L’encéphalopathie associée au sepsis (EAS) est un dysfonctionnement cérébral diffus induit par la réponse systémique à une infection. Elle est bien décrite chez l’adulte, mais seulement 3 cas pédiatriques ont été publiés à notre connaissance. Nous rapportons le cas d’une enfant de 4ans adressée pour trouble de la vigilance dans un contexte de fièvre depuis 48h. L’hypothèse initiale avait été celle d’une encéphalite infectieuse mais le bilan étiologique était négatif. L’imagerie par résonance magnétique (IRM) avait révélé un œdème cérébral diffus et l’activité électrique de l’électroencéphalogramme (EEG) était globalement ralentie. L’origine du sepsis était une péritonite appendiculaire. En l’absence d’arguments pour un sepsis localisé au système nerveux central, le diagnostic final retenu était une EAS d’origine digestive. Cette entité se traduit par des troubles de conscience ou de vigilance, dans un contexte de sepsis avéré, sans signe de choc, après exclusion de toutes autres causes. Le plus souvent, les lésions constatées à l’imagerie et à l’EEG ne sont pas spécifiques et sont diffuses. Le traitement est la prise en charge étiologique du sepsis et symptomatique des signes neurologiques. L’évolution neurologique est lentement favorable. Les hypothèses physiopathologiques sont vasculaire, immunologique et embolique.

Sepsis-associated encephalopathy (SAE) is a diffuse brain dysfunction due to a systemic response to infection. We report the case of a 4-year-old girl with fever and vomiting for 48h, brought to the university hospital of Grenoble because of vigilance disorders, loss of verbal fluency, and a cerebellar syndrome. She had a biological infectious syndrome. Infectious encephalitis was suggested first, but the cerebral scan and the lumbar punction were normal. Magnetic resonance imaging (MRI) showed a diffuse brain edema with extended involvement of cortical and basal ganglia. The electroencephalogram was globally slow. The infectious syndrome was explained by perforated appendicitis with peritonitis, treated by surgery and antibiotic therapy. Other infectious explorations were negative. No metabolic or autoimmune diseases were found. Hence, our final diagnosis was sepsis-associated encephalopathy. After 1 year of follow-up care, her clinical exam, MRI, and EEG were normal. Sepsis-associated encephalopathy has been increasingly described in the adult population, but until today only three pediatric cases have been published. It is diagnosed when the patient has a severe infectious syndrome associated with neurologic symptoms, mostly vigilance or consciousness disorders, no signs of shock, and only when other potential reasons have been ruled out. The MRI shows non-specific diffuse lesions with vasogenic edema on the subcortical substance or on the basal ganglia and the thalami. The electroencephalogram is slowed down on the whole. The main differential diagnoses are infectious encephalitis, acute disseminated encephalomyelitis, and cerebral vasculitis. Posterior reversible encephalopathy syndrome is an MRI diagnosis that presents characteristics similar to SAE. In the future, it could be discovered that it is the same physiopathology. At the moment, we only treat the symptoms and the causative infection. Most of the time, patients have neurologic sequelae that affect their verbal fluency. It can persist from a few months up to 6yrs. Although quite slow, the neurologic progression is good. The mechanisms are studied and there are hopes for specific treatments. The main explanation seems to be immune with alterations of the blood–brain barrier. Cytokines and activated leukocytes may attack the cerebral substance.