12.How does encephalitis enters the body?
Answers
Answer:
Explanation:
What is encephalitis?
Encephalitis is an acute inflammation of the brain.
Encephalitis is an acute inflammation (swelling) of the brain usually resulting from either a viral infection or due to the body's own immune system mistakenly attacking brain tissue.
In medicine, "acute" means it comes on abruptly and develops rapidly; it usually requires urgent care.
The most common cause is a viral infection. The brain becomes inflamed as a result of the body's attempt to fight off the virus.
Encephalitis occurs in 1 in every 1,000 cases of measles.
Encephalitis generally begins with fever and headache. The symptoms rapidly worsen, and there may be seizures (fits), confusion, drowsiness, and loss of consciousness, and even coma.
Encephalitis can be life-threatening, but this is rare. Mortality depends on a number of factors, including the severity of the disease and age.
Younger patients tend to recover without many ongoing health issues, whereas older patients are at higher risk for complications and mortality.
When there is direct viral infection of the brain or spinal cord, it is called primary encephalitis. Secondary encephalitis refers to an infection which started off elsewhere in the body and then spread to the brain.
Types
Different types of encephalitis have different causes.
Japanese encephalitis is spread by mosquitoes
Tick-borne encephalitis is spread by ticks
Rabies can be spread through a bite from a mammal
There is also primary or secondary encephalitis.
Primary or infectious encephalitis can result if a fungus, virus, or bacterium infects the brain.
Secondary, or post-infectious, encephalitis is when the immune system responds to a previous infection and mistakenly attacks the brain.
Symptoms
The patient typically has a fever, headache, and photophobia (excessive sensitivity to light). There may also be general weakness and seizures.
Less common symptoms
The individual may also experience nuchal rigidity (neck stiffness), which can lead to a misdiagnosis of meningitis. There may be stiffness of the limbs, slow movements, and clumsiness. The patient may also be drowsy and have a cough.
More serious cases
In more serious cases, the person may experience very severe headaches, nausea, vomiting, confusion, disorientation, memory loss, speech problems, hearing problems, hallucinations, as well as seizures and possibly coma. In some cases, the patient can become aggressive.
Signs and symptoms in infants
Initially, encephalitis is harder to detect in young children and babies. Parents or guardians should look out for vomiting, a bulging fontanel (the soft area on the top center of the head), incessant crying that does not get better when the baby is picked up and comforted, and body stiffness.
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Causes
Encephalitis can develop as a result of a direct infection to the brain by a virus, bacterium, or fungus, or when the immune system responds to a previous infection; the immune system mistakenly attacks brain tissue.
Primary (infectious) encephalitis can be split into three main categories of viruses:
Common viruses, including HSV (herpes simplex virus) and EBV (Epstein-Barr virus)
Childhood viruses, including measles and mumps
Arboviruses (spread by mosquitoes, ticks, and other insects), including Japanese encephalitis, West Nile encephalitis, and tick-borne encephalitis
Secondary encephalitis: could be caused by a complication of a viral infection. Symptoms start to appear days or even weeks after the initial infection. The patient's immune system treats healthy brain cells as foreign organisms and attacks them. We still do not know why the immune system malfunctions in this way.
In more than 50 percent of encephalitis cases, the exact cause of the illness is not tracked down.
Encephalitis is more likely to affect children, older adults, individuals with weakened immune systems, and people who live in areas where mosquitoes and ticks that spread specific viruses are common.