encephalitis

1. ENCEPHALITIS
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2. WHAT IS ENCEPHALITIS?
 Acute inflammation of the brain.
 Children, elderly and those with a weak immune
system are those who are more prone to
encephalitis.
 The treatment given and the chances to
recovery depend completely on the virus
involved and how severe the inflammation is.
 Acute – encephalitis : affects brain directly
 Para - infectious : brain and spinal chord inflates
two weeks into contracting the virus or bacteria.

3. CAUSES
 The exact cause of encephalitis is unknown.
 Usually caused by a virus or sometimes even a bacterial
infestation as well as non infectious inflammatory
conditions may cause encephalitis .
 Few viruses that may be instrumental in causing
encephalitis includes –
1)Herpes simplex
2) Polio viruses
3) Mosquito – borne viruses
4)Tick – borne
5) Rabies
6) childhood viruses

4. RATE OF INCIDENCE
 There were no studies that specifically addressed the
incidence of AES. However, there were studies from
various countries that mentioned the incidence of
encephalitis in different settings. Those studies
suggested an IR of 1.77 to 6.34 for tropical countries
and an IR of 0.51-7.4 for Western industrialized
countries.
 An IR of 145-185 was recorded during an epidemic in
Nepal in 1997. A hospital-based study from Andhra
Pradesh, India, suggested an IR of 1. A review article
suggested that the minimum IR must be fixed at 6.0
based on earlier studies

5. Biological Base
• Just as a thief with a copied key can open a lock that is not his,
a virus begins to enter a cell via a similar type of crime.
• Outermost layer of virus has special protiens that latch onto a
cell and “pick” the molecular locks on its surface.
• These locks, which cover the surface of a cell, are called
receptors.

6. • When there is no virus, receptors are used to
convey important signals from the outside
world to the inside of the cell.
• Unrelated viruses can attach (bind) at different
times to the same kind of receptor on a cell
surface.
• A virus’s preference for infecting a certain type
of cell (like a neuron) is called tropism, and is
caused by the specific interaction of the virus
with a receptor found on that kind of cell.

7. • In addition to binding to a cell surface receptor,
a virus often has to bind to a second cell
surface receptor, called co-receptor. In these
cases, its only after this second interaction that
a virus can enter into a cell.

8. TYPES OF ENCEPHALITIS

9. • Infectious encephalitis
• Autoimmune encephalitis
• Chronic encephalitis
• Limbic encephalitis
• HIV encephalitis
• Encephalitis Lethargica

10. Infectious Encephalitis
• Viruses are the most common agents that cause
Infectious Encephalitis. Within the British Isles
herpes simplex virus (the cold sore virus) is
the virus most frequently identified.
• Some of the known types of Infectious
Encephalitis are:
o Herpes Simplex Encephalitis
o West Nile Encephalitis
o Tick Borne Encephalitis
o Japanese Encephalitis

11. Autoimmune Encephalitis
• Autoimmune Encephalitis may be triggered by
infection in which case the term "Post-infectious
Encephalitis" is used. ADEM( Acute Disseminated
Encephalomyelitis ) is a Post-infectious Encephalitis.
The illness usually follows in the wake of a mild viral
infection (such as those that cause rashes in childhood)
or immunisations. Typically there is a delay of days to
two to three weeks between the triggering infection and
development of the Encephalitis.
• It has recently been recognised that there are other
types of Autoimmune Encephalitis resulting from an
attack of the brain by the body's immune system.

12. • Some of the known types of Autoimmune
Encephalitis are:
o Acute Disseminated Encephalomyelitis (ADEM)
o NMDA Receptor associated Encephalitis [N-methyl
D-aspartate (NMDA) ]
o Hashimoto’s Encephalopathy
o Rasmussen Encephalitis

13. Chronic Encephalitis
SSPE: A Chronic Encephalitis as a result of Measles
• SSPE stands for Subacute Sclerosing Panencephalitis and
refers specifically to a type of Encephalitis which can
follow natural (wild) measles virus infection. After the
initial measles infection, the virus lies passive in brain cells.
It does not cause SSPE for several years (average 6 years)
when eventually an inflammatory response is initiated
against the infected cells. It is more common in children
younger than 2 years who have had primary measles
infection, although the condition (SSPE) manifests itself
much later- older children and adults.
• Unfortunately SSPE is a progressive form of Encephalitis
without a cure. Despite multiple attempts, no satisfactory
treatment has been developed. In a few cases there has been
remission following use of a certain drug or drug
combination. However most of those affected die within
about 5 years of diagnosis.

14. Limbic Encephalitis
• The term ‘Limbic Encephalitis’ (LE) is used
when the limbic areas of the brain are inflamed
(swollen) and consequently not functioning
properly.

