Encephalitis is an inflammation of the brain. Most often, it is caused by a viral infection. Several different viruses can cause encephalitis. The most common are the herpes viruses, childhood viruses such as measles, and viruses transmitted by mosquito bite.
There are two types of encephalitis -- primary and secondary. In primary encephalitis, a virus attacks the brain and spinal cord directly. In secondary or postinfectious encephalitis, the virus invades another part of your body and travels to your brain. The virus causes inflammation of the nerve cells (encephalitis) or the surrounding membranes (meningitis). Encephalitis is different from meningitis, but these two brain infections often occur together.
Most cases of encephalitis are mild and don't last long. However, in some cases encephalitis can be life threatening. About 10,000 - 20,000 cases of encephalitis are reported each year in the United States.
Signs and Symptoms
- Ninety percent of people with encephalitis have flu-like symptoms, such as fever, sore throat, cough, and malaise.
- If meningitis accompanies encephalitis, the person may experience headache, stiff neck, intolerance to light, and vomiting.
- People with severe encephalitis usually have some change in consciousness, ranging from mild confusion to coma, often including disorientation and delusion with possible hallucinations, agitation, and personality changes.
- Up to 50% of people with encephalitis may have seizures.
- Other signs and symptoms of encephalitis depend on which area of the brain is most affected. These may include trouble using or understanding words or coordinating voluntary muscle movements, muscle weakness or partial paralysis on one side of the body, uncontrollable tremors or involuntary movements, and not being able to regulate body temperature.
- Infants may have bulging in the fontanels or soft spots on the skull.
Arboviruses, or viruses carried by insects, are among the most common causes of viral encephalitis. Some of the major arboviruses that are transmitted by mosquito include:
- Eastern equine encephalitis -- This infection is relatively rare, with only a few cases reported each year. However, about half the people who develop severe symptoms die or suffer permanent brain damage.
- La Crosse encephalitis -- usually affects children under 16 years of age in the upper Midwestern United States. It is rarely fatal.
- St. Louis encephalitis -- People in rural Midwestern and southern United States are primarily affected. Many people have mild symptoms, although symptoms can be severe in people over age 60. Up to 30% of infected seniors die of the condition.
- West Nile encephalitis -- Primarily affects people in Africa and the Middle East, but outbreaks have spread across the United States. Most cases are mild. Symptoms are most severe in older adults and people with weakened immune systems, and it can be fatal among those populations.
- Western equine encephalitis -- People in the western United States and Canada are most at risk. It usually causes a mild infection, except in children under 1 year of age, who can suffer permanent brain damage.
Other viruses that commonly cause viral encephalitis include:
- Herpes simplex virus type 1 (HSV-1), which is responsible for cold sores
- HSV-2, which is responsible for genital herpes
- Varicella zoster virus, which causes chicken pox and shingles
- Epstein-Barr virus, which causes mononucleosis
- Childhood viruses that can cause encephalitis include:
- Measles (rubeola)
- German measles (rubella)
Not all cases of encephalitis are caused by viruses. Some other causes of encephalitis include:
- Bacterial infection
- Fungal infection
- Parasitic infection
- Noninfectious causes, such as allergic reactions or toxins
The following factors may increase your risk of becoming infected with viral encephalitis:
- Being very young or an older adult
- Being exposed to mosquitoes or ticks
- Having a weakened immune system
- Not being vaccinated against measles, mumps, and rubella
- Traveling to areas where viral encephalitis is common
Encephalitis is a serious condition, so you should see a doctor if you or your child start having symptoms of encephalitis. Diagnosis and initial treatment usually happens in a hospital. After doing a physical exam, a doctor may take the following steps to diagnose the condition:
- Blood test -- finds viruses in the blood
- Spinal tap (lumbar puncture) -- finds viruses in the fluid that surrounds the brain and spinal cord
- Brain imaging -- magnetic resonance imaging (MRI) and computerized tomography (CT) scan see whether swelling is present in the brain
- Electroencephalogram (EEG) -- finds abnormal brain waves
The best way to prevent encephalitis is to avoid getting viruses that lead to encephalitis:
- Protect yourself from mosquitoes. Use insect repellent and wear long pants and long sleeves. The most effective bug sprays use DEET, picaridin, or oil of lemon eucalyptus. Do not apply insect repellent to children under 2 years of age.
- Make sure your child is vaccinated against childhood diseases such as the measles, mumps, and rubella (MMR).
- Eat a healthy diet to keep your immune system healthy.
Viral encephalitis is a serious medical condition. Although there are no specific medications to treat encephalitis, often people with symptoms are given the antiviral medication acyclovir (Zovirax). It works against herpes simplex and varicella-zoster viruses. Complementary and alternative therapies have not been studied very much for the treatment of encephalitis. But some studies indicate that scalp acupuncture, combined with proper medication, may help the healing process.
