Anti-MOG antibody encephalitis

Introduction
Anti-myelin oligodendrocyte glycoprotein (MOG) antibodies are associated with various demyelinating conditions such as optic neuritis, myelitis, acute disseminated encephalomyelitis (ADEM), or neuromyelitis optica spectrum disorder (NMOSD). However, in 2020 a series was published of 116 children with anti-MOG antibodies, in which 22 (19%) were found to have evidence of encephalitis other than ADEM. This page will focus on non-ADEM encephalitis.

Epidemiology
This disorder has so far only been described in children.

Signs/symptoms

 * Decreased level of consciousness (100%)
 * Seizures (64%) and status epilepticus (45%)
 * Fever (59%)
 * Abnormal behavior (50%)
 * Motor deficits (40%)
 * Abnormal movements (23%)
 * Brainstem-cerebellar dysfunction (23%)

Anti-MOG antibodies
Of 81 patients, 61% had anti-MOG antibodies in both serum and CSF, 33% had antibodies in serum alone, and 6% had antibodies in CSF alone.

MRI

 * Bilateral cortical involvement
 * Basal ganglia / thalamic changes
 * Meningeal enhancement
 * Focal lesions
 * Normal in up to 10%

Prognosis
Patients with anti-MOG non-ADEM encephalitis have worse outcomes compared to those with ADEM or NMOSD presentations, with 36% having mRS ≥2 at last follow-up compared with 13% in ADEM poatients and 17% in NMOSD patients.