Seizure Disorders USMLE Step 1 Practice Question
A 10-year-old boy presents with multiple daily 5-10 second staring spells accompanied by eyelid fluttering and lip smacking, without postictal confusion. Vital signs are normal; neurologic exam reveals no focal deficits. EEG shows characteristic 3-Hz spike-and-wave discharges. He is started on ethosuximide. Which of the following best describes the mechanism of action of this drug in suppressing abnormal thalamic oscillatory activity responsible for his seizures?
Answer choices
- APresynaptic P Q type voltage gated calcium channel antibodies
- BEthosuximide blocks thalamic T type calcium channelsCorrect answer
- CDiazepam followed by fosphenytoin for status epilepticus
- DCarbamazepine use for focal seizures
- EPostsynaptic nicotinic acetylcholine receptor antibodies
- FEthosuximide enhances GABA-A receptor chloride channel conductance in the thalamus
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