15. HIV Encephalitis
Human Immunodeficiency Virus (HIV) can affect the
brain in different ways.
• HIV-meningoencephalitis is infection of the brain and
the lining of the brain by the HIV virus. It occurs
shortly after the person is first infected with HIV
and may cause headache, neck stiffness, drowsiness,
confusion and/or seizures.
• HIV-encephalopathy (HIV-associated dementia) is the
result of damage to the brain by longstanding HIV
infection. It is a form of dementia and occurs in
advanced HIV infection.
• Mild Neurocognitive Disorder is problems with
thinking and memory in HIV, however is not as severe
as HIV-encephalopathy. Unlike HIV-encephalopathy it
can occur early in HIV infection and is not a feature of
Aquired Immune Deficiency Syndrome - AIDS.

16. Encephalitis Lethargica
• Encephalitis Lethargica (EL) is a serious sporadic
form of Encephalitis.
• a form of encephalitis caused by a virus and
characterized by headache and drowsiness leading to
coma.
• The term "sleeping sickness", where people seem to
fall asleep or freeze whilst eating or working was
first used to describe two cases in Vienna.

17. SYMPTOMATOLOGY

18. Initial Signs
• Headache
• Malaise
• Anorexia
• Nausea and Vomiting
• Abdominal Pain

19. Symptoms
• Fever
• Headache
• Behavioral changes
• Altered level of consciousness
• Focal neurological deficits
• seizures

20. Developing Signs

21. Encephalitis with focus or diffused
neurological symptoms
• Behavioral and personality changes.
• Decreased level of consciousness.
• Stiff neck, photophobia and lethargy.
• Generalized or localized seizure.
• Acute confusion or amnestic states.
• Flaccid paralysis(10%)

22. Neurological Signs
• Aphasia
• Ataxia
• Hemiparesis with hyperactive tendon reflexes
• Involuntary movements
• Cranial nerve deficits (ocular palsies, facial
weakness)

25. Viral encephalitis – clinical symptoms
• Typical presentation
– Acute flu-like prodrome
– High fever, severe headache
– Altered consciousness (lethargy, drowsiness, confusion, coma)
– Seizures
– Focal neurological signs
• More subtle presentations
– Low grade fever
– Speech disturbances (dysphasia, aphasia)
– Behavioural changes
– Subacute and chronic presentations can be caused by CMV,
VZV, HSV (immuno-compromised)

26. Possible Complications
• Permanent brain damage may occur in severe
cases of encephalitis. It can affect:
Hearing
Memory
Muscle control
Sensation
Speech
Vision

27. DIAGNOSIS

28. DIAGNOSIS
• Because the various types of encephalitis produce
similar symptoms, doctors cannot rely on clinical
features to differentiate among the many causes of
brain inflammation. The primary objective in
diagnosing viral encephalitis is to determine if it is
caused by:
• Herpes simplex or other conditions that
can be treated with specific medications
• Arboviruses or other viruses that can be
managed only by targeting symptoms

29. IMAGING TECHNIQUES
• For suspected encephalitis scanning technique is often
the first diagnostic step.
• Computerized tomography (CT) or magnetic resonance
imaging (MRI) scans can show the extent of the
inflammation in the brain and help differentiate
encephalitis from other conditions. MRIs are
recommended over CT scans because they can detect
injuries in parts of the brain that suggest infection with
herpes virus at the onset of the disease, while CT scans
cannot.
• Electroencephalogram (EEG), which records brain
waves, may reveal abnormalities in the temporal lobe
that are indicative of herpes simplex encephalitis.

30. CEREBROSPINAL FLUID TESTS
• When encephalitis is suspected, a sample of
cerebrospinal fluid is taken using a lumbar puncture.
• The sample is taken to count white blood cells and
identify specific blood cell types, to measure proteins
and blood sugar levels, and to determine spinal fluid
pressure.
• Doctors use CSF to test for herpes simplex virus, Epstein-
Barr virus, varicella-zoster virus, enteroviruses, and to
look for the presence of antibodies to the West Nile virus.
• While cerebrospinal fluid tests may help diagnose
encephalitis, they cannot provide information on how
severe the disease will be.

31. BLOOD TESTS
• Blood tests may be used to test for West Nile virus
and other arbovirus infections.
• Blood and urine tests are used to isolate and
identify viruses.
• Enzyme-linked immunosorbent assays (ELISA),
including IgM-capture ELISA (MAC-ELISA) and IgG
ELISA, can identify viruses that cause encephalitis
soon after infection.
• Polymerase chain reaction (PCR) can identify small
amounts of viral DNA.

