
and usually resolve completely. They include:

1. lymphocytic meningitis or meningoencephalitis
2. jerky involuntary movements (chorea)
3. failure of muscle coordination due to dysfunction of the
cerebellum (cerebellar ataxia)
4. cranial neuritis including Bell\'s palsy (a form of facial
paralysis)
5. motor and sensory radiculo-neuritis (symmetric weakness, pain,
strange sensations in the extremities, usually occurring first
in 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 in
approximately 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 left
ventricle and an enlarged heart (cardiomegaly).

When Lyme Disease is contracted during pregnancy, the fetus may or
may not be adversely affected, or may contract congenital Lyme Disease.
In a study of nineteen pregnant women with Lyme Disease, fourteen had
normal pregnancies and normal babies.

If Lyme Disease is contracted during pregnancy, possible fetal
abnormalities and premature birth can occur.


Etiology

Lyme disease is caused by a spirochete bacterium (Borrelia
Burgdorferi) transmitted by a small tick called Ixodes dammini. The
spirochete is probably injected into the victim\'s skin or bloodstream
at the time of the insect bite. After an incubation period of 3 to 32
days, the organism migrates outward in the skin, is spread through the
lymphatic system or is disseminated by the blood to different body
organs or other skin sites.

Lyme Disease was first described in 1909 in European medical
journals. The first outbreak in the United States occurred in the
early 1970\'s in Old lyme, Connecticut. An unusually high incidence of
juvenile arthritis in the area led scientists to investigate and
identify the disorder.