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CBZ TDM – Trough Level — SCE Neurology MCQ

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HardEpilepsy & Seizure DisordersCBZ TDM – Trough LevelSCE Neurology

A 68-year-old develops up to 80 daily one-second unilateral grimaces with ipsilateral arm posturing, sometimes alternating sides. Sodium is 128 mmol/L, cognition is subtly declining and routine ictal scalp EEG is unrevealing. What is the most important next therapeutic step while antibody testing is expedited?

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Correct answer: B — Start immunotherapy for suspected LGI1 disease while completing antibody and malignancy assessment

Explanation lettering: C = shown as A · E = shown as C · A = shown as E

B is correct. This is classic faciobrachial dystonic seizure semiology associated with LGI1 antibodies and often hyponatraemia. Surface EEG is frequently negative. Antiseizure drugs alone rarely stop FBDS, whereas expedited immunotherapy improves seizure cessation and may prevent disabling limbic encephalitis. A delays disease-modifying care. C misuses EEG. D treats the wrong mechanism. E waits for a non-mandatory late feature.

Reference: Early immunotherapy in LGI1 faciobrachial dystonic seizures: https://pmc.ncbi.nlm.nih.gov/articles/PMC5837230/