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Encephalitis is an inflammation of the brain tissue that is usually caused by a viral infection such as herpes simplex, herpes zoster or cytomegalovirus, for example, but which can also be caused by fungi or bacteria, and even an exaggerated reaction of the immune system.
This disease is rare, and can affect people of all ages, however, it is more common in children, the elderly or in people who have a weakened immune system such as in cases of HIV carriers or in patients who take immunosuppressive drugs.
Encephalitis is a serious condition that can affect the brain and spinal cord and cause symptoms such as fever, severe headache, stiff neck and back, seizures, or loss of balance.Therefore, when encephalitis is suspected, it is important to go to the hospital or consult a neurologist so that the diagnosis can be made, the cause identified and appropriate treatment initiated, which may include the use of antibiotics, anti-inflammatory drugs or analgesics.
In an early stage, encephalitis usually has flu-like symptoms such as fever, headache, muscle pain, or excessive tiredness.
However, as inflammation progresses, it can affect the functioning of the brain, causing lesions that lead to more serious symptoms such as:
- Confusion or disorientation;
- Agitation or hallucinations;
- Paralysis or muscle weakness;
- Neck and back stiffness;
- Sensitivity changes in various parts of the body;
- Muscle weakness;
- Difficulty speaking or listening;
- Changes of taste;
- Vision changes such as blurry view;
- Extreme sensitivity to light;
- Loss of balance;
- Loss of consciousness.
Furthermore, other symptoms such as lump formation in the soft spot, nausea, vomiting, body stiffness, difficulty breastfeeding, drowsiness or irritability may appear in babies or children.
It is important to consult a neurologist or pediatrician as soon as these symptoms appear, or to seek the nearest emergency room, in order to diagnose and initiate the most appropriate treatment.
How to confirm the diagnosis
The diagnosis of encephalitis is made by the neurologist through the evaluation of symptoms and blood and urine tests and through the lumbar puncture exam that allows analyzing the cerebrospinal fluid to confirm the inflammation in the brain and detect the cause of encephalitis.Learn how lumbar puncture is performed.
In addition, the doctor may also order imaging tests such as MRI or CT scan to check if there is another condition that could be causing the symptoms, such as a tumor, for example.
Another test that the doctor may order is the electroencephalogram to assess brain activity. In some cases, where the person has worsening symptoms or has started treatment but has not improved, the doctor may also order a biopsy of brain tissue to identify the cause of encephalitis.
Possible causes and main types
Encephalitis can arise due to a virus, fungal or bacterial infection or an overreaction of the immune system, which ends up attacking brain cells.
According to the cause, encephalitis can be classified into different types:
1. Viral encephalitis
The most common cause of viral encephalitis is herpes simplex virus infection, which when it develops in excess, due to a weakened immune system, can affect the brain, causing herpetic encephalitis. This type of encephalitis usually affects parts of the brain related to memory, speech, emotions and behavior.
In children, viral encephalitis can also be caused by the measles or rubella virus and, in rare cases, by the chickenpox virus.
Other viruses that can also cause viral encephalitis are herpes zoster virus, adenovirus or cytomegalovirus. Learn more about viral encephalitis, its symptoms and treatment.
2. Autoimmune encephalitis
The specific cause of autoimmune encephalitis is unknown, and in many cases it occurs in he althy people. However, this type of encephalitis can be caused by cancer and even after infections in the body, causing the antibodies produced by the body in these diseases to react against brain cells as if they were foreign to the body, causing brain inflammation.See other causes of autoimmune encephalitis.
3. Bacterial encephalitis
Bacterial encephalitis occurs when bacteria invade the nervous system, reaching the brain, meninges and spinal cord, causing inflammation and swelling in brain tissue and the development of symptoms such as speech disorders, confusion, memory problems, paralysis or seizures, for example.
This type of encephalitis can be caused due to an infectious disease such as syphilis, tuberculosis, Lyme disease or bacterial meningitis.
How the treatment is done
The treatment of encephalitis must be guided by the neurologist, started as soon as possible, and consists of fighting the cause, relieving the symptoms and allowing the body's functions to be preserved.
Thus, the doctor may recommend rest, food, fluid intake and the use of medication such as:
- Analgesics and anti-inflammatories, such as ibuprofen, acetaminophen, or dipyrone, to reduce fever and relieve headache;
- Anticonvulsants, such as carbamazepine or phenytoin, to prevent seizures;
- Corticosteroids, such as prednisone or methylprednisolone, to fight swelling in the brain;
- Antivirals, such as acyclovir or ganciclovir, to fight the virus in the case of viral encephalitis;
- Antibiotics, specific for bacteria in the case of bacterial encephalitis;
- Immunoglobulin, to reduce the binding of harmful antibodies to brain cells in the case of autoimmune encephalitis;
- Surgery to remove a tumor that may be the source of the antibodies that cause autoimmune encephalitis.
In the most severe cases, in which the person has loss of consciousness or is unable to breathe alone, it may be necessary to be admitted to the hospital to undergo treatment with serum and drugs directly into the vein and to have respiratory support.
The sequelae of encephalitis are more common when treatment is not started quickly, they occur because brain inflammation can cause brain damage, which may improve in a few months or be permanent.
The main sequelae of encephalitis are:
- Persistent excessive tiredness;
- Weakness or lack of muscle coordination;
- Personality changes;
- Memory and learning problems;
- Muscular paralysis;
- Speaking and hearing difficulties;
- Visual changes;
Furthermore, in cases of encephalitis that are severe or do not improve with treatment, brain damage can cause coma and be life-threatening.