How does encephalitis present after a tick bite in a person? - briefly
After a tick bite, viral encephalitis typically begins with abrupt fever, severe headache, and neck stiffness, followed by confusion, altered consciousness, or seizures. Additional signs may include focal neurological deficits such as weakness or speech disturbances.
How does encephalitis present after a tick bite in a person? - in detail
Tick‑borne encephalitis typically emerges within 1 to 3 weeks after the arthropod bite. The incubation period reflects viral replication in skin and regional lymph nodes before central nervous system invasion.
Initial phase may be nonspecific: fever, malaise, headache, and myalgia. These systemic signs often precede neurological involvement and can be mistaken for a viral prodrome.
Neurological phase presents with a constellation of symptoms:
- Severe, persistent headache, frequently described as frontal or occipital.
- High‑grade fever that may fluctuate.
- Neck stiffness and photophobia, indicating meningeal irritation.
- Altered mental status ranging from confusion and lethargy to stupor or coma.
- Focal neurological deficits such as hemiparesis, ataxia, dysarthria, or cranial nerve palsies.
- Seizures, both focal and generalized, occurring in up to 30 % of cases.
- Movement disorders, including tremor or myoclonus, may appear during recovery.
Cerebrospinal fluid analysis commonly shows lymphocytic pleocytosis, elevated protein, and normal to mildly reduced glucose. Polymerase chain reaction or serological testing for specific flavivirus antibodies confirms the etiology.
Magnetic resonance imaging often reveals hyperintense lesions in the thalamus, basal ganglia, hippocampus, and brainstem on T2‑weighted sequences. Diffuse cortical edema may be present in severe cases.
Complications include prolonged cognitive impairment, persistent motor deficits, and, rarely, fatal outcome. Early supportive care—fluid management, antipyretics, and seizure control—remains the mainstay of treatment; no specific antiviral therapy is currently approved.
Prognosis improves with prompt recognition and intensive monitoring. Long‑term follow‑up should assess neurocognitive function and motor recovery.