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Symptoms
By Mayo Clinic staff
Most people with viral encephalitis have either no symptoms or mild flu-like symptoms, such as the following:
- Headache
- Fever
- Aches in muscles or joints
- Fatigue or weakness
More-serious cases require prompt medical care. Signs and symptoms may include the following:
- Severe headache
- Fever
- Altered consciousness
- Confusion or agitation
- Personality changes
- Seizures
- Loss of sensation or paralysis in certain areas of the body
- Muscle weakness
- Hallucinations
- Double vision
- Perception of foul smells
- Problems with speech or hearing
- Loss of consciousness
Signs and symptoms in infants and young children may also include:
- Bulging in the soft spots (fontanels) of the skull in infants
- Nausea and vomiting
- Body stiffness
- Constant, inconsolable crying
- Crying that worsens when the child is picked up
- Poor feeding
When to see a doctor
Get immediate care if you or someone you know is experiencing any of the symptoms associated with more-severe cases of encephalitis. Severe headache, fever and altered consciousness — almost always present with encephalitis in older children and adults — require urgent care.
Infants and young children with any signs or symptoms of encephalitis should receive urgent care.
- Encephalitis and meningitis fact sheet. National Institute of Neurological Disorders and Stroke. http://www.ninds.nih.gov/disorders/encephalitis_meningitis/detail_encephalitis_meningitis.htm. Accessed March 8, 2011.
- Encephalitis. The Merck Manuals: The Merck Manual for Healthcare Professionals. http://www.merckmanuals.com/professional/sec16/ch217/ch217c.html. Accessed March 10, 2011.
- Johnson RP, et al. Viral encephalitis in adults. http://www.uptodate.com/home/index.html. Accessed March 10, 2011.
- Hardarson HS. Acute viral encephalitis in children and adolescents: Clinical manifestations and diagnosis. http://www.uptodate.com/home/index.html. Accessed March 10, 2011.
- Beckham J, et al. Encephalitis. In: Mandell G, et al., eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 7th ed. Philadelphia, Pa.: Churchill Livingstone Elsevier; 2009. http://www.mdconsult.com/books/page.do?sid=1129246002&eid=4-u1.0-B978-0-443-06839-3..00087-4&isbn=978-0-443-06839-3&type=bookPage§ionEid=4-u1.0-B978-0-443-06839-3..00087-4&uniqId=237025740-4. Accessed March 10, 2011.
- Hardarson HS. Acute viral encephalitis in children and adolescents: Pathogenesis and etiology. http://www.uptodate.com/home/index.html. Accessed March 10, 2011.
- Information on arboviral enchephalitides. Centers for Disease Control and Prevention. http://www.cdc.gov/ncidod/dvbid/arbor/arbdet.htm. Accessed March 8, 2011.
- Hardarson HS. Acute viral encephalitis in children and adolescents: Treatment and prevention. http://www.uptodate.com/home/index.html. Accessed March 10, 2011.
- Insect repellant use and safety. Centers for Disease Control and Prevention. http://www.cdc.gov/ncidod/dvbid/westnile/qa/insect_repellent.htm. Accessed March 15, 2011.
- A parent's guide to insect repellent. American Academy of Pediatrics. http://patiented.aap.org/content.aspx?aid=5556. Accessed March 11, 2011.
- Acyclovir. National Center for Biotechnology Medicine. http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0000533. Accessed March 22, 2011.
- Ganciclovir injection. National Center for Biotechnology Medicine. http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0000889. Accessed March 22, 2011.
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