Just wanted to say "Welcome" to the NeuroTalk Support Groups!

I don't have any personal experience with Hydrocephalus or shunts so this is just my unrelated thoughts, but the dark circles under the eyes are often allergy related.

I've seen it in children as it's very common sign in lactose intolerance but also appears with other types of allergies. I don't know if you've noticed anything like that going on since it started.

Folic acid deficiency and Vitamin K are also listed as potential reasons for the dark circles under eyes. There are many, many other reasons.

Wish you the best and hopefully someone with the same conditions as you can help with some information.

take care.