What are the signs of encephalitis after a tick bite in a human and when do symptoms appear? - briefly
Typical signs are fever, severe headache, neck stiffness, confusion, seizures, and altered consciousness. Symptoms usually emerge one to three weeks after the tick bite.
What are the signs of encephalitis after a tick bite in a human and when do symptoms appear? - in detail
Encephalitis caused by a tick‑borne pathogen typically follows an incubation period of several days to weeks after the bite. The earliest neurological signs may appear as soon as 5 days, but most cases present between 10 and 21 days post‑exposure.
Initial manifestations often include nonspecific systemic symptoms such as fever, headache, and malaise. As the infection progresses, the central nervous system becomes involved, producing the following clinical features:
- Severe, persistent headache resistant to analgesics
- Altered mental status ranging from confusion to lethargy or coma
- Photophobia and neck stiffness indicative of meningeal irritation
- Focal neurological deficits (weakness, facial palsy, cranial nerve involvement)
- Seizures, both focal and generalized, occurring without prior epilepsy history
- Movement abnormalities such as tremor, ataxia, or dysarthria
- Visual disturbances, including blurred vision or diplopia
- Behavioral changes, agitation, or psychosis in advanced stages
Laboratory and imaging studies support the diagnosis. Cerebrospinal fluid analysis commonly reveals lymphocytic pleocytosis, elevated protein, and normal or slightly reduced glucose. Magnetic resonance imaging may show hyperintense lesions in the temporal lobes, basal ganglia, or brainstem.
Prompt recognition of these signs is critical because early antimicrobial therapy (e.g., doxycycline for tick‑borne bacterial encephalitis) and supportive care improve outcomes and reduce the risk of permanent neurological impairment.