Nervous System Disorders

1. Nervous System Disorders Meningitis, Encephalitis, West Nile Virus

2. Meningitis What Is Meningitis? • Meningitis can be a serious infection, and it can be contagious — which is why outbreaks make the news. However, it's also pretty rare. • Meningitis means inflammation of the membranes surrounding the brain and spinal cord called the meninges (pronounced: muh-nin-jeez). It often occurs when an infection elsewhere in the body spreads through the blood and into the cerebrospinal fluid (the fluid that circulates in the spaces in and around the brain and spinal cord). People can get meningitis at any age. • There are several types of meningitis, and their severity and treatment can vary depending on which type a person has. Most cases of meningitis are caused by viruses (viral meningitis) or bacteria (bacterial meningitis), but fungi and other organisms can also cause infectious meningitis. Some cases of meningitis result from head injuries, certain cancers or other diseases, or reactions to medications.

3. Meningitis • Viral meningitis is caused by such viruses as enteroviruses, which are very common in summer and early fall. These viruses can spread through contact with saliva, mucus, or feces (poop). That doesn't mean that people need to kiss or share a sandwich to catch the virus, though. People can spread the infection when they touch surfaces that others will touch or when they sneeze without covering their mouths. Enteroviruses begin to multiply in the digestive tract and can spread through the body to cause meningitis. • Bacterial meningitis is a more severe form of the infection. If it isn't treated promptly, it can cause brain damage and, in some circumstances, even death. The most common bacteria that cause bacterial meningitis in teens are Streptococcus pneumoniae and Neisseria meningitidis. People can spread them through throat and respiratory secretions — for example, by coughing or kissing. After a person is started on antibiotic treatment for meningitis, the infection can still be spread to others for at least 24 hours. • One form of bacterial meningitis is related to Lyme disease. Lyme meningitis is generally less severe than other forms of bacterial meningitis and is not fatal

4. What Are the Signs and Symptoms? • Viral and bacterial meningitis can cause similar symptoms. Although it may be difficult to identify which type a person has, a doctor can often find out by doing tests. Some symptoms of both viral and bacterial meningitis are: • fever • stiff neck • severe headache • sensitivity to light • vomiting • nausea • extreme sleepiness • confusion • Seizure • If you or someone you know has these symptoms — especially if you've been around someone with meningitis — be sure to talk to a doctor. Treating the infection early is very important.

5. Can It Be Prevented? • Washing your hands really well and often is one way to defend against meningitis and other infections. • Although bacterial meningitis can seem scary, the chance of getting it is quite low. However, because it can be so serious, doctors now recommend that all teens get vaccinated against meningococcal meningitis (the type caused by Neisseria meningitides bacteria). Many colleges actually require their students to get meningitis vaccines. • There are also vaccines for some other types of meningitis. If you have a medical condition that affects your immune system, for example, a doctor may also recommend a vaccination against the S. pneumoniae type of bacteria. But vaccines don't exist for all types of bacterial meningitis.

6. Encephalitis What Is Encephalitis? • Encephalitis is an inflammation (swelling) of the brain. Encephalitis is usually caused by a virus, but other things, including bacteria, may cause it as well. Although encephalitis sounds scary, most cases aren't serious. • Encephalitis (pronounced: in-seh-fuh-lye-tus) is typically caused by three different groups of viruses. • The herpes viruses is one group, and it includes chickenpox, EBV (Epstein-Barr virus, the virus that causes mono), and herpes simplex (the virus that causes cold sores).

7. Encephalitis • The second group is made up of viruses and other germs that are transmitted by insects. Viruses like West Nile virus, which is transmitted through a mosquito bite, and the germs that cause Lyme disease and Rocky Mountain spotted fever, which are transmitted thorough tick bites, can also cause encephalitis. • The third group is made up of viruses that cause childhood infections that used to be common. These include measles, mumps, and German measles. Because lots of countries immunize against these diseases, it's rarer today that a person will develop encephalitis as a result of an illness like measles or mumps. • Some cases of encephalitis are mild and symptoms only last for a short time. However, it is possible to develop a severe case of encephalitis that can be serious and possibly even life threatening. When a person has encephalitis, his or her brain becomes inflamed — inflammation means swelling and irritation.

8. Is it Contagious? • Infection with many different viruses can lead to encephalitis. So how contagious the infection is depends on which virus caused it. Viruses like West Nile are only transmitted through the bite of infected insects; it's not possible to catch them from other people. But viruses like EBV are passed from person to person. • Even if someone catches a virus that can cause encephalitis, that does not mean that person will automatically develop the condition. In fact, very few people who are infected with these viruses actually develop encephalitis.

9. What Are the Signs and Symptoms? Encephalitis may cause fever, headache, poor appetite, loss of energy, or just a general sick feeling. In more severe cases, other symptoms might occur, including: • high fever • severe headache • sensitivity to light (called photophobia, which means light hurts your eyes) • nausea and vomiting • stiff neck • confusion • sleepiness, difficulty waking, or unconsciousness • convulsions (seizures) When encephalitis happens after a common illness like chickenpox, the signs and symptoms of that illness usually come before symptoms of inflammation in the brain. But encephalitis can also appear without warning. If you have symptoms of encephalitis, get in touch with your doctor right away.

