1. Disease Information
1.1 Overview (current understanding)
Autoimmune encephalitis (AE; also written “autoimmune inflammatory encephalitis”, “autoimmune encephalopathy”, or “antibody-mediated encephalitis” depending on context) is a group of immune-mediated inflammatory brain disorders that typically present subacutely with neuropsychiatric symptoms, cognitive dysfunction, seizures, movement disorders, or altered level of consciousness, and are frequently associated with autoantibodies to neuronal cell-surface/synaptic or (in paraneoplastic neurologic syndromes) intracellular neuronal antigens. In a large real-world validation study, AE is described as being “associated with neuronal autoantibodies against extracellular antigens, which are directly pathogenic.” (steenhoven2023mimicsofautoimmune pages 1-2)
A practical case-definition used in modern guidelines is the 2016 Graus clinical criteria framework, which classifies patients as possible/probable/definite AE based on a subacute encephalopathy plus supportive MRI/CSF/EEG features, and then confirmation with syndrome-specific features and/or neural-specific antibody positivity. (orozco2023autoimmuneencephalitiscriteria pages 1-3, dutra2024brazilianconsensusrecommendations pages 4-5)
1.2 Key identifiers (knowledge-base fields)
Within the evidence corpus retrieved for this run, explicit mappings to MONDO, Orphanet, MeSH, and ICD-10/ICD-11 identifiers for “autoimmune encephalitis” were not available; therefore these identifiers cannot be reliably populated from the cited sources here.
1.3 Common synonyms / alternative names (usage)
Commonly used terms in the literature captured in this run include: - Autoimmune encephalitis (AE) / Autoimmune inflammatory encephalitis (AIE) (dutra2024brazilianconsensusrecommendations pages 1-2) - Antibody-associated encephalitis / antibody-mediated encephalitis (steenhoven2023mimicsofautoimmune pages 1-2, kerstens2024autoimmuneencephalitisand pages 1-2) - Autoimmune encephalopathy (often used in broader clinical coding; discussed as “related autoimmune encephalopathy” in clinical practice series) (orozco2023autoimmuneencephalitiscriteria pages 1-3)
1.4 Evidence sources (patient-level vs aggregated)
Evidence in this report is derived from: - Aggregated consensus guidelines (Canadian 2024; Brazilian 2024) (hahn2024canadianconsensusguidelines pages 8-9, dutra2024brazilianconsensusrecommendations pages 5-7) - Retrospective and nationwide observational cohorts (Mayo Clinic clinical practice study; Netherlands nationwide antibody-testing cohort) (orozco2023autoimmuneencephalitiscriteria pages 1-3, kerstens2024autoimmuneencephalitisand pages 1-2) - Diagnostic criteria validation and mimic studies (national referral center cohort) (steenhoven2023mimicsofautoimmune pages 1-2)
2. Etiology
2.1 Disease causal factors (mechanistic categories)
AE is typically conceptualized as antibody-associated immune-mediated encephalitis. Antibodies may target extracellular antigens (often considered directly pathogenic) or intracellular antigens (frequently paraneoplastic syndromes). (steenhoven2023mimicsofautoimmune pages 1-2, kerstens2024autoimmuneencephalitisand pages 1-2)
2.2 Risk factors
2.2.1 Neoplasm / paraneoplastic association
Neoplasm association varies by antibody subtype. Canadian consensus emphasizes that “all subtypes of AIE may be associated with an underlying neoplasm at varying frequencies” and recommends malignancy screening for all initial adult AE presentations. (hahn2024canadianconsensusguidelines pages 9-10)
Canadian guidance provides a malignancy-risk stratification by antibody (Table 4), e.g. high-risk antibodies (>70%) including Hu/ANNA1, Yo/PCA1, Ma2, KLHL11, etc.; intermediate risk (30–70%) including NMDAR, AMPAR, GABABR; and low risk (<30%) including LGI1, GFAP, GAD65, MOG. (hahn2024canadianconsensusguidelines pages 10-11)
2.2.2 Post-infectious triggers
Post-infectious immune mechanisms are recognized clinically (e.g., secondary AE after herpes encephalitis is a known paradigm in AE practice), and both Canadian and Brazilian guidance require early infectious exclusion (notably HSV PCR in CSF) during diagnostic evaluation. (dutra2024brazilianconsensusrecommendations pages 7-8, dutra2024brazilianconsensusrecommendations pages 5-7)
2.2.3 Iatrogenic triggers (immune checkpoint inhibitors)
Immune checkpoint inhibitor (ICI)-related encephalitis is recognized as an AE phenotype and is treated with immunosuppressive strategies; Canadian consensus notes ICI therapy as a risk factor and discusses AE in the differential of acute encephalopathy. (hahn2024canadianconsensusguidelines pages 2-3)
2.2.4 Genetic susceptibility (HLA/KIR)
Genetic predisposition is increasingly studied; however, in this run, detailed HLA/KIR evidence was retrieved but not processed into the evidence set with citable context IDs. Therefore, genetic susceptibility is not exhaustively summarized here.
2.3 Protective factors
Protective genetic or environmental factors were not explicitly reported in the retrieved, citable evidence for this run.
2.4 Gene–environment interactions
While environmental triggers (tumor, infection, ICI exposure) are recognized, explicit gene–environment interaction analyses were not available in the citable evidence retrieved for this run.
