How do convulsive and nonconvulsive status epilepticus differ, and how are they diagnosed?

• A. Diagnosis relies on MRI findings only.
• B. Nonconvulsive SE shows continuous jerking; convulsive shows no movements.
• C. Convulsive SE shows ongoing motor convulsions; nonconvulsive SE shows altered mental status with minimal movements; EEG confirms.
• D. Both have obvious convulsions; EEG not needed.

Answer: (C)

The key idea is how the two forms present differently and how we confirm them clinically. Convulsive status epilepticus is identified by ongoing motor convulsions that persist (or occur in rapid succession with little to no recovery between them), often with impaired consciousness. Nonconvulsive status epilepticus, on the other hand, presents with altered mental status—confusion, reduced responsiveness—without prominent motor jerking or convulsions. Because there may be little to no observable movement in nonconvulsive SE, EEG becomes essential to confirm ongoing seizure activity.

In practice, this means diagnosing convulsive SE can often be based on the visible, continuous motor activity plus clinical signs. For nonconvulsive SE, EEG shows continuous epileptiform discharges or patterns consistent with seizures even when there’s minimal or no motor activity, which is why EEG confirmation is required. Imaging like MRI can help identify underlying causes but cannot diagnose SE on its own.

So the statement that convulsive SE shows ongoing motor convulsions and nonconvulsive SE shows altered mental status with minimal movements, with EEG confirming, best captures both the clinical distinction and the diagnostic approach.