In Tuesday's episode of the TLC reality show, the 29-year-old revealed he had been having pain over most of his body that made it difficult for him to pick up 1-year-old son Jackson.
"I've been having a lot of pain in my back and my legs," he explained. "There's like a tightness to my thighs, there's a weakness in my knees. Something's not going right."
With all the activity surrounding pumpkin season, as well as playing and coaching soccer and being the dad of a rambunctious little once, Zach wasn't sure what could have triggered his symptoms, but after whatever was going on caused him to be "paralyzed for a minute" while holding Jackson, the couple made sure to get things checked out with an official MRI.
"It's scary, because I can't help him, and it's also like we don't know what's causing the issue," wife Tori Roloff admitted.
Unfortunately, upon getting the results back from the MRI, Zach and Tori were shocked to learn that his prognosis wasn't looking good after being diagnosed with multilevel degenerative disc disease causing spinal stenosis.
"It's a common thing with people with achondroplasia," Zach explained of the spinal stenosis, "but average-sized people only get it when they're like 60."
With bulging and degenerating discs in his spine pinching the nerves, Zach would need to see a spinal specialist to determine whether he would have to undergo surgery now or later.
Learning that he would almost certainly have to undergo massive surgery, Zach admitted he was "in denial," adding, "Two months, three months ago, I was in a soccer tournament, and now I have arthritis in my back? What's going on here?"
Tori was equally freaked out, telling the camera, "I am scared. That's the worst case scenario in my head for him to have surgery. I'm trying really hard not to panic."
Little People, Big World airs Tuesdays at 9 p.m. ET on TLC.
Photo credit: TLC