The causes,pathophysiology,Epidemiology,Symptoms of Encephalitis

1. ENCEPHALITIS
PRESENTED BY:
UDDANDI SATYA KARTHIK
RT/2019/617
DEPARTMENT OF REGULATORY TOXICOLOGY
NIPER HYDERABAD

2. CONTENTS
 Introduction
 Epidemiology
 Types of Encephalitis
 Aetiology
 Mode of transmission
 Signs and Symptoms
 Complications
 Diagnosis
 Prevention
 Summary
 References
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4. WHAT IS ENCEPHALITIS ?
 Encephalitis is inflammation of the brain parenchyma with neurologic dysfunction, and can result
from infectious, post infectious, and non-infectious causes.
 Infection constitutes approximately 50 % of identifiable cases and is the most commonly identified
aetiologic category of encephalitis.
 Encephalitis results in substantial morbidity and mortality worldwide.
 An infectious encephalitis may also be difficult to distinguish from encephalopathy that may be
associated with numerous metabolic causes.
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Source: Solomon T, Hart IJ, Beeching NJ. Viral encephalitis: A clinician's guide. Pract Neurol 2007;7(5):288-305.

5. EPIDEMIOLOGY - INDIA
 The disease was clinically diagnosed in India for the first time in 1955 in the southern state of
Madras, now Tamilnadu.
 At present, the disease is endemic in as many as 171 districts in 9 states.
 Characterized by high case-fatality rate (CFR), the disease occurs in seasonal outbreaks every
year, especially of children below 15 years of age.
 Between 2008 and 2014, there have been more than 44,000 cases and nearly 6000 deaths from
encephalitis in India, particularly in Uttar pradesh , Assam and Bihar.
 The most devastating outbreak was in Gorakhpur in 2005 affecting 6061 cases with 1500
deaths. Japanese Encephalitis Virus was identified as major causative agent.
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6.  This led to India launching a JE
Vaccination programme in 2006,
which in 2014 became part of
National Immunization Programme.
 In 2016, there has been rise in
encephalitis, with over 125 children
reported to have died in one hospital
in Gorakhpur alone.
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Source: Jai Prakash Narain, A. C. Dharwal, and C. Raina Macintyre, Acute encephalitis in India: An unfolding tragedy. 2017 May; 145(5): 584–587.
CONTINUED…..

7. CONTINUED…..WORLD EPIDEMIOLOGY7
Encephalitis deaths per million persons in 2012 .
0-0 1-1 2-2 3-4 5-9 10-14 15-24 25-45
Source: Data from World Health Organization Estimated Deaths 2012 Vector map from BlankMap-World6, compact.svg by Canuckguy et al.
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8. TYPES OF ENCEPHALITIS
 Infectious encephalitis
 Autoimmune encephalitis
 Chronic encephalitis
 Limbic encephalitis
 HIV encephalitis
 Encephalitis Lethargica
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9. AETIOLOGY
 An etiologic agent is only identified in around 50% of cases.
 Viruses are found to be main cause of encephalitis.
 Most diagnosed cases of encephalitis in the United States are caused by Herpes simplex virus
types 1 and 2, arboviruses (such as West Nile Virus)
 In the US, West Nile Virus emerged as a significant cause of encephalitis in the late 2000s, the
incidence has decreased, but this may be cyclical.
 Other Arbovirus (Arthropod-Borne viruses) with ticks and mosquitoes as vectors are main
contributors to encephalitis etiologies worldwide.
 Immune mediated encephalitis could account for one third of cases, especially with the
recognition of anti-N-methyl-D-aspartate (NMDA) receptor encephalitis.
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Source: Kupila L, Vuorinen T, Vainionpää R, Hukkanen V, Marttila RJ, Kotilainen P. Etiology of aseptic meningitis and encephalitis in an adult
population. Neurology 2006; 66: 75-80

10. INFECTIOUS CAUSES OF ENCEPHALITIS10

11. MODE OF TRANSMISSION
 Coughs or sneezes from an infected person that release airborne viruses, which are then inhaled by others.
 Infected insects (such as mosquitoes or ticks) and animals, which can transfer some viruses directly into
the bloodstream via their bite.
 Eating contaminated food or drink.
 From oral and genital mucosa (HSV-1&2)
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Source: Sang- Im Yun and Young-Min Lee , Japanese encephalitis : The virus and vaccines; 2014 Feb 1; 10(2):
263–279.

12. PATHOGENESIS OF ENCEPHALITIS
VIRUS
 JE typically develops in patients after an incubation period of 5–15 days.
 It is possible that during this time, the virus resides and multiplies within host
leukocytes, which act as carriers to the CNS.
 T lymphocytes and IgM play a major role in the recovery and clearance of
the virus after infection .
 A plausible therapy of clearing the virus load while in its incubation period in
peripheral lymphatic tissues and spleen may actually prevent JEV
pathogenesis.
 Besides neuronal cells, researchers have shown that astrocytes are also
infected by JEV .
 Astrocytes, being a component of the blood–brain barrier, may help in the
transmission of JEV from peripheral tissues to the cerebrospinal fluid.
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Source: Debapriya Ghosh and Anirban Basu , A Pathological and
Clinical Perspective, Japanese Encephalitis; ; 3(9): e437, 2009

13. INITIAL SYMPTOMS
 Head ache
 Malaise
 Anorexia
 Nausea and Vomiting
 Abdominal pain
 Neurological signs (aphasia, ataxia etc.,)
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14. SYMPTOMS
 Fever
 Muscle weakness
 Behavioral changes
 Altered level of consciousness
 Loss of sensation or paralysis in some places
 Bulging fontanel (soft spots) of infant’s skull
 Body stiffness
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15. COMPLICATIONS
 Seizures
 Cerebral edema
 Dehydration
 Loss of airway reflexes
 Coma
 Vasomotor collapse
 Respiratory arrest
 Death
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16. DIAGNOSTIC TESTS
1. Cerebrospinal fluid (CSF) analysis:
- This is a primary diagnostic tool for encephalitis.
- CSF is collected using a procedure called a lumbar puncture or spinal tap.
2. Brain biopsy:
- not routinely recommended, but may be indicated if patient continues to decline and no etiology has been established.
3. Neuroimaging studies:
- Magnetic Resonance Imaging (MRI scan)
- Computerized tomography (CT scan)
- Electro encephalogram (EEG)
4. Other tests:
- Polymerase chain reaction (PCR): detection of viral genetic material (DNA, RNA)
- ELISA
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Source:Chaudhuri,PGE Kennedy , Diagnosis and treatment of viral encephalitis ; Med J 2002;78:575–583

17. NON PHARMACOLOGICAL MEASURES
 Maintain personal hygiene.
 Careful hand washing before eating and after toileting
or diaper changes is essential.
 Protection against mosquitoes and ticks.
 Make children to practice hygienic habits.
 Measles, mumps, rubella, chickenpox, and even rabies
encephalitis may be prevented by appropriately timed
vaccines.
 By taking Japanese encephalitis vaccination.
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18. SUMMARY
 Viral encephalitis is frequently devastating and causing morbidity and mortality worldwide.
 All patients with febrile illness and altered behavior or consciousness should be investigated
promptly for viral encephalitis.
 Patients suspected need a lumbar puncture as soon as possible.
 Early institution of therapy improves prognosis of disease.
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