japanese b encephalitis
TRANSCRIPT
Meningoencephalitis
Terms to understand
• Encephalitis• Encephalopathy• Meningitis• Meningism • Myelitis • Radiculitis
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
JEV
JEV
JEV
• Flavivirus• Spread by culex• Single stranded RNAV• 1955 in pondicherry• 2005; 1400 deaths in UP & Bihar
DYNAMICS OF JE TRANSMISSION
EnvironmentVector Mosquito
Host - Amplifying Host - Carrier
Victim-Accidental
Full Recovery
DeathRecovery with residual
complications
Subcutaneous injection
Regional lymph nodes
Extra neural Tissues Connective tissue Striated muscle Pancreas Adrenal Smooth muscle Efferent lymphatics
Thoracic duct
Plasma ViremiaReticuloendothelialcell clearance
Humoral antibody
Olfactory epitheliumVascular endothelium
Neural Parenchyma
Neurons, Glia(?)
CNS antibody
lymphocytes, macrophage
Cellular dysfunction Cellular lysisInflammation
?
?
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
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]
DD
• Meningitis of various organisms
Clues in history
• Travel • Vaccination• Rash• Oral ulcers• Parotitis, orchitis• Dogbite• Pets
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.• Dementia; HIV• Hydrophobia; rabies.
Diagnosis • CSF: lymphocytic predominance
Protein: normal, high in HSV Glucose: normal, low in mumps Culture of organism [entero V] Viral antigen by PCR Culture from NPswab, vesicle, feces, urine IgM, IgG titre
PLED in HSV
MRI brain (T2W image): right temporal lobe high signal in a patient with herpes encephalitis
Bilateral asymmetric thalamic hyper intensity
Substantia nigra involvement
Management
• Monitor GCS• ABC• Restrict IVF• Anticovulsants, antipyresis ,• Treat ICT• Moitor; glucose, BUN, elect, ABG, LFT,• Acyclovir
Infant < 1 yr Child 1-4 yrs > 4 years
EYES4 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
1 No response No response No response
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
1 No response No response No response
Bad Prognosis
• <3 yrs• GCS <6 for 4days• Hyponatremia
• 50-60% sequalae
Prevention
• Vaccine for jEV– Inactivated mouse brain Vaccine– Live attenuated SA-14-14-2 vaccine
• Mosquito control• Management of pigs
Thank you