3. Phenotypes
3.1 Core clinical phenotype spectrum (with frequencies where available)
A Chinese cohort of neuronal-surface antibody AE (n=103) reported presenting frequencies: seizures 74.8%, psychiatric/behavior disorders 66.0%, cognitive deficits 51.5%, disturbances of consciousness 45.6%, and movement disorders/involuntary movements 26.2%. (huang2023clinicalcharacteristicsand pages 1-2)
In the Mayo Clinic real-world series of 538 adults (AE or related autoimmune encephalopathy), “possible AE” required subacute onset plus supportive features; among supportive features within possible AE (n=361), focal findings, seizures, supportive MRI, and CSF pleocytosis were common (as summarized in the paper’s abstract). (orozco2023autoimmuneencephalitiscriteria pages 1-3)
3.2 Suggested HPO terms (examples for knowledge base)
Based on the phenotype frequencies and guideline descriptions in the cited cohorts: - Seizures — HP:0001250 (huang2023clinicalcharacteristicsand pages 1-2) - Psychiatric symptoms / psychosis — HP:0000708 / HP:0000738 (huang2023clinicalcharacteristicsand pages 1-2) - Cognitive impairment — HP:0100543 (huang2023clinicalcharacteristicsand pages 1-2) - Altered mental status / impaired consciousness — HP:0001252 (huang2023clinicalcharacteristicsand pages 1-2) - Movement disorder / dyskinesia — HP:0100022 (huang2023clinicalcharacteristicsand pages 1-2) - CSF pleocytosis — HP:0002181 (dutra2024brazilianconsensusrecommendations pages 4-5)
3.3 Quality of life impact
Guidelines emphasize persistent neuropsychiatric and cognitive sequelae and the need to evaluate cognitive/functional outcomes using tools beyond mRS (e.g., CASE, MMSE, MoCA). (dutra2024brazilianconsensusrecommendations pages 8-10, hahn2024canadianconsensusguidelines pages 10-11)
4. Genetic/Molecular Information
4.1 Primary molecular targets (autoantibodies)
Netherlands nationwide testing study lists major extracellular antigen (EA) targets including NMDAR, LGI1, CASPR2, GABABR, GABAAR, AMPAR, DPPX, GlyR, mGluR1, IgLON5, Tr/DNER and intracellular antigen (IA) targets including Hu/ANNA1, Yo/PCA1, CRMP5/CV2, Ri/ANNA2, Ma1/Ma2, amphiphysin, GAD65, GFAP, KLHL11. (kerstens2024autoimmuneencephalitisand pages 1-2)
In that nationwide cohort, the four most common AIE/PNS types were anti-NMDAR, anti-LGI1, anti-Hu, and anti-GAD65, comprising 364/578 (63.0%) of diagnoses. (kerstens2024autoimmuneencephalitisand pages 1-2)
4.2 Causal genes and pathogenic variants
AE is generally not a monogenic disease; causal Mendelian genes and variant-level pathogenicity (ClinVar-style) were not provided in the citable evidence retrieved in this run.
4.3 Epigenetic information, chromosomal abnormalities
Not reported in the citable evidence retrieved in this run.
5. Environmental Information
5.1 Infectious agents
Workup guidelines emphasize exclusion of infectious encephalitis, specifically recommending CSF PCR testing for herpesviruses as part of AE evaluation and prior to/alongside immunotherapy. (dutra2024brazilianconsensusrecommendations pages 7-8, dutra2024brazilianconsensusrecommendations pages 5-7)
5.2 Neoplasm-associated immune triggers
Neoplasm association is managed as a core environmental/biologic trigger; all adult AE presentations should undergo malignancy screening at diagnosis. (hahn2024canadianconsensusguidelines pages 9-10)
6. Mechanism / Pathophysiology
6.1 Mechanistic framing (causal chain)
A practical mechanistic chain in antibody-mediated AE is: 1) Triggering exposure (e.g., tumor expression of neural antigens, infection, or immune checkpoint dysregulation) → 2) Immune activation and production of neural-specific antibodies (and/or T-cell responses, particularly in intracellular-antigen/paraneoplastic syndromes) → 3) CNS access with neuroinflammation (variable MRI/CSF abnormalities; sometimes normal early) → 4) Disruption of neuronal networks leading to neuropsychiatric symptoms, seizures, cognitive deficits, movement disorders.
This framing is consistent with the guideline and cohort emphasis that extracellular-antigen AE is directly pathogenic and that MRI/EEG/CSF may be normal despite AE. (steenhoven2023mimicsofautoimmune pages 1-2, hahn2024canadianconsensusguidelines pages 6-7)
6.2 Suggested GO biological process terms (examples)
- GO:0006954 inflammatory response
- GO:0006955 immune response
- GO:0042113 B cell activation
- GO:0002376 immune system process
6.3 Suggested CL (Cell Ontology) terms (examples)
- B cell — CL:0000236
- Plasma cell — CL:0000786
- T cell — CL:0000084
- Microglial cell — CL:0000129
6.4 Suggested UBERON anatomy terms (examples)
Given the encephalitic phenotype and limbic predominance in multiple AE syndromes: - Brain — UBERON:0000955 - Hippocampus — UBERON:0001954 - Amygdala — UBERON:0001876
7. Anatomical Structures Affected
7.1 Organ/system level
Primary affected system is the central nervous system (CNS), with presentations including limbic encephalitis phenotypes and diffuse encephalopathy. (orozco2023autoimmuneencephalitiscriteria pages 1-3, hahn2024canadianconsensusguidelines pages 10-11)
7.2 Tissue/cell level
The evidence base in this run does not provide histopathology-level cell targeting across AE subtypes; however, antibody-associated mechanisms imply neuronal synaptic/extracellular target involvement for many EA antibodies and broader neuroinflammatory involvement in some cases. (kerstens2024autoimmuneencephalitisand pages 1-2, steenhoven2023mimicsofautoimmune pages 1-2)
8. Temporal Development
8.1 Onset
Core criteria and guidelines define onset as subacute, typically rapid progression within <3 months for possible AE. (dutra2024brazilianconsensusrecommendations pages 4-5)
8.2 Progression/course patterns
Relapse is a recognized course feature. Canadian consensus defines relapse as objective worsening after improvement or plateau, “usually at least 2–3 months from the original presentation” and preferably supported by MRI/CSF inflammation. (hahn2024canadianconsensusguidelines pages 12-13)
9. Inheritance and Population
9.1 Epidemiology (incidence)
A Netherlands nationwide retrospective cohort (2016–2021) estimated AE/paraneoplastic neurologic syndrome (AIE/PNS) incidence increasing from 4.70 per million person-years (2016) to 5.76 per million person-years (2021), with overall incidence 5.57 per million person-years (95% CI 5.13–6.05). (kerstens2024autoimmuneencephalitisand pages 1-2)
9.2 Demographics
The Canadian consensus notes antibody-specific demographic patterns (e.g., NMDAR tends to affect children/young women; LGI1 often in older men) but does not provide cohort-level sex-ratio statistics in the citable excerpts for this run. (hahn2024canadianconsensusguidelines pages 2-3)
10. Diagnostics
10.1 Clinical criteria and workflow
The Graus 2016 “possible AE” criteria (adult) are a widely implemented entry step: subacute onset plus ≥1 supportive feature and exclusion of alternative causes. (orozco2023autoimmuneencephalitiscriteria pages 1-3, dutra2024brazilianconsensusrecommendations pages 4-5)
A structured diagnostic workflow is supported by both Brazilian and Canadian consensus: - Brain MRI, EEG, CSF analysis including IgG index and oligoclonal bands (OCBs). (dutra2024brazilianconsensusrecommendations pages 5-7) - Infectious exclusion, including CSF PCR for herpesviruses. (dutra2024brazilianconsensusrecommendations pages 7-8, dutra2024brazilianconsensusrecommendations pages 5-7) - Neural antibody testing using paired serum+CSF (Brazil explicitly recommends TBA + CBA). (dutra2024brazilianconsensusrecommendations pages 5-7)
A concise, evidence-backed diagnostic criteria/performance and workflow summary is provided in the table artifact below.
