We had a bit of a shunt scare today. Nickolas was very irritable and didn't stop crying for 2 hours! When do we start worrying about a shunt failure? I couldn't check his fontanelle (the soft spot on his head) because he's crying, and so its not soft. No sunsetting of the eyes (the irises of the eyes are sunken like the sun of a sunset). No vomiting (projectile or otherwise). Head circumfrance - 41cm - looked it up and plotted it on my chart - perfect. OK so I think this is NORMAL infant irritability. Finally another round of changing, cuddling, rocking got him calm enough to feed and he settled down.
Once I checked everything and was reasonally certain it wasn't a shunt thing he started to settle as well. I guess my nervousness rubbed off on him. We were told the rate of shunt failure/infection/break was 50% in the first year, and less after that.