16 month old suddenly wanting milk in the night and not settling

[lynniep]

DS never been a good sleeper, but got to a manageable point (would go down all right in the evening, then might wake once in the night and need a bit of hand holding to get back to sleep although sometimes would take an hour) He's always had milk if he wakes after 5 and will usually go back down for an hour or two.
Then Friday night he woke around 3.15 screaming the place down. Cuddles, dummy, water - nothing would calm him down until I gave him some milk. He drank the lot then turned over and went to sleep! (he never does that - theres always tossing and turning) Saturday was not too bad, then last night was an absoloute nightmare. He woke about 11 screaming again, and once more nothing but milk would pacify - he went straight back down, but woke at one and needed help to get back to sleep. Then he woke screaming at 3ish. Gave him water and he lay down but wouldnt let me leave. DH told me to give up at 4 and take him into the spare room.
Could this be a growth spurt. Or maybe too much brain activity (same thing?!) He's been learning a lot more words lately and I thought maybe its all a lot going on in his little head thats waking him up.