Encephalitis

in childhood

Pegah Katibeh

Pediatric Neurologist

Shiraz University of Medical Sciences

A 7-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

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) (immunosuppressed patients)

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.

Widespread edema and

subarachnoid hemorrhage

areas in medial temporal

and orbitofrontal regions

HSV-1

HSV-1

Fever

Unilateral or generalized headache

Mental changes

Focal seizures

Focal neurological deficits

Dysphasia

Hemiparesis

VZV

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

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

Season

Localisation

Travel

Occupational exposure

Exposure to animals

Immunization

Immune status of the patient

UNC-93B

Lab

CBC

Renal and hepatic tests

Coagulation studies

Plain chest X-ray

Nonspecific

• CSF analysis

• Cranial imaging

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

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

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%

Autoimmune encephalitis

In children, acute encephalopathy might develop several weeks after

infection or vaccination and is then most likely an autoimmune reaction.

Well known autoimmune encephalopathies in children include ADEM and

AHLE.

Recently, antibody mediated autoimmunity in CNS have been described in

an increasing number of children with encephalitis of unknown etiology

ADEM

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 %

www.rochester.edu

Thanks for your attention

Any questions?