Autoimmune Encephalitis

Question 1

What is the definition of acute encephalitis?

Answer 1

Debilitating neurologic disorder
Develops as rapidly progressive encephalopathy (within 6 wks)
Autoimmune causes equally as likely as infectious

Question 2

What are some examples of types of autoimmune encephalitis?

Answer 2

1. NMDAR - young females, movement disorder
2. LGI1 - elderly, males, focal seizures, amnesia, hypoNa
3. GABA(B)R
4. CASPR2
5. GABA(A)R

Question 3

What are MRI findings in autoimmune encephalitis?

Answer 3

Can be normal, non specific or diagnostic

Question 4

Are EEG changes present in autoimmune encephalitis?

Answer 4

Rare but can help rule out other conditions

Question 5

What is the ddx for autoimmune encephalitis?

Answer 5

1. Infectious - most commonly HSV, usually have seizures, fever, focal neurologic
2. Temporal lobe glioma
3. CJD
4. Post ictal MRI changes
5. Metabolic encephalopathies
6. Hashimoto’s encephalopathy

Question 6

What are the Graus diagnostic criteria for definite autoimmune limbic encephalitis?

Answer 6

1. Subacute onset (<3 mos) working memory deficits, seizures or psych symptoms suggesting involvement of limbic system
2. Bilateral brain abnormalities on T2 FLAIR in medial temporal lobes
3. At least one of CSF pleiocytosis (inc WBC), EEG with epileptic or slow wave activity of temporal lobes
4. Reasonable exclusion of alternative causes

Question 7

What are differences in neuroimaging findings between HSV and autoimmune encephalitis?

Answer 7

HSV bilateral asymmetric or unilateral, AI bilateral symmetric temporal lobe
HSV less confined to limbic system
HSV can have hemorrhagic features

Question 8

What does CCCDTD-5 suggest with regards to rapidly progressive dementia?

Answer 8

RPD defined as dementia develops within 12 mos after first cognitive symptoms
Refer to experienced physicians
After excluding delirium and other causes, base investigations on prevalence of causes
Emphasize detection of potentially curable conditions (infections, immune mediated, toxic metabolic)
CSF biomarkers can be of benefit to identify underlying pathology

Question 9

What is the recommended work up for RPD?

Answer 9

1. Routine labs: CBC, lytes, Cr, LFT, TSH, B12, glucose
2. Extra labs: film, ANA, RF, ESR/CRP, ENA, ANCA, C3, C4, lyme
3. MRI>CT
4. CSF - cell count and differential, glucose, protein, +RT-QUIC, oligoclonal bands, IgG, antibodies
5. EEG
   CJD - periodic sharp waves
   AEI - diffuse slow waves +/- epileptiform activity