A severity score for acute necrotizing encephalopathy

To develop a score that predicts the prognosis of children with acute necrotizing encephalopathy (ANE).

We retrospectively evaluated clinical variables and neurological outcome in two cohorts of children with ANE. Firstly, we developed the ANE severity score (ANE-SS) according to the clinical variables that correlated with neurological outcome in 41 children who were included in our previous reports in 2009. We then applied the scoring system to a second cohort of 32 patients who were newly collected in 2011. We investigated the correlation between the ANE-SS and neurological outcome in all 73 patients.

In the first cohort, brain stem lesions on MRI and state of shock at onset were significantly correlated with outcome. Age over 48 months, elevated CSF protein, and low platelet counts tended to be correlated with outcome. No types of treatment were correlated with outcome. The developed ANE-SS ranged from 0 to 9 points, with 3 points for existence of shock, 2 points for brain stem lesions, 2 points for age over 48 months, 1 point for platelet count below 100,000/μL, and 1 point for CSF protein above 60 mg/dl. Patients were classed as low risk (ANE-SS 0-1 points), medium risk (ANE-SS 2-4 points), or high risk (ANE-SS 5-9 points). ANE-SS was significantly correlated with outcome in the group of 73 patients.

ANE-SS can be used to predict outcome in patients with ANE. More effective treatments need to be developed for high-risk patients.