With my daughter there are two types of headaches. Very bad headaches, usually with vomiting, usually begining upon rising. This is a partialily blocked or full shunt failure, requiring surgery.
The second type of headache is milder, over her eyes again. It occurs after she has been up for awile, usually around late morning. It goes away always, by lying flat, with no pillow for 15 t 20 minutes...every time. This has been described to us as an overdraining problem of the shunt. If you have a programable shunt you can have it adjusted in the office and sometimes they will keep you overnight to observe you.
I think the problem for the neurosurgeons is in finding the right adjustment to keep your shunt at. If it drains too much, you get headaches for slit ventricles. If it does not drain enough the higher pressure may affect things in a growing child like spine allignment or have an effect on her eye muscles. This has been our experience. She is now 13.
I think they try to tweak it as best they can. I do not give headach meds to my daughter, nor does my daughter's neurosurgeon tell us too.
She has had her shunt since birth. The same scenarios have played out for 13 years. She has had 7 revisions. She has not had a revision in 5 years now. But from time to time she has had her programable shunt pressure adjusted.