hour long seizure-what was this?

-New grad in the ER, a patient comes in by ambulance, in severe pain, with the left side of the body from the neck down convulsing. The pain was relieved with 10mg Valium, but convulsing did not cease. Pt was alert and orientated, able to communicate but distressed. Pain would return and was treated with ativan IV, 2.5mg Q 10 min, but unable to cease muscle spasms. Blood sugar 85 BP 150/90, CT scan negative for tumor, blood vessel obstruction. After 1 hr 10min, twitching stopped. Pt had left sided weakness (understandable) and was too sedated for home. Stayed the night and went home in the morning.
Everyone including physician and EMTs had not seen anything like this. What could it be? Parkininson's?