Encephalitis Flashcards
What is ADEM?
Acute disseminated encephalomyelitis
What distiguishes ADEM from infective encephalitis?
Distinguished from infective encephalitis by:
- Younger age of patient
- History of recent vaccination / infection
- Absence of fever at onset of symptoms
- Presence of multifocal neurological signs affecting: Optic nerves, brain, spinal cord, peripheral nerves
- Imaging shows demyelination
What is the duration of aciclovir for possible HSV encephalitis?
10 days
What are the MRI findings of encephalitis due to: 1. HSV, 2. Japanese Encephalitis virus, 3. Nipa Virus, 4. Enteroviral encephalitis
- Frontotemporal in Herpes simples encephalitis
- Thalamic involvement in Japanese Encephalitis
- Diffuse punctate lesions in Nipa Virus
- disseminated lesions in brainstem and basal ganglia – Enteroviral Encephalitis
What is the dose of aciclovir?
10mg/kg/dose IV with 8 hourly dosing
Is HSV 1 or HSV 2 more common cause of encephalitis?
HSV1 90%, HSV2 10% (more likely in infants or elderly)
What is the most common cause of viral encephalitis?
HSV
What is the mortality rate of untreated HSE?
70%
What is the duration of therapy for confirmed HSV encephalitis?
14 days
HSV encephalitis: what percentage is due to reactivation of latent infection and what proportion is due to primary infection?
70% reactivation
30% primary
What percentage of encephalitis is a cause not found?
50%
What are the complications of viral encephalitis?
intracranial hypertension cerebral infarction cerebral venous sinus thrombosis SIADH Aspiration pneumonia UTIs DIC Treatment related AEs
Define ADEM
Focal neurological signs and a rapidly progressive course in a usually apyrexial patient
History of febrile illness or immunisation preceding the neurological syndrome by days or weeks (post infectious or post vaccinal encephalomyelitis)
What percentage of encephalitis, where a cause is found, is secondary to a viral cause?
20-50%
What are some sequelae of viral encephalitis?
Motor, sensory, visual or speech deficits
Post-encephalitic parkinsonism
Psychiatric manifestations (Kluver Busy syndrome)
Epilepsy
Movement disorder
Chronic fatigue syndrome
What is the fatality rate of encephalitis?
4.6%
What percentage of viral encephalitis is due to HSV?
50-75%
Define encephalitis
International encephalitis consortium
Major criterion:
Presenting to medical attention with altered mental status – defined as decreased or altered level of consciousness, lethargy or personality change lasting >24 hours
Minor criteria:
Documented fever 38’C within 72hours before or after presentation
Generalised or partial seizures not fully attributable to pre-existing seizure disorder
New onset of focal neurological findings
CSF WBC >=5/mm3
Abnormality on brain parenchyma on neuroimaging suggestive of encephalitis which appears acute
Abnormalities on EEG that is consistent with encephalitis and not attributable to another cause
AND exclusion of encephalopathy caused by trauma, metabolic disturbance, tumour, alcohol abuse, sepsis and other non-infectious causes.
Possible encephalitis: 1 major and 2 minor
Probable or confirmed encephalitis: 1 major and >= 3 minor
Define encephalopathy
Encephalopathy: altered consciousness lasting >24 hours, including lethargy, irritability or change in behaviour / personality
What distinguishes ADEM from infective encephalitis?
Distinguished from infective encephalitis by:
- Younger age of patient
- History of recent vaccination / infection
- Absence of fever at onset of symptoms
- Presence of multifocal neurological signs affecting: Optic nerves, brain, spinal cord, peripheral nerves
- Imaging shows demyelination
