De-novo non-convulsive status epilepticus in adult medical inpatients without known epilepsy: Analysis of mortality related factors and literature review.

Background Non-convulsive status epilepticus (NCSE) often goes unnoticed and is not easily detected in patients with a decreased level of consciousness, especially in older patients. In this sense, lack of data in this population is available. Aims The aim of the present study was to examine daily clinical practice and evaluate factors that may influence the prognosis of NCSE in non-epileptic medical inpatients. Methods We conducted a retrospective analysis including patients admitted by any cause in an Internal Medicine ward. All patients with compatible symptoms, exclusion of other causes, clinical suspicion or diagnosis of NCSE, and compatible EEG were included. Patients with a previous diagnosis of epilepsy were excluded. We also conducted a literature review by searching the PubMed/Medline database with the terms: Nonconvulsive Status OR Non-Convulsive Status. Results We included 54 patients, mortality rate reached 37% and the main factors linked to it were hypernatremia (OR = 16.2; 95% CI, 1.6-165.6; P = 0.019) and atrial fibrillation (OR = 6.7; 95% CI, 1.7-26; P = 0.006). There were no differences regarding mortality when comparing different diagnosis approach or treatment regimens. Our literature review showed that the main etiology of NCSE were neurovascular causes (17.8%), followed by antibiotic treatment (17.2%) and metabolic causes (17%). Global mortality in the literature review, excluding our series, reached 20%. Discussion We present the largest series of NCSE cases in medical patients, which showed that this entity is probably misdiagnosed in older patients and is linked to a high mortality. Conclusion The presence of atrial fibrillation and hypernatremia in patients diagnosed with NCSE should advise physicians of a high mortality risk.