How does encephalitis manifest after a tick bite in people? - briefly
Patients often develop abrupt fever, severe headache, neck stiffness, confusion, and seizures within days to weeks after a tick bite. Neurological deficits such as focal weakness, speech disturbances, or altered consciousness may also emerge.
How does encephalitis manifest after a tick bite in people? - in detail
Encephalitic infection transmitted by ixodid ticks typically presents within a week to several weeks after the bite. The initial stage often includes a localized erythema at the attachment site, sometimes accompanied by a mild fever and headache. As the pathogen reaches the central nervous system, neurological signs become evident.
Common clinical features:
- Altered mental status – confusion, disorientation, lethargy, or coma.
- Cognitive deficits – memory loss, impaired concentration, difficulty finding words.
- Motor abnormalities – weakness, ataxia, tremor, or involuntary movements.
- Sensory disturbances – paresthesia, hyperesthesia, or loss of sensation.
- Seizure activity – focal or generalized convulsions, sometimes progressing to status epilepticus.
- Autonomic dysfunction – irregular heart rate, blood pressure fluctuations, diaphoresis.
- Cranial nerve involvement – facial palsy, ophthalmoplegia, dysphagia, or hearing loss.
Laboratory findings often reveal lymphocytic pleocytosis in cerebrospinal fluid, elevated protein, and normal to low glucose. Magnetic resonance imaging may show hyperintense lesions in the basal ganglia, thalamus, or cerebral cortex, consistent with inflammatory edema. Electroencephalography frequently demonstrates diffuse slowing, with occasional focal epileptiform discharges.
The disease course can be biphasic: an initial systemic phase followed by a neurological phase. Early recognition of the described signs, especially in individuals with recent tick exposure in endemic regions, is essential for prompt antiviral or antimicrobial therapy and supportive care, which improve neurological outcomes and reduce mortality.