Spindle coma in viral encephalitis.

Our patient's EEG evolved from the spindle coma pattern to normality in parallel with his clinical improvement. This clinical and EEG evolution has been described previously, and emphasizes the heterogeneity of the spindle pattern. The initial focal asymmetry implied focal cerebral abnormality, and was one of the clinical findings favoring HSV encephalitis in the absence of radiologic or pathologic support. The ability of partially-damaged cerebral cortex to express spindle activity is well-described with various cerebral lesions, as is the spindle coma pattern after intoxication. We are not aware of a previous report with HSV or other encephalitis, but an infectious etiology could be suspected in two patients of Hansotia et al. and is conceivable in the three comatose patients of Britt in whom no diagnosis could be established. In such cases, the pathophysiology of the spindle coma pattern is likely to involve an aberrant cortical response to normal reticular formation input and thalamic spindle pacemakers.