High CPK level

I recently had a low sodium seizure.  I went for a bike ride, became dehydrated, and drank too much water.  Two days after the seizure my CPK went up to 18000, my doctor told me to go to the hospital right away.  He asked me if my urine was coffee colored or black.  It was not, which surprised him.  My white blood cell count was still really high, too 17,000.  The doctor's suspected Lupus or MS.  Anyway, the hospital admitted me and flushed me out with saline, my kidneys were functioning just fine.  They brought my cpk's down to 1,000 and released me.  Two days later I had another blood teast and they jumped back up to 5000.  They admitted me again.  Finally released me and they went down to 103.  
They concluded that the seizure caused my CPK's to go up that high.  Does that make sense?  Reading the other forums make me think that this level is extremely high.  Could it be something else?