Autoimmune encephalitis

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.