Encephalitis and Meningitis

Encephalitis and meningitis are serious conditions that affect the brain and/or its surrounding tissue. Meningitis is an infection of the membranes surrounding the brain and spinal cord. (Read about "Nervous System") Encephalitis is an inflammation of the brain. (Read about "The Brain") Symptoms of both may appear suddenly and can require emergency treatment.

Below find more information on encephalitis and meningitis.

Encephalitis

Encephalitis is an inflammation of the brain. (Read about "The Brain") According to the National Institute of Neurological Disorders and Stroke (NINDS), there are many types of encephalitis, the majority of which are caused by viral infection. Symptoms can include:

• sudden fever
• headache
• vomiting
• photophobia, which is abnormal visual sensitivity to light
• stiff neck and back
• confusion and drowsiness
• clumsiness or unsteady gait
• irritability

In addition, there may be loss of consciousness, poor responsiveness, seizures (Read about "Seizures"), muscle weakness, sudden severe dementia (Read about "Dementia"), and loss of memory or judgment. Anyone with suspicious symptoms should seek medical help at once.

Most cases of encephalitis are viral. Potential viral causes can include:

• Arboviruses - An arbovirus is transmitted by the bite of an infected mosquito or tick. Examples include West Nile virus or St. Louis encephalitis virus. (Read about "Arboviral Encephalitides" "West Nile Virus")
• Herpes simplex virus (HSV) - The two forms of this herpes virus are HSV type 1 (generally associated with cold sores) and HSV type 2 (generally associated with genital herpes). (Read about "Herpes")
• Varicella-zoster virus - This is the virus responsible for chicken pox and shingles. (Read about "Childhood Illnesses" "Shingles")
• Epstein-Barr virus - This herpes virus is a common cause of mononucleosis. (Read about "Mononucleosis")

Encephalitis can also develop as a complication to other viral infections such as measles, mumps or chicken pox for example. (Read about "Childhood Illnesses")

Encephalitis can be diagnosed by analyzing the cerebrospinal fluid surrounding your brain and spinal cord. This is called a spinal tap or lumbar puncture. Brain imaging scans can also be used, such as electroencephalography (EEG), CT scan or MRI. (Read about "EEG - Electroencephalograph" "CT Scan - Computerized Tomography" "MRI - Magnetic Resonance Imaging")

Most cases of encephalitis are mild, and patients have full recovery with rest, a healthy diet and plenty of fluids. But other cases are severe, and can even be fatal. NINDS says antiviral medications may be prescribed for some cases of encephalitis. Depending on the severity of the individual case, the acute phase of encephalitis may last up to two weeks, but the lingering neurological symptoms may require many months before full recovery. One of the best ways to protect yourself and your family from contracting encephalitis is by taking precautions against insect bites. (Read about "Insect Bites")

Meningitis

Meningitis is an inflammation of the membranes (called meninges) that surround the brain and spinal cord. (Read about "The Brain" "Nervous System") The National Institute of Neurological Disorders and Stroke (NINDS) says that symptoms often include:

• high fever
• stiff neck
• severe and persistent headache
• nausea
• vomiting

There may also be changes in behavior such as confusion, sleepiness and difficulty waking.

Young children and infants with meningitis may show signs of irritability, extreme sleepiness, poor appetite and fever, along with other symptoms.

Meningitis can be very fast moving, so if you or your child develop suspicious symptoms, seek help at once. The complications of meningitis can be very serious and the risk of developing complications increases the longer you got without treatment. Complications can include loss of hearing, loss of sight, learning disabilities and brain damage. (Read about "Hearing Loss" "The Eye")

Meningitis may develop in response to a number of causes, usually bacteria or viruses, but meningitis can also be caused by parasites, fungus, physical injury, lupus, cancer or certain drugs. (Read about "Microorganisms")

• Viral - The American Medical Association says viral meningitis is far more common in the United States than bacterial meningitis. It often occurs in epidemics in the winter months, especially in closed living communities such as dormitories or barracks, and usually lasts about ten days, according to NINDS.
• Bacterial - Bacterial meningitis is less common, but much more serious. The American Academy of Pediatrics says bacterial meningitis poses a particular danger to children under the age of two.
• Parasitic - CDC says primary amebic meningoencephalitis (PAM) is a very rare form of parasitic meningitis that causes a brain infection that is usually fatal. The parasite enters the body through the nose and is caused by the microscopic ameba (a single-celled living organism) Naegleria fowleri. Naegleria fowleri is found around the world. In the United States, the majority of infections have been caused by Naegleria fowleri from warm freshwater located in southern-tier states.
• Fungal - Fungal meningitis is rare and usually the result of spread of a fungus through blood to the spinal cord. Although anyone can get fungal meningitis, people with weakened immune systems, like those with HIV infection or cancer, are at higher risk. CDC says fungal meningitis is not contagious.
• Non-infectious meningitis causes, according to CDC, can include cancers, systemic lupus erythematosus (lupus), certain drugs, head injury or brain surgery. (Read about "Cancer: What It Is" "Lupus" "Head Injury" "Neurosurgery")

There are some things that put you more at risk of meningitis. Young children have a greater risk. People with compromised immune systems (Read about "The Immune System") face a higher risk. Seniors are also more at risk.

People living in community settings face a higher risk too. This includes military personnel, children in day care and college students. American College Health Association (ACHA) officials say young adults account for nearly 30 percent of all cases of meningitis in the United States. In addition, approximately 100 to 125 cases of meningococcal disease occur on college campuses each year, and five to 15 students will die as a result.

Some meningitis can be prevented with a vaccine. The Centers for Disease Control and Prevention (CDC) recommends routine vaccination with meningococcal conjugate vaccine of children 11-12 years old, previously unvaccinated adolescents at high school entry, new recruits to the military and college freshmen living in dormitories. Vaccination may also be appropriate for younger children with certain health problems. You should talk to your child's doctor about the issue. The recommendations are designed to help achieve vaccination among those at highest risk for meningococcal disease. (Read about "Immunizations")

Meningitis can be diagnosed by analyzing the cerebrospinal fluid surrounding your brain and spinal cord. This is called a spinal tap or lumbar puncture. Brain imaging scans can also be used, such as electroencephalography (EEG), CT scan or MRI. (Read about "EEG - Electroencephalograph" "CT Scan - Computerized Tomography" "MRI - Magnetic Resonance Imaging")

Treatment for meningitis depends on the cause and on the symptoms. Antiviral medications may be used if a virus is involved. Antibiotics may be prescribed for bacterial infections. (Read about "Antibiotics") In addition, anticonvulsants may be used if there are seizures (Read about "Seizures"); and corticosteroids may be needed to reduce brain swelling and inflammation. (Read about "Hydrocephalus") In many cases, especially those caused by bacteria, hospitalization is required. NINDS says that with early diagnosis and prompt treatment, most patients, though not all, recover from meningitis. Anyone experiencing symptoms of meningitis or encephalitis should see a doctor immediately.