Sudden onset of hysterical behaviour in 2 yr old

[samusia]

My daughter is 2.5 yrs old and although is a little cheeky chops sometimes, is generally a very sweet natured happy go lucky and confident little girl. She is so popular at nursery with staff and children that they are sad when she's off sick! So it is really concerning me that she suddenly is displaying hysterical 'tantrum' like behaviour.

At first I thought it was just her stamping her ground and reacting to the word 'no'. But she also will randomly wake up at night and scream blue murder, thrash around if I try to comfort her, she'll hit me (and herself), scratch me etc, until she's tired herself out and the screaming turns to sobs and she gives into a cuddle. She'll then latch on to me and either fall asleep or snuggle for ages before engaging with things again.
I don't like the term 'tantrum' because I really don't feel that this is what it is. once she gets going I genuinely believe she has no idea what she's doing i.e.; she's not trying to obtain authority or crying because I said 'no more sweets' or something………
I might add I have 5.5 yr old son who never behaved like this. He has always been well behaved and so I have no experience with this sort of thing.
Her nursery are aldo concerned as the behaviour is so out of character and suggested it could be post viral issues?? (she just had chicken pox followed by chest infection)
Any suggestions or comments would be very VERY much appreciated as I have never used this site before
Thanks in advance

I'd take her straight back to the GP. Make sure they check her throat, ears and tummy

Night times sound like night terrors to me. Are you sure she's awake? With night terrors they can have eyes open sitting up usually very violent and worse if touched. Cannot be comforted.

If so then daytime behaviour may just be tiredness seeping though. IME it's v common for this sort of behaviour to show in a tired 2.5-4yr old.

Any changes going on at home? Kids pick up the most subtle things.

I totally agree with the idea that its possibly night terrors/extreme tiredness but she responds to us so not sure, i.e.; i ask if she wants something, she shakes head screaming no etc.
As for stuff at home going on, then I cannot think of anything, everything calm on the home front, no stresses or unusual things happening at all.
I do think it might possibly be related to need for sleep in some way, which I and her nursery are totally encouraging her to have whenever she needs, plus got her some vitamins to give her a boost.
Whatever the reasons its extremely painful to watch :(
Thanks for replies

DS has had night terrors. Usually in a run of every night for a couple of weeks. It's hugely distressing for you but he doesn't remember much about it in the morning, despite screaming for the best part of an hour.

DS was better if he got some extra food before bed. Also a light in the room helped him get to sleep.

When she's working up into a tantrum in the day have you tried cuddling. Just a quiet voice in her ear saying it's ok, you're there and you'll hold her til she feels better and calmer. A gently restraining cuddle (i do it with DS facing away from me so i don't get kicked!) does seem to quiet DS down faster.

It is horrible watching them lose control so completely, but i do think it's pretty normal. Guessing you were lucky first time around!

Hope it all gets better soon and gp can rule out any illness.

My son was very well behaved and calm! but had loads of medical issues, so swings in roundabouts!
I do try a firm cuddle but wouldn't have considered food before bed…..I suppose a full tummy helps them sleep soundly so will bare in mind. Thank you.