45cm is crazy high pressure. is the shunt blocked or was it intermittently blocked.. Has anyone done a shuntogram or otherwise determined if the shunt is patent? Treatment for IIH is usually with a shunt, so if his shunt is not working and he is getting by without it working, that is amazing and scary should pressures go too high. My daughter's pressures are slowly going up so I've read about IIH because there is only so much to read out there about dealing with higher pressures (slit ventricles are flip side of same coin sometimes). Had to stop reading about it, vision issues freaked me out too much (get double vision, something like dizziness, and other visual effects with many headaches since last summer, even if they appear to be over draining related). Your pediatrician sounds unbelievably certain.

yes it is very high.

neurosurgeon also uncertain on what's going on.
either the pediatrician is correct about the virus causing the pressure to be high or IIH that causing the pressure to be high, the shunt should bring it down to normal if it is working well.

But if it is not working well then the pressure should be high again by now, unless under normal condition he doesn't need shunt anymore.