Neurology

Question 1

What is NMDA encephalitis?

Answer 1

NMDA encephalitis is an auto-immune encephalitis, which has an unknown incidence, but is found predominantly in female at a median age of 23 years.

The NMDA receptor is an excitatory glutamate receptor that participates in memory, learning, cognition, behavior and psychosis.

Question 2

What is the pathophysiology of NMDA encephalitis?

Answer 2

Ovarian teratoma (50% of females with disease), possibly HSV encephalitis (20% of patients develop NMDAR AB), the causes is otherwise unknown in 50% of the patients.

Question 3

How do you diagnose NMDA encephalitis?

Answer 3

Neuroimaging - MRI often normal

EEG - infrequent epileptiform activity, but frequent slow disorganized activity

LP- CSF with lymphocytic pleocytosis, normal or mildly increased protein, or oligoclonal bands

NMDA-R IgG antibodies in CSF and serum

If female, screen for ovarian teratoma

Brain biopsy DOES NOT provide diagnosis

Question 4

How do you treat NMDA encephalitis?

Answer 4

1st line: IV methylprednisolone AND IVIG (x 5 days) OR Plasma Exchange. Recommend tumor resection, if applicable

2nd line:
Rituximab, cylophosphamide or both

Without treatment, progressive neurologic deterioration and death can occur, however spontaneous recovery has also been described in a few patients after several months of severe symptoms