Ticks are more commonly encountered in summer. In Turkey, those who spend time near forests, meadows, and tall-grass areas are at risk.
Lyme disease occurs when the bacterium Borrelia burgdorferi is transmitted to humans through the bite of Ixodes ticks. If not recognized early, the disease can permanently affect the nervous system.
The disease progresses in three stages: early localized, early disseminated, and late. In the early localized stage, a bull's-eye rash appears at the bite site. This is called erythema migrans. It is seen in 70% of patients and appears 7 to 14 days after the bite. In some patients, no rash develops at all. Fever, muscle pain, and fatigue may accompany the rash. If left untreated, the rash can persist for 2 to 3 weeks and expand up to 20 centimeters in diameter.
Neurological symptoms do not appear at this stage — they come later. It takes time for the bacteria to enter the bloodstream and spread. The early disseminated stage typically begins 3 to 12 weeks after the bite. This is when neurological symptoms emerge. In untreated patients, nervous system involvement develops within this window.
Neurological involvement is one of the most serious complications of Lyme disease. In the medical literature, this is called neuroborreliosis. Approximately 20% of patients develop central nervous system involvement. The classic triad consists of meningitis, cranial neuropathy, and motor or sensory radiculopathy. However, these three findings do not always appear together — any one of them may occur in isolation.
The most common neurological finding is facial palsy. The seventh cranial nerve — the facial nerve — is affected. It occurs in approximately 5% of patients. Onset is sudden. The patient notices that one side of the face is not moving. Lyme meningitis presents with headache, light sensitivity, and neck stiffness. It can be confused with classic viral meningitis. In radiculopathy, nerve root involvement causes burning, tingling, and weakness in the arms or legs.
A rarer but more severe presentation is encephalopathy. Memory impairment, difficulty concentrating, and sleep disturbances are prominent. Personality changes, irritability, and depression may also accompany the picture. These findings are often confused with psychiatric disorders. Lyme disease should always be considered in patients diagnosed with depression or anxiety who do not respond to treatment.
Late-stage disease appears months after the initial bite. At this stage, sensory axonal polyneuropathy, encephalomyelitis, or mononeuropathy may be seen. Encephalomyelitis is rare but can cause gait disturbances, seizures, unilateral paralysis, and hearing loss.
Diagnosis relies on blood tests. Serology can be misleading in the first weeks of infection, as seroconversion is not yet complete; a negative result does not rule out Lyme disease. In patients with suspected neurological involvement, cerebrospinal fluid (CSF) analysis is required. Lymphocytic pleocytosis and elevated protein levels are the expected CSF findings.
Treatment varies according to disease stage and clinical presentation. In patients with erythema migrans in endemic areas, antibiotic treatment should be started without waiting for serology. Treatment duration is 14 to 21 days.
Correct management after a tick bite is critical. It is known that bacterial transmission generally does not occur until the tick has been attached for more than 36 hours, making early detection essential. When a tick is found, it should be grasped at the head with tweezers or a tick removal tool and pulled straight out without twisting. The tick must not be crushed — crushing increases the risk of transmission. Applying alcohol, oil, or heat is incorrect and not recommended. After removal, the area should be cleaned with alcohol or soap and water. The date of removal should be noted, and the patient should be monitored for rash and symptoms over the following weeks.
Lyme disease is fully treatable when diagnosed early. Neurological complications represent the most severe form of involvement. In any patient with a history of tick exposure during summer months and unexplained neurological complaints, Lyme disease must be included in the differential diagnosis.
