Answer
B: Generalized tonic-clonic seizure
Educational Objective
Diagnose generalized tonic-clonic seizures.
Critique
The most likely diagnosis is generalized tonic-clonic seizures (GTCS) (Option B). Although this patient's first two seizures were unwitnessed, the third event was characterized by an ictal cry, whole-body stiffening and falling down, rhythmic synchronous limb jerking, and subsequent postictal lethargy and stertorous respirations (slow, deep, snoring-like breathing due to upper airway obstruction); these features characterize a GTCS.
Generalized convulsive status epilepticus (Option A) is defined as a GTCS lasting more than 5 minutes, or two GTCS occurring within 5 minutes of each other without a return to baseline mental status. Convulsive status epilepticus is diagnosed clinically. This patient's clonic activity lasted 2 minutes with an 8-minute postictal period of impaired alertness and does not meet the definition of generalized convulsive status epilepticus. The postictal period of confusion and impaired alertness is not accounted for as part of seizure duration, although the layperson may inadvertently include it when interviewed about the event.
Myoclonic seizures (Option C) typically include jerking or shaking that lasts less than 1 second and may occur in clusters, resulting in a patient falling down. However, unlike this patient's seizure, there is no postictal lethargy or confusion after myoclonic seizures, and 2-minute duration of shaking would be unusually long for this seizure type.
Psychogenic nonepileptic spells/events (PNES) (Option D) may be considered in the differential diagnosis. PNES are most often related to posttraumatic stress disorder or conversion disorder. Patients often have a history of military combat, sexual or physical abuse, chronic medical illness, or prominent life stressors. PNES often mimic GTCS, but certain features help distinguish the diagnoses. PNES findings may include asynchronous flailing of variable limbs, side-to-side head shaking, pelvic thrusting, and prolonged duration (>5 minutes or even hours). Event capture during video EEG monitoring usually is required to confirm the diagnosis. GTCS are a better fit for this patient's symptoms.
Key Points
Generalized tonic-clonic seizures are characterized by an abrupt loss of consciousness and falling down, whole-body stiffening, rhythmic synchronous limb jerking, and subsequent postictal lethargy and stertorous respirations.
Generalized convulsive status epilepticus is defined as a generalized tonic-clonic seizure (GTCS) lasting more than 5 minutes, or two GTCSs occurring within 5 minutes of each other without a return to baseline mental status.
Bibliography
Pack AM. Epilepsy overview and revised classification of seizures and epilepsies. Continuum (Minneap Minn). 2019;25:306-21. [PMID: 30921011] doi: 10.1212/CON.0000000000000707
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