Treatment includes careful observation and supportive care, including rest, proper nutrition, and fluids, to allow the body to fight the infection. You should always see your doctor if you have symptoms of encephalitis; don't try to treat yourself.
Always tell your health care provider about the herbs and supplements you are using or considering using, as some supplements may interfere with conventional treatments.
Medications used to treat viral encephalitis include:
- Acyclovir (Zovirax) -- treats encephalitis caused by HSV, VZV, and EBV
- Ganciclovir (Cytovene) -- treats encephalitis caused by cytomegalovirus and HSV1
- Anticonvulsant medications -- prevent and treat seizures associated with encephalitis
Nutrition and Dietary Supplements
No specific vitamins or supplements have been shown to reduce symptoms of encephalitis. However, following these tips may help your overall health as you recover:
- Eat antioxidant foods, including fruits (such as blueberries, cherries, and tomatoes), and vegetables (such as squash and bell peppers).
- Avoid refined foods, such as white breads, pastas, and especially sugar.
- Eat fewer red meats and more lean meats, cold-water fish, tofu (soy, if no allergy), or beans for protein.
- Use healthy oils in foods, such as olive oil or vegetable oil.
- Avoid caffeine, alcohol, and tobacco.
- Drink 6 - 8 glasses of filtered water daily.
These supplements may also help improve your overall health:
- Omega-3 fatty acids, such as fish oil, one to three times daily, to help decrease inflammation and help with immunity. Fish oil may increase the risk of bleeding, so ask your doctor before taking it.
- Vitamin C, 500 - 1,000 mg one to three times daily, as an antioxidant and for immune system support.
- Probiotic supplement (containing Lactobacillus acidophilus), 5 - 10 billion CFUs (colony forming units) a day, for digestive and immune system health. If you are taking antibiotics, taking probiotics as well may help you avoid some side effects such as diarrhea. You should refrigerate your probiotic supplements for best results.
Herbs are generally a safe way to strengthen and tone the body's systems. As with any therapy, you should work with your health care provider to get your problem diagnosed before starting any treatment. You may use herbs as dried extracts (capsules, powders, teas), glycerites (glycerine extracts), or tinctures (alcohol extracts). Unless otherwise indicated, you should make teas with 1 tsp. herb per cup of hot water. Steep covered 5 - 10 minutes for leaf or flowers, and 10 - 20 minutes for roots. Drink 2 - 4 cups per day.
No herbs have been shown to help treat encephalitis. These herbs may help strengthen the immune system:
- Green tea (Camellia sinensis) standardized extract, 250 - 500 mg daily, for antioxidant, anti-inflammatory, and immune effects. Use caffeine-free products. You may also make teas from the leaf of this herb.
- Cat's claw (Uncaria tomentosa) standardized extract, 20 mg three times a day, for inflammation and antiviral activity. Cat’s claw can interfere with some medications, so ask your doctor before taking it. People with leukemia should not take cat’s claw.
- Garlic (Allium sativum), standardized extract, 400 mg two to three times daily, for immune system support. Garlic can increase the risk of bleeding and interfere with certain medications, so ask your doctor before taking it.
- Astragalus (Astragalus membranaceus) standardized extract, 250 - 500 mg four times daily for immune system support and antiviral activity. Astragalus interacts with lithium and maybe with some other medications, so ask your doctor before taking it.
- Elderberry (Sambucus nigra), one to two teaspoonfuls of standardized liquid extract two to four times daily, for immune system support and antiviral activity.
A study of a small number of people with complications from encephalitis suggests that acupuncture delivered to the scalp may reduce severe complications and symptoms. Some practitioners believe that scalp acupuncture works for people with encephalitis because all meridians converge at the head, and the method can stimulate and regulate qi (energy) throughout the entire body. More research is needed.
The most common cause of encephalitis in newborns is vaginal delivery by a mother who is infected with herpes simplex virus 2 (HSV-2). This infection in newborns is often severe and fatal. For this reason, pregnant women with a history of HSV-2 infection may be advised to have a cesarean section, even if there is no sign of an active infection.
Prognosis and Complications
Full recovery from encephalitis can take weeks or months. People recovering from serious cases may have complications ranging from fatigue and difficulty concentrating to tremors and personality changes.
The most severe problems associated with encephalitis come from the destruction of nerve cells in the brain. How severe the complications are depends on the person's immune system -- whether it is healthy or weak -- and what infection caused the encephalitis. For example, many of those infected with Eastern equine encephalitis and St. Louis encephalitis have permanent brain damage, such as problems with memory, speech, vision, hearing, muscle control, and sensation, and a low survival rate. Those infected with Epstein-Barr or varicella zoster rarely have any serious complications.
Most cases of encephalitis are mild and people make a full recovery.
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Brain inflammation - viral encephalitis