Encephalitis Flashcards
What is it?
Causes
Encephalitis means inflammation of the brain.
This can be the result of infective or non-infective causes.
Non-infective causes are autoimmune, meaning antibodies are created that target brain tissue.
Viral Causes
Most common: herpes simplex virus (HSV)
- HSV 1 cold sores in children
- HSV 2 genital herpes in neonates (contracted during birth)
Varicella zoster virus (VZV) associated with chickenpox
Cytomegalovirus associated with immunodeficiency
Epstein-Barr virus associated with infectious mononucleosis
Clinical Features
Altered consciousness
Altered cognition
Unusual behaviour
Acute onset of focal neurological symptoms
Acute onset of focal seizures
Fever
(i.e. similar to meningitis but with change in behaviour)
Diagnosis
Lumbar puncture, sending cerebrospinal fluid for viral PCR testing
(shows: lymphocytes, raised protein, low glucose)
CT scan if a lumbar puncture is contraindicated
MRI scan after the lumbar puncture to visualise the brain in detail: showing bilateral involvement of the medial temporal lobes
EEG recording can be helpful in mild or ambiguous symptoms but is not always routinely required
Swabs of other areas can help establish the causative organism, such as throat and vesicle swabs
HIV testing is recommended in all patients with encephalitis
Contraindications to lumbar puncture
a GCS below 9
haemodynamically unstable
active seizures or post-ictal.
Management
IV Aciclovir treats herpes simplex virus (HSV) and varicella zoster virus (VZV)
IV Ganciclovir treat cytomegalovirus (CMV)
Repeat lumbar puncture is usually performed to ensure successful treatment prior to stopping antivirals
Aciclovir is usually started empirically in suspected encephalitis until results are available. Other viral causes have no effective treatment and management is supportive.
Followup, support and rehabilitation is required after encephalitis, with help managing the complications.
