Acute encephalitis suresh ppt

Acute encephalitis

1. ACUTE ENCEPHALITIS: INDIAN SCENARIO Dr.Suresh kumar

2. INTRODUCTION Acute encephalitis is a group of similar neurologic manifestation caused by several different viruses, bacteria, fungus, parasites, spirochetes , chemicals/toxins. WHO introduced the term AES(Acute Encephalitis Syndrome) in order to get more number of cases.

3. DEFINTION ETIOLOGY EPIDEMIOLOGY CLINICAL FEATURES DIAGNOSIS MANAGEMENT PREVENTION AND CONTROL

4. DEFINITION Encephalitis : Acute, diffuse, inflammatory process affecting brain parenchyma – Most commonly viral Encephalopathy : Clinical syndrome of altered mental status, manifesting as reduced consciousness or altered behaviour – Many causes, incl. viral encephalitis Acute Encephalitis Syndrome : Defined as a person of any age, at any time of year with the acute onset of fever and a change in mental status(confusion, disorientation, coma, or inability to talk) and/ or new onset of seizures ( excluding simple febrile sz .)

5. AES is a spectrum of diseases with equal contribution of JE and non JE etiology . Till date, Japanese encephalitis is the leading cause of AES all over India, both in pediatric and adult population.

6. EPIDEMIOLOGY OF JE Agent Geographical Distribution Hosts Transmission Morbidity and Mortality

7. Definition : JE is an inapparent to acute arboviral infection of horses, pigs and humans. It’s a zoonotic disease i.e. infecting mainly animals and incidentally man.

8. AGENT Flavivirus related to St. Louis encephalitis Most important cause of arboviral encephalitis worldwide, with over 45,000 cases reported annually Transmitted by culex mosquito, which breeds in rice fields Mosquitoes become infected by feeding on domestic pigs and wild birds infected with Japanese encephalitis virus. Infected mosquitoes transmit virus to humans and animals during the feeding process.

9. History of Japanese Encephalitis 1800s – recognized in Japan 1924 – Japan epidemic. 6125 cases, 3797 deaths 1935 – virus isolated in brain of Japanese patient who died of encephalitis 1938 – virus isolated from Culex mosquitoes in Japan Today – extremely prevalent in South East Asia. 30,000-50,000 cases reported each year.

10. FOUR GENOTYPES OF JE Genotype 3 is mostly found in panindia Genotype 1 is found in UP and west Bengal Genotypes 2 and 4 rarely found in India The JE virus is mainly isolated in ardied birds (cattle egrets and pond herons) – natural reservoirs The JE virus multiply in the body of some animals particularly pigs – amplifying host

11. NATURAL RESERVOIRS

12. Mosquito Vectors C . Tritaeniorhynchus C. Vishnui C. Gelidus Anopheles

13. PATHOGENESIS Virus enters the body through the bite of the insect vector – mosquito After multiplication in local and regional lymph nodes,viremia of varying duration ensues Virus is transported to target organ (brain) via blood Virus proliferate and damage the neuronal tissue, thereby elicits nervous manifestations

14. CLINICAL FEATURES Incubation Period - 5 to 15 days Only 1 in 300 to 1 in 1000 infections develop into encephalitis, rest asymptomatic Course of disease- 3 stages Prodromal stage Acute encephalitic stage Late stage and sequelae

15. PRODROMAL STAGE Fever Headache Nausea,Vomiting Diarrhea Myalgia Lasts for 1 to 5 days

16. ACUTE ENCEPHALITIS STAGE Fever Irritability Altered behaviour Convulsions Coma Signs of increased intracranial tension

17. LATE STAGE Aphasis or Dysarthria Ocular palsies Pyrimidal and extra pyramidal signs in the form of hemiplegia, quadriplegia, dystonia , choreoathetosis and coarse tremors.

18. SEQUELAE Full recovery Recovery with residual complications Death

19. Morbidity/Mortality Swine – High mortality in piglets – Death rare in adult pigs Equine – Morbidity: 2%, during an outbreak – Mortality: 5% Humans – Mortality: 5-35% – Serious neurologic sequelae : 33-50%

20. 30-50 % of the people that survive the infection develop paralysis, brain damage, or other serious permanent sequelae Average period between the onset of illness & death is about 9 days In utero infection possible: Abortion of fetus

21. DIFFERENTIATION OF JE AND NON JE, AES Acute fever with altered sensorium persisting for more than 2 hours with focal seizures of any part of body, suggestive of encephalitis Rash with fever excludes encephalitis AES with symmetrical neurological signs likely to be cerebral malaria

22. DIAGNOSIS OF AES Imaging EEG CSF fluid analysis

23. IMAGING

24. HSV ENCEPHALITIS

25. JE

26. JE

27. EEG EEG usually shows abnormal spikes in acute encephalitis. Spikes in temporal lobe region suggestive of HSV Encephalitis

28. CSF STUDY High CSF pressure Increased WBC count ( usually < 250/cu mm ;predominantly lymphocytes) Elevated protein concentration (usually < 150 mg/dl) Normal glucose concentration Specific diagnostic tests – PCR tests for viruses, culture for bacteria, fungi and mycobacteria, serology for arboviruses .

29. SEROLOGY Detection of virus specific IgM antibody – provide definitive diagnosis IgM antibody is present only for 1 to 3 months and hence denote acute encephalitis

30. TREATMENT OF AES A broad spectrum antibiotic such as ceftriaxone – can be stopped when investigations does not reveal bacterial meningitis Acyclovir must be started in all cases of sporadic viral encephalitis – should be stopped when an alternate diagnosis has been made or HSV PCR is negative

31. PREVENTION AND CONTROL OF AES Surveillance for cases of AES Vector control Reduction in man vector contact Vaccination

32. JE VACCINATION – TWO TYPES Inacivated vaccine derived from vero cell prepared from an I ndian strain of JE virus (JENVAC) Very safe and effective 2 doses given 1 month apart

33. The recently introduced Chinese live attenuated SA 14 14 2 JE vaccine Now available in routine immunization in children under universal immunization program in 181 endemic districts of India since 2011 NVBDCP has identified 20 hyperendemic districts in assam , UP and west Bengal for introduction of adult JE vaccination (>15 to 65 yrs ) Till now, 8 districts have been covered by adult vaccination programme In 3 rd july 2014, the GOI had announced the introduction the single dose of JE vaccine for adults in endemic districts

34. RECENT TRENDS OF AES IN INDIA In recent years, investigations into large outbreaks of AES have been negative for JEV Instead outbreaks were found to be due to a rhabdovirus ( Chandipura virus) or water borne entero viruses Factor might account for Entero viruses replacing JEV as the major cause of AES is JE vaccination campaigns launched in endemic districts

35. A multisector approach involving health, water resources, sanitation and rural development departments is needed for designing and implementing novel preventive strategies that would focus on containment of water borne entero viruses and vectors for chandipura virus We also need to move from JE surveillance to surveillance for the entire spectrum of AES

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