First seizure that did not recover — the viva

The key finding is the failure to recover consciousness, not the ECG. A patient who has not regained consciousness 20 to 30 minutes after the overt convulsive movements have stopped is in non-convulsive status epilepticus until proven otherwise — the seizure has continued electrically beneath the suppressed motor activity (subtle eyelid or facial twitching, nystagmoid eye movements, or simply a vacant unresponsive state). The bedside glucose is normal, so hypoglycaemia is excluded. The diagnosis is confirmed with an urgent EEG; in interim patient is treated empirically with a benzodiazepine and a second-line antiepileptic (the status ladder — lorazepam 4 mg IV, then levetiracetam 60 mg/kg, fosphenytoin 20 mg PE/kg, or valproate 40 mg/kg), the airway is protected, and the intensive-care and neurology teams are involved early. This bridges directly to the status epilepticus topic.

The long QT (520 ms) is the second trap and changes the differential. A markedly prolonged QT interval in a patient presenting with a "seizure" raises the possibility that the convulsion was a cardiac arrhythmia (torsades de pointes or ventricular tachycardia) with secondary cerebral hypoperfusion, not an epileptic seizure. The QT is prolonged by congenital long-QT syndrome, electrolyte disturbance (hypokalaemia, hypocalcaemia, hypomagnesaemia), and drugs (antiarrhythmics, antipsychotics, macrolides, fluoroquinolones, methadone, ondansetron). I check the potassium, calcium and magnesium and correct any abnormality, review the drug history for QT-prolonging agents, place the patient on continuous cardiac monitoring, and involve cardiology — a congenital or drug-induced long-QT syndrome presenting as a "first seizure" is easily missed and is a cause of sudden death. The lesson: perform an ECG on every patient with a suspected first seizure, and read it for the QT and the inherited channelopathies — a "seizure" with a long QT is a cardiac event until proven otherwise.^[1][2]

Management in parallel. Airway, breathing, circulation; IV access; continuous monitoring and a 12-lead ECG; treat as non-convulsive status empirically with the benzodiazepine ladder; arrange an urgent EEG; correct the electrolytes (potassium, calcium, magnesium) and stop any QT-prolonging drug; non-contrast CT to seek a structural cause; involve ICU, neurology and cardiology; admit to a monitored bed. The two diagnoses are not mutually exclusive — a primary cardiac arrhythmia can produce both a convulsion and a prolonged post-ictal state, and non-convulsive status can coexist with a cardiac cause.^[1]