Encephalitis Flashcards
Definition of Encephalitis
Encephalitis refers to the inflammation of the brain parenchyma, which is the tissue of the brain itself. It is often caused by viral infections, but it can also result from bacterial or fungal infections, autoimmune disorders, or as a complication of other systemic infections.
Pathomechanism of Encephalitis
Encephalitis usually occurs when a virus or other infectious agent enters the body and reaches the brain.
In viral encephalitis, the virus infects and replicates within the brain cells, triggering an immune response. The immune system’s response leads to inflammation, causing damage to the brain tissue. This inflammation can result in edema (swelling) of the brain, increased intracranial pressure, and neuronal dysfunction.
Causes of Encephalitis
Herpes simplex virus (HSV): HSV type 1 is a common cause of viral encephalitis in adults, while HSV type 2 is more commonly associated with genital herpes.
Varicella-zoster virus (VZV): This virus causes chickenpox and shingles and can also lead to encephalitis.
Enteroviruses: Various enteroviruses, such as coxsackievirus and echovirus, can cause encephalitis, especially in infants and young children.
Mosquito-borne viruses: Viruses transmitted by mosquitoes, such as West Nile virus, Japanese encephalitis virus, and St. Louis encephalitis virus, can cause encephalitis.
Tick-borne viruses: Tick-borne encephalitis virus, found in parts of Europe and Asia, is transmitted through tick bites.
Other viruses: Measles virus, mumps virus, Epstein-Barr virus (EBV), and cytomegalovirus (CMV) can also cause encephalitis.
Symptoms of Encephalitis
Fever
Headache
Altered mental status, confusion, or disorientation
Seizures
Changes in behavior or personality
Sensory disturbances, such as abnormal sensations or hallucinations
Muscle weakness or paralysis
Difficulty speaking or understanding speech
Nausea and vomiting
Neck stiffness (in some cases)
Diagnosis of Encephalitis
Lumbar puncture (spinal tap): Cerebrospinal fluid (CSF) analysis is crucial for diagnosing encephalitis. It involves collecting a sample of CSF through a lumbar puncture and analyzing it for cell count, protein levels, glucose levels, and culture or PCR testing to identify the infectious agent.
Blood tests: Blood tests may help identify specific viral antibodies or detect viral DNA or RNA.
Imaging studies: Imaging, such as a CT scan or MRI, may be performed to assess the brain for signs of inflammation, edema, or other abnormalities.
Differential diagnosis of Encephalitis
Meningitis
Stroke
Autoimmune encephalitis: Autoimmune disorders targeting the brain can mimic infectious encephalitis.
Treatment and Prevention of Encephalitis
Antiviral medications: For viral encephalitis caused by specific viruses, such as herpes simplex virus, antiviral medications may be prescribed to help control the infection.
Supportive care: This includes managing symptoms, ensuring hydration, and providing adequate nutrition.
Anti-inflammatory medications: In some cases, corticosteroids may be used to reduce brain inflammation.
Seizure management: Anticonvulsant medications may be prescribed to control seizures
Prevention:
Vaccination: Vaccination against specific viruses, such as measles, mumps, varicella, and tick-borne encephalitis, can help prevent those forms of encephalitis.
Mosquito control: Taking precautions to prevent mosquito bites, such as using insect repellents and wearing protective clothing, can reduce the risk of mosquito-borne encephalitis.
Hygiene practices: Practicing good hygiene, such as frequent handwashing, can help reduce the spread of viral infections.
Complications of Encephalitis
Neurological deficits: Cognitive impairment, memory problems, motor deficits, and behavioral changes.
Seizures: Recurrent seizures may occur, requiring ongoing management.
Brain damage: In severe cases, encephalitis can cause permanent brain damage.
Respiratory or cardiovascular complications
Death:
