encephalitis - dr. p. soundararajan

ACUTE ENCEPHALITIS

DR. P. SOUNDARARAJAN,PROFESSOR OF PEDIATRICS,

MGMCRI.

Terms to understand

• Encephalitis• Encephalopathy• Meningitis• Meningism • Myelitis

Meningoencephalitis

• Acute inflammation of meninges & brain tissue

• CSF – pleocytosis• Gram stain & culture negative• Changes in MRI brain • Mostly self limiting

Etiology

• Enterovirus; coxsackie, polio, echo• Arbovirus; JEV, WNV, Dengue• Herpes virus; HSV1&2, VZ, EBV, CMV.• Others; mumps, measles, rabies, adenoV.• Bacteria; TB, mycoplasma, rickettsiae• Protozoa; acanthameba, toxoplasma

• Annual incidence : 16/100 000 in children [4-8 /100 000 in adults]

• HSV; 22%• VZV; 21%• Adeno V; 4%• JBE in asia; 35000 – 50000 cases / year. 1/3 die , june to september.

JEV

• Flavivirus• Spread by culex• Single stranded RNAV• 1955 in pondicherry; 1st case• 2005; 1400 deaths in UP & Bihar• 2014; WB, UP, assam; ~ 300deaths

Pathogenesis • Direct invasion & destruction by virus• Host reaction to viral antigens• Meningeal congestion• Mononuclear infiltration• Neuronal disruption• Neuronophagia, vasculitis• Demyelination [ADEM]

Structures affected

• HSV; temporal lobe• Arbovirus; entire brain• Rabies; basal parts• Varicella; cerebellum

4 stages

• 0-3d ; prodrome• 4-7d; acute• 8-10d; subacute• 1-4wk; recovery

Clinical features• Depends on parenchymal involvement• Preceding mild febrile illness & exantheme• Acute onset of high fever, headache, irritability,

lethargy, nausea, myalgia• Convulsions, stupor, coma• Fluctuating FND, emotional outburst• Ant.horn cell injuryflaccid paralysis [west nile,

entero virus]

Clues in history

• Travel to endemic places

Clues in examination • Cranial N palsy; HSV, EBV, TB.• Ataxia; VZV, • AFP; polio, enteroV, tick borne.• Rash; VZV, typhus, mycoplasma• Parotitis; mumps,• LN; HIV, EBV, CMV, Rubella.• Hydrophobia; rabies.

Diagnosis CSF: lymphocytic predominance

Protein: normal, high in HSV Glucose: normal, low in mumps Hemorrhagic; measles Viral antigen by PCR Blood: Culture from NP swab, vesicle, feces, urine IgM, IgG titre

EEG in HSV

Bilateral asymmetric thalamic hyper intensity

Substantia nigra involvement

http://www.ajnr.org/cgi/content/full/21/10/1978/F1

Management in ICU

Management

• Monitor GCS• ABC• Restrict IVF• Anticovulsants, antipyresis ,• Treat ICT• Moitor; glucose, BUN, elect, ABG, LFT,

Infant < 1 yr Child 1-4 yrs > 4 yearsEYES

4 Open Open Open

3 To voice To voice To voice

2 To pain To pain To pain

1 No response No response No response

VERBAL5 Coos, babbles Oriented, speaks,

interacts, socialOriented and Alert

4 Irritable cry, consolable

Confused speech, disoriented, consolable

Disoriented

3 Cries persistently to pain

Inappropriate words, inconsolable

Nonsensical speech

2 Moans to pain Incomprehensible, agitated

Moans, unintelligible


MOTOR6 Normal spontaneous

movementNormal spontaneous movement

Follows commands

5 Withdraws to touch Localizes pain Localizes pain

4 Withdraws to pain Withdraws to pain Withdraws to pain

3 Decorticate flexion Decorticate flexion Decorticate flexion

2 Decerebrate extension Decerebrate extension Decerebrate extension


Bad Prognosis

• <3 yrs• GCS <6 for 4days• Hyponatremia

• 50-60% sequalae

Prevention

Thank you

encephalitis - dr. p. soundararajan

Healthcare