Table (click to expand)
| Topic | Key points (with numbers) | Evidence type | Source (authors/year/journal) | URL |
|---|---|---|---|---|
| Graus 2016 possible AE criteria | Adult possible AE requires all 3: (1) subacute onset, rapid progression in <3 months, of working memory deficits/altered mental status/psychiatric symptoms; (2) ≥1 supportive feature: new focal CNS findings, unexplained seizures, CSF pleocytosis, or MRI suggestive of encephalitis; (3) reasonable exclusion of alternative causes. In Mayo real-world application, 361/538 (67%) met at least possible criteria. (orozco2023autoimmuneencephalitiscriteria pages 1-3, dutra2024brazilianconsensusrecommendations pages 4-5) | Human clinical cohort + consensus criteria | Orozco et al. 2023, Neurology Clinical Practice; Dutra et al. 2024, Arquivos de Neuro-Psiquiatria | https://doi.org/10.1212/cpj.0000000000200151 ; https://doi.org/10.1055/s-0044-1788586 |
| Pediatric possible AE criteria | Pediatric possible AE: onset of neurologic/psychiatric symptoms over <3 months in a previously healthy child plus 2 of the following: altered mental status/EEG slowing or epileptiform activity, focal deficits, cognitive difficulties, acute developmental regression, movement disorder, psychiatric symptoms, or unexplained seizures; and exclusion of alternatives. (dutra2024brazilianconsensusrecommendations pages 4-5) | Consensus criteria | Dutra et al. 2024, Arquivos de Neuro-Psiquiatria | https://doi.org/10.1055/s-0044-1788586 |
| Criteria performance and specificity | In a national referral cohort (n=239), criteria performance was: possible AE sensitivity 83%, specificity 27%; definite autoimmune limbic encephalitis sensitivity 10%, specificity 98%; probable anti-NMDAR sensitivity 50%, specificity 96%; probable seronegative AE specificity 99%; proposed probable anti-LGI1 sensitivity 66%, specificity 96%. Authors note probable/definite categories are useful for early immunotherapy decisions because specificity is high. (steenhoven2023mimicsofautoimmune pages 1-2) | Human clinical validation cohort | van Steenhoven et al. 2023, Neurology Neuroimmunology & Neuroinflammation | https://doi.org/10.1212/nxi.0000000000200148 |
| Definite AE / antibody-defined cases in practice | In Mayo review (n=538), definite AE cases included limbic encephalitis 127/221 (57%), anti-NMDAR 32/221 (15%), ADEM 8/221 (4%), and other AE-specific IgG defined syndromes 54/221 (24%). Most common definite AE-IgGs: LGI1 76 (34%), NMDA-R 32 (16%), high-titer GAD65 23 (12%). Criteria were judged highly specific but may miss AE-IgG positive isolated seizures/brainstem disease. (orozco2023autoimmuneencephalitiscriteria pages 1-3) | Human clinical cohort | Orozco et al. 2023, Neurology Clinical Practice | https://doi.org/10.1212/cpj.0000000000200151 |
| Common mimics and diagnostic pitfalls | Among 239 suspected cases, AE was 104/239 (44%) and mimics 109/239 (46%). Common mimics: neuroinflammatory CNS disorders 26%, psychiatric disorders 19%, noninflammatory epilepsy 13%, CNS infections 7%, neurodegenerative diseases 7%, CNS neoplasms 6%. Confounders included mesiotemporal MRI lesions 17% and false-positive serum antibodies 12%; atypical mesiotemporal features were more frequent in mimics (61% vs 24%). (steenhoven2023mimicsofautoimmune pages 1-2) | Human clinical cohort | van Steenhoven et al. 2023, Neurology Neuroimmunology & Neuroinflammation | https://doi.org/10.1212/nxi.0000000000200148 |
| Antibody assay PPV limitations | Nationwide Netherlands testing (30,246 samples) found 2,877 (9.5%) positive samples from 1,228 patients; clinical data on 940 patients yielded 578 AIE/PNS diagnoses. Sensitivity and specificity were generally >95% to >99%, but PPV was only moderate-to-poor in mass testing; for serum intracellular-antigen antibodies PPV ranged 25%–80%. This supports cautious interpretation of positive serum results in low-pretest-probability settings. (kerstens2024autoimmuneencephalitisand pages 1-2) | Nationwide retrospective laboratory-clinical cohort | Kerstens et al. 2024, Neurology Neuroimmunology & Neuroinflammation | https://doi.org/10.1212/nxi.0000000000200318 |
| Core diagnostic workflow tests | Brazilian consensus recommends that adults meeting Graus possible AE or children meeting Cellucci criteria should undergo brain MRI, EEG, and CSF analysis, including IgG index and oligoclonal bands (OCBs). These are baseline tests before/alongside antibody evaluation. (dutra2024brazilianconsensusrecommendations pages 5-7, dutra2024brazilianconsensusrecommendations pages 4-5) | Consensus guideline | Dutra et al. 2024, Arquivos de Neuro-Psiquiatria | https://doi.org/10.1055/s-0044-1788586 |
| CSF infectious exclusion and paired antibody testing | Consensus recommends paired serum + CSF antineuronal antibody testing using TBA and CBA; anti-MOG should be added in all pediatric possible AE. CSF workup should include PCR for herpesvirus; sample collection should preferably occur before immunotherapy, but treatment should not be delayed while awaiting results. (dutra2024brazilianconsensusrecommendations pages 5-7) | Consensus guideline | Dutra et al. 2024, Arquivos de Neuro-Psiquiatria | https://doi.org/10.1055/s-0044-1788586 |
| Imaging caveats and antibody confirmation | Canadian guidance emphasizes MRI/EEG may be normal and unexpected antibody results should prompt confirmatory testing (e.g., tissue indirect immunofluorescence/immunohistochemistry). Initial screening should not wait for antibody results. (hahn2024canadianconsensusguidelines pages 9-10, hahn2024canadianconsensusguidelines pages 10-11) | Consensus guideline | Hahn et al. 2024, Canadian Journal of Neurological Sciences | https://doi.org/10.1017/cjn.2024.16 |
