A.C.
Based on my own experience I am also going with night terrors. A two year old, that has previously slept through the night, isn't waking up without reason. There is a difference between not going down and waking in the middle of the night.
True, they do usually occur within 3 hours of so of going to sleep BUT my daughter has definitely had night terrors and has had them at all times. However, I know if she has one early on she will have several in a night.
The sound of her screaming scared you because it was probably nothing like you've heard come out of her before...lol. My daughter has acutally chased me through the house screaming once when I had to use the bathroom after being awakened by her terror...my otherwise rational mind actually considered that she might be possessed.
There actually isn't that much information available, so I'll tell you what has worked for us.
Triggers are:
major disruption in schedule, environment, etc. (like when we changed daycares and she had at least one every night for two weeks)
come medications--noticed them a lot when we tried some allegy medications at different times (singulair and zyrtec)
the occasional random one
overtiredness--an unusually active day combined with a late bedtime (too much sugar...lol)
her two year old molars
Dealing with:
Keep a notebook by the bed and mark down the time(s) when they occur. If they occur more than two days in a row, you can try a sleep interruption technique. You'll find that they often occur nearly at the same time all the time. You can set and alarm to fifteen minutes before go time and just jostle your child until she starts to wake up--you may notice that she is already restless. Now that my daughter is potty trained, I just carry her to the bathroom, let her go and put her back in bed. She can pee without really waking up, but it is enough to "re-set" her.
While she's having one. Turn on the lights to avoid scary shadows. Hold her if she'll let you. Repeat something soothing over and over again--a favorite song or just reassuring words...just be repetitive.
We've had them last 5 to 45 minutes. They generally end as quick as they start and she will just lay down and go back to sleep. I would be willing to bet that if you go to her and soothe her, she'll go back to sleep.
Her eyes will be open, she will seem awake, she may or may not respond directly to your advances. Shaking her or trying to wake her up pobably won't help and may prolong the episode--at least it does in our case. She won't have any recollection of waking. You SHOULD make her crib into a bed. Sleepwalking is associated with night terrors and she could hurt herself trying to get out during her panic.
Good luck. This is developmentally normal and usually resolves itself relatively quickly. We had about 6 months that were really hard, but hardly have any now that she is three. I expected that she would have them. I was and still am a very vivid dreamer and sleptwalked as a child.
