Occipital intermittent rhythmic delta activity only following eye closure in atypical CNS Salmonellosis

Abstract

Objective A statement recently published on the base of a large retrospective analysis, report that the occipital intermittent rhythmic delta activity (OIRDA) “is associated with epilepsy but not acute encephalopathy” [Gullapalli and Fountain. J Clin Neurophysiol 2003;20:35–41]. Our aim is to report, the exception from a child with an intermittent fever, in which the finding of an occipital intermittent rhythmic delta activity (OIRDA) following the eye closure in the EEG recording was the first clinical sign addressing to a CNS involvement. Methods To review the record from a five-year-old girl with a normal basal electroencephalogram and OIRDA that only appeared following eye closure. Results We found OIRDA associated with atypical CNS Salmonellosis. Brain MRI and CSF examination confirmed an acute encephalopathy, which was due to Salmonella infection.The only symptoms of the infection were episodes of nightly fever that had lasted for four weeks, sometimes associated with headache and vomiting. Both OIRDA only induced by eye closing and other symptoms disappeared after starting antimicrobial therapy. Conclusions OIRDA only following eye closure is a non-specific abnormality and the present findings, based on a single case, merely indicate that intracranial infection is among the possible causes. Significance The new clinical association is certainly worth recording, as the presence of this electrophysiological sign may provoke clinicians to then delve further into a diagnostic work up.