The document discusses autoimmune encephalitis, a group of neuro-psychiatric disorders characterized by symptoms such as memory loss, seizures, and changes in behavior, with reversibility achievable through immunotherapy. Various types of autoimmune encephalitis are detailed, including anti-NMDAR and anti-GABAB receptor encephalitis, highlighting their common presentations, laboratory findings, and treatment strategies. Emphasis is placed on the importance of early diagnosis and treatment to improve patient outcomes.

1. AUTOIMMUNE ENCEPHALITIS
DR. HARSH M. PATEL
D.M. NEUROLOGY S.R.

2. INTRODUCTION
• Autoimmune encephalitis- group of neuro-psychiatric disorders
• Reversibility with immunotherapy.

3. Memory loss
Changes in
behaviour/cognition
Psychosis
Seizures
Movement disorders

4. • Total 12 types:
• Anti-NMDAR encephalitis
• Anti GABAB receptor encephalitis
• Anti AMPA receptor encephalitis
• Anti LGI1 limbic encephalitis
• Anti CASPR2 associated encephalitis
• Anti GABAA receptor encephalitis
• Anti DPPX encephalitis
• Anti mGluR5 encephalitis
• Anti mGluR1 cerebellar dysfunction
• Anti dopamine receptor encephalitis
• Anti neurexin 3@ encephalitis
• Anti IgLON5 disease
SPECIFIC
SYNDROMES:

5. Anti NMDAR encephalitis:
• Most common of all
• 2nd MCC of immune mediated encephalitis after ADEM
• 80%- children and young women
• Presentation:
acute psychiatric symptoms
Seizures
Memory deficits
Decreased level of consciousness
Dyskinesias( orofacial, limb & trunk)
Autonomic instability
Central hypoventilation

6. • Viral prodrome
• Atypical-cerebellar ataxia/hemiparesis
• Approx. 40% of female >18 yrs– ovarian teratoma(u/l or b/l) compared to 9% in < 14
yrs.
• Other tumours- mediastinal teratoma, hodgkins, SCLC, neuroblastoma, breast cancer,
germ cell tumour of testis
LABS:
- CSF: Usually lymphocytic pleocytosis
- MRI: T2 and FLAIR hyperintensity with transient contrast enhancement of cerebral
cortex, overlying meninges, basal ganglia or brainstem
- EEG- focal or generalized slowing. 30%-- extreme delta brush pattern
- Confirmation– NMDAR ab. In CSF and serum

9. Anti GABAB receptor encephalitis:
• Usually >60 yrs and M:F
• > 50 %- tumours
• Presentation
Memory loss
Confusion Typical of LIMBIC ENCEPHALITIS
Seizures[TLE]
Rarely: ataxia or opsoclonus-myoclonus syn.

10. LABS:
Brain MRI: 2/3 pts. Showing u/l or b/l medial temporal lobe hyperintensity over FLAIR/T2
signal- consistent with Limbic encephalitis
CSF: lymphocytic pleocytosis
Confirmation: GABAB R antibodies
(others:- TPO, ANA, GAD65)

11. Anti- AMPA receptor encephalitis:
• Middle aged women
• Presentation:
As limbic encephalitis (>50%)
Others: diffuse encephalopathy
• >60%- tumours:- (lung, breast or thymus)
LABS:
CSF- lymphocytic pleocytosis
MRI brain- medial temporal lobes shows hyperintense signal
Confirmation: antibodies to GluA1/2 subunits of the AMPAR
others- GAD, TPO, ANA

12. Anti- LGI 1 limbic encephalitis:
• older M>F
• Memory loss, confusion and temporal lobe seizures
• >60 %- hyponatremia and less often REM sleep disorders
• 30-40%- faciobrachial dystonic seizures( brief tonic- myoclonic like)
• Few- Morvans syndrome
• Mimic CJD
• Usually not cancer associated( few– thymoma)
LABS:
MRI brain- as limbic encephalitis
CSF- usually normal. May show OGBs
Confirmation:- Anti LGI1 antibodies

13. Anti- CASPR2 associated encephalitis:
- encephalopathy - peripheral nerve hypersensitivity
- cerebellar dysfunction - neuropathy
- autonomic dysfunction - allodynia
- hallucinations
- insomnia
- seizures
CNS SYMTOMS PNS SYMPTOMS

14. • This combo is called morvan’s syndrome.
• Usually not cancer associated.(few- thymoma)
LABS:
• Confirmation: anti-CASPR2 ab.

15. Anti- GABAA receptor encephalitis:
• Age- around 40 usually
• Presentation:
Progressive severe encephalopathy- 90% develops refractory seizures mostly refractory
SE.
Others features include: cognitive decline, altered behaviour, decreased consciousness
and movement disorders.
LABS:
- CSF- lymphocytic pleocytosis
- MRI: In contrast to other autoimmune encephalitis having normal MRI or limbic
involvement, it shows T2/FLAIR Extensive multifocal cortical- subcortical involvement
without contrast enhancement.
- 1/3- tumours
- Confirmation: anti GABAA rec. ab.. Others: GAD, TPO.

17. Anti- DPPX encephalitis:
• Presentation :
Severe prodromal weight loss or diarrhea(4 months prior) f/b neuropsychiatric
symptoms, CNS hyperexcitability( agitation, hallucinations, myoclonus, tremors, seizures,
hyperekplexia and/ cerebellar or brainstem dysfunction.
Weight loss
Cognitive decline
CNS
hyperexcitability

18. - Some develop syndrome resembling PERM( progressive Encephalomyelitis with rigidity
and myoclonus)
LABS:
- CSF- pleocytosis or OGBs
- MRI- nonspecific
- Confirmation: anti- DPPX ab.

19. Anti- GluR5 encephalitis:
• Presentation: like limbic encephalitis
• A/w tumours most commonly Hodgkins.
• Csf- pleocytosis
• MRI- FLAIR abnormalities in limbic/ extralimbic areas.
• Confirmation: anti mGluR5 antibodies

20. Anti- mGluR1 cerebellar dysfunction:
- Cerebellar ataxia
- Confimation- anti mGluR1 ab.

21. Anti- dopamine receptor encephalitis:
-Mostly children with basal ganglia encephalitis, syndenhams chorea and tourette
syndrome
- confirmation: anti dopamine 2 receptor ab.( most also have anti NMDAR ab)

22. Anti- neurexin 3 @ encephalitis:
-prodromal fever, headache or gastrointestinal symptoms f/b confusion, seizures and
decreased level of consciousness
-confirmation: anti- neurexin 3 @ ab. ( some may have anti NMDAR ab)

23. Anti IgLON5 disease:
• sleep disorder
• Starting before or concurrently with the onset of bulbar symptoms, gait abnormalities,
chorea, oculomotor problems and less commonly cognitive decline.
• Sleep disorder includes REM and non REM sleep disturbances characterized by
abnormal movements and behaviours that predominate in early hours of sleep.
• MRI, Eeg and CSF normal
• Confirmation: anti IgLON5 ab.

24. WHEN TO SUSPECT AUTOIMMUNE ENCEPHALOPATHY?
Any patient who presents with classical
symptoms complex already described PLUS

25. FLOW CHART FOR MANAGEMENT OF AUTOIMMUNE ENCEPHALOPATHIES:
MAINTAINANCE
THERAPHY:
If patient responds to
treatment maintainance
of 6-9 months is enough.

28. TAKE HOME MESSAGE
• All encephalitis are not infectious
• Autoimmune encephalitis is not uncommon
so think of it as they are potentially reversible.
• Early diagnosis and treatment are
essential for better outcomes.