A 20-year-old man comes to the office for evaluation of abnormal behavior. Over the past 4 months, the patient has had several episodes of unresponsiveness, during which he would stare blankly while smacking his lips. He spontaneously becomes responsive after about 2 minutes and has no recollection of the event. The patient says these episodes are often preceded by an uneasy sensation in his upper abdomen and the pungent smell of something burning. He has had no falls or jerky movements of the extremities. The patient has no history of recent fever, headaches, head trauma, nausea, vomiting, or focal neurologic deficit. He had seizures in early childhood precipitated by high fevers but has had none since then and reports no other medical conditions. Cranial nerve examination reveals no abnormalities. Motor strength, sensation, and deep tendon reflexes are normal throughout. Neuroimaging is most likely to reveal an abnormality in which of the following locations in the brain?

Question

A 20-year-old man comes to the office for evaluation of abnormal behavior.  Over the past 4 months, the patient has had several episodes of unresponsiveness, during which he would stare blankly while smacking his lips.  He spontaneously becomes responsive after about 2 minutes and has no recollection of the event.  The patient says these episodes are often preceded by an uneasy sensation in his upper abdomen and the pungent smell of something burning.  He has had no falls or jerky movements of the extremities.  The patient has no history of recent fever, headaches, head trauma, nausea, vomiting, or focal neurologic deficit.  He had seizures in early childhood precipitated by high fevers but has had none since then and reports no other medical conditions.  Cranial nerve examination reveals no abnormalities.  Motor strength, sensation, and deep tendon reflexes are normal throughout.  Neuroimaging is most likely to reveal an abnormality in which of the following locations in the brain?

Quizplus · Accepted Answer

Focal seizures originate in a single hemisphere (vs generalized seizures, which originate throughout the cerebral cortex) and are subcategorized as: Focal aware seizures (previously simple partial seizure): Patients are aware and interactive but have symptoms corresponding to the involved area of the brain (eg, face or limb twitching/jerking - frontal lobe motor cortex, auditory/olfactory hallucinations - temporal lobe, visual phenomena - occipital lobe). Focal impaired awareness seizures (previously complex partial seizures): Patients appear awake but do not interact appropriately (eg, blank stare) and frequently engage in repetitive, stereotyped automatisms (eg, lip smacking, hand wringing, repeating words). Focal seizures with impaired awareness are the typical manifestation of temporal lobe epilepsy, the most common type of recurrent seizure disorder. Seizures are often preceded by a distinctive aura (eg, uneasy epigastric sensation, unpleasant olfactory hallucinations) that localizes the origin of the epileptiform discharges to the mesial temporal lobe (eg, hippocampus, amygdala, parahippocampal gyrus). The disorder is usually due to underlying hippocampal sclerosis (ie, mesial temporal sclerosis), which is associated with childhood febrile seizures. (Choice A) The cerebellar vermis is responsible for vestibular function, balance, and coordination. Although patients with temporal lobe epilepsy for several years can exhibit cerebellar atrophy with accompanying ataxia, this patient has only had seizure activity for 4 months and has no evidence of ataxia on examination. (Choice C) The nondominant parietal lobe plays a role in nonverbal spatial mapping and orientation. A seizure affecting this part of the brain can cause distortions in a patient's sense of position (eg, a feeling of floating, changes in posture) or visual interpretation (eg, the size of objects). (Choice D) The occipital pole contains the primary visual cortex. Seizures that originate in the occipital pole characteristically have visual auras (eg, flashing lights, visual distortions, complex hallucinations). (Choice E) The premotor frontal cortex is responsible for the selection of movements in response to internal and external cues. A seizure affecting this part of the brain can result in abnormal posturing or repetitive movements, but abdominal and olfactory auras would not be seen. Educational objective: Recurrent focal impaired awareness seizures that are preceded by a distinctive aura (eg, uneasy epigastric sensation, olfactory hallucinations) are characteristic of mesial temporal lobe epilepsy. The most common etiology is hippocampal sclerosis (mesial temporal sclerosis), which is associated with childhood febrile seizures.

A 20-Year-Old Man Comes to the Office for Evaluation of Abnormal