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The majority of headaches are not dangerous, however, it helps to know the signs and symptoms of potentially dangerous headaches so that you can seek medical help promptly.
One type of dangerous headache is caused by viral encephalitis. The term "encephalitis" comes from the Greek word for head, enkephalos, and "itis" means inflammation so "viral encephalitis" is a brain inflammation caused by a virus.
Examples of different types of viruses that can cause viral encephalitis are:
• Herpes Simplex viruses – these are the most common types of viral encephalitis
• West Nile Virus
• Japanese Encephalitis
• Dengue fever
• Influenza viruses
• Rabies virus
• Mumps virus – mumps encephalitis usually resolves without any complications
• Echo Virus
• Viral meningitis – this is usually mild and resolves without complications
Some encephalitis causing viruses are transmitted via mosquito bites.
Sometimes viral encephalitis can occur as an immunological complication of vaccination as the immune system attacks central nervous system antigens that resemble proteins of the infectious illness. This is more common with live virus vaccines.
The initial symptoms of viral encephalitis are headache, stiff neck and fever. The headache can be severe. Lethargy, drowsiness and confusion can then develop.
The person may have speech difficulties, coordination difficulties and alterations in their behavior. They may suffer a seizure or go into a coma. In some cases, encephalitis can be fatal.
If you or a loved one has a severe headache, accompanied by changes in levels of consciousness and/or unusual behaviour you should contact a doctor or the emergency services immediately as encephalitis is a medical emergency.
Symptoms in Infants and Children
Symptoms in infants may be slightly different to those in adults. Their encephalitis usually begins with fever. Other symptoms are:
• Being fussy
• Refusal to breast feed or have a bottle
• Bulging fontanelle (soft spot on the baby’s head)
• Crying when picked up (because they have a headache and the movement hurts their head)