From the Guidelines
Rasmussen's encephalitis, also known as Chronic Focal Encephalitis, is a rare and severe inflammatory neurological disorder that primarily affects one half of the brain, often presenting with seizures and progressive neurological deterioration 1.
Key Characteristics
- It is a rare condition, often misdiagnosed as other forms of encephalitis, such as HSV encephalitis 1
- The clinical picture can vary with disease severity and aetiological agent, making diagnosis challenging 1
- Seizures are a common presenting feature, and can be subtle, including subtle motor status 1
Diagnosis and Treatment
- Diagnosis is often based on a combination of clinical presentation, EEG, MRI scans, and histological examination of brain tissue 1
- Treatment typically involves a combination of immunomodulatory and antiepileptic medications, although the exact treatment plan may vary depending on the individual case 1
- Close monitoring of the patient's condition is crucial to adjust the treatment plan accordingly 1
Important Considerations
- Rasmussen's encephalitis is often associated with significant morbidity and mortality, and prompt diagnosis and treatment are essential to improve outcomes 1
- The condition can be difficult to distinguish from other forms of encephalitis, and a high index of suspicion is necessary to make the diagnosis 1
From the Research
Definition and Characteristics
- Rasmussen's encephalitis (RE) is a rare disease of unknown etiology that causes severe chronic unihemispheric inflammatory disease of the central nervous system, mainly in children 2.
- It is characterized by frequent and severe seizures, progressive neurological dysfunction, and unilateral brain atrophy 3.
- The main clinical features of RE include frequent seizures with drug-resistant, unilateral hemispheric atrophy, and progressive neurological deficits 4.
Pathogenesis
- The pathogenesis of RE is probably associated with single nucleotide polymorphisms on immune-related genes, which is driven by affecting inherent antiretroviral innate immunity 4.
- The importance of cytotoxic CD8+ T lymphocytes and activated microglial and the role of their immune mechanism in RE development are gradually emerging with the deep study 4.
- Neuropathological and immunological studies support the notion that Rasmussen's encephalitis is probably driven by a T-cell response to one or more antigenic epitopes, with potential additional contribution by autoantibodies 5.
Diagnosis and Treatment
- The diagnosis of RE is based on clinical (intractable epilepsy and neurological deterioration), electrophysiological (unilateral EEG slowing), and MRI (hemiatrophy) criteria 6.
- Antiseizure medications are generally unable to stop seizures, and the most effective procedure is hemispherotomy (surgical disconnection of one cerebral hemisphere), but this is associated with permanent motor and neurological deficits 6.
- Immunotherapy could partially slow down the progression of RE according to the histopathology and clinical presentation, which aimed at the initial damage to the brain by T cells and microglia in the early stage 4.
- Cerebral hemispherectomy remains the only cure for seizures, but there are inevitable functional compromises, and the optimum time for surgery is not yet well understood 5.