Table 1.
Key features of unilateral cortical FLAMES/UCCE.
| Description of typical findings | Additional considerations | |
|---|---|---|
| MRI findings | Unilateral cortical T2-FLAIR hyperintensity is observed that can affect any lobe of the brain | The frontal and parietal lobes are most often involved, while occipital lobe involvement is least common |
| Corresponding hyperintensity on T2WI may be minimal or absent | Progression to bilateral cortical T2-FLAIR hyperintensity, as well as sulcal T2-FLAIR hyperintensity and/or overlying leptomeningeal enhancement, is reported in a subset of patients and supports a broader disease spectrum | |
| T2-FLAIR hyperintensity of adjacent juxtacortical white matter is characteristically absent at presentation, but may be seen with other cerebral manifestations of MOGAD including ADEM | T2-FLAIR hypointensity of adjacent juxtacortical white matter may be a supportive diagnostic feature | |
| Clinical symptoms | Seizures are most prominent clinical manifestation and are observed in large majority of patients | Seizures are focal-onset, most often present as motor seizures, ictal aphasia or somatosensory symptoms, and frequently progress to bilateral tonic-clonic seizures |
| Headache, fever, cortical symptoms referable to the lesion location, and other features of encephalopathy are also characteristic manifestations | Cortical symptoms referable to the lesion that are most commonly reported include aphasia and hemiparesis, although depending on the lesion location symptoms such as hemianopsia may occur | |
| Patients may have other attacks compatible with MOGAD prior to, concurrent with, or after unilateral cortical FLAMES/UCCE | Headache may have features suggestive of increased intracranial pressure | |
| Prior to diagnosing cerebral dysfunction in the absence of seizures, consider prolonged EEG to assess for the possibility that symptoms are ictal/post-ictal phenomena | ||
| CSF evaluation | Pleocytosis is observed that can be >100 WBC/μl but is usually < 1000 WBC/μl | Approximately 10% of patients have been reported to have normal CSF WBC count |
| Opening pressure may be elevated and should be measured at time of lumbar puncture | Less than 20% of patients have been reported to have CSF-specific oligoclonal bands | |
| A minority of patients have been reported to have co-existent anti-NMDAR, for which testing should be considered and detection is optimal in CSF | While testing for anti-MOG in serum is generally recommended, testing of stored CSF may be helpful if serum at time of attack is not available | |
| Treatment | Excellent response to corticosteroids is observed, typically with resolution of clinical symptoms and neuroimaging findings | Although treatment with corticosteroids is generally recommended, cases of resolution without immunotherapy have also been reported |
| Anti-seizure medications are commonly administered once seizures are identified but their necessity, particularly long-term, is uncertain | Optimal maintenance immunotherapy in patients with relapsing disease is unclear |
ADEM, acute disseminated encephalomyelitis; CSF, cerebrospinal fluid; DWI, diffusion-weighted imaging; EEG, electroencephalography; MOG, myelin oligodendrocyte glycoprotein; MOGAD, MOG antibody-associated disease; MRI, magnetic resonance imaging; NMDAR, N-methyl-D-aspartate receptor; T2-FLAIR, T2-fluid-attenuated inversion recovery; T2WI, T2-weighted imaging; WBC, white blood cell.