| Neoplasm screening: who to screen | All adult patients with AIE should undergo malignancy screening at diagnosis; screening should not be delayed while awaiting neural antibody results. Screening should also be considered at relapse. (hahn2024canadianconsensusguidelines pages 9-10, hahn2024canadianconsensusguidelines pages 10-11) | Consensus guideline | Hahn et al. 2024, Canadian Journal of Neurological Sciences | https://doi.org/10.1017/cjn.2024.16 |
| Neoplasm screening: three-step approach | Canadian consensus describes a 3-step imaging strategy: (1) conventional CT body, (2) focused sex-specific imaging, and (3) whole-body PET if needed; terminate early if a neoplasm is found. First-line PET can be considered when there is a strong antibody-neoplasm association. Pelvic US or MRI is preferred over PET for ovarian teratoma. (hahn2024canadianconsensusguidelines pages 9-10, hahn2024canadianconsensusguidelines pages 10-11) | Consensus guideline | Hahn et al. 2024, Canadian Journal of Neurological Sciences | https://doi.org/10.1017/cjn.2024.16 |
| Sex-specific / directed tumor studies | Examples of directed testing include immediate ovarian ultrasound for young women with NMDAR encephalitis and testicular ultrasound for men with KLHL11 antibody encephalitis. Brazilian consensus similarly recommends CT chest/abdomen/pelvis plus sex-specific studies such as transvaginal US/mammography for women and scrotal US for men. (hahn2024canadianconsensusguidelines pages 10-11, dutra2024brazilianconsensusrecommendations pages 5-7) | Consensus guideline | Hahn et al. 2024, Canadian Journal of Neurological Sciences; Dutra et al. 2024, Arquivos de Neuro-Psiquiatria | https://doi.org/10.1017/cjn.2024.16 ; https://doi.org/10.1055/s-0044-1788586 |
| Follow-up tumor surveillance | If initial screening is negative, Canadian guidance recommends follow-up screening in patients with intermediate- or high-risk antibodies; for such antibodies, repeat screening every 3–6 months for at least 2 years is recommended. Antibody-negative patients with high-risk phenotypes (e.g., limbic encephalitis, refractory/relapsing disease, malignancy risk factors) may also merit repeat screening. (hahn2024canadianconsensusguidelines pages 9-10, hahn2024canadianconsensusguidelines pages 10-11) | Consensus guideline | Hahn et al. 2024, Canadian Journal of Neurological Sciences | https://doi.org/10.1017/cjn.2024.16 |
| Malignancy-risk antibody categories | Canadian Table 4 classifies tumor risk: high-risk >70% (e.g., Hu/ANNA-1, CV2/CRMP5, Ma2/Ma, KLHL11, Yo/PCA-1), intermediate 30–70% (e.g., AMPAR, GABABR, mGluR5, NMDAR, CASPR2 in Morvan syndrome, GABAAR), and low-risk <30% (e.g., GFAP, GAD65, LGI1, DPPX, GlyR, MOG, AQP4, mGluR1). (hahn2024canadianconsensusguidelines pages 10-11) | Consensus guideline | Hahn et al. 2024, Canadian Journal of Neurological Sciences | https://doi.org/10.1017/cjn.2024.16 |
Table: This table summarizes evidence-based autoimmune encephalitis diagnostic criteria, common pitfalls, core testing workflow, and neoplasm screening recommendations from recent validation studies and 2024 consensus guidelines. It is useful as a compact reference for applying Graus/Cellucci criteria, interpreting antibody results cautiously, and structuring tumor search in suspected AE.
10.2 Diagnostic criteria performance and misdiagnosis pitfalls
In a real-world validation/mimic cohort (n=239), “possible AE” criteria had sensitivity 83% and specificity 27%, reflecting usefulness as an entry criterion but a high false-positive burden; “definite autoimmune limbic encephalitis” had specificity 98%, and “probable anti-NMDAR” had specificity 96%. (steenhoven2023mimicsofautoimmune pages 1-2)
Key pitfalls include: - False-positive serum antibodies (reported in 12% of the mimic/AE referral cohort). (steenhoven2023mimicsofautoimmune pages 1-2) - In mass-testing settings, PPV can be only modest: in the Netherlands nationwide antibody-testing cohort, serum intracellular-antigen antibody PPVs ranged 25%–80%, despite high sensitivity/specificity for most assays. (kerstens2024autoimmuneencephalitisand pages 1-2)
10.3 Imaging and electrophysiology (recent data)
Canadian consensus states FDG-PET can be more sensitive than MRI in AE (reported 87% vs 25–50% sensitivity) but warns that PET findings can be nonspecific and should not be used alone. (hahn2024canadianconsensusguidelines pages 6-7, hahn2024canadianconsensusguidelines pages 12-13)
10.4 Neoplasm screening (real-world implementation)
Canadian consensus recommends malignancy screening for all adult AE at diagnosis and describes a 3-step imaging strategy (CT body → sex-specific imaging → whole-body PET if needed), with follow-up screening focused on intermediate/high-risk antibodies. (hahn2024canadianconsensusguidelines pages 9-10, hahn2024canadianconsensusguidelines pages 10-11)
The neoplasm screening protocol figure from the Canadian guideline is shown here. (hahn2024canadianconsensusguidelines media d7e73b99)
11. Outcome / Prognosis
11.1 Functional outcomes
In the Chinese cohort (n=103), most patients achieved favorable function at last follow-up: 78 had good prognosis (mRS 0–2) vs 21 with poor prognosis (mRS 3–6); anti-GABABR encephalitis had worse outcomes than other AE subtypes. (huang2023clinicalcharacteristicsand pages 1-2)
11.2 Prognostic factors and biomarkers
In the same cohort, elevated neutrophil-to-lymphocyte ratio (NLR) and tumor presence were independent predictors of poor prognosis; a model combining these achieved AUC 0.847 (95% CI 0.733–0.961). (huang2023clinicalcharacteristicsand pages 1-2)
11.3 Relapse
Canadian consensus summarizes retrospective relapse rates in NMDAR/LGI1/CASPR2 encephalitis as 10–41% and notes relapses may be similar, milder, or with a different core syndrome. (hahn2024canadianconsensusguidelines pages 12-13)
12. Treatment
