Differential Diagnosis for Rasmussen Encephalitis

To approach the differential diagnosis of Rasmussen Encephalitis, it's crucial to consider a range of conditions that can mimic its clinical and radiological presentation. The following categories help organize the differential diagnoses:

• Single Most Likely Diagnosis

  • Rasmussen Encephalitis itself is a rare but distinct condition characterized by chronic inflammation of one half of the brain, leading to seizures, hemiparesis, and eventual brain atrophy. The diagnosis is often based on clinical presentation, imaging findings, and histopathological examination.

• Other Likely Diagnoses

  • Epilepsy: Various forms of epilepsy, especially those with focal seizures, can mimic the seizure presentation of Rasmussen Encephalitis.
  • Stroke or Cerebrovascular Accidents: In children, strokes can present with sudden onset of hemiparesis and seizures, mimicking the initial presentation of Rasmussen Encephalitis.
  • Infectious Encephalitis: Other forms of encephalitis, such as those caused by herpes simplex virus, can present with seizures and focal neurological deficits.
  • Autoimmune Encephalitis: Conditions like NMDA receptor encephalitis can present with seizures, psychiatric symptoms, and decreased level of consciousness, overlapping with Rasmussen Encephalitis.

• Do Not Miss Diagnoses

  • Tuberculous Meningoencephalitis: Although less common in some regions, tuberculous meningitis can present with chronic inflammation, seizures, and focal neurological signs, making it a critical diagnosis not to miss due to its treatability.
  • Neurosyphilis: This condition can cause a wide range of neurological symptoms, including seizures and focal deficits, and is important to diagnose due to its treatability with antibiotics.
  • Brain Tumors: Certain brain tumors, especially low-grade gliomas, can present with seizures and gradual onset of focal neurological deficits, mimicking Rasmussen Encephalitis.

• Rare Diagnoses

  • Subacute Sclerosing Panencephalitis (SSPE): A rare condition caused by a persistent measles virus infection, leading to progressive neurological deterioration, including seizures.
  • Inflammatory Pseudotumors: These are rare, benign lesions that can mimic tumors or infectious processes on imaging and can cause seizures and focal neurological signs.
  • Mitochondrial Encephalomyopathies: Certain mitochondrial disorders can present with seizures, neurological regression, and may mimic some aspects of Rasmussen Encephalitis, especially in their chronic progression and multi-system involvement.

Each of these diagnoses requires careful consideration of the clinical presentation, imaging findings, and laboratory results to differentiate Rasmussen Encephalitis from its mimickers. A thorough diagnostic approach is essential to ensure appropriate management and treatment.