One of Kim Zolciak's sons is in the hospital recovering from an operation after he was bitten by a dog this weekend. 

Kim posted a pic Sunday of 4-year-old Kash Kade Biermann in a hospital bed, with a pretty gnarly description. Apparently, he's been there since Saturday night after he was bitten by a dog ... which sent him to the operating room.

In the post, Kim says Kash suffered "traumatic injuries" and the operation lasted a couple hours. 

The whole family seems to be there by his side. Kim noted she'd be missing her guest spot on Andy Cohen's show Sunday night.