Lyme disease - symptoms, causes, diagnosis

International Classification (ICD)	A69.-
Symptoms	Sweating, Joint pain, Facial nerve palsy, Muscle pain, Lyme arthritis, Schwellungen am Knie, Ellenbogen, Sprung-, Handwurzel-, Zehen- und Kiefergelenken, Meningitis, Disorders of the sensory organs, Heart problems, Vascular inflammation
Possible causes	Transmission of the pathogen through tick bite
Possible risk factors	Outdoor stay, Contact with plants near the ground

Basics

The causative agent of Lyme disease is the bacterium Borrelia burgdorferi. The bacteria are transmitted to humans through tick bites.

In 1975, an increased incidence of joint inflammation after tick bites was observed for the first time in Lyme (USA). This is also the origin of the name Lyme disease. The pathogen Borrelia burgdorferi was then discovered by Wilhelm Burgdorfer in 1981.

Lyme disease progresses in several stages, which do not necessarily occur in all sufferers. One indication is a noticeable reddening of the skin around the tick bite, which also heals without treatment. In severe courses and in later stages, muscles, joints and nerves may be affected, which can have permanent consequences. The most effective treatment is early treatment with antibiotics.

Lyme disease is more common in people who spend a lot of time outdoors for work or leisure, e.g. forestry workers or gardeners. Most tick bites occur in the months of June/July, but most infections usually occur between March and October.

Causes

The pathogens are mainly transmitted by ticks (Ixodes ricinus), rarely also by horseflies. According to studies in Switzerland and Germany, a Borrelia infection was detected in 2.6 to 5.6% of those affected after a tick bite. The bacteria live in the intestine of the tick. Thus, the transmission (in contrast to the very fast transmission of TBE pathogens) takes 6 to 48 hours. A decisive and preventive measure here is the rapid removal of the tick.

A direct transmission from person to person is not known, infected persons are therefore not contagious. However, an illness during pregnancy can lead to damage to the child or to stillbirth.

Illustration of the Lyme disease bacterium

creative commons CC BY-ND 3.0 / www.medicalgraphics.de

A direct transmission from person to person is not known, infected persons are therefore not contagious. However, an illness during pregnancy can lead to damage to the child or to stillbirth.

Symptoms

Stage 1: Local infection

After transmission of the pathogen and an incubation period of usually 5 to 29 days, a local infection of the skin may (but does not have to) occur. The wandering redness (erythema migrans) is a characteristic sign of a Borrelia infection, but there are also infections that do not show any skin symptoms. The approximately 5 cm wide, ring-shaped skin redness spreads around the bite site and gradually disappears on its own. However, recession is not evidence of cure because the pathogen may have already spread.

The wandering redness can be accompanied by unspecific general symptoms, such as a diffuse feeling of illness with fatigue and exhaustion (also possible with gastrointestinal symptoms). Furthermore, the so-called "Lyme disease flu" can also autfret with fever, sweating, headache and joint pain, but without cough and cold.

Stage 2: Spread of the bacteria

If the pathogen in stage 1 is not eliminated by the immune system or by therapy with antibiotics, it can spread throughout the body and, after a latency period of about 4 to 16 weeks, lead to a recurrence of the symptoms of the disease. The rather diffuse, flu-like symptoms make a clear diagnosis difficult.

The spreading pathogen can settle in all organs, joints and muscles, as well as in the nervous system. This results in a variety of serious symptoms: for example, paralysis of a facial muscle (facial paresis), wandering joint and muscle pain, and burning pain at the injection site may occur. Rarely, the brain and peripheral nervous system are also affected (neuro-Borreliosis). At this stage, the pathogen is not well recognized by the body's immune system and can be eradicated only poorly even with antibiotics, since it has already established itself in the connective tissue.

Stage 3: Chronic infection

If the Borrelia infection is not treated in time, symptoms can reappear or become increasingly worse even after months to years of symptom-free periods. Typical late symptoms are Lyme arthritis with swelling and pain in the knee, elbow, ankle, wrist, toe and jaw joints.

Furthermore, skin changes or neuroborreliosis with nerve pain, meningitis, disorders of the sensory organs, as well as heart problems, vascular inflammation, and fatigue persist.

Diagnosis

The presence of a tick bite with wandering redness is the most common indication of infection. In some, few laboratories there is the possibility to detect the Borrelia in the early stage with a bacterial culture.

Only 2-4 weeks after infection, antibodies against Borrelia can be detected by a blood test, but these do not necessarily indicate only an acute infection. The antibodies are also present when an infection has been successfully fought off by the immune system and no clinical symptoms are present. In the case of neuro-Borreliosis, an attempt can be made to examine the cerebrospinal fluid for the bacterium by means of cerebrospinal fluid puncture.

Because of the wide variety of symptom patterns, other serious diseases must also be ruled out by differential diagnosis to facilitate an accurate diagnosis.

Therapy

Lyme disease can also heal completely without treatment. However, because of the risk of chronification and the serious consequences, treatment with antibiotics is recommended.

In the first stage after the penetration of the pathogen by a tick bite, possibly with erythema migrans (wandering redness), a complete elimination of the Borrelia is easiest. An antibiotic treatment of about two weeks is sufficient in most cases. In this stage, neuro-Borreliosis is also cured in 95% of cases without late consequences.

In stage two, the pathogen is much more difficult to eliminate. It quickly passes from the blood into the connective tissue, where it then takes hold. Because of this, a longer antibiotic therapy over a period of about four weeks is necessary.

Antibiotics for oral therapy	Doxycycline Amoxicillin Cefuroxime axetil Azithromycin
Antibiotics for intravenous therapy	Ceftriaxone Cefotaxime Penicillin G

How long antibiotics would have to be administered and with what chances of success an infection in the chronic stage can be cured with them is discussed internationally.

Forecast

At an early stage, the disease can be cured well with antibiotics; the prospects deteriorate as the stage progresses, since the complaints in the nervous system and joints persist. Even after a Lyme disease infection has been passed through, a new infection with the pathogens can occur, as there is no reliable immunity.

andriano_cz / iStock

Prevent

Wearing long clothing and using effective insect repellents can prevent tick bites.
In general, it is recommended to check the body for ticks after spending time in high grass and under bushes.
Since the transmission of Borrelia from ticks to humans takes a long time (6 - 48 hours), it is very useful to remove already attached ticks as quickly and gently as possible. For this purpose, tweezers or special tick forceps and cards are suitable, with which the tick can be pulled slowly and straight out of the skin. Care should be taken not to crush the tick.

Currently, no vaccinations against Lyme disease are approved in Europe.