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Unknown threats to the brain: Why do some encephalitis remain unexplained?
Encephalitis refers to inflammation of the brain, which can vary in severity. Symptoms may include decreased or altered consciousness, loss of speech, headache, fever, confusion, stiff neck, and vomiting. These symptoms may lead to complications such as seizures, hallucinations, speech disorders, memory problems, and hearing impairment. Encephalitis is most often caused by various viruses, such as herpes simplex virus and rabies virus, but may also be caused by bacteria, fungi or parasites. Other causes may include autoimmune diseases and certain medications. In many cases, the cause remains unexplained.
According to statistics, encephalitis affected 4.3 million people worldwide in 2015, and caused 150,000 deaths.
Symptoms and manifestations of encephalitis
In adults, encephalitis usually develops suddenly with fever, headache, confusion, and sometimes seizures. Infants and young children may show symptoms such as irritability, loss of appetite and fever. Neurological examination often reveals a drowsy or confused state, and a stiff neck due to meningitis may indicate meningitis or meningoencephalitis.
Special types of encephalitis
Limbic encephalitis
Limbic encephalitis refers to an inflammatory disease limited to the limbic system of the brain, and its clinical manifestations are often accompanied by cognitive impairment, disinhibition, memory loss, epilepsy and abnormal behavior. MRI images showed T2 high signal intensity in the medial temporal lobe structures. In some cases, limbic encephalitis may be associated with autoimmunity.
Encephalitis lethargica
Encephalitis lethargica is characterized by high fever, headache, delayed reaction times, and drowsiness. People may experience upper body weakness, muscle pain, and tremors. However, the specific cause of encephalitis lethargica remains unclear.
Unknown pathogenic mechanismIn about 30% to 40% of encephalitis cases, the cause remains unknown. Viral infections are usually the main infectious cause of encephalitis, but some cases may be the result of a direct acute infection or part of a latent infection.
The exact cause of most viral encephalitis is unknown, but the most common identifiable cause is herpes simplex infection.
Diagnosis and prevention
The diagnosis of encephalitis usually relies on clinical symptoms and is confirmed by various testing methods. These tests may include an MRI brain scan to check for inflammation, an electroencephalogram to monitor brain activity, and a lumbar puncture to analyze cerebrospinal fluid. Vaccination can effectively prevent some types of encephalitis.
Treatment methods
Treatment of encephalitis mainly involves the use of antiviral drugs (such as acyclovir), anti-epileptic drugs, and corticosteroids. Even after the acute problem is under control, some patients may still require rehabilitation. Since treatment must be carried out in the hospital, patients with severe encephalitis may even need to rely on artificial respiration.
Maintenance therapy for encephalitis caused by Toxoplasma gondii is usually praziquantel-based therapy, which may be crucial, particularly in patients with weakened immune systems.
Prognosis of encephalitis
The prognosis of encephalitis often varies depending on multiple factors, and the identification of poor prognostic factors (such as cerebral edema and ongoing seizures) can help improve treatment outcomes. A normal EEG at early diagnosis is associated with a high survival rate.
ConclusionAlthough the conditions and causes of encephalitis are diverse and complex, ongoing research and progress are ongoing in exploring the unexplained causes of encephalitis. Why is it that in many cases of encephalitis, we still cannot identify the cause?