10. How Is It Diagnosed and Treated? • To diagnose encephalitis, the doctor may take blood samples and order a spinal tap (also called a lumbar puncture), a procedure that involves inserting a very thin needle into the lower back to remove some cerebrospinal fluid (CSF) that surrounds the brain and spinal cord. The samples will be sent to a laboratory to be checked for viruses or bacteria. • A special brain scan (an MRI or a CT scan) also may be ordered to look for inflammation. The doctor might also order an electroencephalogram (EEG), a test that records your brain waves and can reveal any abnormalities that are consistent with encephalitis. • Treatment for encephalitis depends on the virus or other germ that caused it. Teens with mild cases of encephalitis can recover at home as long as they're watched carefully by a parent or other adult in the household. Most cases of encephalitis just run their course and the person gets better without treatment.

11. How is it diagnosed and treated? • Some viruses that cause encephalitis can be treated with medication. For example, acyclovir, an antiviral drug, can help treat encephalitis caused by the herpes simplex virus. In addition, steroid medications can be used to reduce swelling in the brain (these aren't the same as the dangerous performance-enhancing steroids that some athletes use). Because antibiotics are not effective against viruses, they're not used to treat viral encephalitis. • Severe cases of encephalitis require a hospital stay so the patient can be carefully monitored and medical treatment is close at hand if needed. For people who have had severe encephalitis that has affected some of the brain's functions, doctors may recommend physical therapy or speech therapy to help with recovery.

12. Can I Prevent Encephalitis? • The best way to prevent encephalitis is to avoid getting infected with the viruses or other germs that can cause it. Regular hand washing will help limit the spread of some of these germs. Staying as healthy as possible by eating a balanced diet and getting plenty of rest can help keep your immune system in shape. Immunizations are also an important way to protect people from diseases like chickenpox and measles. • In areas where viruses and other germs are transmitted by insect bites, protect yourself by wearing long sleeves and pants and applying an insect repellent. Also, try to avoid unnecessary outdoor activities at dawn and dusk when mosquitoes are most likely to bite.

13. West Nile Virus Most mosquitoes are simply annoying. But a small percentage can carry diseases like West Nile virus. Over the past few years, West Nile virus has been found in animals, birds, and humans in all continental states in the United States. • West Nile virus is transmitted to humans from the bite of mosquitoes that probably picked up the virus after feeding on infected birds. Pets and other animals can also become infected with West Nile virus. But you can't get the virus from touching (or other casual contact with) people or animals. • Most people are unlikely to become seriously ill from West Nile virus. In fact, someone who does get infected with West Nile virus may not even know it. That's because most people who do get the virus usually have few or no symptoms. A small number may have symptoms like those of the flu, such as fever and body aches. But they usually get better quickly.

14. West Nile Virus • The Centers for Disease Control and Prevention (CDC) believes that, after becoming infected, a person becomes immune and won't get sick from the virus again. • A small number of people (less than 1%) who are infected with West Nile virus do become seriously ill, though. They are usually people over the age of 50 who are at greater risk of developing a more severe form of the infection, such as encephalitis. Encephalitis or meningitis meningitis.Thesemore serious forms of infection can cause long-term illness, brain damage, permanent disability, and — in rare cases — even death. Symptoms usually begin 3 to 14 days after a person has been infected.

15. Signs and Symptoms • Severe West Nile virus infection causes symptoms such as: • high fever • very stiff neck and back (people are unable to bend their necks) • severe headache • confusion or disorientation • weak muscles • convulsions or seizures • People who think they may have symptoms of West Nile virus should see a doctor right away. Diagnosing the infection early can help improve a person's chances of recovery.

16. Tips for protecting yourself • Although it's unlikely you'll be infected with West Nile virus, mosquito bites can still be an itchy nuisance. The CDC advises people to protect themselves from mosquito bites by using mosquito repellent, especially at times when mosquitoes are most active, such as at dusk and dawn. • The CDC recommends mosquito repellents that include one of the following ingredients: • DEET (N,N-diethyl-meta-toluamide) — those that contain between 10% and 30% of DEET are best • Picaridin(KBR 3023) • Oil of lemon eucalyptus (p-menthane 3,8-diol or PMD)

17. Tips for protecting yourself • The Environmental Protection Agency (EPA) offers the following tips for using insect repellents: • Don't use insect repellent on skin that is already covered by clothing. • Don't spray products directly onto your face (spray the repellent onto your hands first and then rub it onto your face) and don't use repellent on your eyes or mouth. • Wash repellent off once you get back indoors. • Don't use repellent on areas of the skin that are irritated or cut. • Stop using a repellent if it gives you a rash or other skin reaction, wash it off, and call the doctor. • Don't let little kids touch the repellent.