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Peng et al. Autoimmune encephalitis

Diagnosis of possible AE should exclude other asking history. So, near-term memory disorder could
probable diseases reasonably. Increased signal on be included into the diagnostic criteria, but still needs
T2-weighted fluid-attenuated inversion recovery further clinical validation.
(FLAIR) imaging in the medial aspect of the temporal
lobes is an important differential diagnosis essential. AUTOIMMUNE ENCEPHALITIS AND OTHER
Cerebrospinal fluid (CSF) analysis and characteristic NERVOUS SYSTEM DISEASE OVERLAP
clinical manifestations also count. However, some SYNDROME
diseases are difficult to preclude due to atypical
clinical manifestations or due to the lack of relevant Demyelinating disease
detection methods, such as viral encephalitis. [6-8] A recent case study of a large number of patients
Whether to continue in accordance with the showed that a group of patients with anti-NMDAR
recommendations of diagnostic path remains to be antibody encephalitis have an overlap in clinical/
further verified. Concerned to the imaging features of MR manifestations with optic neuromyelitis and
LE, the guideline emphasizes that bilateral temporal myelitis. In this group of patients, MR usually
[13]
lobes involvement is one of the necessary factors for shows multifocal, subscapular or extensive T2/FLAIR
the definite diagnosis of autoimmune LE. However, it phase abnormalities which suggests an overlap with
does not imply to deny the existence of LE which is demyelinating disease such as optic neuromyelitis.
just unilateral temporal lobe involved or with normal More than half of these patients suffered demyelinating
imaging. [9,10] When the autoantibody test results disease before or after the onset of anti-NMDAR
are unknown, the diagnostic criteria of autoimmune antibody encephalitis. In some patients in this group,
LE can exclude the disease involving the limbic anti-NMDAR antibody encephalitis and demyelinating
system as well, such as viral encephalitis, glioma, disease occurred at the same time, which greatly
epilepsy, etc., to avoid over-diagnosis. challenges the diagnosis. Some patients with early
diagnosis of ADEM, neuromyelitis optica or multiple
The guideline lists anti-NMDA receptor encephalitis sclerosis could appear psychiatric symptoms,
separately, and for the first time presents faciobrachial dystonic seizures and/or autonomic
[11]
detailed probable and definite diagnostic criteria. dysfunction which strongly suggests a diagnosis of
The diagnosis is based on the specific symptoms, anti-NMDAR encephalitis.
auxiliary examination, autoantibody detection and
tumor evidence. Anti-NMDAR encephalitis is singled Herpes simplex virus encephalitis (HSE)
as an independent diagnosis may be due to the It is reported that HSE has a recurrence rate of
following reasons: (1) anti-NMDAR encephalitis 25%. Some of the recurrent patients would recover
[14]
has a characteristic manifestation other than typical after antiviral treatment. But some recurrent patients
LE, such as the involuntary movement of the face, presented with new symptoms such as choreoathetosis
speech disorders, autonomic dysfunction and central and so on. As for them, virological examination was
hypoventilation; (2) although the exact incidence of negative and antiviral therapy was not effective.
various types of AE cannot be calculated, anti-NMDAR This part of patients’ serum and CSF anti-NMDAR
is much higher than other types of AE based on current antibody was positive. Their conditions improved
[15]
data; [5,12] (3) there was a clear correlation between after immunotherapy. Some studies have reported
NMDAR encephalitis and teratoma; (4) the most anti-NMDAR antibody encephalitis could occur after
common magnetic resonance imaging manifestations HSE. [16,17] Since then, HSE recurrent patients were
of anti-NMDAR encephalitis are abnormal non-specific found other non-specific neuronal surface-mediated
signals in cortical or subcortical, and the positive rate antibody positive in serum or CSF, suggesting that
is low. Moreover, Imaging evidence of bilateral limbic HSE infection may be one of the causes of AE.
system involvement is the necessary condition of
the clinical diagnosis of autoimmune LE. [5,12] To sum AE combined with other antibodies
up, anti-NMDAR encephalitis is currently diagnosed Overlap anti-neuronal antibodies in AE is rare. Anti-
independently of autoimmune limbic encephalitis NMDAR encephalitis is the most common type of
disease. It is noteworthy that the diagnostic criteria AE. This disease combined with other neuronal
for anti-NMDAR encephalitis do not include near-term antibodies, such as anti-Aquaporin antibody, anti-
memory impairment in the clinical manifestations. myelin oligodendrocyte glycoproteinantibody is
Because it is difficult to assess memory impairment rarely reported. The proportion of anti-GABABR
in those patients with psychiatric symptoms or in encephalitis with multiple antibodies appears to
child patients. As the more common symptom of the be higher. Höftberger et al. reported 20 patients
[18]
[5]
disease, memory disorders can often be obtained by with GABABR antibodies, seven of them had
[4]
Neuroimmunology and Neuroinflammation ¦ Volume 4 ¦ July 11, 2017 133