A 40-year-old man comes to the emergency department 30 minutes after experiencing a seizure. Over the past 3 months, the patient has had several episodes of brief twitching of the right hand, but today the abnormal movement gradually progressed to involve the entire right upper extremity, followed by shaking of the whole body for about a minute. He also lost consciousness and urinated involuntarily during the event. The patient feels groggy and has a mild headache. He has no other medical conditions but reports several concussions from playing football in college. Vital signs are within normal limits. Physical examination shows mild weakness of right hand grip but is otherwise normal. This patient's seizure presentation is most suggestive of which of the following etiologic processes?

Question

A 40-year-old man comes to the emergency department 30 minutes after experiencing a seizure.  Over the past 3 months, the patient has had several episodes of brief twitching of the right hand, but today the abnormal movement gradually progressed to involve the entire right upper extremity, followed by shaking of the whole body for about a minute.  He also lost consciousness and urinated involuntarily during the event.  The patient feels groggy and has a mild headache.  He has no other medical conditions but reports several concussions from playing football in college.  Vital signs are within normal limits.  Physical examination shows mild weakness of right hand grip but is otherwise normal.  This patient's seizure presentation is most suggestive of which of the following etiologic processes?

Quizplus · Accepted Answer

This patient with prior episodes of isolated hand twitching (characteristic of focal aware seizures) now experienced a focal-onset seizure that progressed to a bilateral tonic-clonic seizure (previously secondarily generalized seizure) with loss of consciousness and involuntary urination. Focal-onset seizures are caused by a regional area of hypersynchronized excitatory neural activity that originates in a single hemisphere (in contrast to generalized-onset seizures, which originate globally throughout the cerebral cortex) and are subcategorized by level of consciousness during the event: Focal aware seizures (formerly simple partial seizures): Patients remain aware and interactive. Symptoms correspond to the area of brain involvement; for example, twitching/jerking of the face or limb (motor cortex of frontal lobe), paresthesia (somatosensory cortex of parietal lobe), auditory/olfactory hallucinations (temporal lobe), or visual hallucinations (occipital lobe). Focal impaired awareness seizures (formerly complex partial seizures): Patients appear awake but do not interact appropriately with their environment (eg, blank stare). They frequently engage in repetitive, stereotyped actions known as automatisms (eg, lip smacking, hand wringing, repeating words). The most common underlying cause of focal-onset seizures is a focal structural brain abnormality (eg, cerebral neoplasms, stroke, hippocampal sclerosis). These seizures can remain localized or generalize to involve both hemispheres (focal to bilateral tonic-clonic) and are frequently associated with postictal focal neurologic deficits (eg, this patient's right hand weakness). (Choices A, D, and E) Diffuse cerebral hypoperfusion, neuroexcitatory substance use, and neuronal metabolic disturbances (except hyperglycemia, which can cause focal seizures) all affect the brain globally and therefore are more likely to present as a generalized seizure rather than a focal seizure. Generalized seizures are characterized by widespread and rapid propagation of neuronal hyperexcitability without the initial localizing symptoms of a focal abnormality. (Choice C) Genetic epilepsy syndromes can have either focal seizures (eg, benign focal epilepsy of infancy) or generalized seizures (eg, Lennox-Gastaut syndrome), but these conditions typically present in childhood and persist into adulthood. Educational objective: Focal-onset seizures most commonly occur due to a focal structural abnormality (eg, stroke, neoplasm) that causes a region of hyperexcitable neuronal activity in one cerebral hemisphere. These seizures begin with localized symptomatology (eg, muscle twitching, paresthesia) and are classified according to level of consciousness (eg, aware, impaired awareness). They can progress to bilateral tonic-clonic seizures if the excitatory neuronal activity spreads to involve both cerebral hemispheres.

A 40-Year-Old Man Comes to the Emergency Department 30 Minutes