A systematic review of human status epilepticus in organophosphate poisoning: A real-world Stage 1 Plus model?

OBJECTIVE

To describe clinical phenotypes of organophosphate (OP)-related status epilepticus (SE) and to determine whether they could represent a real-world model of Stage 1 Plus SE, a stage possibly requiring early polytherapy from the start.

METHODS

We conducted a systematic review, searching PubMed and Scopus, complemented by Google Scholar and reference/citation screening to find human OP-related SE. Two reviewers independently screened records, extracted patient-level data, and appraised methodological quality following the PRISMA guidelines; disagreements were resolved by consensus. Studies including single epileptic seizures not meeting the International League Against Epilepsy (ILAE) criteria for SE were excluded.

RESULTS

Twelve cases met the inclusion criteria. A specific OP agent was identified in 7/12. Convulsive SE was reported in 8/12, while nonconvulsive and myoclonic SE were documented in a minority of cases; phenotypes could overlap. SE onset after exposure ranged from 2 to 36 h, with one case linked to chronic intoxication. Concomitant cholinergic features were reported in almost all cases (11/12). Seizure persistence after an initial benzodiazepine (BDZ) bolus was reported in all cases in which a first-line BDZ bolus was administered (7/7), prompting a sequential shift to antiseizure medications or anesthetic agents. Mechanical ventilation was required in 11/12; reported outcomes were favorable in 11/12.

SIGNIFICANCE: OP poisoning is a polymorphic entity including several cholinergic features and a broad SE spectrum, mainly convulsive SE. Ongoing seizures after early BDZ therapy suggest a possible direction toward a Stage 1 Plus phenotype, mirroring experimental evidence from preclinical animal models of OP-induced SE, possibly requiring early polytherapy.