What is Lyme disease and how is it treated?

Lyme disease is also known as tick-borne borreliosis is an infectious disease caused by bacteria of the genus Borrelia, transmitted by ixodid ticks, as well as deer flies. Borrelia enters the victim’s bloodstream when bitten by an infected arthropod. Lyme disease is the most common among diseases transmitted by tick bites.

Understanding Lyme disease

Lyme disease is the most common disease transmitted by ticks and biting flies in the Northern Hemisphere. Bacteria are transmitted to humans by being bitten by infected ixodid ticks as well as deer biting flies. Borreliosis is caused by spirochetes (spiral bacteria) of at least five species of the genus Borrelia.

With tick saliva, the causative agent of systemic tick-borne borreliosis penetrates the human body. On the skin, at the point of suction of the tick, a migrating ring-shaped inflammation develops. From the place of introduction with the flow of lymph and blood, the pathogen enters the internal organs, joints, lymph formations; perineural, and later the rostral route of distribution involving the meninges in the inflammatory process. When perishing, Borrelia secrete endotoxin, which causes a cascade of immunopathological reactions.

Early manifestations of the disease may include fever, headaches, fatigue, and a characteristic skin rash called erythema migrans. In some cases, in the presence of a genetic predisposition, joint tissues, the heart, as well as the nervous system, and eyes are involved in the pathological process. In most cases, the disease can be cured with antibiotics such as Zithromax (Azithromycin).

When the pathogen enters various organs and tissues, an active irritation of the immune system occurs, which leads to a generalized and local and cellular immune response.

Immune complexes can also form in the affected tissues, which activate the main factors of inflammation - the generation of leukotactic stimuli and phagocytosis. A characteristic feature is the presence of lymphoplasmic infiltrates found in the skin, subcutaneous tissue, lymph nodes, spleen, brain, peripheral ganglia.

The accumulation of immune complexes attracts neutrophils, which produce various inflammatory mediators, biologically active substances and enzymes that cause inflammatory and dystrophic changes in the tissues. The causative agent persists for a long time (more than 10 years) in the body, apparently, in the lymphatic system, but the causes leading to this are unknown.

A delayed immune response associated with relatively late and mild borrelemia, the development of autoimmune reactions and the possibility of intracellular persistence of the pathogen are some of the main causes of chronic infection.

The outcome of the disease largely depends on the timeliness and accuracy of the diagnosis and early treatment of the infection. Untimely and inadequate therapy can lead to the development of a "late-stage", which is difficult to cure and can result in disability or even death of the patient.

Symptoms of Lyme disease

The time from infection till the occurrence of symptoms is from 2 to 30 days and on average is 14 days.

The infection can develop without any symptoms or cause various symptoms such as:

- Round-shaped reddening of the skin;
- Fever;
- Headache;
- Fatigue, and general malaise.

The infection is divided into three stages:

1 stage: Early local infection manifests in a single (sometimes several) rounded red spots (erythema) at the site of a bite, which over several weeks, gradually centrifugally expanding, reaches 15 - 20 cm or more in diameter. As the diameter grows, the center part gets smaller. Most commonly, the foci is located on the torso and limbs but can also occur on the face.

The marginal border of erythema with its growth can tear, turning into a garland-like strip, which sometimes passes through the chest, neck, or face of the patient. Erythema is usually hot to the touch, painful, often accompanied by itching and burning, its shape is round or oval, sometimes uneven. Erythema can persist for a long time (months), sometimes disappears without treatment after 2 to 3 weeks, in some cases faster (after 2 to 3 days) leaving pigmentation and peeling or no traces. As the bacteria spread through the body, several erythemas can occur but without the central mark left by the tick bite.

Patients often have intoxication syndrome manifested in headache, chills, nausea, fever, muscle and joint pain, severe weakness, fatigue, drowsiness, and stiff neck muscles.

2 stage: Early disseminated borreliosis is a stage when the disease spreads through the body with the lymph and blood. It occurs in 2-21 weeks (usually, on the 4-5 week) after a tick bite.

The infection can cause lesions of the nervous system (serous meningitis, cranial neuritis, radiculoneuritis), cardiovascular system (myocarditis, pericarditis, conduction disorders (especially atrioventricular block)). Often there is a flu-like syndrome (headache, fever, weakness, muscle pain). Skin lesions at this stage may be secondary ring-shaped elements with a diameter of 1 - 5 cm.

