Autoimmune encephalitis (AIE) is one of the most common causes of noninfectious encephalitis. It can be triggered by tumors, infections, or it may be cryptogenic. The neurological manifestations can be either acute or subacute and usually develop within six weeks. There are a variety of clinical manifestations including behavioral and psychiatric symptoms, autonomic disturbances, movement disorders, and seizures. We reviewed common forms of AIE and discuss their diagnostic approach and treatment.

The cerebellum is no longer considered a purely motor control device, and convincing evidence has demonstrated its relationship to cognitive and emotional neural circuits. The aims of the present study were to establish the core cognitive features in our patient population and to determine the presence of Cerebellar Cognitive Affective Syndrome (CCAS) in this group. We recruited 38 patients with spinocerebellar ataxia type 3 (SCA3) or Machado–Joseph disease (MJD)-SCA3/MJD and 31 controls. Data on disease status were recorded (disease duration, age, age at onset, ataxia severity, and CAG repeat length). The severity of cerebellar symptoms was measured using the International Cooperative Ataxia Rating Scale and the Scale for the Assessment and Rating of Ataxia. The neuropsychological assessment consisted of the Mini-Mental State Examination, Clock Drawing Test, Wechsler Adult Intelligence Scale, Rey–Osterrieth Complex Figure, Wisconsin Card Sorting Test, Stroop Color–Word Test, Trail-Making Test, Verbal Paired Associates, and verbal fluency tests. All subjects were also submitted to the Hamilton Anxiety Scale and Beck Depression Inventory. After controlling for multiple comparisons, spatial span, picture completion, symbol search, Stroop Color–Word Test, phonemic verbal fluency, and Trail-Making Tests A and B were significantly more impaired in patients with SCA3/MJD than in controls. Executive and visuospatial functions are impaired in patients with SCA3/MJD, consistent with the symptoms reported in the CCAS. We speculate on a possible role in visual cortical processing degeneration and executive dysfunction in our patients as a model to explain their main cognitive deficit.

Objective:To clinically characterize patients with anti-metabotropic glutamate receptor (mGluR)1 encephalitis, identify prognostic factors, and study the IgG subclasses and effects of antibodies on neuronal mGluR1 clusters.Methods:Clinical information of new and previously reported patients was reviewed. Antibodies to mGluR1 and IgG subclasses were determined with brain immunohistochemistry and cell-based assays, and their effects on mGluR1 clusters were studied on rat hippocampal neurons.Results:Eleven new patients were identified (10 adults, 1 child), 4 females. In these and 19 previously reported cases (n=30, median age 55) the main clinical manifestation was a subacute cerebellar syndrome that in 25 (86%) patients was associated with behavioral/cognitive changes or other neurological symptoms. A tumor was found in 3/26 (11%). Brain MRI was abnormal in 7/19 (37%) at onset and showed cerebellar atrophy in 10/12 (83%) at follow-up. Twenty-five/30 (83%) patients received immunotherapy. Follow-up was available from 25: 13 (52%) had clinical stabilization, 10 (40%) significant improvement, and 2 died. At the peak of the disease, patients with bad outcome (mRS>2, n=7) were more likely to have higher degree of initial disability, as reflected by a worse SARA (Scale for Assessment and Rating of Ataxia) score, and the more frequent need of assistance to walk. Antibodies to mGluR1 were mainly IgG1 and caused a significant decrease of mGluR1 clusters in cultured neurons.Conclusions:Anti-mGluR1 encephalitis manifests as a severe cerebellar syndrome, often resulting in long-term disability and cerebellar atrophy. The antibodies are pathogenic and cause significant decrease of mGluR1 clusters in cultured neurons.