Rationale:
Acute necrotizing encephalopathy (ANE) is a rare condition characterized by hyperacute progressive encephalopathy preceded by viral illness and is associated with high mortality. Brain MRI findings include symmetric involvement of the thalami, cerebral and cerebellar white matter and brainstem. Proposed prognostic factors include the presence of sleep architecture and early steroid administration.
Method:
A single-institution case series review was performed on 7 patients with ANE. Diagnosis was made based on clinical presentation of acute progressive encephalopathy after viral illness and characteristic neuroimaging findings. Electroencephalogram (EEG) recordings were performed during the acute phase of their illness – within the first 48 hours of presentation. The modified Rankin Score (mRS) at the 6-month follow-up was assigned based on chart review.
Results:
We report on 7 patients with ANE who presented with acute encephalopathy and new onset seizures in the setting of an acute viral infection. Influenza A and B appeared to be the most common virus preceding ANE. EEG findings revealed varying degrees of low-amplitude slowing consistent with encephalopathy. Sleep spindles were present in 3 patients and were associated with lower mRS of 0-4 range and less functional disability, compared to the remainder of the patients who lacked normal sleep features and had higher mRS of 5-6, indicating severe disability. There were 2 patients with lateralizing epileptiform discharges in the absence of sleep features. Corticosteroids was initiated for the 6 surviving patients, but the one patient who did not receive therapy had a fatal outcome within 24 hrs. Mounting an aggressive therapeutic approach with intravenous immunoglobulin (IVIG) and tocilizumab in 2 patients led to improved outcomes with lower mRS (0 and 2) at the 6-month follow-up.
Conclusion:
Electroencephalographic sleep spindles represent intact thalamocortical connections, a necessity for arousal mechanisms. We observed that bilateral sleep spindles and early corticosteroid administration were associated with improved outcomes. Our series highlights the need for early ANE recognition and the benefit of EEG monitoring and early corticosteroid administration.
Funding:
:None
FIGURES
Figure 1