3 stage: Late chronic borreliosis is diagnosed when the infection affects the joints. It begins after 2 months and later from the onset of the disease, sometimes after 1 to 2 years. Large joints are usually affected, especially knee joints, often on one side of the body. In some cases, symmetrical polyarthritis develops. Arthritis usually recurs within a few years and acquires a chronic course with the destruction of bones and cartilages. At a late stage of the disease, the persistence of the pathogen in the patient's body leads to a chronic course of Lyme disease. Chronic disease is manifested in alternating remissions and relapses, sometimes acquiring a continuously relapsing character. The most common syndrome is arthritis. Changes typical of chronic inflammation develop such as osteoporosis, thinning, and loss of cartilage, less commonly, degenerative changes. Often there is a skin lesion in the form of a benign lymphocytoma, a dense, slightly painful, swollen, bright crimson-colored nodule, located on the earlobe or around the breast nipple and lasting from several days to months and even years.

Another lesion typical of the late stage is chronic atrophic acrodermatitis, cyanotic red spots on the extensor surfaces of the extremities, with a tendency to peripheral growth, fusion, and periodic inflammation. Gradually, the skin at the spot spots atrophies and becomes thin as tissue paper. The process develops over several months and years.

The disease also can cause symptoms resembling multiple sclerosis, disorders of memory, sleep, speech, etc. The prolonged and chronic course of the disease sometimes leads to partial or complete disability.

Diagnosis of Lyme disease

The diagnosis is made based on symptoms when the skin manifestation is visible and epidemiological data, i.e. if the region is known for the frequent incidence of Lyme disease and its carriers, when it is tick activity season, and so on.

In the classic picture of migratory erythema (bite and characteristic reddening of the skin), the diagnosis is made according to clinical signs, the diagnosis can be made even in the absence of laboratory confirmation and data on a tick bite. In other cases, the diagnosis is confirmed by laboratory methods. Inoculation, detection of the pathogen antigen and histological examination of the skin are not sensitive and specific enough, histological examination is also invasive. Therefore, the diagnosis is confirmed mainly by serological methods - the detection of specific antibodies to the pathogen in the blood.

IgG antibodies circulate in the blood for a long time (from several months to several years), even after successful antimicrobial therapy and cure of the infection. Immunity against borrelia is not sterile. In patients who are ill, reinfection is possible after a few years. False-positive results for the determination of IgG antibodies to Borrelia may be due to the presence of specific antibodies in the blood for diseases caused by spirochetes (syphilis, typhoid fever); low IgG antibodies are possible with infectious mononucleosis, hepatitis B, rheumatic diseases (SLE), periodontal diseases, in 5 - 15% of healthy individuals from the epidemic zone.

Therapy of Lyme disease

Patients with a moderate course of Lyme disease are subject to mandatory hospitalization in an infectious diseases hospital at all stages of the disease.

Patients with a mild course of the disease (tick-borne erythema, in the absence of fever and intoxication phenomena) can be treated at home. Antibiotics are prescribed in all cases but their choice, dose and duration of use depend on the stage of the disease, the prevailing clinical syndrome, and severity. All bitten by ticks and having had the disease need to undergo follow-ups for 2 years. Clinical examination is carried out by an infectious disease specialist or general practitioner. Patients should undergo examination after 3, 6, 12 months, and after 2 years.

According to indications, consultations with a cardiologist, rheumatologist, and neurologist are prescribed. Particularly noteworthy are pregnant bitten by a tick. Due to the lack of specific prophylaxis and the known teratogenic (harmful effect on the fetus) effect of borrelia in early pregnancy, it is advisable to individually resolve the issue of maintaining pregnancy.

In case of late manifestations of borreliosis, patients are treated in specialized hospitals (rheumatological, neurological, cardiological) according to clinical indications. Recovering patients with residual effects are observed by narrow-profile specialists, depending on the damage to a particular system (neuropathologist, cardiologist, or rheumatologist).

Proposed treatment plans

Prophylaxis of Lyme disease

There is no prophylactic vaccine to prevent Lyme disease. The best prevention is protection against tick bites. Prevention consists in observing personal protective measures against tick attacks and rising awareness among the general population.

Of great importance for the prevention of infection is the correct removal of the tick. Borrelia live in the intestines of the tick and do not immediately enter the bloodstream. The longer the tick has been on the body, the higher the risk of borreliosis. Thus, it must be removed as soon as it is noticed.

The question of the benefits of preventing borreliosis after a tick bite with antibiotics is debatable. Prescribing antibiotics in the first days after a bite can reduce the risk of illness. But they should be prescribed only by a doctor. If a bite has occurred, then it is urgent to seek medical help.

Due to the lack of specific preventive measures, the identification of patients by early clinical signs and mandatory antibiotic therapy according to a rational scheme, which avoids severe late complications, are of particular importance.