What signs of encephalitis appear after a tick bite in a person and when do they manifest? - briefly
Fever, severe headache, neck rigidity, altered mental status, and seizures are typical neurological manifestations following a tick‑borne infection, and they may be accompanied by photophobia, vomiting, or focal deficits. These symptoms generally emerge within 7–14 days after the bite, though onset can vary from a few days to several weeks.
What signs of encephalitis appear after a tick bite in a person and when do they manifest? - in detail
Tick‑borne encephalitis typically begins with an incubation period of 7–14 days after the bite, although intervals of 4–28 days are reported. The disease often proceeds in two phases; the first phase resembles a nonspecific viral infection, while the second phase involves central‑nervous‑system involvement.
During the initial stage, patients may experience:
- Fever of 38–40 °C
- Headache
- Malaise
- Myalgia
- Nausea or vomiting
- Mild gastrointestinal upset
These symptoms usually appear within the first week after exposure and resolve spontaneously after 2–5 days. In a subset of cases, the illness progresses to the neurologic phase, which emerges after a brief asymptomatic interval of 1–5 days.
Neurological manifestations include:
- High fever persisting beyond the first phase
- Severe headache, often retro‑orbital
- Neck stiffness and photophobia
- Altered consciousness ranging from confusion to stupor
- Focal neurological deficits (e.g., hemiparesis, cranial nerve palsies)
- Tremor, ataxia, and gait instability
- Seizures, both focal and generalized
- Cognitive disturbances such as memory loss and reduced attention
- Psychiatric symptoms, including agitation or anxiety
These signs typically develop between days 8 and 21 post‑bite, with the peak of neurologic involvement occurring around day 14. The duration of the second phase varies; most patients improve within weeks, but residual deficits may persist for months.
Laboratory confirmation relies on detection of specific IgM antibodies in serum or cerebrospinal fluid, often accompanied by a rise in IgG titers. Neuroimaging (MRI) frequently reveals hyperintense lesions in the thalamus, basal ganglia, or brainstem, correlating with clinical severity.
Early recognition of the biphasic pattern and prompt supportive care reduce mortality and long‑term complications. Vaccination remains the most effective preventive measure for individuals at risk of tick exposure.