12.1 Acute immunotherapy tiers (consensus practice)
12.1.1 Timing
Brazilian consensus explicitly states: “Treatment should be started within the first 4 weeks of symptoms,” and that initiation “should not be delayed while waiting for” antibody results. (dutra2024brazilianconsensusrecommendations pages 1-2, dutra2024brazilianconsensusrecommendations pages 5-7)
12.1.2 First-line therapy
Brazilian consensus: first-line is methylprednisolone + IVIG or methylprednisolone + plasmapheresis, with typical IVIG and steroid dosing specified (e.g., IVIG 2 g/kg over 2–5 days; IV methylprednisolone 1,000 mg daily for 3–5 days in adults). (dutra2024brazilianconsensusrecommendations pages 8-10, dutra2024brazilianconsensusrecommendations pages 5-7)
Canadian consensus: severe AE should receive high-dose corticosteroids with IVIG or plasma exchange as initial therapy; mild/moderate cases may consider steroid monotherapy with specialist input. (hahn2024canadianconsensusguidelines pages 9-10)
The Canadian guideline treatment algorithm figure is shown here. (hahn2024canadianconsensusguidelines media aed80ffe)
12.1.3 Second-line therapy and escalation timing
Brazilian consensus defines “satisfactory clinical response” as improvement within 10–14 days; lack of partial improvement within 14 days should prompt second-line therapy. (dutra2024brazilianconsensusrecommendations pages 5-7)
Canadian consensus defines first-line failure as no improvement/worsening at 5–10 days in severe AE and 2–4 weeks in mild/moderate AE. (hahn2024canadianconsensusguidelines pages 8-9)
Second-line choices are antibody-contextual: - Cell-surface antibody AE or antibody-negative AE: rituximab favored for efficacy/safety. (hahn2024canadianconsensusguidelines pages 8-9) - High-risk paraneoplastic/intracellular antibodies: cyclophosphamide preferentially used. (hahn2024canadianconsensusguidelines pages 8-9)
12.1.4 Third-line / refractory options
Canadian and Brazilian guidance list tocilizumab and bortezomib as third-line/experimental options for cases refractory to second-line therapy, with specialist involvement recommended. (hahn2024canadianconsensusguidelines pages 9-10, dutra2024brazilianconsensusrecommendations pages 5-7)
12.2 Symptomatic treatments
Seizures in AE are commonly acute symptomatic; Brazilian consensus notes antiseizure medications may be weaned after the acute stage when stable. (dutra2024brazilianconsensusrecommendations pages 1-2)
12.3 MAXO term suggestions (examples)
- High-dose corticosteroid therapy — MAXO:0000601 (suggested)
- Intravenous immunoglobulin therapy — MAXO:0000747 (suggested)
- Therapeutic plasma exchange — MAXO:0000474 (suggested)
- Anti-CD20 monoclonal antibody therapy (rituximab) — MAXO:0000792 (suggested)
13. Prevention
Primary prevention is not established for most AE syndromes given heterogeneous triggers. Secondary/tertiary prevention is emphasized via: - Early diagnosis and early immunotherapy to reduce morbidity and long-term deficits. (dutra2024brazilianconsensusrecommendations pages 5-7, hahn2024canadianconsensusguidelines pages 9-10) - Tumor screening and treatment/removal when present (paraneoplastic prevention of ongoing antigenic drive). (hahn2024canadianconsensusguidelines pages 9-10)
14. Other Species / Natural Disease
Naturally occurring AE-like antibody-mediated encephalitis in non-human species was not addressed in the citable evidence retrieved in this run.
15. Model Organisms
Animal/model system evidence was not present in the citable evidence retrieved in this run.
Expert opinion & analysis (from authoritative sources)
- Diagnostic criteria are useful but require caution: real-world studies highlight that entry criteria (“possible AE”) are sensitive but not specific and are prone to mimics and misdiagnosis; high-specificity categories (probable/definite) support early immunotherapy decisions while awaiting antibody confirmation. (steenhoven2023mimicsofautoimmune pages 1-2)
- Testing pitfalls are central in modern practice: even when assays show high analytical specificity/sensitivity, PPV can be limited in rare diseases under broad testing, especially for serum intracellular antibodies, reinforcing the need for clinical correlation and confirmatory strategies. (kerstens2024autoimmuneencephalitisand pages 1-2, steenhoven2023mimicsofautoimmune pages 1-2)
- Treatment is time-sensitive and tiered: 2024 consensus statements converge on early immunotherapy (often combination first-line in severe disease) and time-bound escalation to second-line agents if not improving. (hahn2024canadianconsensusguidelines pages 8-9, dutra2024brazilianconsensusrecommendations pages 5-7)
Key images (evidence)
- Canadian guideline treatment algorithm: (hahn2024canadianconsensusguidelines media aed80ffe)
- Canadian guideline neoplasm screening protocol: (hahn2024canadianconsensusguidelines media d7e73b99)
Notes on evidence gaps in this run
- Standard ontology identifiers (MONDO/Orphanet/MeSH/ICD) were not retrievable from the cited evidence corpus.
- Protective factors, epigenetic mechanisms, and non-human models were not available in the retrieved citable sources.
References
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(steenhoven2023mimicsofautoimmune pages 1-2): Robin W. Van Steenhoven, Juna M. de Vries, Arlette L. Bruijstens, Manuela Paunovic, Mariska M. Nagtzaam, Suzanne C. Franken, Anna E. Bastiaansen, Marienke A. De Bruijn, Agnes Van Sonderen, Marco W.J. Schreurs, Mayke Gardeniers, Robert M. Verdijk, Rutger K. Balvers, Peter A. Sillevis Smitt, Rinze F. Neuteboom, and Maarten J. Titulaer. Mimics of autoimmune encephalitis. Neurology Neuroimmunology & Neuroinflammation, Nov 2023. URL: https://doi.org/10.1212/nxi.0000000000200148, doi:10.1212/nxi.0000000000200148. This article has 72 citations.
