Transcript Acute Encephalitis

Encephalitis
Brain Abscess
Reşat Özaras, MD, Prof.
Infection Dept.
• A 37-year-old male
• Headache, stupor, tendency to sleep, fever,
unaware to recognise the time and the place...
Acute Encephalitis
• The inflammation of the parenchyma of
the brain especially that of the cerebral
cortex
The inflammation of the CNS
• Encephalitis… the parenchyma...mostly due to viral
infections
• Meningitis… the meninges... mostly due to bacterial
infections
Symptoms
• Fever
• Headache
• Mental changes
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Confusion
Hallucinations
Personality changes
Diplopia
Fatigue
Tremors
Rash
Loss of consciousness
Acute Encephalitis
• Mostly due to viral inf.
– Herpes simplex virus (HSV) (the most common
etiology of acute sporadic encephalitis)
– Arboviruses – arthropod-borne virus (outbreaks in
summer time…mosquitos and ticks)
– Varicella zoster virus (VZV)
patients)
(immunosuppressed
HSV-1
• The most common etiology of acute sporadic
encephalitis
• HSV-1
– acquired in childhood period,
– re-activates after years
HSV-1
• Primary infection;
• On the mucosa of oropharynx, mostly asymptomatic
• fever, pain, dysphagia
• 2-3 weeks
• Following primary infection, a
latent infection in trigeminal
ganglion
HSV-1
• Inferior and medial temporal lobe
• Orbito-frontal lobe
• Limbic structures
Inflammation
necrotizing lesions
Hemorrhagic necrosis in herpes encephalitis
especially when remains untreated.
HSV-1
Widespread edema and
subarachnoid hemorrhage
areas in medial temporal
and orbitofrontal regions
HSV-1
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Fever
Unilateral or generalized headache
Mental changes
Focal seizures
Focal neurological deficits
• Dysphasia
• Hemiparesis
VZV
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Primary infection… chickenpox
Latent infection thereafter
The commonest reactivation… herpes labialis
Chickenpox, herpes labialis and zona may be
complicated with encephalitis
Epstein Barr Virus
• Causes infectious mononucleosis
• May cause encephalitis
• Direct invasion of CNS or immune
mechanisms
• Cortex, brain stem, basal ganglia,
temporal lobe
CMV
• Encephalitis in both immunocompetent and
immunosuppressed
• Risk is higher
– immunosuppressed,
– organ transplanted
– HIV-infected patients
• Organ transplantation, highest risk… CMV (-)
donor to CMV (+) recipient
HIV
• In 10-50% of AIDS patients, HIV infection
in CNS
• Multinuclear giant cells in gray matter and
central white matter are pathognomonic.
Rabies
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Lyssavirus
Acute progresive fatal encephalitis.
Transmitted with infected saliva of the animal
Incubation period: 5 days-6 mo.(20-60 days)
III, IV and IXth canial nerve palsies
Prodromal period, neurological disease period, paralysis,
coma, and death.
Mumps
• The commonest complication;
inflammation in CNS
• A pleocytosis in CSF in half of the cases
• In 5-30%: headache, vomiting, neck
stiffnes
Clinical Evaluation
• History
• PE
• Neck stiffness
• CBC
• Biochemistry
• Culture
• Imaging
• Serology
• CSF analysis
History
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Season
Localisation
Travel
Occupational exposure
Exposure to animals
Immunization
Immune status of the patient
Lab
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CBC
Renal and hepatic tests
Coagulation studies
Plain chest X-ray
• CSF analysis
• Cranial imaging
Nonspecific
Main diagnostic
methods
Cranial Imaging
MRI
• Sensitive for early
period HSV
encephalitis
• Edema in
orbitofrontal and
temporal regions
CT
• Less sensitive than MRI
Herpes simplex encepalitis CT(A) and MRI (B-F) temporal lobe
involvement
CSF Analysis
• Cell count: 10-2000 cells/mm3
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Mostly <500 cell/mm3
Lymphocyte predominance
Erythrocytes (in 80% of the cases)
Normal CSF findings in 10%
Glucose (mg/dl): normal or low
CSF glucose/serum glucose: normal (>0.6) or low
Protein (mg/dl): >50
Gram staining: no microorganisms
Culture: none
Microbiology
• HSV PCR: For the first 24-48 hours,
detecting HSV DNA by PCR in CSF:
– specific (100%) and
– sensitive (75-98%)
Herpes simplex encephalitis; Neurons including Cowdry A type intranuclear
inclusion bodies. Hematoxylen-Eosin, X400.
Treatment
• If shock/hypotension exists, crystaloid
infusion
• If unconscious, provide airway/breathing
• Seizure, lorazepam 0.1 mg/kg, IV
Treatment
• For encephalitis, give acyclovir
Treatment
• Acyclovir IV, 14 – 21 days
– HSV encephalitis
– VZV encephalitis
Some keys
• Atypical lymphocytes on peripheral
smear… IMN
• High amylase … Mumps
Complications
Acute period
• Seizure
• Inappropriate ADH synd.
• Intracranial pressure inc.
• Resp. arrest
• Coma
• Death
Chronic period
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Chronic fatigue
Depression
Personality changes
Gait disorders
Memory disorders
Speech disorders
Visual problems
Mental retardation
Hemiplegia
Seizure
Prognosis
• The virulence of the virus
• Patient’s;
– previous health status
– immune status (chemotherapy, transplantation, AIDS)
– age(<1, and >55 years)
– any neurological symptoms
Prognosis
• Being in coma on prsentation: severe
inflammation in the brain, poor prognosis
• Treated
– Mortality… 20%
– Morbidity… 40%
• Untreated
– Mortality … 50-75%
– Morbidity… 100%
Brain Abscess
• Focal collection in the brain parenchyma due
to
– Infection
– Trauma
– Surgery
Pathogenesis
• Hematogenous: multiple abscess
– Chronic pulmonary inf. (lung abscess, empyema…)
– Skin inf.
– Pelvic inf.
– Intraabdominal inf.
– Bacterial endocarditis
– Cyanotic congenital heart dis.
• Direct transmission
– Subacute or chronic otitis media, mastoiditis
(inferior temporal lobe and cerebellum)
– Frontal or ethmoid sinusitis (frontal lobes)
– Dental infections (frontal lobes)
• Early lesion (first 1-2 weeks):
– The borders are not clearly defined, localised
edema
– Inflammation, no necrosis
– “Cerebritis”
• After 2-3 weeks, necrosis
• A fibrous capsule
Etiology
• Aerobs+Anaerobs
Signs&Symptoms
• Headache
• Fever
• Neck stiffness
• Mental changes
• Nausea, vomiting
Warning
• LP is contraindicated!
Diagnosis
• Imaging
–MRI
–CT
Treatment
• Intervention
• Antibiotics
– Ceftriaxone + metronidazole
Mortality 0-30 %
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