When the Brain Seizes Silently: Recognizing NCSE

Nonconvulsive status epilepticus (NCSE) remains an underrecognized yet potentially reversible cause of altered sensorium, often presenting without the dramatic motor manifestations seen in convulsive seizures. Instead, patients may exhibit subtle features such as confusion, reduced responsiveness, or fluctuating levels of consciousness, frequently leading to misdiagnosis as metabolic or septic encephalopathy. This diagnostic overlap delays appropriate management and can adversely impact outcomes. In this case series, we describe seven patients who presented with unexplained altered or fluctuating sensorium, all of whom underwent electroencephalography (EEG), with diagnosis established using the Salzburg criteria. A striking clinical observation across cases was the presence of fluctuating sensorium, often creating initial uncertainty in diagnosis. Three predominant etiological patterns were identified: drug-induced NCSE, associated with agents such as cefepime, ceftazidime-avibactam, and tramadol; neurodegenerative disease-associated NCSE in patients with advanced dementia compounded by systemic illness; and metabolic NCSE in the context of chronic kidney disease and uremia. Electroencephalographic findings in all patients were consistent with NCSE, reinforcing the critical role of EEG in such ambiguous presentations. Patients with drug-induced NCSE demonstrated rapid and often dramatic improvement following withdrawal of the offending agent along with benzodiazepine therapy. Those with metabolic or systemic causes showed gradual recovery with combined antiepileptic treatment and correction of underlying derangements. Importantly, cases occurring in advanced dementia emphasized that baseline cognitive impairment should not preclude consideration of NCSE. Overall, early recognition through timely EEG evaluation led to meaningful clinical recovery in the majority of patients. This series highlights a crucial clinical message: not all confusion represents delirium; in some cases, the brain may be seizing silently, and recognizing this distinction can be life-altering. Publication History Article published online: 15 July 2026 © 2026. The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution License, permitting unrestricted use, distribution, and reproduction so long as the original work is properly cited. (https://creativecommons.org/licenses/by/4.0/) Thieme Medical and Scientific Publishers Private Limited A-13A, Graphix Tower 1, 6th floor, Sector 62, Noida 201309, Uttar Pradesh, India