Encephalitis

Encephalitis is defined as inflammation of the brain. This definition means encephalitis is different from meningitis, which is defined as inflammation of the layers of tissue, or membranes, covering the brain. Encephalitis is a rare condition and occurs most often in the first year of life and decreases with age. The major causes of encephalitis are viral infections where the virus is transmitted by breathing in respiratory droplets from an infected person,contaminated food or drinks,mosquitoes and other insects.

Symptoms

Some patients may have symptoms of cold or stomach infection but when the infection is severe the symptoms may include:

• Fever
• Mild headache
• Low energy and poor appetite
• Clumsiness
• Confusion
• Drowsiness
• Light sensitivity
• Vomiting

Diagnosis and Treatment

Blood and urine tests that may be helpful include the following:

• Complete blood count (CBC)
• Serum glucose level
• Blood urea nitrogen (BUN) and creatinine levels
• Urine electrolyte levels

A lumbar puncture (LP) should be performed in all cases of suspected viral encephalitis. Cases of encephalitis due to certain viruses usually require intravenous antiviral treatments. Antiviral drugs commonly used to treat encephalitis include: • Acyclovir (Zovirax) • Ganciclovir (Cytovene) • Foscarnet (Foscavir)

Epidemology

Determining the true incidence of encephalitis is impossible, because reporting policies are neither standardized nor rigorously enforced. The arbovirus group is the most common cause of episodic encephalitis, with a reported incidence. Individuals at the extremes of age are at highest risk, particularly for HSE.