What is Encephalitis ?
Encephalitis is an acute inflammation of the brain, commonly caused by a viral infection.

Victims are usually exposed to viruses resulting in encephalitis by insect bites or food and drink. The most frequently encountered agents are arboviruses (carried by mosquitoes or ticks) and enteroviruses ( coxsackievirus, poliovirus and echovirus ). Some of the less frequent agents are measles, rabies, mumps, varicella and herpes simplex viruses.

Patients with encephalitis suffer from fever, headache, vomiting, confusion, drowsiness and photophobia. The symptoms of encephalitis are caused by brain's defense mechanisms being activated to get rid of infection (brain swelling, small bleedings and cell death). Neurologic examination usually reveals a stiff neck due to the irritation of the meninges covering the brain. Examination of the cerebrospinal fluidCerebrospinal fluid CSF in short, is the clear fluid that occupies the subarachnoid space (the space between the skull and cortex of the brain). It acts as a "cushion" or buffer for the cortex. Also, CSF occupies the ventricular system of the brain and th obtained by a lumbar punctureIn medicine, a lumbar puncture (colloquially known as a spinal tap is a diagnostic procedure that is done to collect a sample of cerebrospinal fluid (CSF) for biochemical, microbiological and cytological analysis. Indications The most common indication fo procedure reveals increased amounts of proteins and white blood cells with normal glucose. A CT scan examination is performed to reveal possible complications of brain swelling, brain abscessBrain abscess (or cerebral abscess) is an abscess caused by inflammation and collection of infected material coming from local (ear infection, infection of paranasal sinuses, infection of the mastoid air cells of the temporal bone, epidural abscess) or re or bleeding. Lumbar puncture procedure is performed only after the possibility of a prominent brain swelling is excluded by a CT scan examination.

what are the main Symptoms?
Some patients may have symptoms of a cold or stomach infection before encephalitis symptoms begin.
When a case of encephalitis is not very severe, the symptoms may be similar to those of other illnesses, including:
• Fever that is not very high
• Mild headache
• Low energy and a poor appetite
Other symptoms include:
• Clumsiness, unsteady gait
• Confusion, disorientation
• Drowsiness
• Irritability or poor temper control
• Light sensitivity
• Stiff neck and back (occasionally)
• Vomiting
Symptoms in newborns and younger infants may not be as easy to recognize:
• Body stiffness
• Irritability and crying more often (these symptoms may get worse when the baby is picked up)
• Poor feeding
• Soft spot on the top of the head may bulge out more
• Vomiting
Emergency symptoms:
• Loss of consciousness, poor responsiveness, stupor, coma
• Muscle weakness or paralysis
• Seizures
• Severe headache
• Sudden change in mental functions:
• "Flat" mood, lack of mood, or mood that is inappropriate for the situation
• Impaired judgment
• Inflexibility, extreme self-centeredness, inability to make a decision, or withdrawal from social interaction
• Less interest in daily activities
• Memory loss (amnesia), impaired short-term or long-term memory

Signs and tests
An examination may show:
• Abnormal reflexes
• Increased intracranial pressure
• Mental confusion
• Mouth ulcers
• Muscle weakness
• Neck stiffness
• Signs in other organs, such as the liver and lungs
• Skin rash
• Speech problems

Tests may include:
• Brain MRI
• CT scan of the head
• Culture of cerebrospinal fluid (CSF), blood, or urine (however, this test is rarely useful)
• Electroencephalogram (EEG)
• Lumbar puncture and CSF examination
• Tests that detect antibodies to a virus (serology tests)
• Test that detects tiny amounts of virus DNA (polymerase chain reaction -- PCR)

Prevention
Children and adults should avoid contact with anyone who has encephalitis.
Controlling mosquitoes (a mosquito bite can transmit some viruses) may reduce the chance of some infections that can lead to encephalitis.
• Apply an insect repellant containing the chemical, DEET when you go outside (but never use DEET products on infants younger than 2 months).
• Remove any sources of standing water (such as old tires, cans, gutters, and wading pools).
• Wear long-sleeved shirts and pants when outside, particularly at dusk.
Vaccinate animals to prevent encephalitis caused by the rabies virus.
 

  Bacterial infections

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