Index
- How are the 3 phases of Lyme disease characterized?
- The primary phase
- The secondary phase
- The tertiary or late phase
- Causes and factors of the disease
- Diagnosis
- How is the disease treated?
- Evolution of Lyme disease
How are the 3 phases of Lyme disease characterized?
Lyme disease is a disease caused by the bacterium Borrelia burgdoferi. This bacterium can be carried by the ticks Ixodes scapularis. The disease causes a rash and flu-like symptoms. The patient may also experience joint pain and weakness in the limbs. The majority of sufferers recover completely after appropriate antibiotic treatment. For those who develop symptoms after treatment, it is possible to take prescribed analgesics to relieve symptoms. In addition, the disease evolves in 3 phases. These phases of Lyme disease are separated by asymptomatic periods.
The primary phase
This first and one of the phases of Lyme disease is characterized by a skin lesion: chronic erythema migrans (ECM). The lesion occurs between 3 and 30 days after the tick bite. It is a red erythematous papule, centered by the point of the bite. It spreads progressively in a centrifugal manner. The lesion is oval in shape and measures up to 50 cm. Its border is redder than its centre, which gradually regains a normal cutaneous appearance. It is often non-itchy, in other words, there is no itching. The lesion is usually found on the lower limbs, sometimes on the upper limbs, or even on the face in children. General manifestations (joint pain, headaches, ...) and ganglia close to the lesion may be associated. This indicates the spread of the bacterium. In the absence of treatment, the ECM evolves during a few weeks and disappears without sequelae.
The secondary phase
The second phase occurs a few weeks or months after the disappearance of the ECM. However, it may reveal the disease, as the ECM has gone unnoticed. It manifests itself as:
- Cutaneous manifestations: lesions similar to those of the primary phase
- Joint manifestations: frequent joint pain
- Cardiac manifestations: loss of consciousness, palpitation, atrioventricular conduction disorder, chest pain. These cardiac manifestations often evolve towards the cure of the disease, without after-effects
- Neurological manifestations: hyper-algic radiculitis. This is a very painful inflammation of the nerve roots innervating the area of the sting. The facial nerve is often affected. Meningitis can also be observed
The tertiary or late phase
Of all the stages of Lyme disease, this is the most dangerous. It occurs a few months or years after the onset of infection with :
- Joint damage: such as that observed during the secondary phase
- Skin disorders: benign cutaneous lymphocytoma, Pick Herxheimer's disease (skin inflammation that develops into skin atrophy)
- Neurological damage: affects the spinal cord or the brain, with various neuro-psychiatric manifestations
Causes and factors of the disease
The origin of this disease is still a matter of debate. For a long time, researchers have attributed Lyme disease to the single bacterium borreliosis (Borrelia burgdorferi), a spiral-shaped bacterium (spirochete). However, recent studies have demonstrated the multi-microbial nature of the disease. Ticks are the main vector. Thus, the activities that lead to contact with these arachnids are the main risk factors for the occurrence of the disease. Such as agricultural work or walks in the forest. Moreover, the germ reservoir is very vast: domestic (horses, dogs, cattle) and wild mammals (voles, deer, field mice, squirrels), ticks.
Diagnosis
It is not easy to diagnose the disease. This is because of the many aspects it is capable of presenting, but also because of its still insufficient knowledge both by doctors and patients. However, it is essentially based on the clinical signs that can be observed. For this reason, the doctor will carefully examine the patient and perform an electrocardiogram if necessary. This will make it possible to look for, among other things, atrioventricular conduction disorders. A complete neurological examination is also necessary according to the phases of Lyme disease. For the second phase, this examination may be normal, in order to reveal a decrease in muscle sensitivity. On the other hand, the presence of antibodies in the cerebrospinal fluid (obtained by lumbar puncture) is an argument in favour of the disease, in case of neurological damage.
How is the disease treated?
Since it is due to a bacterial infection, its treatment is based on antibiotic therapy (doxycycline or amoxicillin). In the case of atrioventricular conduction disorders, it may be combined with a corticosteroid. Among the phases of Lyme disease, the treatment of the first one consists in making the first symptoms disappear and preventing the occurrence of late manifestations. This is done by removing the germ from organs that may be infected. Depending on the severity of the disease and for each phase, the treatment may vary and require hospitalization.
Evolution of Lyme disease
It is important to know that the evolution of the disease towards a tertiary phase remains very rare. Even without treatment. In general, the disease has a favourable course when treatment is available.