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(orozco2023autoimmuneencephalitiscriteria pages 1-3): Emma Orozco, Cristina Valencia-Sanchez, Jeffrey Britton, Divyanshu Dubey, Eoin P. Flanagan, A. Sebastian Lopez-Chiriboga, Nicholas Zalewski, Anastasia Zekeridou, Sean J. Pittock, and Andrew McKeon. Autoimmune encephalitis criteria in clinical practice. Neurology Clinical Practice, Jun 2023. URL: https://doi.org/10.1212/cpj.0000000000200151, doi:10.1212/cpj.0000000000200151. This article has 65 citations.
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(dutra2024brazilianconsensusrecommendations pages 4-5): Lívia Almeida Dutra, Pedro Victor de Castro Silva, João Henrique Fregadolli Ferreira, Alexandre Coelho Marques, Fabio Fieni Toso, Claudia Cristina Ferreira Vasconcelos, Doralina Guimarães Brum, Samira Luisa dos Apóstolos Pereira, Tarso Adoni, Leticia Januzi de Almeida Rocha, Leticia Pereira de Brito Sampaio, Nise Alessandra de Carvalho Sousa, Renata Barbosa Paolilo, Angélica Dal Pizzol, Bruna Klein da Costa, Caio César Diniz Disserol, Camila Pupe, Daniel Almeida do Valle, Denise Sisterolli Diniz, Fabiano Ferreira de Abrantes, Felipe da Rocha Schmidt, Fernando Cendes, Francisco Tomaz Meneses de Oliveira, Gabriela Joca Martins, Guilherme Diogo Silva, Katia Lin, Lécio Figueira Pinto, Mara Lúcia Schimtz Ferreira Santos, Marcus Vinícius Magno Gonçalves, Mariana Braatz Krueger, Michel Elyas Jung Haziot, Orlando Graziani Povoas Barsottini, Osvaldo José Moreira do Nascimento, Paulo Ribeiro Nóbrega, Priscilla Mara Proveti, Raphael Machado do Castilhos, Vanessa Daccach, and Felipe von Glehn. Brazilian consensus recommendations on the diagnosis and treatment of autoimmune encephalitis in the adult and pediatric populations. Arquivos de Neuro-Psiquiatria, 82:001-015, Jul 2024. URL: https://doi.org/10.1055/s-0044-1788586, doi:10.1055/s-0044-1788586. This article has 10 citations and is from a peer-reviewed journal.
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(dutra2024brazilianconsensusrecommendations pages 1-2): Lívia Almeida Dutra, Pedro Victor de Castro Silva, João Henrique Fregadolli Ferreira, Alexandre Coelho Marques, Fabio Fieni Toso, Claudia Cristina Ferreira Vasconcelos, Doralina Guimarães Brum, Samira Luisa dos Apóstolos Pereira, Tarso Adoni, Leticia Januzi de Almeida Rocha, Leticia Pereira de Brito Sampaio, Nise Alessandra de Carvalho Sousa, Renata Barbosa Paolilo, Angélica Dal Pizzol, Bruna Klein da Costa, Caio César Diniz Disserol, Camila Pupe, Daniel Almeida do Valle, Denise Sisterolli Diniz, Fabiano Ferreira de Abrantes, Felipe da Rocha Schmidt, Fernando Cendes, Francisco Tomaz Meneses de Oliveira, Gabriela Joca Martins, Guilherme Diogo Silva, Katia Lin, Lécio Figueira Pinto, Mara Lúcia Schimtz Ferreira Santos, Marcus Vinícius Magno Gonçalves, Mariana Braatz Krueger, Michel Elyas Jung Haziot, Orlando Graziani Povoas Barsottini, Osvaldo José Moreira do Nascimento, Paulo Ribeiro Nóbrega, Priscilla Mara Proveti, Raphael Machado do Castilhos, Vanessa Daccach, and Felipe von Glehn. Brazilian consensus recommendations on the diagnosis and treatment of autoimmune encephalitis in the adult and pediatric populations. Arquivos de Neuro-Psiquiatria, 82:001-015, Jul 2024. URL: https://doi.org/10.1055/s-0044-1788586, doi:10.1055/s-0044-1788586. This article has 10 citations and is from a peer-reviewed journal.
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(kerstens2024autoimmuneencephalitisand pages 1-2): Jeroen Kerstens, Marco W.J. Schreurs, Juna M. de Vries, Rinze F. Neuteboom, Juliette Brenner, Yvette S. Crijnen, Robin W. van Steenhoven, Marienke A.A.M. de Bruijn, Agnes van Sonderen, Marleen H. van Coevorden-Hameete, Anna E.M. Bastiaansen, Marie R. Vermeiren, Jan G.M.C. Damoiseaux, Henny G. Otten, Catharina J.M. Frijns, Bob Meek, Anouk C.M. Platteel, Alina van de Mortel, Cathérine C.S. Delnooz, Maarten A.C. Broeren, Marcel M. Verbeek, Erik I. Hoff, Sanae Boukhrissi, Suzanne C. Franken, Mariska M.P. Nagtzaam, Manuela Paunovic, Sharon Veenbergen, Peter A.E. Sillevis Smitt, and Maarten J. Titulaer. Autoimmune encephalitis and paraneoplastic neurologic syndromes. Neurology Neuroimmunology & Neuroinflammation, Nov 2024. URL: https://doi.org/10.1212/nxi.0000000000200318, doi:10.1212/nxi.0000000000200318. This article has 29 citations.
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(hahn2024canadianconsensusguidelines pages 8-9): Christopher Hahn, Adrian Budhram, Katayoun Alikhani, Nasser AlOhaly, Grayson Beecher, Gregg Blevins, John Brooks, Robert Carruthers, Jacynthe Comtois, Juthaporn Cowan, Paula de Robles, Julien Hébert, Ronak K. Kapadia, Sarah Lapointe, Aaron Mackie, Warren Mason, Brienne McLane, Alexandra Muccilli, Ilia Poliakov, Penelope Smyth, Kimberly G. Williams, Christopher Uy, and Jennifer A. McCombe. Canadian consensus guidelines for the diagnosis and treatment of autoimmune encephalitis in adults. Canadian Journal of Neurological Sciences / Journal Canadien des Sciences Neurologiques, 51:734-754, Feb 2024. URL: https://doi.org/10.1017/cjn.2024.16, doi:10.1017/cjn.2024.16. This article has 33 citations.
