Well, the routine care of active duty Army and Marine Corps is about 90% adolescent medicine.
To be a little more serious, since we don't deploy kids, and US and TCN civilian contractors aren't kids, and we all leave our kids at home, every kid that gets seen while deployed is a local national. These fall into two broad groups - "elective" humanitarian work, and trauma.
Speaking only of my recent firsthand experience at a R3, we've done almost no humanitarian work. I'm sure the PRTs are doing lots of it.
Trauma care of civilians has dropped off
tremendously over the last year as the medical ROE have changed. There's some regional variation in the ROE. The group prior to ours was swamped with local nationals. Now, we
only care for civilians who are injured by ISAF forces. Short version - if we shoot them, run them over, drop something on them, we take care of them. Everyone else goes to the Afghan hospitals where they sink or swim. We don't shoot, squish, or bomb locals very often, despite what CNN says, so we don't see many civilians, and almost never any kids. Consequently, our pediatrician (actually a peds intensivist) doesn't see many. Maybe he's cared for five under the age of 10 in seven months? Perhaps five more under 16 - and most of those were probably Al-Queda-JROTC ... bad guys start young here.
Common themes? Malnutrition. Parasites. Standard 3rd world medicine.
Again though, there's so much variation in the medical missions and medical ROE across Afghanistan. Even just considering the R3s, there's a huge difference in the case load and patient profile comparing Bagram, Kandahar, and Bastion. If you know where you're going, the best thing to do is find out who's there and ask what they're doing.