| Framework/source | Intended diagnosis level | Criteria/workup elements | Notes/thresholds | Source URL + publication month/year |
|---|---|---|---|---|
| Graus et al. 2016, *A clinical approach to diagnosis of autoimmune encephalitis* | **Definite autoimmune limbic encephalitis** | 1) **Subacute onset** of working memory deficits, seizures, or psychiatric symptoms suggesting limbic system involvement; 2) **Bilateral** brain abnormalities on **T2-weighted FLAIR MRI** highly restricted to the **medial temporal lobes**; 3) At least one of: **CSF pleocytosis** or **EEG** with epileptic/slow-wave activity involving temporal lobes; 4) **Reasonable exclusion of alternative causes** (pqac-00000001, pqac-00000002) | Symptom onset should be **<3 months**; CSF pleocytosis threshold **>5 cells/mm³**; **18F-FDG-PET can substitute for criterion 2** if MRI unavailable/negative in some cases; if one of first 3 criteria is missing, diagnosis of definite LE requires detection of antibodies against **cell-surface, synaptic, or onconeural proteins** (pqac-00000001, pqac-00000006) | https://doi.org/10.1016/S1474-4422(15)00401-9 — **Apr 2016** (pqac-00000001, pqac-00000002) |
| Graus et al. 2016, syndrome-based AE approach | **Possible autoimmune encephalitis** / early diagnostic framework | Use **clinical syndrome + conventional tests** rather than waiting for antibody confirmation: neurologic assessment, **MRI**, **CSF**, **EEG**, differential diagnosis, and staged evidence levels (possible/probable/definite) (pqac-00000002) | Designed to avoid over-reliance on antibody tests and treatment response; supports **early immunotherapy once mimics are excluded** because delayed treatment worsens outcomes (pqac-00000002) | https://doi.org/10.1016/S1474-4422(15)00401-9 — **Apr 2016** (pqac-00000002) |
| Canadian Consensus Guidelines 2024 | **Adult AE diagnostic workup in acute care** | Core workup includes **MRI brain**, **EEG**, **CSF**, neural antibody testing, repeat/follow-up MRI if initial imaging is unrevealing, and consideration of **FDG-PET** and malignancy screening where appropriate (pqac-00000005, pqac-00000009) | **FDG-PET** reported as more sensitive than MRI (**87% vs 25–50%**) but **should not be used alone for diagnosis**; **whole-body FDG-PET** is useful for **occult malignancy**, especially with intermediate-/high-risk antibodies; EEG contributes to definite limbic AIE criteria (pqac-00000009) | https://doi.org/10.1017/cjn.2024.16 — **Feb 2024** (pqac-00000005, pqac-00000009) |
| Canadian Consensus Guidelines 2024 | **Ancillary test interpretation** | **EEG** abnormalities support diagnosis; specific recognition of **extreme delta brush** in anti-NMDAR encephalitis; imaging and antibody results should be interpreted in clinical context (pqac-00000009) | **Extreme delta brush** occurs in **up to 30%** of anti-NMDAR encephalitis cases; clinicians should contact testing laboratories for **unexpected antibody results** and consider confirmatory testing ("TIIF/IHC") for broad neural antibody panels (pqac-00000009) | https://doi.org/10.1017/cjn.2024.16 — **Feb 2024** (pqac-00000009) |
| Brazilian Consensus Recommendations 2024 | **Possible or definite AE diagnostic workup** | Initial investigations should include **brain MRI**, **EEG**, **CSF analysis**, **oligoclonal bands**, **IgG index**, and **CSF PCR for herpesviruses**; collect **paired serum and CSF** for antineuronal antibody testing **before treatment** when feasible (pqac-00000012) | MRI findings suggestive of AIE include **medial temporal T2/FLAIR hyperintensities** and multifocal inflammatory/demyelinating changes; herpes simplex and other herpesvirus encephalitides should be excluded with CSF PCR (pqac-00000012) | https://doi.org/10.1055/s-0044-1788586 — **Jul 2024** (pqac-00000012) |
| Brazilian Consensus Recommendations 2024 | **Antibody-confirmed AE / comprehensive laboratory workup** | Test **serum and CSF** using both **tissue-based assay (TBA)** and **cell-based assay (CBA)**; **CBA** specifically recommended for **anti-MOG** and **anti-glycine receptor** antibodies; children should also be screened for **anti-MOG** (pqac-00000010, pqac-00000012, pqac-00000013) | Combined **TBA + CBA** improves sensitivity/specificity; **TBA (rat-brain immunohistochemistry)** may detect noncommercial/novel antibodies; the panel **recommended against anti-VGKC testing**; low-titer serum-only antibodies and low-titer anti-CASPR2 require cautious interpretation (pqac-00000012, pqac-00000013) | https://doi.org/10.1055/s-0044-1788586 — **Jul 2024** (pqac-00000010, pqac-00000012, pqac-00000013) |
| Brazilian Consensus Recommendations 2024 | **Cancer/paraneoplastic workup** | Perform **neoplasm screening at presentation** and repeat surveillance for antibodies linked to cancer; use **contrast-enhanced CT chest/abdomen/pelvis** or MRI if CT contraindicated; consider **whole-body FDG-PET** if CT is negative (pqac-00000012, pqac-00000013) | Screening at presentation had **100% panel agreement**; CT chest/abdomen/pelvis **92% agreement**; whole-body FDG-PET after negative CT **84% agreement**; repeat cancer screening **annually for 4 years** for tumor-associated antibodies (pqac-00000012, pqac-00000013) | https://doi.org/10.1055/s-0044-1788586 — **Jul 2024** (pqac-00000012, pqac-00000013) |
| Practical cross-framework synthesis | **Real-world diagnostic implementation for autoimmune limbic encephalitis** | Suspected limbic encephalitis should be approached with rapid **syndrome recognition**, **MRI/EEG/CSF**, paired **serum+CSF antibody testing**, selective **FDG-PET** when MRI is negative or malignancy is suspected, and prompt exclusion of infectious mimics (pqac-00000001, pqac-00000009, pqac-00000012) | Key thresholds/features: **subacute <3 months**, **CSF >5 cells/mm³**, **bilateral medial temporal FLAIR lesions**, temporal **EEG slow waves/epileptiform activity**, **extreme delta brush** mainly in anti-NMDAR, and annual tumor surveillance for high-risk antibodies (pqac-00000001, pqac-00000009, pqac-00000013) | Graus 2016: https://doi.org/10.1016/S1474-4422(15)00401-9 (**Apr 2016**); Canadian 2024: https://doi.org/10.1017/cjn.2024.16 (**Feb 2024**); Brazilian 2024: https://doi.org/10.1055/s-0044-1788586 (**Jul 2024**) (pqac-00000001, pqac-00000009, pqac-00000013) |


*Table: This table condenses the core diagnostic criteria for definite autoimmune limbic encephalitis from Graus 2016 and aligns them with 2024 Canadian and Brazilian consensus diagnostic workup recommendations. It is useful for quickly comparing formal criteria, practical testing steps, thresholds, and malignancy-screening guidance.*