An 7-year-old child from rural India presents with a 6-month history of intractable focal motor seizures and continuous jerking of the left arm lasting hours at a time (epilepsia partialis continua). MRI shows progressive right hemispheric atrophy with T2/FLAIR hyperintensity. The EEG pattern marked **A** in the diagram — focal polymorphic delta slowing and multifocal epileptiform discharges over one hemisphere — is characteristic of which condition?
A. Rasmussen encephalitis with right hemispheric involvement
B. Focal cortical dysplasia with secondary generalization
C. Tuberous sclerosis complex with multifocal seizure foci
D. Autoimmune limbic encephalitis with temporal lobe involvement
Explanation
Why Rasmussen encephalitis with right hemispheric involvement is right
The clinical triad of intractable focal motor seizures, epilepsia partialis continua (EPC), and progressive unihemispheric atrophy in a child is pathognomonic for Rasmussen encephalitis (RE). The EEG pattern marked A — focal polymorphic delta slowing with loss of normal background rhythms and multifocal interictal epileptiform discharges confined to one hemisphere — is the characteristic asymmetric EEG hallmark of RE. This pattern reflects the chronic progressive unihemispheric inflammatory process (T-cell mediated autoimmunity of unknown etiology) with neuronal loss, microglial nodules, and gliosis. The combination of clinical presentation (EPC, hemiparesis, progressive hemispheric atrophy on MRI) with this specific EEG pattern is diagnostic of RE according to the European Consensus Statement (Bien et al., Brain 2005).
Why each distractor is wrong
Tuberous sclerosis complex with multifocal seizure foci: TSC causes multifocal seizures from multiple cortical tubers, but the EEG shows multifocal discharges from MULTIPLE independent foci across both hemispheres, not the characteristic unihemispheric focal polymorphic delta slowing. TSC also lacks the progressive unihemispheric atrophy and EPC that define RE.
Focal cortical dysplasia with secondary generalization: FCD presents with seizures from a single localized lesion, not the multifocal interictal discharges from variable foci within one hemisphere seen in RE. FCD does not produce the progressive hemispheric atrophy, EPC, or hemiparesis characteristic of RE's chronic inflammatory course.
Autoimmune limbic encephalitis with temporal lobe involvement: Limbic encephalitis shows EEG abnormalities predominantly in the temporal lobes (often bilateral or asymmetric temporal), not the broad unihemispheric polymorphic delta slowing. It does not cause EPC or the progressive hemispheric atrophy seen in RE, and CSF typically shows higher lymphocytic pleocytosis.
High-YieldNEET PG
Rasmussen encephalitis = unihemispheric polymorphic delta slowing + multifocal interictal spikes + EPC + progressive hemiparesis + hemispheric atrophy in a child = functional hemispherectomy for seizure freedom.
European Consensus Statement on Rasmussen Encephalitis, Bien et al., Brain 2005
Practice similar questions
Sign up free to access AI-powered MCQ practice with detailed explanations and adaptive learning.
