Convulsive status epilepticus (CSE) is the most common medical neurological emergency and continues to be associated with significant morbidity and mortality. The two primary determinants of outcome from CSE are underlying aetiology and seizure length. It is unclear whether a prolonged seizure worsens the prognosis of an underlying aetiology or whether a more severe underlying disorder is more likely to result in CSE. Acceptance of the former hypothesis means that seizures need rapid treatment as their early termination could potentially reduce brain damage and morbidity. Pathophysiology, epidemiology, and outcomes from CSE have recently been reviewed elsewhere.