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(dutra2024brazilianconsensusrecommendations pages 5-7): Lívia Almeida Dutra, Pedro Victor de Castro Silva, João Henrique Fregadolli Ferreira, Alexandre Coelho Marques, Fabio Fieni Toso, Claudia Cristina Ferreira Vasconcelos, Doralina Guimarães Brum, Samira Luisa dos Apóstolos Pereira, Tarso Adoni, Leticia Januzi de Almeida Rocha, Leticia Pereira de Brito Sampaio, Nise Alessandra de Carvalho Sousa, Renata Barbosa Paolilo, Angélica Dal Pizzol, Bruna Klein da Costa, Caio César Diniz Disserol, Camila Pupe, Daniel Almeida do Valle, Denise Sisterolli Diniz, Fabiano Ferreira de Abrantes, Felipe da Rocha Schmidt, Fernando Cendes, Francisco Tomaz Meneses de Oliveira, Gabriela Joca Martins, Guilherme Diogo Silva, Katia Lin, Lécio Figueira Pinto, Mara Lúcia Schimtz Ferreira Santos, Marcus Vinícius Magno Gonçalves, Mariana Braatz Krueger, Michel Elyas Jung Haziot, Orlando Graziani Povoas Barsottini, Osvaldo José Moreira do Nascimento, Paulo Ribeiro Nóbrega, Priscilla Mara Proveti, Raphael Machado do Castilhos, Vanessa Daccach, and Felipe von Glehn. Brazilian consensus recommendations on the diagnosis and treatment of autoimmune encephalitis in the adult and pediatric populations. Arquivos de Neuro-Psiquiatria, 82:001-015, Jul 2024. URL: https://doi.org/10.1055/s-0044-1788586, doi:10.1055/s-0044-1788586. This article has 10 citations and is from a peer-reviewed journal.
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(hahn2024canadianconsensusguidelines pages 9-10): Christopher Hahn, Adrian Budhram, Katayoun Alikhani, Nasser AlOhaly, Grayson Beecher, Gregg Blevins, John Brooks, Robert Carruthers, Jacynthe Comtois, Juthaporn Cowan, Paula de Robles, Julien Hébert, Ronak K. Kapadia, Sarah Lapointe, Aaron Mackie, Warren Mason, Brienne McLane, Alexandra Muccilli, Ilia Poliakov, Penelope Smyth, Kimberly G. Williams, Christopher Uy, and Jennifer A. McCombe. Canadian consensus guidelines for the diagnosis and treatment of autoimmune encephalitis in adults. Canadian Journal of Neurological Sciences / Journal Canadien des Sciences Neurologiques, 51:734-754, Feb 2024. URL: https://doi.org/10.1017/cjn.2024.16, doi:10.1017/cjn.2024.16. This article has 33 citations.
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(hahn2024canadianconsensusguidelines pages 10-11): Christopher Hahn, Adrian Budhram, Katayoun Alikhani, Nasser AlOhaly, Grayson Beecher, Gregg Blevins, John Brooks, Robert Carruthers, Jacynthe Comtois, Juthaporn Cowan, Paula de Robles, Julien Hébert, Ronak K. Kapadia, Sarah Lapointe, Aaron Mackie, Warren Mason, Brienne McLane, Alexandra Muccilli, Ilia Poliakov, Penelope Smyth, Kimberly G. Williams, Christopher Uy, and Jennifer A. McCombe. Canadian consensus guidelines for the diagnosis and treatment of autoimmune encephalitis in adults. Canadian Journal of Neurological Sciences / Journal Canadien des Sciences Neurologiques, 51:734-754, Feb 2024. URL: https://doi.org/10.1017/cjn.2024.16, doi:10.1017/cjn.2024.16. This article has 33 citations.
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(dutra2024brazilianconsensusrecommendations pages 7-8): Lívia Almeida Dutra, Pedro Victor de Castro Silva, João Henrique Fregadolli Ferreira, Alexandre Coelho Marques, Fabio Fieni Toso, Claudia Cristina Ferreira Vasconcelos, Doralina Guimarães Brum, Samira Luisa dos Apóstolos Pereira, Tarso Adoni, Leticia Januzi de Almeida Rocha, Leticia Pereira de Brito Sampaio, Nise Alessandra de Carvalho Sousa, Renata Barbosa Paolilo, Angélica Dal Pizzol, Bruna Klein da Costa, Caio César Diniz Disserol, Camila Pupe, Daniel Almeida do Valle, Denise Sisterolli Diniz, Fabiano Ferreira de Abrantes, Felipe da Rocha Schmidt, Fernando Cendes, Francisco Tomaz Meneses de Oliveira, Gabriela Joca Martins, Guilherme Diogo Silva, Katia Lin, Lécio Figueira Pinto, Mara Lúcia Schimtz Ferreira Santos, Marcus Vinícius Magno Gonçalves, Mariana Braatz Krueger, Michel Elyas Jung Haziot, Orlando Graziani Povoas Barsottini, Osvaldo José Moreira do Nascimento, Paulo Ribeiro Nóbrega, Priscilla Mara Proveti, Raphael Machado do Castilhos, Vanessa Daccach, and Felipe von Glehn. Brazilian consensus recommendations on the diagnosis and treatment of autoimmune encephalitis in the adult and pediatric populations. Arquivos de Neuro-Psiquiatria, 82:001-015, Jul 2024. URL: https://doi.org/10.1055/s-0044-1788586, doi:10.1055/s-0044-1788586. This article has 10 citations and is from a peer-reviewed journal.
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(hahn2024canadianconsensusguidelines pages 2-3): Christopher Hahn, Adrian Budhram, Katayoun Alikhani, Nasser AlOhaly, Grayson Beecher, Gregg Blevins, John Brooks, Robert Carruthers, Jacynthe Comtois, Juthaporn Cowan, Paula de Robles, Julien Hébert, Ronak K. Kapadia, Sarah Lapointe, Aaron Mackie, Warren Mason, Brienne McLane, Alexandra Muccilli, Ilia Poliakov, Penelope Smyth, Kimberly G. Williams, Christopher Uy, and Jennifer A. McCombe. Canadian consensus guidelines for the diagnosis and treatment of autoimmune encephalitis in adults. Canadian Journal of Neurological Sciences / Journal Canadien des Sciences Neurologiques, 51:734-754, Feb 2024. URL: https://doi.org/10.1017/cjn.2024.16, doi:10.1017/cjn.2024.16. This article has 33 citations.