32. BRAIN BIOPSY
• Tiny samples of brain tissue are surgically removed
for examination and testing for the presence of the
virus.
• Tissue is prepared using staining techniques and
then viewed under an electron microscope.
• In a few cases, the viruses in brain cells are able to
be cultured; that is, the viruses can actually be
made to replicate in samples.
• A brain biopsy is the gold standard for diagnosing
rabies.

33. TREATMENT
• The goals of treatment are to provide supportive care (rest,
nutrition, fluids) to help the body fight the infection, and to relieve
symptoms. Reorientation and emotional support for confused or
delirious people may be helpful.
Medications may include:
• Antiviral medications, such as acyclovir (Zovirax) and
foscarnet (Foscavir) -- to treat herpes encephalitis or other severe
viral infections (however, no specific antiviral drugs are available
to fight encephalitis)
• Antibiotics -- if the infection is caused by certain bacteria
• Anti-seizure medications (such as phenytoin) -- to prevent
seizures.
• Steroids (such as dexamethasone) -- to reduce brain swelling
(in rare cases)
• Sedatives -- to treat irritability or restlessness
• Acetaminophen -- for fever and headache.

34. TREATING PROBABLE CAUSES OF
ENCEPHALITIS
• Since it is difficult to determine the cause of encephalitis, and
rapid treatment is essential, clinical guidelines recommend
immediately administering intravenously the antiviral drug
acyclovir without waiting to determine the cause of the illness.
• Once the doctor receives results from diagnostic tests, drug
treatment depends on the cause of the encephalitis. Antiviral
drug treatments for specific causes of encephalitis include:
• Herpes Simplex Virus . Acyclovir is recommended.
• Varicella-Zoster Virus . Acyclovir is recommended.
Ganciclovir or adjunctive corticosteroids may also be
considered.
• Epstein-Barr Virus . Corticosteroids may be used,
although risks may outweigh benefits. (Acyclovir is not
recommended.)
• For bacterial meningitis, antibiotics (not antiviral drugs) are
used.

35. ADDITIONAL TREATMENTS
• Other encephalitis treatments are aimed at
reducing symptoms.
• Seizures may be prevented by using oral
anticonvulsant drugs or intravenous lorazepam
(Ativan).
• Sedatives may be prescribed for irritability or
restlessness.
• Simple pain relievers may be used for fever and
headache.

36. Prognosis
• Acute phase of illness different from person to
person
• Some recover with slight disability, others
profound disability and a few need residential
care for a life time
• Degree and type of damage
cause of inflammation
severity of the infection
area affected
delay in seeking treatment

37. Post encephalitis
presentation
• Personality changes
• Physical difficulties
• Memory problems
• Emotional problems
• Problems with pain and
other sensations
• Problems with daily living
skills
• Fatigue
• Hormone problems
• Cognitive Problems
• Problems with new
learning
• Inability to understand
and communicate
• Epilepsy
• Inappropriate behavior
and poor social skills

38. Psychosocial Rehabilitation
After acute phase,
safe environment +gentle stimulation
spontaneous recovery
Later phase,
new skills, habits and strategies to cope
Family and Patient requirement of time to cope varies

39. Barbara Wilson – Cutting Edge developments in Neurological
Rehabilitation and possible Future directions (2011)
• Comparison focused therapy (CFT) – refocus emotional
responses from self-critical to self acceptance
• Music intonation therapy- music engages brain and
behavior functions. Improve attention, memory, executive
functions, unilateral neglect, anxiety, depression
• Virtual reality assessments – make more able for patients
to become more able to participate in community life.
• Restitution of working memory deficits by computerized
working memory training
• Errorless learning for people with language deficits
• Problem solving therapy for people with executive
function deficits
• Assistance in early stages of deterioration.

40. Recent trends
Extensive frontal gray matter volume reduction related to a
possible sequalae of encephalitis (Evernsel & etal, 2015)
39 year old man
Normal growth till 2 years
At 2, a febrile illness with convulsions- unconscious for a week.
No treatment given
Could walk only at 5, no speech, lacking self-care,
disorganized behavior and mental retardation
Untreated encephalitis at 2 years damaged frontal region

41. • Encephalitis sequalae causes
mental retardation
• Frontal Necrosis leads to
disinhibition
• Low dose of antipsychotic and
antiepileptic drugs for
symptomatic treatment
Fig 1. MRI of the brain showing extensive
frontal and mild right parietal gliosis and
encephalomalacia.

42. Encephalitis – a service orphan: The need for more
research and access to neuropsychology (Easton,
Alkin & Dowell 2006)
• Aimed to spread awareness of neuropsychology in
management of encephalitis
• More psychological disorders in people with Acquired
Brain Injury
• After acute phase of encephalitis, marked changes in
behavior
Memory problems, personality change, personality and
spatial disorders etc
• Family and caregiver outcomes
• Social Outcomes
• Rehabilitation

43. Thank You