This document discusses several types of autoimmune encephalitis: - Acute disseminated encephalomyelitis (ADEM) typically occurs after infections or vaccinations and is characterized by inflammation and demyelination in the central nervous system. - Hashimoto's encephalopathy presents with cognitive and psychiatric symptoms and is associated with anti-thyroid antibodies. - Rasmussen's encephalitis is a rare disease that causes seizures, neurological deficits, and brain inflammation localized to one hemisphere, typically in children. - Anti-NMDA receptor encephalitis is an acute form associated with ovarian teratomas that presents with psychiatric symptoms, seizures, and dyskinesias.

1. Autoimmune Encephalitides
Dr.Roopchand.P.S
Senior Resident Academic
Department of Neurology

2. Introduction.
• Autoimmune Encephalitis resulting from an
attack of the brain by the body's immune
system
– Acute Disseminated Encephalitis (ADEM)
– Hashimoto's Encephalitis
– Rasmussen's Encephalitis
– NMDA-Receptor Antibody Encephalitis
– Limbic Encephalitis

3. ADEM
• occurs in association with an immunization or
vaccination (postvaccination
encephalomyelitis) or systemic viral infection
(parainfectious encephalomyelitis).
• perivascular inflammation, edema, and
demyelination within the CNS in
characteristic.

4. • Postvaccination Acute Disseminated
Encephalomyelitis.
– subject of medicolegal controversy.
• Measles-Induced Acute Disseminated
Encephalomyelitis.
– complicate 1 in 400 to 1 in 1000 cases of measles
infection.
• Idiopathic Acute Disseminated
Encephalomyelitis
– in the setting of nonspecific viral illness.

5. • bilateral ON
• loss of consciousness,
• Meningismus
• loss of deep tendon reflexes and retained
abdominal reflexes in the presence of Babinski
sign
• central body temperature over 100°F
• severe shooting limb pains.

6. • development of a focal or multifocal
neurological disorder following exposure to
virus or receipt of vaccine.
• peak dysfunction within several days.
• Recovery can begin within days
• Complete resolution day to months.
• Measles virus–associated ADEM may carry a
worse prognosis.

7. Investigations
• MRI: multifocal CNS lesions.
– majority of the T2 lesions enhance, suggesting
they were of recent onset.
– after several weeks, lesions show at least partial
resolution.
• CSF:
– Normal pressure, cells <100/mm3, moderate
increase in protein.
– OCB not usually seen.

8. • The current favored therapy for ADEM is high-
dose corticosteroids.
• Acute Hemorrhagic Leukoencephalitis.
• Isolated ON
• Cerebellitis
• ATM.
• c/c recurrent.

9. Hashimoto encephalopathy
• acute to subacute
• evidence of cognitive impairment
• variable psychiatric symptoms, alteration in
consciousness, hallucinations
• Involuntary
movements, seizures, myoclonus, opsoclonus,
chorea, ataxia, stroke like episodes, and
myelopathy.
• Adolescent females are mostly affected.

10. • Diagnosis:
– Clinical triad of neuropsychiatric
symptoms, detection of antimicrosomal or
antithyroglobulin antibodies, and exclusion of
other causes.
– antithyroid
– peroxidase, antithyroglobulin,
– lesser extent thyroid-stimulating hormone
receptor–blocking antibodies.
– α-enolase
• autoimmune cerebral vasculitis perhaps
related to immune complex deposition.

11. • CSF show moderately elevated protein, may
be positive for anti thyroid Ab, OCB seen
• EEG: slowing, triphasic waves, epileptiform
discharges.
• MRI usually normal, occasionally non-specific
sub cortical white matter T2 signal changes.
• Thyroid status may be normal.
• Treatment: short course high dose steroids
(55% full recovery)
• Recurrence – continued steroids, IVIG, other
immunomodulatory drugs.

12. Rasmussen's encephalitis
• chronic focal encephalitis (CFE)
• rare inflammatory neurological disease
• frequent and severe seizures, loss of motor
skills and speech, hemiparesis encephalitis
and dementia.
• Usually <15 yrs
• Affects one cerebral hemisphere.

13. • auto-antibodies against the glutamate
receptor GluR3.
• T lymphocyte mediated destruction of
neurons.
• C/F:
– mostly affects children(avg 6yrs)
– prodromal stage ,Acute stage and residual stage.

14. • Diagnosis is usually clinical.
• EEG shows slowing in affected hemisphere.
• MRI : gradual shrinkage of the affected
hemisphere with signs of inflammation or
scarring.
• Treatment:
– Control of seizures
– Steroids, IVIG
– Severe cases Hemispherectomy.

15. Anti-NMDA receptor encephalitis:
• acute form of encephalitis.
• Potentially Lethal.
• caused by autoimmune reaction against NR1- and
NR2-subunits of the glutamate NMDA receptor.
• Associated with ovarian teratomas.
• Previously thought entirely as a paraneoplastic
manifestation.
• psychiatric symptoms or memory
problems, seizures, unresponsiveness
, dyskinesias, autonomic
instability, hypoventilation.

16. • MC in young women and children.
• Treatment with Steroids, IVIG.
– PLEX
– Cyclophosphamide and /or rituximab.

17. Limbic and Brainstem Encephalitis:
• Limbic encephalitis:
Confusion,depression, agitation, anxiety, mem
ory deficits, dementia, and partial complex
seizures.
• Brainstem encephalitis:
oscillopsia, diplopia, dysarthria, dysphagia, gaz
e abnormalities, and subacute hearing loss.
• Symptoms can overlap.

18. • MRI:
– unilateral or bilateral mesial temporal lobe
abnormalities on T2-weighted and FLAIR images’
– The temporal-limbic regions may be hypointense on
T1-weighted sequences and may enhance with
contrast.
• Associated with testicular germ cell
tumors, Hodgkin lymphoma, thymoma.
• Antigens:
– Intra cellular: Hu, Ma2, CV2/CRMP5
– Cell surface antigens: AMPA receptors, leucine-rich
glioma inactivated 1 (LGI1) and γ-aminobutyric acid
type B [GABA-B] receptors.

19. Graus and Saiz criteria(2005)
All four of
• Subacute onset (<12 weeks) of seizures, short-term
memory loss, confusion, and psychiatric symptoms
• Neuropathologic or radiologic evidence (MRI, SPECT, PET)
of involvement of the limbic system
• Exclusion of other possible aetiologies of limbic
dysfunction
• Demonstration of a cancer within 5 years of the diagnosis
of neurologic symptoms, or the development of classic
symptoms of limbic dysfunction in association with a well-
characterized paraneoplastic antibody
(Hu, Ma2, CV2, amphiphysin, Ri)

20. Treatment:
• immunomodulation with steroids and IVIg.
– The likelihood of improvement is higher if the
disorder is associated with antibodies to cell-
surface receptors or ion channels.
• removal of the antigenic source (tumor) and
antibodies with antibody depleting treatments
are often successful.
• Treatment is disappointing when antigens are
intracellular.