Rasmussen's syndrome is a chronic encephalitis characterized by intractable focal epilepsy and progressive neurologic deterioration with lateralized brain destruction. In the early stages of the disease, the diagnosis can be difficult to make, and brain biopsy is often performed. We evaluated the patterns of cerebral glucose metabolism using 2-deoxy-2-[18F]-fluoro-D-glucose positron emission tomography (PET) in 15 children (age range 2.9-15.4 years, mean age 8.7 +/- 4.3 years) with Rasmussen's syndrome. In 6 patients evaluated early (< or = 1 year of onset of seizures), the PET scan showed areas of abnormal metabolism restricted mostly to the frontal and temporal regions, whereas the posterior cortex was preserved. Pathologic changes seen in the resected cortex were more pronounced in cortical areas of abnormal metabolism than in regions showing normal metabolism. In 9 patients evaluated later (>1 year after onset of seizures), the PET scan showed more diffuse hemispheric metabolic abnormalities including the occipital cortex, but the abnormalities remained highly lateralized. These patterns of glucose metabolic abnormalities in the early and late stages of the disease may facilitate the diagnosis of Rasmussen's syndrome and assist guidance of biopsy in early cases, when structural neuroimaging is still normal.

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Background: Children with Down syndrome frequently develop infantile spasms (IS); however, variable seizure outcome has been reported and not much is known about the clinical-electrophysiological factors affecting these outcomes. Therefore, we evaluated the clinical, neuroimaging and electrophysiological data in our DS with IS patient cohort, with a relatively long follow-up duration, to address some of these issues.  Methods: Disease characteristics, diagnostic tests and treatment outcomes from 15 children (F: M=7:8) with IS and DS (follow-up duration: 10-197 months) were analyzed. Results: The median age at onset of spasms was 7 (2-16) months. EEG showed hypsarrhythmia in 10 infants, and patterns of diffusely disorganised background with multifocal independent spike-wave activity in the remaining five. Brain MRI (n=8) revealed no abnormality in 3, microcephaly in 2, delayed myelination in one, and minimal volume changes in 2. PET scans (n=5) showed diffuse glucose hypometabolism in 3, focal hypo- or hypermetabolism in 1 and 2 patients, respectively, and increased or decreased basal-ganglia metabolism in one each. Spasms disappeared in 8 patients (53.3%; six off medication), with girls (5/7; 71%) responding slightly better than boys (3/8; 37.5%). Seven of the 8 responders had shown hypsarrhythmia. Cessation of spasms was achieved by ACTH alone (n=1) or in combination with vigabatrin or zonisamide (n=1, each), and monotherapy with zonisamide (n=2), topiramate (n=1), prednisone (n=1), and ketogenic diet (n=1). Two patients showed evolution into complex partial seizure or Lennox-Gastaut syndrome. One child had dystonic cerebral palsy associated with perinatal asphyxia. Conclusions: Spasms developed relatively later in patients with IS and DS, compared to cryptogenic IS patients, and showed modest response to treatment. Girls appear to have a better treatment response, with presence of hypsarrhythmia may signal a better treatment outcome.