What Causes Ammonia Toxicity Along With Severe Confusion?

Just a few days ago I was with a friend at a restaurant. About 15 minutes after I got my food my friend noticed I was repeating myself and became quieter. We said our goodbyes and then I found myself so confused I was in tears. My husband brought me to the hospital and ruled out a stroke after the MRI. What they found in my blood work a very high ammonia toxicity. The doctor was sure that this was the cause of my confusion. About 4 hours later I started to come back to myself remembering some of the events in the evening. Needless to say it was very scary. How could I of gotten this high ammonia toxicity? I ate a hamburger with wild rice, coleslaw and just had ice water.