RESUMEN
To develop a radiological score system to assess the severity of acute cerebellitis (AC) and to compare radiological severity score at the onset to cerebellar atrophy at follow-up. Clinical and MRI findings were recorded in 16 patients with AC. Radiological severity score considering topographic patterns, gray/white matter involvement, enhancement, tonsillar herniation or hydrocephalus development and clinical severity score taking into account clinical symptoms were assessed for each patient at the onset of the symptoms. Radiological and neurological sequelae were assessed at follow-up. At symptoms onset, clinical severity scale ranged from mild to severe and radiological severity score ranged from 3 to 7 with higher scores indicating a greater severity. The cut-off value of 5 for radiological score well segregated severe patients defined by clinical scale. A significant correlation between clinical scale and radiological severity scores (p < 0.001, r = 0.75) was found. At follow-up visit, all children developed cerebellar atrophy and 5 children showed neurologic sequelae while adults showed complete resolution without atrophy. Patients in whom atrophy was not observed had both older ages (p < 0.001) and a focal cerebellar involvement (p = 0.03). In patients with AC, radiological severity score may be a useful tool in evaluating clinical severity, but it is not capable to predict neither neurological sequelae nor evolution towards atrophy. Cerebellar atrophy, observed in children with AC, may be caused by several factors such as the age of patient and the extension of cerebellar involvement and it may be counterbalanced by neuronal restoring processes due to neuroplasticity.