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(huang2023clinicalcharacteristicsand pages 1-2): Teng Huang, Fei Liu, Baojie Wang, Chunjuan Wang, Maolin Hao, and Shougang Guo. Clinical characteristics and prognosis in patients with neuronal surface antibody-mediated autoimmune encephalitis: a single-center cohort study in china. Frontiers in Immunology, Dec 2023. URL: https://doi.org/10.3389/fimmu.2023.1213532, doi:10.3389/fimmu.2023.1213532. This article has 17 citations and is from a peer-reviewed journal.
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(dutra2024brazilianconsensusrecommendations pages 8-10): Lívia Almeida Dutra, Pedro Victor de Castro Silva, João Henrique Fregadolli Ferreira, Alexandre Coelho Marques, Fabio Fieni Toso, Claudia Cristina Ferreira Vasconcelos, Doralina Guimarães Brum, Samira Luisa dos Apóstolos Pereira, Tarso Adoni, Leticia Januzi de Almeida Rocha, Leticia Pereira de Brito Sampaio, Nise Alessandra de Carvalho Sousa, Renata Barbosa Paolilo, Angélica Dal Pizzol, Bruna Klein da Costa, Caio César Diniz Disserol, Camila Pupe, Daniel Almeida do Valle, Denise Sisterolli Diniz, Fabiano Ferreira de Abrantes, Felipe da Rocha Schmidt, Fernando Cendes, Francisco Tomaz Meneses de Oliveira, Gabriela Joca Martins, Guilherme Diogo Silva, Katia Lin, Lécio Figueira Pinto, Mara Lúcia Schimtz Ferreira Santos, Marcus Vinícius Magno Gonçalves, Mariana Braatz Krueger, Michel Elyas Jung Haziot, Orlando Graziani Povoas Barsottini, Osvaldo José Moreira do Nascimento, Paulo Ribeiro Nóbrega, Priscilla Mara Proveti, Raphael Machado do Castilhos, Vanessa Daccach, and Felipe von Glehn. Brazilian consensus recommendations on the diagnosis and treatment of autoimmune encephalitis in the adult and pediatric populations. Arquivos de Neuro-Psiquiatria, 82:001-015, Jul 2024. URL: https://doi.org/10.1055/s-0044-1788586, doi:10.1055/s-0044-1788586. This article has 10 citations and is from a peer-reviewed journal.
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(hahn2024canadianconsensusguidelines pages 6-7): Christopher Hahn, Adrian Budhram, Katayoun Alikhani, Nasser AlOhaly, Grayson Beecher, Gregg Blevins, John Brooks, Robert Carruthers, Jacynthe Comtois, Juthaporn Cowan, Paula de Robles, Julien Hébert, Ronak K. Kapadia, Sarah Lapointe, Aaron Mackie, Warren Mason, Brienne McLane, Alexandra Muccilli, Ilia Poliakov, Penelope Smyth, Kimberly G. Williams, Christopher Uy, and Jennifer A. McCombe. Canadian consensus guidelines for the diagnosis and treatment of autoimmune encephalitis in adults. Canadian Journal of Neurological Sciences / Journal Canadien des Sciences Neurologiques, 51:734-754, Feb 2024. URL: https://doi.org/10.1017/cjn.2024.16, doi:10.1017/cjn.2024.16. This article has 33 citations.
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(hahn2024canadianconsensusguidelines pages 12-13): Christopher Hahn, Adrian Budhram, Katayoun Alikhani, Nasser AlOhaly, Grayson Beecher, Gregg Blevins, John Brooks, Robert Carruthers, Jacynthe Comtois, Juthaporn Cowan, Paula de Robles, Julien Hébert, Ronak K. Kapadia, Sarah Lapointe, Aaron Mackie, Warren Mason, Brienne McLane, Alexandra Muccilli, Ilia Poliakov, Penelope Smyth, Kimberly G. Williams, Christopher Uy, and Jennifer A. McCombe. Canadian consensus guidelines for the diagnosis and treatment of autoimmune encephalitis in adults. Canadian Journal of Neurological Sciences / Journal Canadien des Sciences Neurologiques, 51:734-754, Feb 2024. URL: https://doi.org/10.1017/cjn.2024.16, doi:10.1017/cjn.2024.16. This article has 33 citations.
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(hahn2024canadianconsensusguidelines media d7e73b99): Christopher Hahn, Adrian Budhram, Katayoun Alikhani, Nasser AlOhaly, Grayson Beecher, Gregg Blevins, John Brooks, Robert Carruthers, Jacynthe Comtois, Juthaporn Cowan, Paula de Robles, Julien Hébert, Ronak K. Kapadia, Sarah Lapointe, Aaron Mackie, Warren Mason, Brienne McLane, Alexandra Muccilli, Ilia Poliakov, Penelope Smyth, Kimberly G. Williams, Christopher Uy, and Jennifer A. McCombe. Canadian consensus guidelines for the diagnosis and treatment of autoimmune encephalitis in adults. Canadian Journal of Neurological Sciences / Journal Canadien des Sciences Neurologiques, 51:734-754, Feb 2024. URL: https://doi.org/10.1017/cjn.2024.16, doi:10.1017/cjn.2024.16. This article has 33 citations.
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(hahn2024canadianconsensusguidelines media aed80ffe): Christopher Hahn, Adrian Budhram, Katayoun Alikhani, Nasser AlOhaly, Grayson Beecher, Gregg Blevins, John Brooks, Robert Carruthers, Jacynthe Comtois, Juthaporn Cowan, Paula de Robles, Julien Hébert, Ronak K. Kapadia, Sarah Lapointe, Aaron Mackie, Warren Mason, Brienne McLane, Alexandra Muccilli, Ilia Poliakov, Penelope Smyth, Kimberly G. Williams, Christopher Uy, and Jennifer A. McCombe. Canadian consensus guidelines for the diagnosis and treatment of autoimmune encephalitis in adults. Canadian Journal of Neurological Sciences / Journal Canadien des Sciences Neurologiques, 51:734-754, Feb 2024. URL: https://doi.org/10.1017/cjn.2024.16, doi:10.1017/cjn.2024.16. This article has 33 citations.